Full Title: Sub-Lumbar Muscles
Author: Lisa McPherson
Date of Publication: April 6, 2012
Research Paper Text:
The lumbar and pelvic areas of a dog are an integrated group of bones, muscles, tendons, blood vessels, nerves and fascia. There are many sub-sections of these areas but I would like to concentrate specifically the sub-lumbar muscles.
The sub-lumbar muscle structures are found under the last three thoracic and the lumbar vertebrae and are also considered pelvic limb muscles. This muscle structure is made up of four muscles: quadratus lumborum, minor psoas, major psoas and the iliacus muscles (the major psoas and iliacus together form the iliopsoas). All these muscles lie on one another in layers.
The Quadratus Lumborum is the most dorsal of the muscle group and has a thoracic as well as a lumbar portion to it. This muscle’s origin is from the last three thoracic vertebrae as well as the last rib and lumbar transverse process. It inserts into the lumbar transverse process or the lumbar vertebrae and the surface of the wing of the ilium. The lateral portion overhangs the transverse process of the lumbar vertebrae and lies on the ventral surface of the transverse abdominus origin tendon.
The thoracic portion of the muscle is made up of incomplete bundles of tendons and these bundles extend from the body to the last three thoracic vertebrae to the transverse process as far as the seventh lumbar vertebrae. It is covered by tendon leaves dorsally and ventrally.
The nerve supply of this muscle is the rami of the ventral branches of the lumbar nerves.
In the dog, this muscle is extremely strong and it flexes and fixes the vertebral column in the loins.
This muscle runs towards the pelvis under the middle of the spine. It lies between the iliac fascia and peritoneum ventrally and iliopsoas and quadratus lumborum dorsally. The psoas minor runs medial to the psoas major.
The psoas minor originates at the tendon of the quadratus lumborum under the last thoracic vertebrae and the first four or five lumbar vertebrae. The insertion is a corklike tendon on the ilium adjacent to the iliopubic eminence or inlet.
The nerve supply is the lateral branches of the rami ventrals of lumbar nerves one to four or five.
This muscle is responsible for steeping the pelvis and flexing the lumbar portion of the spine.
The iliopsoas is formed with the fusion of the psoas major and iliacus. It is a very deep narrow muscle ventral to the quadratus lumborum and dorsal to the psoas minor. It covers the psoas minor laterally and medially. It is easily isolated at the attachment.
The origin of the muscle (psoas major) is the transverse process of the second and third lumbar vertebrae and lies lateral to the quadratus lumborum. It also attaches by flat broad tendons (aponerosis) to lumbar three and four and lumbar four to seven ventral and laterally.
After the iliopsoas passes over the ilium as the psoas major, it joins to the iliacus from the ventral surface of the ilium between the arcuate line and lateral border of the ilium (hip bone). The two muscles insert at the minor trochanter of the femur.
The innervations of these muscles are the branches of the rami ventrales of the lumbar nerves.
The iliopsoas muscle is important in drawing the pelvic limb forward by flexion and rotation of the hip joint, flexes and fixes the vertebral column, draws the trunk backward and advances the hindlimb.
The sublumbar muscles are very important for the fixation and flexion of the spine and for ambulation. In extremely active and athletic dogs this area is prone to overuse and injury and rehabilitating the area can be problematic. It is thought that tears, specifically in the Iliopsoas, are relatively common but not often diagnosed in dogs. This can be because they are not shown on X-ray and ultrasound, while useful, often does not show microscopic tears. Usually the diagnosis of an iliopsoas strain is found clinically with specific testing on examination.
- Adams, Donald R. Canine Anatomy A Systemic Study: Fourth Addition. Iowa State Press: Blackwell Publishing, 2004
- Anatomy Expert. Structure Detail http://www.anatomy expert.com
- Canapp, Sherman O. Non-Responsive Hind-Limb Lambness in Agility Dogs: Iliopsoas Strain: Clean Run Magazine March, 2007
- Dyce, K. M. (Keith M.). Texbook of Veterinary Anatomy Canada. W. B. Saunders Company 1987
- Goody, Peter C. Dog Anatomy A Pictorial Approach to Canine Structure. Great Britian: Midas Printing International Limited, 2010
- Kainer, Robert. Dog Anatomy A Colouring Atlas. Jackson: Teton NewMedia, 2003
- Miller, Malcolm Eugene. Millers Anatomy of the Dog Third addition. A Saunders Title, 1993
- Stepnik, Matthew Olby, Natasha Thompson, R. Randall Marcellin-Little, Denis. Femoral Neuropathy in a Dog with Iliopsoas Muscle Injury: Veterinary Surgery 35:186-190, 2006
Full Title: The (Canine) Thymus Gland
Author: Mary Van Assche
Date of Publication: March 20, 2012
Research Paper Text:
Introduction/Scope To place the assignment into perspective, a sense of context needs to be established. First of all, it was very difficult to find material on the animal Thymus Gland. However, there was plenty of information to be found on the human Thymus Gland. Therefore, this paper will make the assumption that any references to the human Thymus Gland will also apply to the Thymus Gland of the animal or dog. In this regard, as the human possesses a heart, a set of lungs, intestines, etc., the dog also possesses the same types of organs including the Thymus Gland. The only animal Thymus Gland material that was quite readily available was to the culinary Sweetbread. Being a vegetarian and with culinary Thymus out of scope, this paper will not be addressing that aspect of it.
The paper will introduce material as mentioned in the Table of Contents as well as the physical, metaphysical, emotional and spiritual aspects of the Thymus Gland as it pertains to health and well being.
History The thymus has had a varied history in terms of attribution of function, from at least the time of Galen of Pergamum (130-200A.D.), who named it the seat of the soul due to the halo of mystery that surrounded it as well as due to its close proximity to the heart.1 Although, Descartes thought that the seat of the soul was the pineal gland.2 From Galen we can ascertain that the Thymus Gland from the early days was unknown. Galen was the first to note that the size of the organ changed over the duration of a person’s life. Galen conducted many nerve ligation experiments that supported the theory, which is still accepted today, that the brain controls all the motions of the muscles by means of the cranial and peripheral nervous systems.3
In addition, the thymus was known to the Ancient Greeks, and its name comes from the Greek word θυµός (thumos), meaning heart, soul, desire, life—possibly because of its location in the chest, near where emotions are subjectively felt; or else the name comes from the herb thyme (also in Greek θύµος or θυµάρι), which became the name for a “warty excrescence”, possibly due to its resemblance to a bunch of thyme.4
Historical Function/Function Where is your Junction? When was the function of the thymus gland understood? The functions of the thymus were not well understood until the early 1960s, when its role in the development of the body’s system of immunity was discovered.5
Earlier this century, it was thought that the Thymus Gland had no function beyond puberty.6
Like much of medicine, ideas with regard to thymic anatomy and physiology languished for centuries between the Fall of Rome and the 18th century. Signaling a renewed interest in the thymic gland, Vesalius wrote in the 1600s that the thymus was simply a protective thoracic cushion. In the 1700s, the predominant new theory was that the thymus somehow regulated fetal and neonatal pulmonary function. Hence, it became known as the “organ of vicarious respiration.” Others thought that the thymus simply filled the space that would later be occupied by the growing neonatal lungs. In 1777, William Hewson published the first scientific treatise on the thymus. On the basis of findings of his investigations in dogs and calves, Hewson described the evolution of thymic size during fetal and infant life, thus verifying Galen’s observation. He concluded that the thymus itself was some sort of modified lymph gland.7
From this cited reference we have, “Due to the large numbers of apoptotic (programmed cell death) lymphocytes, the thymus was originally dismissed as a “lymphocyte graveyard”, without functional importance”. The importance of the thymus in the immune system was discovered in 1961 by Jacques Miller.8 He surgically removed the thymus from three day old mice, and observed the subsequent deficiency in a lymphocyte population, subsequently named T-cells after the organ of their origin (T for Thymus). Recently, advances in immunology have allowed the function of the thymus in T-cell maturation to be more fully understood.9
The Thymus Gland defined here as: thy·mus / (also thy·mus gland) • n. (pl. -mus·es or -mi / -mī/ ) a lymphoid organ situated in the neck of vertebrates that produces T cells for the immune system. The human thymus becomes much smaller at the approach of puberty.10
When autopsies were performed in the elderly, it was found that the gland was quite small. It is now known that in response to acute stress such as infection; it can shrivel to half the size within 24 hours. Subsequently, doctors thought that after puberty the Thymus Gland had no useful function and it was removed in many young children. Remember those days when tonsils were excised in a surgical frenzy! I digress, sorry. Consequently, these children had destroyed immune systems that allowed them susceptibility to infections and chronic diseases and some of these children died from serious illness. Later in the 1950’s and after further medical research, it became clear that children naturally have large Thymus Glands.
