Spinalis capitis: spinous processes of C6-T2 and nuchal ligament
Spinalis cervicis: spinous processes of C7-T1 and nuchal ligament
Spinalis thoracis: spinous processes of T11-L2 vertebrae
Longissimus capitis: transverse processes of C4-T4
Longissimus cervicis: transverse processes of T1-T4
Longissimus thoracis: dorsal surface of sacrum & median sacral crest, posterior superior iliac spine, & transverse processes of L1-L5
Iliocostalis cervicis: angle of ribs 3-6
Iliocostalis thoracis: angle of ribs 7-12
Iliocostalis lumborum: medial end of iliac crest, lateral crest of sacrum, & thoracolumbar fascia
Spinalis capitis: occiput
Spinalis cervicis: spinous processes of C2/C3
Spinalis thoracis: spinous processes of T2-T8
Longissimus capitis: posterior edge of mastoid process
Longissimus cervicis: transverse processes of C2-C6
Longissimus thoracis: transverse process of T1-T12 & dorsal aspect of ribs 3-12
Iliocostalis cervicis: transverse process of C4-C6
Iliocostalis thoracis: transverse process of C7 & angles of ribs 1-6
Iliocostalis lumborum: transverse processes of L1-L4 & angles of ribs 4-12
|Action||Bilateral contraction: extension of the trunk, neck and vertebral column|
Unilateral contraction: lateral flexion of the trunk, neck and vertebral column
|Nerve||Posterior rami of corresponding spinal nerves|
Dorsal branches of posterior intercostal artery, deep cervical artery, muscular branches of vertebral artery
Vertebral artery, deep cervical artery, occipital artery, transverse cervical artery, superior intercostal artery, posterior intercostal artery, subcostal artery, lateral sacral artery, median sacral artery
Dorsal branches of posterior intercostal, subcostal, lumbar & lateral sacral arteries
Location & Overview
The erector spinae is a large and long group of muscles which are located on the posterior of the body. The erector spinae group consists of: the spinalis, the longissimus, and the iliocostalis. These three muscles run parallel to the spine, from the sacrum to the neck. The erector spinae muscles are responsible for extension and lateral flexion movements, as well spinal stabilisation .
The spinalis muscle is located in the middle and upper back, as well as the neck . It is the most medial of the erector spinae muscles, blending laterally with the longissimus. The spinalis muscle is comprised of three sections: the capitis, cervicis and thoracis. The capitis is the most superior of these three sections, the cervicis is in the middle, and the thoracis is the most inferior .
The longissimus is the largest and longest muscle of the erector spinae group. It is located between the spinalis and iliocostalis. The longissimus is divided into three sections: the longissimus capitis, longissimus cervicis, and longissimus thoracis. This muscle extends from the sacrum to the edge of the mastoid process .
The iliocostalis muscle is the most lateral muscle in this group. It is divided into three sections based on their point of origin: iliocostalis cervicis, iliocostalis thoracis, and iliocostalis lumborum. These sections span from the lumbar region to the cervical region of the spine .
Origin & Insertion
The erector spinae muscles each have their own distinct origins and insertions, varying across their respective sections and among individuals. The erector spinae group of muscles includes the spinalis, longissimus, and iliocostalis muscles.
The spinalis muscle, the most medial muscle of the erector spinae, consisting of three distinct sections: spinalis capitis, spinalis cervicis, and spinalis thoracis. The spinalis capitis originates from the spinous processes of C6 to T2 and the associated nuchal ligament and inserts onto the occiput’s medial and inferior aspect. The occiput is a section of bone located at the back of the skull and the nuchal ligament is a ligament on the back of the neck (running from the occiput to C7). The spinalis cervicis begins at the nuchal ligament and the spinous processes of the lower cervical to upper thoracic vertebrae (C7 and T1) and inserts onto the spinous processes of the second or third cervical vertebra (C2 or C3) . Lastly, the spinalis thoracis takes origin on the spinous processes of T11-L2, and inserts onto the spinous processes of the upper thoracic vertebrae T2-T8 .
The longissimus muscle, the intermediate column of the erector spinae, also has three sections: longissimus capitis, longissimus cervicis, and longissimus thoracis. The longissimus capitis originates from the transverse processes of C4 to T4 vertebrae and inserts at the posterior edge of the mastoid process. The mastoid process is a bony projection on the temporal bone, at the posterior base of the skull. You can feel the bump of the mastoid process on the skull close to the area behind your earlobe. The longissimus cervicis originates from the transverse processes of T1 to T4 vertebrae and inserts at the posterior tubercle of C2 to C6 transverse processes . The longissimus thoracis originates from the dorsal surface of the sacrum and its median sacral crest, the medial surface of the posterior superior iliac spine, and the transverse processes of L1 to L5 vertebrae. The insertion is on the transverse processes of T1 to T12 vertebrae and the dorsal aspect of ribs 3 to 12, between the rib angle and tubercle .
