Back Muscles: Origin, Insertion, Innervation, Blood Supply & Action
Levatores Costarum Origin
12 pairs, from the TP's of C7 and first through eleventh thoracic vertebrae
Semispinalis Capitis Insertion
Occipital bone between superior and inferior nuchal lines
Levatores Costarum Insertion
On external surface of rib below vertebra of origin between the tubercle and angle
Rotatores Longus and Rotatores Brevis Action
Rotation of the vertebral column
Latissimus Dorsi Innervation
Thoracodorsal nerve (from the posterior cord of the brachial plexus, containing fibers from C6 to C8)
Longissimus Thoracis Origin
Thoracolmbar fascia and accessory processes of the lumbar vertebrae
Iliocostalis Lumborum Origin
Thoracolumbar Fascia
Semispinalis Capitis Action
Bilaterally: Extension of the neck Unilaterally: Turns face toward opposite side
Semispinalis Thoracis Action
Bilaterally: Extension of the vertebral column Unilaterally: Rotation of the vertebral column toward the opposite side
Longissimus Capitis Action
Bilaterally: Extension of vertebral column Unilaterally: Rotation of face towards same side
Semispinalis Cervicis Action
Bilaterally: Extension of vertebral column Unilaterally: Rotation of vertebral column toward opposite side
Spinalis Thoracis Origin
Blends with longissimus thoracis and arises from spinous processes of T11-L2
Splenius Capitis Origin
Caudal half of ligament niche and SP of C7 to T3/T4
Serratus Anterior Insertion
Costal surface of the vertebral border of the scapula
Latissimus Dorsi Insertion
Crest of the lesser tubercle and floor of the bicipital groove of the humerus
Semispinalis Cervicis Blood Supply
Deep branch of the costocervical trunk, posterior intercostal arteries
Serratus Posterior Inferior Action
Depresses lower ribs, draws them down and back (muscle of inspiration)
Semispinalis Capitis Blood Supply
Descending branch of occipital artery, deep branch of the costocervical trunk
Iliocostalis Cervicis Innervation
Dorsal Rami of spinal nerves C4-C6
Rhomboideus Minor Innervation
Dorsal Scapular Nerve (C4, C5)
Splenius Cervicis Innervation
Dorsal rami lower cervical spinal nerves
Spinalis Thoracis Innervation
Dorsal rami of T1 to T12
Multifidus (Lumborum, Thoracis, and Cervicis) Innervation
Dorsal rami of all spinal nerves
Spinalis Cervicis Innervation
Dorsal rami of cervical spinal nerves
Splenius Capitis Innervation
Dorsal rami of middle cervical spinal nerves
Interspinales Innervation
Dorsal rami of spinal nerves
Rotatores Longus and Rotatores Brevis Innervation
Dorsal rami of spinal nerves
Longissimus Capitis Innervation
Dorsal rami of spinal nerves C3 to C8
Longissimus Cervicis Innervation
Dorsal rami of spinal nerves C4-C8
Semispinalis Thoracis Innervation
Dorsal rami of spinal nerves T1 to T6
Longissimus Thoracis Innervation
Dorsal rami of spinal nerves T1-T12
Intertransversarii Innervation
Dorsal rami of spinal nerves, except lateral Intertransversarii in lumbar and lower thoracic, and anterior and posterior Intertransversarii in cervical Exceptions are innervated by ventral rami
Iliocostalis Lumborum Innervation
Dorsal rami of the lumbar spinal nerves
Iliocostalis Thoracis Innervation
Dorsal rami of the thoracic spinal nerves
Levatores Costarum Innervation
Dorsal rami of thoracic spinal nerves
Rhomboideus Major Innervation
Dorsal scapular nerve (C4, C5)
Trapezius Origin
EOP, medial 1/3 of the Sup. Nuchal Line, Ligamentum Nuchae, spinous processes of C7-T12
Levatores Costarum Action
Elevate ribs, assist in inspiration, rotates and laterally flexes vertebral column
Levator Scapulae Action
Elevates and retracts scapula with trapezius, laterally flexes cervical vertebral column if scapula is fixed
Rhomboideus Major Action
Elevates the medial border and retracts the scapula (same as R. Minor), rotation of the scapula
Rhomboideus Minor Action
Elevates the medial border and retracts the scapula (same os R. Major), rotation of the scapula
Serratus Posterior Superior Action
Elevates upper ribs (muscle of inspiration)
Iliocostalis Cervicis Action
Extension and lateral flexion of the vertebral column
Iliocostalis Lumborum Action
Extension and lateral flexion of the vertebral column
Longissimus Cervicis Action
Extension and lateral flexion of the vertebral column
Longissimus Thoracis Action
Extension and lateral flexion of the vertebral column
Spinalis Thoracis Action
Extension and lateral flexion of the vertebral column
Spinalis Cervicis Action