Would this be true of dogs, cats, animals? I was unable to find research that pointed to the same. But, again, if infants have large Thymus Glands, we will make the assumption here that puppies, kittens, etc. experience the same growth cycle along with its functionality.
The Thymus Gland is described as relatively large in the newborn infant (about the size of the baby’s fist), and continues to grow throughout childhood up to the age of puberty when it weighs about 1.2 oz. (35 grams), then it gradually decreases in size until it blends in with the surrounding tissue.11
From, my research, I found that modern medicine has not always understood the function of the Thymus Gland, but now recognizes the fact that it is closely related to the immune system, possible stress, and general well being.
The main function of the thymus gland is to produce mature T cells. The immature cells produced at the bone marrow, migrate and come into the thymus, where the maturation process takes place. This maturation process is a remarkable one, as it allows only the beneficial T cells to be released into the bloodstream. T cells that evoke a detrimental autoimmune response get eliminated.12
Today, we now know that it has a very important function not only physically, but also neurologically (mentally), emotionally and spiritually.
Description/Location The thymus is an organ that varies in size depending on the age of the individual. It is largest in young animals and shrinks to a very small size in the adult.13
In general and simply stated, the thymus is located in the upper part of the chest underneath the breastbone. In infants, the thymus is quite large. It continues to grow until puberty, when it begins to shrink. The size of the thymus in most adults is very small. Like some other endocrine glands, the thymus has two lobes connected by a stalk. The thymus secretes several hormones that promote the development of the body’s immune system.14
More specifically, the thymus is a flat, long structure with two lobes located in the mediastinum, inferior to the thyroid gland in the neck, posterior to the sternum. The thymus is surrounded by a connective tissue capsule. Similar to other lymphoid tissue, the thymus contains lymphocytes, macrophages, and reticular epithelial cells. The thymus is fully developed at birth, and it continues to grow until puberty. After puberty, it slowly decreases in size. The thymus is important in the development of the immune system. It is the first organ to begin manufacture of lymphocytes. In the absence of the thymus, immunity is significantly lowered. The thymus is considered an endocrine organ because it secretes the hormone thymosin.15
A reference source for dogs states that the thymus is located in the front part of the chest cavity, between the trachea (windpipe) and the ribs.16
In human anatomy, the thymus is a ductless gland located in the upper anterior portion of the chest cavity. 17
The thymus will, if examined when its growth is most active, be found to consist of two lateral lobes placed in close contact along the middle line, situated partly in the thorax, partly in the neck, and extending from the fourth costal cartilage upward, as high as the lower border of the thyroid gland. It is covered by the sternum, and by the origins of the Sternohyoidei and Sternothyreoidei. Below, it rests upon the pericardium, being separated from the aortic arch and great vessels by a layer of fascia. In the neck it lies on the front and sides of the trachea, behind the Sternohyoidei and Sternothyreoidei. The two lobes generally differ in size; they are occasionally united, so as to form a single mass; and sometimes separated by an intermediate lobe. The thymus is of a pinkish-gray color, soft, and lobulated on its surfaces. It is about 5 cm in length, 4 cm in breadth below, and about 6 mm in thickness. At birth it weighs about 15 grams, at puberty it weighs about 35 grams; after this it gradually decreases to 25 grams at twenty-five years, less than 15 grams at sixty, and about 6 grams at seventy years. 18
Yet another source describes the thymus gland as a mass of glandular tissue located in the neck or chest of most vertebrate animals. In humans, the thymus is a soft, flattened, pinkish-gray organ located in the upper chest under the breastbone. It is relatively large in the newborn infant (about the size of the baby’s fist), and continues to grow throughout childhood up to the age of puberty when it weighs about 1.2 oz (35 grams). Then it gradually decreases in size until it blends in with the surrounding tissue. Beginning during fetal development, the thymus processes many of the body’s lymphocytes, which migrate throughout the body via the bloodstream, seeding lymph nodes and other lymphatic tissue. The main cells undergoing this processing are the T cells, a heterogeneous group of cells essential in protecting the body against invasions by foreign organisms. If the thymus fails to develop or is removed early in fetal life, the immune system cannot develop completely. Normally, by the time the infant is a few months old, the immune system has sufficiently formed so as to function throughout life. However, further growth and development of lymphoid tissue still depends on intervention by the thymic cells.19
This particular reference is verbatim from the “Nationmaster” reference and only mentioned here again not for emphasis but to demonstrate that this source originally came from Henry Gray, the British anatomist who was born in 1827. He studied the development of the endocrine glands and spleen. Newer editions of Gray’s Anatomy –and even several recent older ones– are still considered about the most comprehensive and detailed textbooks on the subject. Even the movie, Grey’s Anatomy (different spelling) was named after his book. Henry Gray (1821–1865), in the Anatomy of the Human Body (1918) stated that the thymus (Fig. 1178) is a temporary organ, attaining its largest size at the time of puberty (Hammar), when it ceases to grow, gradually dwindles, and almost disappears. If examined when its growth is most active, it will be found to consist of two lateral lobes placed in close contact along the middle line, situated partly in the thorax, partly in the neck, and extending from the fourth costal cartilage upward, as high as the lower border of the thyroid gland. It is covered by the sternum, and by the origins of the Sternohyoidei and Sternothyreoidei. Below, it rests upon the pericardium, being separated from the aortic arch and great vessels by a layer of fascia. In the neck it lies on the front and sides of the trachea, behind the Sternohyoidei and Sternothyreoidei. The two lobes generally differ in size; they are occasionally united, so as to form a single mass; and sometimes separated by an intermediate lobe. The thymus is of a pinkish-gray color, soft, and lobulated on its surfaces. It is about 5 cm. in length, 4 cm. in breadth below, and about 6 mm. in thickness. At birth it weighs about 15 grams, at puberty it weighs about 35 grams; after this it gradually decreases to 25 grams at twenty five years, less than 15 grams at sixty, and about 6 grams at seventy years.20
See illustrations below of the thymus gland in a young child, a fetus and view of location in the adult male along with their respective references.
A CXR showing a normal thymus gland in a young child http://en.wikipedia.org/wiki/File:Pthymousgland.png
File:Thoracic cavity of foetus 2.JPG http://en.wikipedia.org/wiki/File:Thoracic_cavity_of_foetus_2.JPG
Anterior view of chest showing location and size of adult thymus http://en.wikipedia.org/wiki/File:DH_thymus.jpg
The thymus of a full-time fetus, exposed in situ. http://www.bartleby.com/107/illus1178.html
Development The thymus appears in the form of two flask-shaped entodermal diverticula, which arise, one on either side, from the third branchial pouch (Fig. 1175), (below) and extend lateralward and backward into the surrounding mesoderm in front of the ventral aortæ. Here they meet and become joined to one another by connective tissue, but there is never any fusion of the thymus tissue proper. The pharyngeal opening of each diverticulum is soon obliterated, but the neck of the flask persists for some time as a cellular cord. By further proliferation of the cells lining the flask, buds of cells are formed, which become surrounded and isolated by the invading mesoderm. In the latter, numerous lymphoid cells make their appearance, and are aggregated to form lymphoid follicles. These lymphoid cells are probably derivatives of the entodermal cells which lined the original diverticula and their subdivisions. Additional portions of thymus tissue are sometimes developed from the fourth branchial pouches. Thymus continues to grow until the time of puberty and then begins to atrophy.21
See illustrations below that show the thymus lobes in relation to the thyroid gland. In addition to the structure in a calf showing veins and arteries, a stained of a camel labeled A and B. The next photo is showing the thymus gland (although the reference failed to state if it was human or other) with the explanation that it is an endocrine gland attached to the heart in a crainoventral manner by connective tissues.
