The erector spinae muscles are really three muscles: spinalis, longissimus, and iliocostalis. To get more specific, anatomists subdivide each of these three muscles into smaller muscles based on the region of the spine they are in.
It refers to the bumpy projections that you can feel along the length of the spine, the spinous processes. Spinalis is the most medial of the erector spinae muscles. It can be further subdivided into three sections, the spinalis thoracis, spinalis cervicis, and spinalis capitis. The longissimus is the middle muscle of the erector spinae group.
It can be further subdivided into three muscles: the longissimus thoracis, longissimus cervicis, and longissimus capitis muscles.
Iliocostalis is the most lateral of the muscles in the erector spinae group. It can be further subdivided into two smaller muscles, the iliocostalis lumborum and iliocostalis cervicis. Spinalis thoracis originates on the spinous processes from about T10 — L3.
Longissimus thoracis originates on the sacrum and the spinous and transverse processes of all lumbar and thoracic vertebrae. But, longissimus cervicis originates on the transverse processes of T1 — T5 and longissimus capitis originates on the transverse processes of of T1 — T5 and the articular processes of C5 — C7.
The three iliocostalis muscle sections vary in their origins as well. Iliocostalis lumborum originates on the medial aspect of the iliac crest, the sacrum, and spinous processes of the lumbar vertebrae. But, iliocostalis thoracis originates on the superior border of the lower 6 ribs, just medial to the iliocostalis lumborum. Finally, iliocostalis cervicis originates on the angle of the ribs 3 — 6. The spinalis muscles are most medially located. That is, they are closest to the spine.
Next to spinalis we find the longissimus muscles. The iliocostalis are located most laterally of the erector spinae muscles. While the erector spinae muscle group is very important for extending the spine, there are also many other muscles that contribute to moving the spine in different ways. If you want to learn more about other muscles that move the spine check out our post: Exploring The Spine!
We have a course that teaches you 65 muscles in 79 lessons using high-quality 3D models. What are the erector spinae muscles? Where are the erector spinae muscles? Several texts state that the erector spinae muscles have a single, common insertion point of a large broad tendon on the back of the sacrum, the inner side of the iliac crest, sacroiliac ligaments, and lumbosacral spinous processes The reference for the following origin and insertion points is Gray's Anatomy 40 th edition 1 unless otherwise referenced.
The spinalis group consists of the spinalis capitis, spinalis cervicis and spinalis thoracis. The spinalis thoracis is the most consistent and prominent muscle of this group. The spinalis capitis and spinalis cervicis are variably developed and variably present. The longissimus group is the predominant component of the erector spinae group and consists of longissimus capitis, longissimus cervicis, and longissimus thoracis. The iliocostalis muscles are the most lateral components of the erector spinae group.
This subgroup includes the iliocostalis cervicis, iliocostalis thoracis, and iliocostalis lumborum. Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. Updating… Please wait. Unable to process the form. Check for errors and try again. Thank you for updating your details. Log In. Sign Up. Become a Gold Supporter and see no ads.
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