Muscles of the Back Region - Listed Alphabetically
Muscle
Origin
Insertion
Action
Innervation
Artery
Notes
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
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
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Anatomy of the Muscles of the Back
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