Scheme showing development of branchial epithelial bodies. (Modified from Koh.) I, II, III, IV.Branchial pouches. http://www.bartleby.com/107/illus1175.html
Minute structure of thymus. Follicle of injected thymus from calf, four days old, slightly diagrammatic, magnified about 50 diameters. The large vessels are disposed in two rings, one of which surrounds the follicle, the other lies just within the margin of the medulla. (Watney.) A and B.From thymus of camel, examined without addition of any reagent. Magnified about 400 diameters.A. Large colorless cell, containing small oval masses of hemoglobin. Similar cells are found in the lymph glands, spleen, and medulla of bone. B. Colored blood corpuscles. http://www.bartleby.com/107/illus1179.html
In this picture the probe is just under the thymus. http://anatomy.wikispaces.com/Thymus
Structure Each lateral lobe is composed of numerous lobules held together by delicate areolar tissue; the entire gland being enclosed in an investing capsule of a similar but denser structure. The primary lobules vary in size from that of a pin’s head to that of a small pea, and are made up of a number of small nodules or follicles.22
The primary lobules vary in size from that of a pin’s head to that of a small pea, and are made up of a number of small nodules or follicles, which are irregular in shape and are more or less fused together, especially toward the interior of the gland. Each follicle is from 1 to 2 mm. in diameter and consists of a medullary and a cortical portion, and these differ in many essential particulars from each other. The cortical portion is mainly composed of lymphoid cells, supported by a network of finely branched cells, which is continuous with a similar network in the medullary portion. This network forms an adventitia to the blood vessels. In the medullary portion the reticulum is coarser than in the cortex, the lymphoid cells are relatively fewer in number, and there are found peculiar nest-like bodies, the concentric corpuscles of Hassall. These concentric corpuscles are composed of a central mass, consisting of one or more granular cells, and of a capsule which is formed of epithelioid cells (Fig. 1179). They are the remains of the epithelial tubes which grow out from the third branchial pouches of the embryo to form the thymus.23 Each follicle is surrounded by a vascular plexus, from which vessels pass into the interior, and radiate from the periphery toward the center, forming a second zone just within the margin of the medullary portion. In the center of the medullary portion there are very few vessels, and they are of minute size.24
The thymus is formed from a diverticulum, on each side, from the entoderm lining the third branchial groove, but the connexion with the pharynx is soon lost. The lymphoid cells and concentric corpuscles are probably the derivatives of the original cells lining the diverticulum.25
Vasculature The arteries supplying the thymus are derived from the internal mammary and from the superior thyroid artery and inferior thyroids. The veins end in the left brachiocephalic vein (innominate vein), and in the thyroid veins. The nerves are exceedingly minute; they are derived from the vagi and sympathetic nervous system. Branches from the descendens hypoglossi and phrenic reach the investing capsule, but do not penetrate into the substance of the organ.26
Watney (H. Watney (Phil. Trans., 1882) has discovered haemoglobin, and apparently developing red blood corpuscles, in the thymus)27 has made the important observation that hemoglobin is found in the thymus, either in cysts or in cells situated near to, or forming part of, the concentric corpuscles. This hemoglobin occurs as granules or as circular masses exactly resembling colored blood corpuscles. He has also discovered, in the lymph issuing from the thymus, similar cells to those found in the gland, and, like them, containing hemoglobin in the form of either granules or masses. From these facts he arrives at the conclusion that the gland is one source of the colored blood corpuscles.28
Vessels and Nerves The arteries supplying the thymus are derived from the internal mammary, and from the superior and inferior thyroids. The veins end in the left innominate vein, and in the thyroid veins. The nerves are exceedingly minute; they are derived from the vagi and sympathetic. Branches from the descendens hypoglossi and phrenic reach the investing capsule, but do not penetrate into the substance of the gland.29
The lymphatics are described in the next paragraph because is warrants additional information to understand the relationship of the lymph to the thymus.
As previously mentioned above, we need to understand a bit about the lymphatic system so that when we begin to put all the systems together we will have a better understanding of how this system works with all the other systems. The lymphatic system is important because it is the one system that is closely tied to the immune system. However, we will shortly see that all the systems are related as far as the Thymus Gland is concerned.
The thymus is part of the immune system. In its lobules lymphocytes mature into T cells (where T stands for “thymus”) that behave in different ways according to their type. Some are passed into the bloodstream where they perform vital immune functions. Others remain in the thymus to give rise to future generations of T cells.30
Lymphatic System Primer & Other Systems First off, we will need to know where the lymphatic system is and how it functions to bring the relationship together for the Thymus gland.
The lymphatic system is located throughout the body and has many components: Lymph nodes or glands are small round, oval or bean-shaped structures that are located at various locations throughout the body. The lymph nodes are connected to each other by a series of vessels called lymphatics, which carry lymph from place to place. Some lymph nodes lie along the surface of the body (along the neck, under the arms, in the groin, behind the knees), while others lie deep within the body (chest and abdomen).31
Then we need to understand the general structure of the lymphatic system, however, it is a complex and vital system primarily responsible for the transportation of lymph and for participating in many immune functions of the body.
Lymph is a milky fluid that flows throughout the system. It contains proteins, fats and a type of white blood cell called lymphocytes. Lymph is collected from the fluid of various tissues and eventually is returned to the blood circulatory system. The lymphatic system provides another route by which fluid can flow from distant tissues back into the blood stream, one that is separate from capillaries and veins. It also carries proteins and other substances away from tissues that cannot be removed or transported directly into the blood system.32
Similar to the blood circulatory system, the lymphatic system is comprised of fine channels that lie adjacent to the blood vessels. These lymphatic vessels eventually merge into a rather large vessel called the thoracic duct. As the lymph is carried from distant parts of the body, it is collected into larger and larger vessels until the vessels all converge in the chest and deposit the lymph in the large vein (cranial vena cava) leading to the right atrium of the heart.33
The lymph moves through the lymphatic vessels toward the lymph nodes. The lymph nodes lie at varying points along the course of the lymphatic chain and can form clusters in some areas of the body. Lymph nodes have a dense fibrous outer coating, called a capsule and are filled with white blood cells and spaces containing lymph fluid. Several types of white blood cells predominate in the lymph nodes, particularly lymphocytes, plasma cells, and macrophages.34
The lymphatic system filters and removes debris from the tissues of the body. Cells produce proteins and waste products. The lymph absorbs these products and carries them away from the tissues because they are often too large to be effectively absorbed and removed by the bloodstream.35
The lymph nodes filter out cellular waste products and foreign material in the lymph fluid, including potentially dangerous infectious particles like bacteria and viruses. They trap material received from the lymphatic vessels and provide a site for white blood cells to mount an immune response. They act as a barrier against the entrance of these foreign substances into the bloodstream. 36
The important point to take away from all this explanation is the fact that the since the thymus cells are produced while still in the fetus, it is a very important part of the immune system in the newborn. It is the site where the earliest immune cells are made and where immune functions take place in the young animal. 37
What is it With the Systems Now we will attempt to put it all together and talk about all the systems and how they are related to the Thymus Gland. The Thymus Gland is part of many systems such as the immune system, circulatory system, endocrine system, nervous system and the neuroendocrine immune network. But mainly its role, as described earlier, is with the immune system. One would think that the primary system is the endocrine system because it is considered an endocrine organ as the reference states above. Because its role is so closely aligned with the immune system, therein “lies the rub” or should I say tap! No not beer tap. We will define that later when we begin to make the link between the thymus thump and homeostasis.
The endocrine system is the human body’s network of glands that produce more than 100 hormones to maintain and regulate basic bodily functions. Hormones are chemical substances carried in the bloodstream to tissues and organs, stimulating them to perform some action. The glands of the endocrine system include the pituitary, pineal, thyroid, parathyroids, thymus, pancreas, adrenals, and ovaries or testes. 38
The endocrine system oversees many critical life processes. These involve growth, reproduction, immunity (the body’s ability to resist disease), and homeostasis (the body’s ability to maintain a balance of internal functions).39
The lymphatic system, functioning along with the circulatory system, absorbs nutrients from the small intestines. A large portion of digested fats is absorbed via the lymphatic capillaries. Fat absorbed from the small intestinal lymphatic capillaries or lacteals is termed chyle.40
We have travelled from the thymus gland all the way to the small intestines absorbing digested fats. As stated previously, it is attached to the heart in a crainoventral manner by connective tissues and it helps to mature T lymphocytes for immune system defense with Thymosin. Thymosin stimulates maturation of lymphocytes. Lymphocytes travel through the circulatory system and on and on with every system doing their respective functions. But why is it so special?
Gets Complicated The reason that the thymus is a specialized organ of the immune system is because it “educates” Tlymphocytes (T-cell), which are critical cells of the adaptive immune system.41
The adaptive immune system, also known as the specific immune system, is composed of highly specialized, systemic cells and processes that eliminate or prevent pathogenic growth. It is adaptive immunity because the body’s immune system prepares itself for future challenges.42
From here on end, we can become complicated as for as these T cells or T lymphocytes, cell mediated immunity, antigen specific cytotoxic T-lymphocytes, etc. and how these things work at the cellular level. This is beyond the scope of this paper. The Notes list contains references for further reading on this topic. The important thing to take away from these complex definitions is how and where the thymus cells are developed from the get go.
