Full Title: The Digital Flexor Tendon of Forepaw
Author: Lisa Schmit, PhD, CCFT
Date of Publication: November 22, 2017
Research Paper Text:
Dogs are digitgrade animals- meaning they walk on their toes not their heels like humans. The function of toes is vast and dogs would be lost without them! The toes are weight bearing, shock absorbers that allow for balance and stability with jumping, running, standing, pivoting on multiple surfaces. To handle the different surfaces and motions, the toes will spread and provide the balance and stability they need. The toes also allow the dog to dig and hold objects.
While there are many parts of the paw, this paper focus’ on the digital flexor tendons.
In the forelimb, dogs have five digits or toes per paw with digit 1 being the dew claw. Paws are made up of bones, ligaments, tendons, skin, blood and connective tissue. The bones of the toes are not structured straight and flat like human feet, but are aligned in an angled fashion and are moved by digital extensor and flexor tendons (Henneman, 14) Tendons are strong , flexible, elastic, connective tissues that are composed of collagen fibers. (Zink, 13) They are like a bridge between the muscle and the bone. At one end, tendon is connected to the muscle fibers and at the other end tendons are connected to components of the bone. When a muscle contracts to move a joint, the tendon pulls on the bone moving the body part. On the top side of the digits are the extensor tendons that extend the wrist and toes. On the bottom side of the digits are the flexor tendons that flex the wrist and toes. There are two digital flexor tendons: deep digital flexor tendon and the superficial digital flexor. (Henneman, 2014) The Superficial digital flexor muscle attaches to the medial epicondyle of the humerus. The muscle splits into 4 tendons that insert on the underside of the middle phalanges 2-5. The deep digital flexor muscle attaches at attaches to the medial epicondyle of the humerus and caudal-medial aspect of the radius and ulna and inserts on the underside of middle phalange 2-5. (Mills, Levine,2014 )
Figure 2: Digital Extensor and Flexor Muscles
Function of the Digital Flexors
The main function of the digital flexor muscles and tendons are to flex the digits. When the dog flexes its wrist or digits, the flexor muscles and tendons are engaged. They serve other functions as well. The digital flexor muscles/tendons also prevent hyperextension and helps maintain the proper structure of the foot. (Henneman,14) Superficial digital flexor tendon works as a shock absorber when the foot hits the ground which limits the potential damage to muscles. The flexor tendons also helps with traction allowing nails to dig into the surface the dog in moving on (Lotsikas, nd) They also work to bring the bend back into the toes after foot is flattened by weight bearing movement (Henneman, 14)
An injury can happen suddenly or a little at a time. It can be a result of an accident, traumatic injury, hyperextension or repetitive strains (Lundin, nd) Tendons can be stretched, strained, partially torn or ruptured. Many injuries to the flexor tendons involve lacerations that cut into the tendon. Other injuries to the digital flexor tendons are result of tiny tears to the tendon that happen over time. This occurs as a result of gradual wear and tear of the tendon from overuse or aging. Any repetitive actions are more likely to damage a tendon. So repetitive concussive training such as jumping, flyball box turns etc can cause tendon damage over time.
Symptoms of a digital flexor injury include the toe will stick up more than normal because the flexor tendon will be unable to keep the bent structure of the foot in place. Instead, the toe will be in a straight line and flat so the nail will stick up more than the normal toes. There may be lameness, pain, non-weight bearing and swelling. (Henneman, 14) Tendons may be repaired surgically for cosmetic reasons and for improved athletic function. (Mills, 2014)
What Owners should do
All dog owners should look at your dog’s feet
Check for signs of injury or disease (blood, swelling, growths, sores, discoloration abnormal looking)
Palpate your dogs feet-
Pay attention for signs of pain lameness, licking or chewing
Do you feel anything abnormal (scabs, growths, heat, swelling, foreign objects such as burs) ?
How long is the hair? Does it need to be trimmed?
Don’t forget to check the webbing of the foot as well, again looking/feeling for abnormalities
Check pad of the foot for injuries
Pay attention to the shape of the foot and length and location of the toes: are they symmetric or is one sticking out more than the other?
Trim nails on regular basis. Is one nail more worn than the other?
Pay attention to the surface your dog in walking and running on. Avoid hot surfaces such as asphalt but also watch for other hazards such as glass or other debris on the ground. Avoid slippery surfaces such as ice or other slippery surfaces.
Be cognizant of repetitive concussive behaviors your dog may perform such as jumping off the bed onto a hard surface. If this is occurring, you may want to get stairs or a ramp.
