Medical Gross Anatomy
Anatomy Tables - Muscles
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Medical Gross Anatomy |
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Muscles of the Back Region - Listed Alphabetically |
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| Muscle | Origin | Insertion | Action | Innervation | Artery | Notes | Image |
| erector spinae | iliac crest, sacrum, transverse and spinous processes of vertebrae and supraspinal ligament | angles of the ribs, transverse and spinous processes of vertebrae, posterior aspect of the skull | extends and laterally bends the trunk, neck and head | segmentally innervated by dorsal primary rami of spinal nerves C1-S5 | supplied segmentally by: deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa. | the erector spinae m. is separated into 3 columns of muscle: iliocostalis laterally, longissimus in an intermediate position and spinalis medially; each of these columns has multiple named parts | ) |
| iliocostalis | iliac crest and sacrum | angles of the ribs | extends and laterally bends the trunk and neck | dorsal primary rami of spinal nerves C4-S5 | supplied segmentally by: deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa. | the most lateral part of the erector spinae; it may be subdivided into lumborum, thoracis and cervicis portions | ) |
| interspinales | upper border of spinous process | lower border of spinous process above | extend trunk and neck | dorsal primary rami of spinal nerves C1-L5 | supplied segmentally by: deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa. | these are small and fairly insignificant muscles | ) |
| intertransversarii | upper border of transverse process | lower border of transverse process above | laterally bend trunk and neck | dorsal primary rami of spinal nerves C1-L5 | supplied segmentally by: deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa. | these are small and fairly insignificant muscles | ){kind=spacer} |
| longissimus | transverse process at inferior vertebral levels | transverse process at superior vertebral levels and mastoid process | extends and laterally bends the trunk, neck and head | dorsal primary rami of spinal nerves C1-S1 | supplied segmentally by: deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa. | the intermediate part of the erector spinae;it may be subdivided into thoracis, cervicis and capitis portions | ) |
| multifidus | sacrum, transverse processes of C3-L5 | spinous processes 2-4 vertebral levels superior to their origin | extend and laterally bend trunk and neck, rotate to opposite side | dorsal primary rami of spinal nerves C1-L5 | supplied segmentally by: deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa. | semispinalis, multifidus and rotatores make up the transversospinal muscle group | ) |
| obliquus capitis inferior | spinous process of the axis | transverse process of atlas | rotates the head to the same side | suboccipital nerve (DPR of C1) | occipital a. | greater occipital nerve (DPR of C2) passes superiorly around the inferior margin of inferior oblique | ) |
| obliquus capitis superior | transverse process of atlas | occipital bone above inferior nuchal line | extends the head, rotates the head to the same side | suboccipital nerve (DPR of C1) | occipital a. | the suboccipital triangle is formed by obliquus capitis superior and inferior and rectus capitis posterior major | ) |
| rectus capitis posterior major | spinous process of axis | inferior nuchal line | extends the head, rotate to same side | suboccipital nerve (DPR of C1) | occipital a. | none | ) |
| rectus capitis posterior minor | posterior tubercle of atlas | inferior nuchal line medially | extends the head | suboccipital nerve (DPR of C1) | occipital a. | rectus capitis posterior minor is deeper and inserts more medial than rectus capitis posterior major | ) |
| rotatores | transverse processes | long rotatores: spines 2 vertebrae above origin; short rotatores: spines 1 vertebrae above origin | rotates the vertebral column to the opposite side | dorsal primary rami of spinal nerves C1-L5 | supplied segmentally by: deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa. | semispinalis, multifidus and rotatores make up the transversospinal muscle group | ) |
| semispinalis | transverse processes of C7-T12 | capitis: back of skull between nuchal lines; cervicis & thoracis: spines 4-6 vertebrae above origin | extends the trunk and laterally bends the trunk, rotates the trunk to the opposite side | dorsal primary rami of spinal nerves C1-T12 | supplied segmentally by: deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa. | three parts are named based on their insertions: capitis, cervicis and thoracis; semispinalis, multifidus and rotatores make up the transversospinal muscle group | ) |
| spinalis | spinous processes at inferior vertebral levels | spinous processes at superior vertebral levels and base of the skull | extends and laterally bends trunk and neck | dorsal primary rami of spinal nerves C2-L3 | supplied segmentally by: deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa. | most medial part of the erector spinae; may be subdivided into thoracis, cervicis and capitis portions | ) |
| splenius | ligamentum nuchae and spines C7-T6 | capitis: mastoid process & superior nuchal line laterally; cervicis: posterior tubercles of C1-C3 vertebrae | extends and laterally bends neck and head; rotates head to same side | dorsal primary rami of spinal nerves C2-C6 | supplied segmentally by: deep cervical a., posterior intercostal aa. | splenius means bandage; it gets its name from its broad, flat shape | ) |
| splenius capitis | ligamentum nuchae and spines of C7-T6 vertebrae | mastoid process and lateral end of the superior nuchal line | extends and laterally bends the neck and head, rotates head to the same side | dorsal primary rami of spinal nerves C2-C6 | supplied segmentally by: deep cervical a., posterior intercostal aa. | named for its shape: splenius means bandage and capitis refers to the insertion of this portion of the muscle | ) |
| splenius cervicis | ligamentum nuchae and spines of C7-T6 vertebrae | posterior tubercles of the transverse processes of C1-C3 vertebrae | extends and laterally bends neck and head, rotates head to the same side | dorsal primary rami of spinal nerves C2-C6 | supplied segmentally by: deep cervical a., posterior intercostal aa. | named for its shape: splenius means bandage and cervicis refers to the insertion of this portion of the muscle | ) |
| The material presented in these tables is
contained in the book: MedCharts Anatomy by Thomas R. Gest & Jaye Schlesinger Published by ILOC, Inc., New York Copyright © 1995, unauthorized use prohibited. |
The excellent editorial assistance of Dr. Pat Tank, UAMS is gratefully acknowledged. |
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| Copyright© 2000 The University of Michigan. Unauthorized use prohibited. |
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