We will now begin to tie the loose ends up to determine how taking care of the Thymus gland during massage techniques helps to enable homeostasis.
Making the Link We have just observed how complicated and related all those systems are in relation to the immune system. All those cells that reside in all those systems were “born” or differentiated from either the Thymus (T Cells) or Bone Marrow (B Cells) and activated to perform their specific functions. So how does this relate to the thymus thump that is performed during PetMassage TM and how can it help with health and well being?
Some research suggests that there is a communication link between the immune and nervous systems especially. A citing from this resource states that “complex bidirectional signaling occurs between the nervous and immune systems that impacts the functions of both systems. In response to stressors, the central nervous system has modulatory effects on the immune system through release of hormones, paracrine signals, and by direct contacts between nerves and immune cells. Conversely, in response to antigens and pathogens, immune system activation results in production of cytokines that induce altered neural activity”.43
Can we safely say now that the thymus gland is part of the Neuroendocrine Immune Network? How do they communicate? The nervous system and the immune systems communicate through hormones. The thymus continues to grow between birth and puberty and then begins to atrophy; this thymic involution is directed by the high levels of circulating hormones.44
New studies reveal that there may actually be a direct link between them. “There are remarkable similarities between the nervous system and the immune system.
• They both contain a variety of highly specialized cells, which are designed for specific tasks. This specialization begins early in development, but remains adaptable even in adult life. • Memory is an essential feature of both the nervous and immune systems. The brain has the most sophisticated ability to record and recall information, but immune cells also carry biological intelligence gained over millions of years of evolutionary experience. These biological memories are encoded in our genes. They allow us to respond to new challenges as if we’ve already faced and overcome them in the past. • Both systems are designed for adaptation, which is the ability to maintain a dynamic balance as previously mentioned homeostasis in an ever changing environment. The body is constantly evaluating incoming impulses and deciding if they are potentially nourishing or potentially toxic. Both the nervous system and the immune system participate in continuous, active surveillance of the surroundings. Useful input is welcomed, while potential threats are quickly identified and avoided. • The many diverse cells of the nervous and immune systems communicate with each other via potent chemical messengers. Many of these messengers, initially called neuropeptides, are now also known as immunomodulators. Electron microscopes have captured fascinating images of one immune cell directly releasing a chemical messenger into an immune cell of a different type. This process is almost identical to the exchange of information that takes place when a nerve cell releases a neurochemical that travels across a gap, or synaptic cleft, and communicates with a neighboring neuron.
The close similarities in both form and function of the nervous system and immune systems suggest that the immune system can be thought of as a circulating nervous system. Immune cells respond to our ever changing states of mind and mood, whose fluctuations are reflected in the changing chemistry of our brain. In other words, our immune cells are constantly eavesdropping on our mind’s internal dialogue.”45 Does this also happen to dogs? Why not. They experience a flight or fight response mechanisms just like us humans. They are either prey or preyed animals, so why wouldn’t they be affected in the same way.
Emotions Playing a Role Temple Grandin, in her book, Animals in Translation, states that animals experience emotion. She says that everyone uses emotion to make decisions. She says that in the brain, reason and logic are never separated from emotion. This, she says is important to understanding fear in an animal. “The single most important thing emotions do for an animal is to allow him to predict the future. Nature seems to have tried to wire animals and people to have useful emotions, useful meaning emotions that keep us alive by letting us make good predictions about the future, and good decisions about what comes next.”46 The point she makes about emotions is that it is necessary for survival. One example she sites is calm breeding of Lab dogs. The breeding involves taking out the startle out of Labs, so that when a car backfires, he won’t jump and run off with the blind person he’s supposed to be leading.47
In addition, Temple Grandin states that the body and brain aren’t two different things controlled by two completely different sets of genes. Many of the same chemicals that work in your heart and organs also work in your brain, and many genes do one thing in your body and another in your brain.48 Again, she was referencing the fact of selective breeding of animals. She said that if you over select for any trait at all, eventually you get neurological damage and neurological damage almost always means emotional damage, or at least important emotional changes. So the breeders for the selective breeding of particular traits only check for the physical trait but not the emotional or behavioral changes.49
So here we have the connection that emotion and neurons are related. If emotions come from the brain, can we think ourselves out of stress and disease? There are many publications and experiments on the mind/body phenomena. Way too many to get into. The explanation of the thymus cells was bad enough. Suffice it to say that, we have evolved a remarkable system to transmit our mental and emotional states into bodily reactions. Through the mind-brain-endocrine-immune-system network we continuously monitor our internal and external environment and orchestrate a response. These changes can happen instantaneously but have effects that extend well beyond the moment of the event. Learning how to influence these consequences is a hallmark of mind body approaches.
One way humans can influence these changes is through meditation. A relaxing massage may start you on your way. However, I was unable to find that any studies that were done on dogs meditating. Although, by performing a massage on them greatly accelerates their mind body connection. (PetMassage Workshop 2-2012.)50
So how does massage play into the role of the mental and emotional responses that is experienced by dogs? But first what is the purpose of massage. Among the many purposes of massage, one of them is to help relieve tension. Now habitual tension fatigues nerves and shortens muscles. Tension that has taken time to harden like cement in the body will take time to dissipate. Habitual tension weakens the stamina of the nerves that inform the body parts how to maintain proper physical alignment in order to maximize the energy flows in the channel. Over the years, habitual contractions shorten the length of the small muscles as well as their associated ligaments and tendons. Shortened muscles add to the aches and pains of maintaining the alignments. Tension activates the nerves (i.e. flight or fight response), the muscles contract, further shortening the muscles, pulling on the insertion points where they attach to bones and ligaments, which then causes fatigue and strain, which then causes blood circulation to diminish, which then blocks the chi in the energy channels. The blocked chi causes pain, which causes more tension and the whole process continues.
So what does a relaxing massage do? Relaxation comes from mentally letting go of habitual tension in the nerves. Can dogs do this? Why not? Nerve relaxation causes muscles to relax. When relaxation occurs, soft tissues and associated fluids; blood, lymph will gradually and gently pull on other soft tissues including ligaments, tendons, and especially fascia. This gentle pulling without tension gradually stretches soft tissues and thereby lengthens them. Large stretching movements are effective on big muscles but not the tiny muscles that are bound up with fascia. The fascia and shortened muscles and tendons will stretch in increments, with plateaus that need time to be transverse before advancing to the next increment. They will not stretch out instantaneously.
How quickly nerves will relax and subsequently strengthen, as well as how rapidly shortened muscles will stretch cannot be predicted. It depends on each individual dog. Just like us humans, all dogs have different genetic make ups and varying degrees of sensitivity and talent in connecting with internal subtle sensations. The presence or absence of trauma can also affect the rate of the process.
Full Circle – Remembering Galen
Taking a look at the spiritual, physical and metaphysical aspect as it relates to the Thymus Gland the world according to Dr. John Diamond’s Your Body Doesn’t Lie book, he states that in the second century Galen gave the name Thymus to the pinkish grey two lobed organ in the chest because it is said that it reminded him of a bunch of thyme. But the thyme plant itself was so named because it was burned as incense to the gods. Thymus, a Greek God was the rising up of smoke, a sacrificing to the Gods. It was aspiration, songs of praise, spirit and love. It was breath soul. The Thymus was the “seat of life energy”. This aspiration took place in the chest cavity considered the inner altar. 51
In Homer’s works, thumos was used to denote emotions, desire, or an internal urge. Thumos was a permanent possession of living man, to which his thinking and feeling belonged. When a Homeric hero is under emotional stress he may externalize his thumos, conversing with it or scolding it. Plato’s Phaedrus and his later work The Republic discuss thumos as one of the three constituent parts of the human psyche. In the Phaedrus, Plato depicts logos as a charioteer driving the two horses eros and thumos (i.e. love and spiritedness are to be guided by rationality). “In the Republic (Book IV) soul … becomes divided into nous (“intellect”), thumos (“passion”), and epithumia (“appetite”). To its appetitive part are ascribed bodily desires; thumos is the emotional element in virtue of which we feel anger, fear, etc.; nous is (or should be) the controlling part which subjugates the appetites with the help of thumos.”52
Dr. Diamond places great importance on the activation of the thymus gland in his practice. The thymus gland has many important functions. Among them are: (A) the production in early life of special lymphocytes called T-cells which are vitally important in immunological surveillance, which is directly concerned with resistance to infections and cancer, (B) the activation, after puberty, of the T-cells by thymus hormones, (C) involvement in the flow of lymph throughout the body, (D) the monitoring and regulation of energy flow throughout the body energy systems, initiating instantaneous corrections to overcome imbalances as they occur so as to achieve a rebalancing and harmony of body energy, and (E) the thymus serves as the link between mind and body, being the first organ to be affected by mental attitudes and stress. Hence activation and stimulation of the thymus is an essential, primary foundation of achieving and maintaining positive health.53 The Goal The goal of attaining and maintaining health is by obtaining an optimal balance in mental (mind) and emotional (heart) state. Western medical experts refer to this healthy balance as homeostasis. The key to achieving this balance is by relaxation. However, this is easier said than done. The intent of the pet massage practitioner is to be relaxed and to relax the dog. This relaxation depends on intent. If the massage practitioner is relaxed and calm, then the dog will respond with being relaxed and calm. So how does one become relaxed? From breathing properly. Taoist Breathing Techniques offers techniques to train your awareness so that you can become conscious of the inside of your physical body and its energies.54
How this relates to the Thymus gland is twofold. As we just proved that the Thymus Gland is affected by the nervous system and the immune system which are connected to the circulatory system, endocrine system, etc. The physical location of the Thymus Gland is in the Heart Chakra, Ayurvedically speaking. It is also associated with the thymus gland. If there is an imbalance in the Heart Chakra, some of the physical situations that may occur are high blood pressure, asthma, allergies, cardiovascular and respiratory disorders, upper back and shoulder problems. There is much more to it when we look at the emotional aspects. The Heart Chakra is our center of love, hope, trust, forgiveness and compassion, so if there is an imbalance, some of the emotional issues are said to be insincerity, difficulty accepting or giving love, self-centeredness, loneliness, lack of commitment, resentment and bitterness. 55 (Deepak Chopra Seminar 5-2009). This correlates to what the Greek physicians and Galen were saying all along.