Extension of the vertebral column
Iliocostalis Thoracis Action
Extension of vertebra column
Interspinales Action
Extension of vertebral column
Multifidus (Lumborum, Thoracis, and Cervicis) Action
Extension, lateral flexion, and rotation of vertebral column, extension and lateral motions of the pelvis
Latissimus Dorsi Action
Extension, medial rotation, and adduction of the arm
Serratus Posterior Superior Innervation
First four intercostal nerves (ventral rami of first four thoracic nerves)
Serratus Anterior Origin
Fleshy digitation form the external surfaces of the upper eight or nine ribs
Triangle of Auscultation
Formed by: Latissimus Dorsi Trapezius Medial border of the scapula (Floor formed by R. Major)
Semispinalis Thoracis Origin
From the TP's of the lower 6 thoracic vertebrae
Rotatores Longus and Rotatores Brevis Origin
From the TP's of vertebrae
Spinalis Cervicis Origin
From the lower part of ligament nuchal and SP's of C7 to T2
Serratus Posterior Superior Blood Supply
Highest intercostal artery, posterior intercostal arteries
Intertransversarii Insertion
Inferiorly on TP's of vertebrae immediately superior to vertebra of origin Most highly developed in cervical and lumbar regions
Interspinales Insertion
Inferiorly on spine of vertebra immediately superior to vertebra of origin Not always present in thoracic region Frequently double in cervical region
Rotatores Longus and Rotatores Brevis Insertion
Lamina of the vertebra immediately superior (R. Brevis), or into the lamina of the second vertebra above the vertebra of origin (R. Longus)
Intermediate Intrinsic Back Muscles
Lat- Iliocostalis (iliocostalis lumborum/thoracis/cervicis) Inter- Longissimus (longissimus thoracis/cervicis/capitis) Med- Spinalis (Spinalis thoracis/cervicis/capitis) All of which form the ERECTOR SPINAE
Intertransversarii Action
Lateral flexion of vertebral column
Serratus Anterior Innervation
Long thoracic nerve (C5, C6, C7)
Iliocostalis Lumborum Insertion
Lower borders of the lower six or seven ribs near the angles
Serratus Posterior Superior Origin
Lower end of ligament niche, and SP's of C7 to T2 or T3
Rhomboideus Minor Origin
Lower part of ligament niche and SP of C7 and T1
Serratus Posterior Inferior Insertion
Lower three of four ribs lateral to their angles
Serratus Posterior Inferior Innervation
Lowest four intercostal nerves (ventral rami of lowest four thoracic nerves)
Splenius Capitis Insertion
Mastoid process and occipital bone just inferior to lateral one third of superior nuchal line
Spinalis Capitis
May originate form upper thoracic SP's Usually blends laterally with semispinalis capitis. Considered with the semispinalis capitis
Rhomboideus Minor Insertion
Medial border of scapula at base (root) of the spine
Levator Scapulae Insertion
Medial border of scapula from superior angle to base of spine
Rhomboideus Major Insertion
Medial border of the scapula between the base of the spine and inferior angle
Semispinalis Capitis Innervation
Medial branches of dorsal rami of C1-C6
Semispinalis Cervicis Innervation
Medial branches of the dorsal rami of C6 to C8
Longissimus Capitis Origin
Medial to upper border of longissimus cervicis partly from the tendons of origin of this muscle and from the articular processes of the lower four cervical vertebrae
Semispinalis
Most superficial of the transversospinalis group Extend 5-6 vertebral levels
Splenius Cervicis Blood Supply
Muscular and defending branches of the occipital artery, superficial branch of the transverse cervical artery
Splenius Capitis Blood Supply
Muscular and descending branches of the occipital artery, superficial branch of the transverse cervical artery
Longissimus Capitis Blood Supply
Muscular branches of occipital artery, deep cervical branch of the costocervical trunk
Intertransversarii Blood Supply
Muscular branches of posterior intercostal and lumbar arteries
Interspinales Blood Supply
Muscular branches of the posterior intercostal arteries, lumbar arteries, deep cervical branches of the costocervical trunk
Splenius Cervicis Origin
Narrow tendinous band from SP's of T3-T6
Iliocostalis Cervicis Blood Supply
Posterior Intercostal arteries
Levator Scapulae Origin
Posterior Tubercles of the TP's of C1-C3/C4
Longissimus Capitis Insertion
Posterior edge of the mastoid process
Longissimus Thoracis Blood Supply
Posterior intercostal and lumbar arteries
Multifidus (Lumborum, Thoracis, and Cervicis) Blood Supply
