The spinalis is a portion of the
erector spinae
The erector spinae ( ) or spinal erectors is a set of muscles that straighten and rotate the back. The spinal erectors work together with the glutes (gluteus maximus, gluteus medius and gluteus minimus) to maintain stable posture standing or sittin ...
, a bundle of
muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
s and
tendons, located nearest to the spine. It is divided into three parts: Spinalis dorsi, spinalis cervicis, and spinalis capitis.
Spinalis dorsi
Spinalis dorsi, the medial continuation of the
sacrospinalis, is scarcely separable as a distinct muscle. It is situated at the medial side of the
longissimus dorsi, and is intimately blended with it; it arises by three or four tendons from the
spinous processes of the first two
lumbar
In tetrapod anatomy, lumbar is an adjective that means ''of or pertaining to the abdominal segment of the torso, between the diaphragm and the sacrum.''
The lumbar region is sometimes referred to as the lower spine, or as an area of the back i ...
and the last two
thoracic vertebrae: these, uniting, form a small muscle which is inserted by separate tendons into the spinous processes of the upper thoracic vertebrae, the number varying from four to eight.
It is intimately united with the
semispinalis dorsi, situated beneath it.
Spinalis cervicis
Spinalis cervicis, or spinalis colli, is an inconstant muscle, which arises from the lower part of the
nuchal ligament, the
spinous process of the seventh cervical, and sometimes from the spinous processes of the first and
second thoracic vertebrae, and is inserted into the spinous process of the
axis, and occasionally into the spinous processes of the two cervical vertebrae below it.
Spinalis capitis
Spinalis capitis (biventer cervicis) is usually inseparably connected with the
semispinalis capitis.
Spinalis capitis is not well characterized in modern anatomy textbooks and atlases, and is often
omitted from anatomical illustration. However, it can be identified as fibers that extend from the spinous processes of TV1 and CV7 to the cranium, often blending with semispinalis capitis
See also
*
Iliocostalis
*
Longissimus
*
Semispinalis muscle
References
External links
* - "Intrinsic muscles of the back."
Dissection at ithaca.edu
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Muscles of the torso