Secondly, it is all about intention. Isn’t that the difference between petting the dog and massage? The following description of the Thymic chakra is by John O’Neill. The Thymic chakra is where “intent” originates; it is the link between the emotions of the heart and the reason of language. It is what makes you inhale a breath before you speak, since this is where the intent behind the words you are about to speak actually starts forming.56 He continues to describe….. ‘So, lets say that your heart feels a certain way about something that it would like to voice. The energy shoots up to the Throat chakra but passes through the Thymic chakra first, giving it a heads up to start getting prepared to speak by drawing a breath – or by stopping the breath to prevent you from speaking. This is why you don’t always say what’s on the tip of your tongue. This is also why emotions can wreck havoc with your health, as the Thymic chakra can be bombarded by emotions to the point of fatigue. When the Crown chakra speaks, on the other hand, it sends its energy down through the Brow chakra which embellishes it.. The result is creative expression which may or may not be truthful. The Thymic chakra acts as something of a “lie detector” by interfering with energy that is not truthful. This is why we have trouble speaking when we are upset. The flow of energy from the heart is always meant to be peaceful and that’s really the only kind of energy that the Thymic chakra “understands”’.57
So what does this mean? It means that the seven chakras of the yogic system are gateways to consciousness and the three dantiens of the Chinese system are also gateways to the different levels of consciousness. Does that mean that the Thymus Gland could possibly be part of one of those gateways? Seems that way. See the chart that shows the chakras and their relationships.
Summary/Conclusion It all starts with breathing and intention. We breathe in and out; Yin and Yang. We breathe in oxygen and exhale carbon dioxide. We inhale goodness, we exhale grief, sorrow, things that do not serve us any longer. Our soul’s desire is to achieve everlasting love. Think there is a song by this name. Our thymic cells begin in the womb and differentiate and activate to become our guardians to our bodies to protect us physically/internally. Love protects us spiritually/internally. When it’s functioning well, the immune system is a magnificently complex and coordinated sequence of responses. The ability to cope with immune challenges will always be around. It is how we choose to deal with them to balance ourselves to achieve homeostasis. A good and sound way is to relax, breathe, and focus intent on being well. It starts with us and we pass it on to the dogs we massage. They know it, they feel it, and they will mostly appreciate it. By tapping the thymus by performing the thymus thump, we awaken those immune cells through the vibration of tapping. And the communication with all those systems we mentioned previously – begins. The end.
Bibliography 1http://books.google.com/books?id=hTI8arzsI8C&pg=PA1&lpg=PA1&dq=seat+of+the+soul+thymus&source=bl&ots=c5KOij3uP4&sig=KqJLf2kV NFs9v60ylMpfPk85iMI&hl=en&sa=X&ei=rpHLT5KyIcHL2QWqxsXZCw&ved=0CFMQ6AEwBTg K#v=onepage&q=seat%20of%20the%20soul%20thymus&f=false 2http://plato.stanford.edu/entries/pineal-gland/ 3http://en.wikipedia.org/wiki/Galen 4http://en.wikipedia.org/wiki/Thymus 5COLIN BLAKEMORE and SHELIA JENNETT. “Galen.” The Oxford Companion to the Body. 2001.Encyclopedia.com. 12 Mar. 2012 <http://www.encyclopedia.com> 6 ibid. 7http://radiology.rsna.org/content/210/1/11.full 8http://en.wikipedia.org/wiki/Jacques_Miller 9http://en.wikipedia.org/wiki/Thymus and http://onlinelibrary.wiley.com/doi/10.1034/j.1600065X.2002.18502.x/abstract 10“thymus” 2009. Encyclopedia.com. (February 29, 2012) http://www.encyclopedia.com/doc/1O999thymus.html 11http://www.encyclopedia.com/topic/thymus_gland.aspx#2 12 http://www.buzzle.com/articles/organs-of-the-immune-system.html 13http://www.petplace.com/dogs/structure-and-function-of-the-lymphatic-system-in-dogs/page1.aspx 14http://www.encyclopedia.com/topic/Endocrinology.aspx#1-1G2:3438100274-full 15http://medical-dictionary.thefreedictionary.com/thymosin and http://www.howtodowell.com/entry/The-Thymus-The-Massage-connection-ANATOMY-ANDPHYSIOLOGY 16http://www.petplace.com/dogs/structure-and-function-of-the-lymphatic-system-in-dogs/page1.aspx 17http://www.nationmaster.com/encyclopedia/Thymus-gland 18ibid. 19The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (February 29, 2012). http://www.encyclopedia.com/doc/1O999-thymus.html 20Gray, Henry. Anatomy of the Human Body. Philadelphia: Lea & Febiger, 1918; Bartleby.com, 2000. www.bartleby.com/107/. [Date of Printout]. 21ibid. and http://www.nationmaster.com/encyclopedia/Thymus-gland 22http://en.wikipedia.org/wiki/Thymus 23Gray, Henry. Anatomy of the Human Body. Philadelphia: Lea & Febiger, 1918; Bartleby.com, 2000. www.bartleby.com/107/. [Date of Printout]. and http://www.nationmaster.com/encyclopedia/Thymus-gland 24ibid. 25http://www.1911encyclopedia.org/Ductless_Glands
26http://en.wikipedia.org/wiki/Thymus 27http://www.1911encyclopedia.org/Ductless_Glands 28Gray, Henry. Anatomy of the Human Body. Philadelphia: Lea & Febiger, 1918; Bartleby.com, 2000. www.bartleby.com/107/. [Date of Printout]. and http://www.nationmaster.com/encyclopedia/Thymus-gland 29ibid. 30http://www.nationmaster.com/encyclopedia/Thymus-gland 31 http://www.petplace.com/dogs/structure-and-function-of-the-lymphatic-system-in-dogs/page1.aspx 32ibid. 33ibid. 34ibid. 35ibid. 36ibid. 37ibid. 38″Endocrine System.” UXL Encyclopedia of Science. 2002. Encyclopedia.com. 12 Mar. 2012<http://www.encyclopedia.com>. 39ibid. 40http://www.petplace.com/dogs/structure-and-function-of-the-lymphatic-system-in-dogs/page1.aspx 41http://en.wikipedia.org/wiki/Thymus 42 http://en.wikipedia.org/wiki/Adaptive_immune_system 43http://rd.springer.com/referenceworkentry/10.1007/978-0-387-30398-7_4. Age-Related Alterations in Autonomic Nervous System Innervation of Lymphoid Tissue. 44http://en.wikipedia.org/wiki/Thymus 45“The Wisdom of Healing”, Dr. David Simon, M.D., Chaper 13, Psychoneuroimmunology – Mind, Body, and Immunity, p.194-4. 46“Animals in Translation”, Temple Grandin, Chapter 3, Animal Feelings, Breeding Emotions, p.127-8. 47 ibid. 48 ibid. 49 ibid. 50PetMassage Workshop, 2-2012. 51“Your Body Doesn’t Lie”, Dr. John Diamond, M.D., p.129. 52http://en.wikipedia.org/wiki/Thymos 53 http://www.drjohndiamond.com/qdiamond-wikipediaq/129-thymus-gland-the 54“Relaxing into Your Being”, B.K. Frantzis, Chapter 1, Connecting with Chi, p.39. 55 Deepak Chopra Seminar, 5-2009. 56http://www.kheper.net/topics/chakras/Thymic.htm 57ibid.