The iliocostalis muscle, the lateral column of the erector spinae, includes the iliocostalis cervicis, iliocostalis thoracis, and iliocostalis lumborum. The iliocostalis cervicis has its origin at the angles of ribs 3 to 6 and inserts at the posterior tubercle of the transverse process of vertebrae C4 to C6. The iliocostalis thoracis originates at the angles of the bottom six ribs and inserts at the transverse process of vertebra C7 and the angles of the top six ribs . The iliocostalis lumborum originates at the medial end and dorsal segment of the iliac crest and the lateral crest of the sacrum, inserting at the lumbar transverse processes of L1 to L4, the angles of ribs 4 to 12, and the thoracolumbar fascia. The thoracolumbar fascia is a large, diamond-shaped connective tissue structure located in the lower back, spanning from the lower thoracic to the upper lumbar spine. It encases the muscles of the lower back .
The erector spinae, consisting of the spinalis, longissimus, and iliocostalis muscles, plays an important role in various actions of the spine, neck, and trunk. The effects of these muscles are contingent on whether unilateral or bilateral contractions occur, with unilateral referring to a single side contracting and bilateral involving simultaneous contractions on both sides   .
The spinalis muscle, divided into thoracis, cervicis, and capitis sections, each influences its corresponding vertebral region. For the thoracis segment, unilateral contraction results in lateral flexion of the trunk, while bilateral contraction leads to trunk extension  . The cervicis and capitis sections of the spinalis primarily affect the neck’s movement, with bilateral contractions extending the neck, and unilateral contractions causing ipsilateral lateral flexion  .
The longissimus muscle, with its capitis, cervicis, and thoracis segments also influences both trunk and neck movements. Bilateral contractions lead to the extension of the trunk and neck, whereas unilateral contractions result in lateral flexion. The longissimus capitis affects movements of the neck and upper thoracic vertebrae, whereas the longissimus thoracis influences trunk movements   .
The iliocostalis muscle with its cervicis, thoracis, and lumborum sections contributes to the movements of the trunk and vertebral column, with unilateral contractions causing lateral flexion and bilateral contractions leading to extension. The cervicis segment of the iliocostalis also provides weak support for lateral flexion at the neck’s base during unilateral contractions and weak extension at the neck’s base during bilateral contractions   .
The erector spinae group of muscles receive their innervation through the lateral branches of the posterior rami of the spinal nerves, with the specificity of nerve supply corresponding to the different sections of each muscle .
The spinalis muscle receives innervation in its thoracic portion from the posterior rami of the thoracic and upper lumbar nerves. Its cervicis and capitis segments are innervated by the posterior rami of the cervical and upper thoracic nerves .
Similarly, the longissimus muscle gets its innervation from the corresponding lateral branches of the spinal nerves. The cervical, thoracic, and lumbar portions of the longissimus muscle are each innervated by the lateral branches of the corresponding spinal nerves’ posterior rami .
The longissimus muscle gets its blood supply from the vertebral artery, deep cervical artery, occipital artery, and transverse cervical artery for the capitis and cervicis parts. The thoracis segment of the longissimus muscle receives blood from the superior intercostal artery, posterior intercostal artery, subcostal artery, lateral sacral artery, and median sacral artery .
|↑1, ↑19, ↑22, ↑24, ↑26, ↑29||Standring S. (2015). Gray’s Anatomy: The Anatomical Basis of Clinical Practice, 41st Edn. Amsterdam: Elsevier.|
|↑2, ↑5, ↑8, ↑9, ↑14, ↑15, ↑17, ↑21, ↑23, ↑28, ↑30, ↑35, ↑39, ↑40, ↑43, ↑48, ↑49||Henson B, Kadiyala B, Edens MA. Anatomy, Back, Muscles. [Updated 2022 Aug 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537074/|
|↑3, ↑12, ↑13, ↑36, ↑44||Greiner TM, Bedford ME, Walker RA. Variability in the human m. spinalis capitis and cervicis: frequencies and definitions. Ann Anat. 2004 Apr;186(2):185-91. doi: 10.1016/S0940-9602(04)80039-6. PMID: 15125051.|
|↑4, ↑7, ↑10, ↑16, ↑18, ↑20, ↑25, ↑32, ↑37, ↑41, ↑45, ↑47, ↑50||Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017.|
|↑6, ↑27, ↑33, ↑38, ↑46||Cramer, G. D., & Darby, S. A. (2014). Clinical anatomy of the spine, spinal cord, and ANS (3rd ed.). St. Louis: Elsevier. ISBN 9780323079549.|
|↑11, ↑31, ↑34, ↑42, ↑51||Chaitow, Leon, and DeLany, Judith (2011), Clinical Application of Neuromuscular Techniques, Volume 2 (Second Edition), Oxford: Churchill Livingstone, ISBN 978-0-443-06815-7|