Posterior intercostal and lumbar arteries, deep cervical branch of the costocervical trunk
Iliocostalis Thoracis Blood Supply
Posterior intercostal arteries
Levatores Costarum Blood Supply
Posterior intercostal arteries
Longissimus Cervicis Blood Supply
Posterior intercostal arteries
Semispinalis Thoracis Blood Supply
Posterior intercostal arteries
Serratus Posterior Inferior Blood Supply
Posterior intercostal arteries
Spinalis Cervicis Blood Supply
Posterior intercostal arteries
Spinalis Thoracis Blood Supply
Posterior intercostal arteries
Iliocostalis Lumborum Blood Supply
Posterior intercostal arteries, lumbar arteries
Rotatores Longus and Rotatores Brevis Blood Supply
Posterior intercostal arteries, lumbar arteries
Multifidus (Lumborum, Thoracis, and Cervicis) Origin
Posterior surface of sacrum, posterior sacroiliac ligament, mammillary processes of lumbar vertebrae, TP's of thoracic vertebrae, and articular processes of C4-C7
Splenius Cervicis Insertion
Posterior tubercles of the TP's of upper 2 or 3 cervical vertebrae
Trapezius Action
Raises, retracts and rotates the scapula Bilateral contraction of sup. fibers extends the head Unilateral contraction of upper fibers laterally flexes the head and cervical vertebral column Sup. Fibers- Elevate scapula, works with levator scapulae and serrates anterior to rotate the shoulder Mid. Fibers- Retract the scapula Inf. Fibers- Depress the scapula and lower the shoulders
Rhomboideus Major Origin
SP of T2-T5
Spinalis Cervicis Insertion
SP's of C2 to C3, sometimes C4
Serratus Posterior Inferior Origin
SP's of T10 or T11 to L2
Spinalis Thoracis Insertion
SP's of upper 4 to 8 cervical vertebrae
Multifidus (Lumborum, Thoracis, and Cervicis) Insertion
SP's of vertebrae 2-4 segments superior to the vertebrae of origin
Semispinalis Cervicis Insertion
Second through fifth cervical SP's
Serratus Posterior Superior Insertion
Second through fifth ribs lateral to the angles
Transversospinalis Group
Semispinalis Multifidus Rotatores Longus Rotatores Brevis
Trapezius Innervation
Spinal accessory nerve and ventral rami of third and fourth cervical nerves
Latissimus Dorsi Origin
Spinous process of the lower 6 thoracic, all lumbar, and the upper sacral vertebrae, from the posterior part of the iliac crest, and from the lower three or four ribs by muscular slips which interdigitate with the external oblique
Superficial Intrinsic Back Muscles
Splenius Capitis Splenius Cervicis
Trapezius Insertion
Sup. fibers- Lateral 1/3 of the clavicle Mid. fibers- Spine and acromion of the scapula Inf. fibers- Base of spine of scapula
Trapezius Blood Supply
Superficial branch of the transverse cervical artery
Interspinales Origin
Superiorly on spine of vertebra
Intertransversarii Origin
Superiorly on transverse processes of vertebrae
Semispinalis Thoracis Insertion
Sys of the upper thoracic and lower cervical vertebrae
Longissimus Cervicis Insertion
TP's of C2-C6
Iliocostalis Cervicis Insertion
TP's of the C4, C5, and C6
Longissimus Thoracis Insertion
TP's of the lower nine thoracic vertebrae and the lower nine ribs
Semispinalis Cervicis Origin
TP's of the upper 5 or 6 thoracic vertebrae
Semispinalis Capitis Origin
TP's of the upper 6 or 7 thr=oracic vertebrae
Longissimus Cervicis Origin
TP's of the upper four to six thoracic vertebrae medial to the insertion of the longissimus thoracis
Latissimus Dorsi Blood Supply
The Thoracodorsal artery
Levator Scapulae Blood Supply
The deep branch of the transverse cervical artery
Rhomboideus Major Blood Supply
The deep branch of the transverse cervical artery
Rhomboideus Minor Blood Supply
The deep branch of the transverse cervical artery
Deep Intrinsic Back Muscles
Transversospinalis Group Segmental muscles
Splenius Cervicis Action
Unilaterally: Draws head to one side and slightly rotates Bilaterally: Extends head
Splenius Capitis Action
Unilaterally: Rotation of head and neck Bilaterally: Extension of head and neck
Iliocostalis Thoracis Origin
Upper borders of lower six ribs medial to insertions of iliocostalis lumborum
Iliocostalis Thoracis Insertion
Upper six ribs and sometimes the TP's of C7
Iliocostalis Cervicis Origin
Upper six ribs medial to the insertion of iliocostalis thoracis
Serratus Anterior Action
Upward rotation and protraction of the scapula, raises ribs if scapula is fixed
Levator Scapulae Innervation
Ventral rami of C3 and C4 from deep branches of the cervical plexus, twig from the dorsal scapular nerve