Notes For additional reading Felten, S.Y., and D.L. Felten. 1991. Innervation of lymphoid tissue. In Psychoneuroimmunology, ed. R.Ader, D.L.Felten, and N. Cohen, 27-69. San Diego: Academic Press. • Renoux, G. and M. Renoux. 1992. The positive regulation of T-cells by the neocortex is likely to involve a dopamine pathway. In Psychoneuroimmunology, ed. Schmoll, U. Tewes, and N.P. Plotnikoff, 39-47. Lewiston, N.Y. :Hogrefe and Huber Publishers. • Nossal, G.J.V.1993. Life, death and the immune system. Scientific American 269:52-62. • The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (February 29, 2012). http://www.encyclopedia.com/doc/1O999thymus.html • “thymus gland.” The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. 29 Feb. 2012 <http://www.encyclopedia.com>. • MICHAEL ALLABY. “thymus.” A Dictionary of Zoology. 1999. Encyclopedia.com. 29 Feb. 2012 <http://www.encyclopedia.com>. • “Endocrine System.” UXL Encyclopedia of Science. 2002. Encyclopedia.com. 12 Mar. 2012<http://www.encyclopedia.com>. • http://en.wikipedia.org/wiki/Cell-mediated_immune_response • http://www.banyanbotanicals.com/yoga/kapha/thymus.html Kapha Focus: Fully filling the lungs as you tap the chest. Benefits: stimulates the thymus gland which builds immunity and massages the lungs, heart, bronchial tubes and throat through the vibration of the tapping.
• http://www.kheper.net/topics/chakras/Thymic.htm Just as this chakra acts as a bridge in waking life, between emotion and reason, it also acts as a bridge in dreaming, but in a totally different way. If you have ever had a dream about a person that you would later meet in real life, then you were using this chakra in your dream. If this chakra is open in your “dreaming body” then you will be able to connect your dreams with actual reality, that is, the subject matter of your dreams will be the actual waking world instead of a representation of it. If this chakra is closed in the waking body then the individual will not have the intent to express their emotions even though they can feel them and actually know what they want to say. Correspondently, if this chakra is closed in the dreaming body then you will not have the intent to bridge the chasm between dreaming and waking from the dreaming side, to visit this world while you are asleep. One last important point to mention is that there is a certain vulnerability that this chakra has to being manipulated by outside forces while either awake or dreaming. The end result is the same, you end up dreaming somebody else’s dream and sharing their intent for better or worse. The symbol for the Thymic chakra in waking is a map rolled up like a scroll, it represents the path of one’s life. The symbol for this chakra in dreaming is a pair of wings, representing the ability to cross the chasm of the unknown under one’s own power. • “thymus gland.” The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. 29 Feb. 2012 <http://www.encyclopedia.com>. thymus An organ, present only in vertebrates, that is concerned with development of lymphoid tissue, particularly the white blood cells involved in cell-mediated immune responses (see T cell). In mammals it is a bilobed organ in the region of the lower neck, above and in front of the heart. The thymus undergoes progressive shrinkage (involution) throughout life, starting after the first 12 months. Haemopoietic stem cells from the bone marrow migrate to the thymus, attracted by chemotactic factors, and begin to divide and differentiate to form the many subpopulations of T cells. As their progeny cells migrate through the thymus from its cortex to medulla, they interact with thymic ‘nurse cells’ and with each other and are influenced by various extracellular proteins and thymic peptide hormones (e.g. thymosin and thymopoietin). All these
factors help to promote the differential expression of surface antigens and development of distinctive immunological competences.
• http://www.holisticwebs.com/sound/thymus.html,,The Thymus Chakra, Immune System & Sound Healing, Renee Brodie, The Healing Tones, of Holographic Sound Healing techniques. • http://www.acupuncture-and-chinese-medicine.com/thymus-tapping.html • http://www.indiadivine.org/audarya/ayurveda-health-wellbeing/915188-thymus-gland.html • See also autoimmune disease; immune system; lymphatic system. • http://en.wikipedia.org/wiki/File:Hematopoiesis_simple.svg • http://en.wikipedia.org/wiki/Hematopoiesis • http://upload.wikimedia.org/wikipedia/commons/6/69/Hematopoiesis_%28human%29_diagram.png • http://en.wikipedia.org/wiki/Hematopoiesis • http://upload.wikimedia.org/wikipedia/commons/thumb/6/63/Hematopoesis_EN.svg/2000pxHematopoesis_EN.svg.png • http://upload.wikimedia.org/wikipedia/commons/a/a1/Hematopoietic_growth_factors.png • http://en.wikipedia.org/wiki/Multipotent_hematopoietic_stem_cell • http://en.wikipedia.org/wiki/File:Blood_cells_differentiation_chart.jpg • http://en.wikipedia.org/wiki/T_cell • http://en.wikipedia.org/wiki/Adaptive_immune_system • http://en.wikipedia.org/wiki/Naive_T_cells • http://en.wikipedia.org/wiki/Cell-mediated_immune_response
Full Title: (Canine) Anal Sphincter Muscle
Author: Mariana Elaine Purcell
Date of Publication: March 5, 2012
Research Paper Text:
A sphincter muscle is a structure or circular muscle (circular in form) that normally maintains constriction of a natural body passage or orifice, which relaxes as required by normal function.
The External anal sphincter muscle is named this because it is located in the anus and is a circular muscle that normally maintains constriction. The job of the anal sphincter muscle is to constrict and maintain continence. This muscle helps the contraction of waste to be secreted from the body. It is voluntarily used by pressure and allows for the storage of wastes to exit the body. The size of this muscle depends on the dog. The size can be anywhere from 1cm to 2cm in diameter, up to a few cm.
There is no insertion/attachment site on a sphincter muscle. The whole muscle is basically attached to the Levator ani, which is the broad muscle attaching to the pelvis and making up the perineum. The anal sphincter is just muscle tissue so there is no tendon or ligaments either. The blood supply and innervations come from the external obturator artery, vein and nerve.
Full Title: Latissimus Dorsi
Author: Kathy Clark
Date of Publication: February 27, 2012
Research Paper Text:
There are two main groups of muscles in the back of a canine the Longissimus Dorsi and the Latissimus Dorsi. These two groups work together to move the dog. The muscle toward the dog’s head is the latissimus, which pulls the body forward. As part of the Teres Major muscle group, the latissimus assists the shoulders in pulling the dog forward when running. Since there is no boney attachment in the axial skeleton (there is no clavicle in the canine), this means that muscular strength is of the utmost importance to the full functionality of the front limb.
The teres major muscle originates from the caudal edge of the scapula and inserts into the eminence if the proximal, medial surface if the humerus. The latissimus dorsi shares a common tendon of insertion with this muscle group. These muscles are all involved in forward propulsion, drawing the trunk forward when the front leg is fixed. /the tensor fascia antebrachii utilizes the fascia on the lateral side of the latissimus dorsi which can mean that a malfunctioning muscle complex may have an effect on elbow extension.
Additionally, the teres major group assists in the return of the forelimb to neutral from an outstretched position or to move the body from an outstretched front limb. Essentially the latissimus dorsi assists in the action of flexion, adduction and internal rotation of the shoulder joint.
If there are problems with the latissimus dorsi, there could be stiffness in the shoulders and notable spasms behind the shoulder blade. Applying heat, such as a heating pad or hands, will help with the circulation in the muscle. Passive touch, not pressure, is all that is needed for the latissimus dorsi muscle.
- Backing up your dog with Massage, Maria K. Duthie c.e.f.m.p.; Article, Annisage.com
- Anatomy, Biomechanic, Physiology, Diagnosis and Treatment of Teres Major Strains in the Canine: Four Leg Rehabilitation Therapy & The Canine Fitness Centre, Ltd, Calgary, AB, Canada, The Canadian Horse and Animal Physical Rehabilitation Assn., The Animal Rehab Institute, Loxahatchee, Florida USA; Laurie Edge-Hughes, BScPT, CAFCI, CCRT ; Proceedings of the RVC 2nd Annual Veterinary Physiotherapy Conference, Suppl. 2004.
