Longissimus Thoracis Muscle

Full Title: Longissimus Thoracis Muscle

Author: Okada Takashi

Date of Publication: December 3, 2012

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Research Paper Text:


Sacrospinalis is a lateral part of an epaxial (on the back panel) muscle and a very thick deep muscle which continues toward neck. The sacrospinalis emerges on the spine of the last four thoracic vertebrae and attaches to the first thoracic vertebrae and the cervical vertebrae. There are three muscles, namely 1) semispinalis, 2) longissimus, and 3) iliocostalis. The sacrospinalis is a critical muscle to extend the vertebrae column.


The longissimus muscles are located side by side with the spinal and semispinal muscles. The word ‘longissimus’ means the longest and the longissimus muscle is the longest muscle among the sacrospinalis. Also, the longissimus is the largest muscle among the sacrospinalis. The action of the longisimus muscle is to extend and bend the trunk, neck, and head. The origin is the transverse process at inferior vertebral levels and the insertion is the transverse process at superior vertebral levels and mastoid process.

Longissimus Thoracis Muscle

Longisimus muscle is subdivided into the thoracis, cervicis, and capitis portion. It is also called ‘longissimus dorsi.’ The longissimus thoracis muscle is located on the lumber region and it is categorized as a thoracis part of the longissimus muscle. The origin is the transverse processes of the lower thoracic vertebrae and the insertion is the lower ribs and the transverse processes of the upper lumbar vertebrae. The nerve supply is from the dorsal branches of the thoracic and the lumbar nerves.


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