For the sports owner in addition to the above mentioned recommendations, there are other things to do to prevent injury.
it is important for you to warm up your dogs’ toes prior to your activity.
Stretch and massage forelimbs and toes
Perform Range of Motion of forelimbs and toes
Perform strength training exercises that strengthen core and forelimbs
Perform balance exercises
I recommend taking pictures of your dogs feet every so often so that you can see if there any changes in their feet and their structure
Be aware of the activities you are asking of your dog and the repercussions on their body
I recommend your canine athlete see a chiropractor, canine fitness expert and a massage therapist on a regular basis
Conditioning & Fitness
From a conditioning perspective, perform exercises to increase strength and flexibility in the digital flexor muscles and tendons. The following pictures are of my dogs performing conditioning exercises. If you look closely, you can see their toes are spread out to help balance the dog on various surfaces.
Some Conditioning Exercises to strengthen and increase flexibility of digital flexor muscles/tendons:
*Warmup the forelimbs and toes prior to activity
*Perform Range of Motion Exercises
-Performing weight shifting on the flat and then on unstable equipment will work the muscles of the forelimbs, paws and toes to stabilize and balance the dog.
-Tight circles on the ground and then on unstable equipment such as rocker board will engage the digital flexors as the dog uses its toes to balance.
As the dog steps sideways on the ground or various pieces of equipment or surfaces, the dog may will use his toes to balance.
In the following pictures, the dog is taking lateral steps on and off the bones. You can see the toes spreading out to help with balance.
Pods are small balance discs. They are smaller in diameter so the dog has to use strength balance and body awareness to stand on the pods.
Perform weight shifts while dog in standing with feet on paw pods. -Sidestepping on and off Paw Pods, High Fives, use only 2 pods etc.
-Standing on a 4X4 or something skinny
Standing, walking, sitting, high fives on 4×4 or skinnier piece of equipment will engage forelimbs. The dog will use their toes to help balance.
Front Paws on Foam Roller
Front Paws on a foam roller (or pool noodle) will engage front limbs and toes. When rocking the pool noodle forward and backwards, the digital extensors and flexors will engage.
The following are various massage techniques used on the front limb and digits.
*Friction to warm up the toes
Frictioning is back and forth motion over a specific body part which creates heat. This warms up the area preparing it for other massage techniques (Rudinger, 2012)
*Range of Motion of the toes
Checking range of motion of the toes is important to see if there is anything ‘off’. Is one toe more stiff than another? In order to perform range of motion of the toes, I press down on the pad of each digit. The toe should easily move. (Cupp, nd)
According to Rudinger, “compression uses pressure to compact the tissues of the body beneath your hands.” It increases circulation and relaxes the muscles and tissues (Rudinger, 2012). Compression can be used up and down the forelimb all the way to the end of the toes.
* Chucking of the forelimb
With one hand around the dog’s leg, move the hand up and down the leg in short movements. (Quizlet website)
. Thumb Rolling
I take my thumb and with light pressure glide my thumb down the digits.
I will also use my thumb to glide down each individual toe and webbing. In doing so, I am working range of motion of the digits and stimulating circulation.
Stretch the Digital Flexor Tendons
In order to stretch the digital flexors, the elbow is bend and the toes are extended upward.(Foster, 2009).
I take each digit and cross it on top of the neighboring digit. This helps stretch digits, provide blood flow and increase flexibility of the toes (Foster, 2009).
In conclusion, it is very important to pay attention to dog’s toes !! From a pet owner to a high level sports dog trainer, a dog’s forelimbs and paws should be examined on a regular basis. In addition, conditioning, massage and chiropractic care is also recommended to keep the dog’s body in top condition.
Cupp, Letha, Canine Massage Therapist, Reiki Master
Foster, Sasha, (February 2009) Healthy Way to Stretch Your Dog: A Physical Therapy Approach. Dogwise Manual
Furman, C Sue (2003) Balance your Dog Canine Massage. Wolfchase Publishing
Henneman, Kimberly (June 2014) The Biomechanics of Toes and Nails Clean Run.
Kainer, Robert & McCracken, Thomas (2003) Dog Anatomy A Coloring Atlas. Teton NewMedia
Lotsikas, Peter and Lotsikas Faith (nd) Why Toes Are So Important! Clean Run
Millis, Darryl, * Levine David. (2014) Canine Rehabilitation and Physical Therapy 2nd edition. Saunders, Elsevier Inc.
Rudinger, Jonathan (2012) Art and Essence of Canine Massage PetMassage for Dogs. PetMasage Books
Zink, Christine (2013) Canine Sports Medicine and Rehabilitation. John Wiley & Sons, Inc.