Full Title: Structural Muscle Groups
Author: Goldie Berencsi
Date of Publication: December 30, 2011
Research Paper Text:
The muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. They are classified as skeletal, cardiac, or smooth muscles. Their function is to produce force and cause motion.
Smooth muscle= Smooth muscles are found within the internal organs such as the intestines, stomach, and bladder. They are involuntary muscles and are under the control of the autonomic nervous system.
There are 3 types of muscle tissue:
- Smooth muscle= Smooth muscles are found within the internal organs such as the intestines, stomach, and bladder. They are involuntary muscles and are under the control of the autonomic nervous system.
- Skeletal muscle= These muscles are called striated muscles and are voluntary muscles. They predominately attach to portions of the skeleton. They are involved with such things as walking, eating, tail wagging and eye movement.
- Cardiac muscle= Cardiac muscle fibers are found in the heart and are involuntary muscles. Cardiac muscle is unique in that it is striated muscle, like skeletal muscle, but is not under voluntary control.
Each individual muscle is composed of many cells held together by connective tissue. Skeletal muscles attach to bones by means of connective tissue tendons, which are elastic and strong. When muscles contract, they pull on the tendons, which then pull on the bones and cause the limbs to move. Each muscle fiber receives its own nerve impulses, which trigger various motions. Once a signal or an impulse travels down the nerve to the muscle, the muscle fiber changes chemical energy into mechanical energy, and the result is muscle contraction.The muscles are located throughout the entire skeletal system and are attached to bones, other muscles and skin.
They account for about half the weight of an animal. Parts of the walls of hollow internal organs such as the heart, stomach and intestines, and blood vessels are composed of smooth muscles.
The muscular system is one of the largest systems in the dog’s body.
Each dog has 9 muscle groups, they are the head. neck, thorax, abdomen, pelvic area, pelvic and thoracic extremities, trunk and tail. Each muscle is connected to the bone by tendons and ligaments. The muscles can be under voluntary or involuntary control. Voluntary muscles, such as those found in the arms and legs, can be controlled by thought. Involuntary muscles are those that are automatically controlled by the nervous system and cannot be moved at will.
The primary function of muscles is to bring about movement to all or part of the dog’s body. Muscle is used to stabilize joints to prevent their collapse under a load. Smooth muscles maintain continence of the bladder and propel food through the bowel. Muscles also help to generate heat by shivering. Voluntary muscles can contract and pull, but they cannot push, so they must work in pairs that flex and extend. Extensor muscles straighten the limbs and attach to the bones, so the bones act as levers. The flexor muscles, which bend the joints, act to pick up the limb. Their partners, the extensor muscles, in turn contract to bring the limb back down. The abductor muscles move the limbs away from the midline, and the adductor muscles move the limbs toward the midline.
Full Title: Cerebrospinal Fluid (CSF)
Author: Kathy Mayher
Date of Publication: December 30, 2011
Research Paper Text:
Cerebrospinal fluid (CSF) is fluid found in the subarachnoid space, surrounding the brain and spinal cord. The subarachnoid space is the area between the tough outermost membrane layer (dura mater) and the softer innermost layer ( pia mater) that covers the brain and spinal column. The brain and the spinal cord are the two organs that form the central nervous system (CNS) (“Cerebrospinal Fluid Tap in Dogs”).
According to PetPlace, a website with a library of articles written by veterinarians and specialist, “The fluid resembles serum, and its purpose is to maintain equal pressure within the brain and spinal cord” (“Cerebrospinal Fluid Tap in Dogs”). A cerebrospinal fluid tap is the collection of this fluid for diagnostic purposes. Veterinarians collect a sample of this fluid to diagnose brain or spinal cord diseases. It is often performed after imaging techniques, such as computed tomography (CT scan) and magnetic resonance imaging (MRI) to detect some abnormality in the central nervous system (“Cerebrospinal Fluid Tap in Dogs”).
Abnormalities may include inflammation, viral or bacterial infection, bleeding or suspected tumors (“Cerebrospinal Fluid Tap in Dogs”).
A cerebrospinal fluid tap may also be performed to deliver pain-relieving medication before a surgical procedure. It may also be performed to inject dye in the spinal column to detect an abnormal position of the spinal cord. After the dye is injected, x-rays are taken, this is known as a myelogram (“Cerebrospinal Fluid Tap in Dogs”).
There are two different types of taps: a cisternal tap and a lumbar tap (“Cerebrospinal Fluid Tap in Dogs”).
According to PetPlace, the process to performing a cisternal tap is, “the back of the top of the neck is shaved and sterilized. A needle is inserted at the base of the skull, and into the spinal column, passing through the dura mater and arachnoid membranes to the subarachnoid space” (“Cerebrospinal Fluid Tap in Dogs”). Then a syringe is attached to the spinal needle to draw out the fluid. The fluid can also be allowed to drip into a tube. Rapid withdraw of the spinal needle may result in rupture of vessels in the subarachnoid space causing the sample to be contaminated with blood (Vernau, “Cerebrospinal Fluid Assessment in Dogs and Cats”).
A lumbar tap, also known as a lumbar puncture, occurs on the lower back. The lower back is first sterilized, and then a spinal needle is inserted. A syringe is attached to the needle and fluid is withdrawn or the fluid is allowed to drip into a collection tube (“Cerebrospinal Fluid Tap in Dogs”).
The cerebrospinal fluid pressure is measured before and after the withdraw of fluid. The device used for measurement is called the manometer.
When the cerebrospinal fluid is under abnormally high pressure it will sometimes stream out of the needle hub and in spite of the attachment of the manometer, a large volume of fluid is lost. This result is an accurate reading of pressure (Palumbo, “The Role Of The Cerebrospinal Fluid Tap In The Neurological Examination Of The Dog”).
When the initial pressure is high and the final pressure is low it indicates a small reservoir of fluid. A tumor or lesion that is occupying space within the cranial cavity could be responsible. If there is interference with reabsorption of cerebrospinal fluid (meningitis or communication hydrocephalus) there will be a large fluid reservoir and a smaller difference between the initial and final readings (Palumbo, “The Role Of The Cerebrospinal Fluid Tap In The Neurological Examination Of The Dog”).
General anesthesia is necessary to perform the procedure. Pets undergoing this procedure usually receive a pre-anesthetic sedative and or analgesic drug to encourage relaxation. Because the procedure is performed under anesthesia, no pain is involved. There may be some discomfort following the procedure. The pain will vary among individual dogs (“Cerebrospinal Fluid Tap in Dogs”).
After the cerebrospinal fluid is obtained the color and character should be recorded. And due to the fragile cellular elements of this fluid, if smears (samples) are to be made, this should be done within 20 minutes of the collection. The two most important procedures are the cell counts and the protein concentration. The analysis of cerebrospinal fluid has been described as the central nervous system equivalent of the complete blood count. The primary function of CSF analysis in most cases is to assist in the diagnostic process by excluding the likelihood of certain diseases (Palumbo, “The Role Of The Cerebrospinal Fluid Tap In The Neurological Examination Of The Dog”). Dr. Vernau, an Assistant Professor at the School of Veterinary Medicine at the University of California states, “As is the case with all tests, CSF analysis is only useful when the results are used in conjunction with the history, clinical findings, imaging studies and laboratory test” (“Cerebrospinal Fluid Assessment in Dogs and Cats”).
Measurement of total protein concentration in cerebrospinal spinal fluid is important in the diagnosis of neurologic disease; the protein concentration of CSF in normal dogs is 0.3g/L. A normal CSF analysis does not exclude the presence of disease. However abnormal CSF findings always indicate the presence of pathologic abnormality. An increase in the cellularity of CSF is called pleocytosis. The proportions of the different cell types present in CSF in disease vary according to the nature of the disease process and provide useful information for the diagnosis of neurologic disease (Vernau, “Cerebrospinal Fluid Assessment in Dogs and Cats”). Due to the accurateness of the CSF, it proves to be a useful diagnostic tool for veterinarians.
- “Cerebrospinal Fluid Tap in Dogs.” Petplace.com. Intelligent Content Corp. Web. 08 Oct. 2011. http://www.petplace.com/dogs/cerebrospinal-fluid-tap-in-dogs/page1.aspx
- Palumbo, N. “The Role Of The Cerebrospinal Fluid Tap In The Neurological Examination Of The Dog.” Canadian Veterinary Journal 5.6 (1964): 135-39. The National Center for Biotechnology Information. The National Center for Biotechnology Information. Web. 13 Oct. 2011. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1695701/pdf/canvetj00535-0025.pdf
- Vernau, William. “Cerebrospinal Fluid Assessment in Dogs and Cats.” Http://www.scivac.it/. Proc. of 50° Congresso Nazionale Multisala SCIVAC, Italy, Rimini. International Veterinary Information Service, 2005. Web. 13 Oct. 2011. http://www.ivis.org/proceedings/scivac/2005/Vernau5_en.pdf?LA=1
Full Title: Hip Problems, Canine
Author: Jean Ramalho
Date of Publication: December 19, 2011
Research Paper Text:
We all love our dogs and want to give them the best life possible – a life where they are happy, healthy and pain free. We are constantly monitoring their body language – from the way they walk (their gait), run and jump, to how they act during “play time”. We are always looking for a limp or something out of the ordinary. When it comes to senior dogs, most animal owners do not realize how their older dogs are subject to chronic pain. Most pet owners don’t see chronic pain as actual pain. Chronic pain will cause your dog to slow down. They are very good at hiding pain. Their survival skills make them tough, so you need to watch for the early signs of pain.
Some of the signs are:
- Not as active
- Less interaction with others in home
- Eating less and starting to lose weight
- Not going up or down stairs as frequent
- Not going in and out of vehicles with ease
Just because genetics is mostly to blame for hip problems, it does not necessarily mean that we have control over whether or not our dogs have hip issues. It is also very important that we make sure they get enough exercise and that we watch their diet. Continuing proper nutrition throughout their life will benefit them greatly as they become older. One of the most important things we can do for our dogs is to keep them FIT! Do not let your dog put on any extra weight. The extra weight will put more pressure on any already unstable and painful hip joints, resulting in weakening the muscles and ligaments surrounding the joints. The ligament most affected is the thick “Capital Ligament” also known as the “Round Ligament”. This ligament holds the femoral head in place. It is the main tissue anchoring the femur to the hip. The hip joints are the most important in retaining balance, so it is extremely important to pay careful attention to the health of these joints.
The health of the “Capital Ligament” plays a key role in the development of Chronic Hip Disease. The earliest sign of hip problems is not the wear and tear of cartilage, but the swelling and inflammation of this ligament. Eventually, the ligament stretches, frays and finally ruptures as Chronic Hip Disease progresses. Then the severity of joint damage in Chronic Hip Disease is strongly correlated to the integrity of the Capital Ligament. The strength of this ligament varies greatly in different dogs. Exercise will strengthen the muscles around the joint to help stabilize it.
What can we do to help keep our dog’s Capital Ligament and hip joints flexible? As a pet owner, we can do a few things. A basic home health care of massaging the hip area with the capital Ligament, will prolong your dog’s quality of life. This daily home health care routine for your dog will play a major role in making your dog live a much more enjoyable life with less pain and with and with more ease of movements.
Lightly massaging this area will assist the blood and lymph circulation to bring more oxygen and nutrients to the various body parts, especially in the hip joint area.
Doing gentle stretching exercises will also help your dog’s joints stay flexible. However, be careful not to over exercise your dog, as this will make the hip joints painful.
- Jean-Pierre Hourdebait, LMT: Animal Awareness Article
- Wikipedia: Hip Dysplesia
Full Title: Frontal Muscle
Author: Cheryl Peacock
Date of Publication: December 9, 2011
Research Paper Text:
The frontal muscle of the canine is an under researched superficial muscle of the dogs head. It is located between the eyebrow and the ears (Dog Anatomy Coloring Atlas, Kainer and McCracken). After a search of the internet, the local library, the local Barnes and Nobel bookstore, and the assistance of my vet and my instructor (Jonathan Rudinger), this researcher has found it necessary to look at the human frontalis muscle for any detail on this superficial facial muscle. From this point forward the dog’s frontal muscle and the human frontalis muscle will be referenced for this paper.
The frontal muscle of the dog is located on the fore face of the dog above the eyebrow and below the ear, hence it has been named for its location.. It is a superficial muscle so it has no bony attachments. To be exact, the origin in the galea aponeurotica. “The galea aponeurotica (epicranial aponeurosis, aponeurosis epicranialis) is a tough layer of dense fibrous tissue which covers the upper part of the cranium; behind, it is attached, in the interval between its union with the Occipitales, to the external occipital protuberance and highest nuchal lines of the occipital bone; in front, it forms a short and narrow prolongation between its union with the Frontales(Wikipedia,2011).” The insert is located in the skin above the eyebrows (Wikipedia, 2011). It is innervated by the temporal branches of the facial nerve (VII) and is supplied with blood by the superficial temporal artery (face-and-emotion.com).the size of this muscle is not mentioned in the research available.
The function of the frontalis muscle is to wrinkle forehead and in humans it assists in raising parts of the eyebrow. Its superficial functions are probably why it has not been studied much in dogs (not to many plastic surgeries or facelifts done on dogs). When referring to dogs all references to function refer to the wrinkling of the brow and there is no mention of the muscle assisting in lifting the brow, although we may assume, do to its attachment sites, that it may also assists the dog in moving its eyebrows. Again the frontal muscle is an under examined superficial muscle of the dog’s head; much more information can be found by referencing the human frontalis muscle.
Full Title: Teres Muscle (Major and Minor)
Author: LIsa Giknis
Date of Publication: November 8, 2011
Research Paper Text:
The teres muscle is a muscle that is located in the shoulder of the dog and it’s function is to flex teh shoulder as well as to adduct and internally rotate the shoulder when the front limb is in an outstretched position. This shares a common tendon called the lattisimus dorsi which is used for forward propulsion.
The teres major muscle is a thick but somewhat flattened muscle and is located deep within the shoulder of the dog. Teres means long and round which is how the muscle got it’s name.
Together the teres major and teres minor muscle form an axillary space through which several important arteries and veins pass.
The teres major is a medical rotator and adductor of the humerus and the lattisimus dorsi as states above. The teres major also helps stabilize the humeral head in the glenoid cavity.
The teres major originates from the caudal angle and caudal edge of the scapula and inserts into the eminence on the proximal 1/3 of the medial surface of the humerus.
The innervation is the axillary nerve and the teres major and minor get their blood supply from the axillary artery.
The teres major is the most commonly strained muscle of the dog as it acts like their front wheel drive to assist in propulsion, jumping and pulling their front end and plays an important roll in the dog’s activity.
Full Title: Action of Tail when Elevated
Author: Kimberly Gradin
Date of Publication: October 31, 2011
Research Paper Text:
The report agreed upon with instructor, Jonathan, was regarding a specific articulation of the body. It was describing the action of the tail when elevated. I found this to be very difficult, just trying to find much on the tail itself. Here is what perseverance has taught me.
The soft tissues around the anus harden as muscles contract and press on the anal gland, also stretching the hamstring muscles. Every time a dog moves its tail it acts like a fan for scent. Therefore a dominant dog that carries his tail high will release much more natural scent from his anal glands than a dog that holds his tail lower.
The Sacrocaudalis muscles give mobility to the tail. The dog’s tail is elevated (extended) by contraction of the medial and lateral dorsal sacrocaudal muscles.
The dorsal sacrocaudal muscles get there name from being dorsally attached to the sacral and caudal (coccygeal) vertebrae, which is part of the axial skeleton. They are a small group of muscles in the hind limb area.
The lateral dorsal sacrocaudal muscle’s origin is a continuation of the longissimus, fleshy from aponeurosis of the longissimus and a tendinous origin from the mamillary processes of the first to sixth lumbar vertebra, the articular processes of the sacrum, and the mamillary processes of at least the first eight caudal vertebrae. Its insertion is mamillary processes of the fifth to last caudal vertebrae. The action is the extension or lifting of the tail, possibly also to move it to the side. The nerve innervations are branches of the plexus caudalis dorsalis (caudal and sacral nerves).
The medial dorsal sacrocaudal muscle’s origin is the small processes that are dorsolateral to the caudal edge of the caudal vertebrae. It is direct extension of the multifidus muscle. Its insertion is mamillary processes of the fifth through last caudal vertebrae. Its action is extension of the tail and possibly lateral flexion. The nerve innervations are also the branches of the plexus caudalis dorsalis (caudal and sacral nerves).
The medial caudal artery, and the bilaterally paired lateral caudal arteries (2), and branches of the caudal gluteal arteries are the 3 major sources of blood to the tail.
The ligaments attached are the dorsal sacroiliac ligament and the sacrotuberous ligament.
Basically when the dorsal sacrocaudal muscles contract, the tail elevates pressing on anal glands secreting the animals scent into the air. The sacral and caudal nerves supply the motion and feeling in the skin. The caudal and gluteal arteries supply blood to these muscles, and the dorsal sacroiliac and sacrotuberous ligaments keep it in line.