superficial and deep muscles of the back

Splenius Capitis Origin

Lower half of nucheal ligament, spinous processes of C7-T4

Splenius Capitis Insertion

Occipital bone (lateral superior nuchal line, mastoid process of temporal bone.

splenius capitis action

extends the craniocervical region, Unilateral: ipsilateral axial rotation and lateral flexion of the head and cervicle spine.

splenius capitus innervation

Dorsal Rami of spinal nerves

splenius cervicis origin

Spinous processes of T3-T6

splenius cervicis insertion

transverse processes of C1-C3

splenius cervicis action

Bilateral: extends the craniocervical region, Unilateral: ipsilateral axial rotation and lateral flexion of the head and cervical spine. (same as splenius capitis)

Superficial Layer of the deep back: Splenius Muscles:

Splenius Capitus and Spenius Cervicis

Intermediate layer of the deep back muscles: Erector Spinea Group

Iliocostalis, Longissimus, Spinalis (I like Spaghetti- lateral to medial)

iliocostalis origin

Common tendon attachment and angle of ribs 3-12

iliocostalis insertion

cervical transverse processes of c4-c6 and angles of ribs

iliocostalis action All erector Spinea Muscles have the same bilateral actions:

Bilateral: extend the spine and tilt the pelvis anteriorly, Unilateral: iliocostalis cause ipsilateral flexion of the axial skeleton.

iliocostalis innervation

dorsal rami of spinal nerves

longissimus origin

common tendon attatchment, transverse processes of T1-T5, articular processes of C4-C7

longissimus insertion

posterial lateral ribs 3-12, transverse processes of thoracic and cervical vertebrae, mastoid process of the temporal bone

longissimus action, All erector Spinea Muscles have the same bilateral actions:

Bilateral: extend the spine and tilt the pelvis anteriorly, Unilateral: iliocostalis cause ipsilateral flexion of the axial skeleton.

longissimus innervation

dorsal rami of spinal nerves

spinalis origin

common tendon attachment, ligamentum nuchae, and spinous process of C7-T1

spinalis action, All erector Spinea Muscles have the same bilateral actions:

Bilateral: extend the spine and tilt the pelvis anteriorly, Unilateral: iliocostalis cause ipsilateral flexion of the axial skeleton.

spinalis innervation

dorsal rami

Deep Layer: Transversospinalis Group

Semispinalis, multifidus, rotators

semispinalis origin

Transverse processes of C4-T12

semispinalis insertion

Semispinalis Cervisis: spinous process from C2-T4, Capitis: attaches to skull

semispinalis action

powerful extension of the craniocervicle region

semispinalis innervation

dorsal rami of spinal nerves

multifidus origin

present for C2-Sacrum between the transverse and spinous processes of adjacent vertebrae.

multifidus insertion

present for C2-Sacrum between the transverse and spinous processes of adjacent vertebrae.

multifidus action

Bilateral: extend the axial skeleton and cause an anterior pelvic tilt, Unilateral: contralateral rotation of the spine

multifidus innervation

Dorsal rami of spinal nerves

rotatores (longi and brevi) origin

present from T1-T12 between the transverse and spinous processes of adjacent vertebrae

Rotatores longi and brevi Insertion

present from T1-T12 between the transverse and spinous processes of adjacent vertebrae

rotatores innervation

Dorsal rami of spinal nerves

Deep Layer: Suboccipital Muscles

Rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis superior, obliquus capitis inferior.

rectus capitis posterior major origin

spinous process of axis (C2)

rectus capitis major insertion

occipital bone (inferior nuchal line, lateral to the rectus capitis posterior minor)

rectus capitis posterior major action:

Bilateral: extension of AOJ and AAJ, Unilateral: Lateral flexion about AOJ, ipsilateral rotation of AAJ

rectus capitis posterior major innervation

suboccipital nerve, dorsal ramus of C1

rectus capitis posterior minor origin

posterior tubercle of C1 (atlas)

rectus capitis posterior minor insertion

occipital bone (anterior to inferior nuchael line, medial to rectus capitis posterior major)

rectus capitis posterior minor action

Bilateral: extends AOJ, Unilateral: lateral flexion of AOJ

rectus capitis posterior minor innervation

suboccipital nerve, dorsal ramus of C1

obliquus capitis superior origin

transverse process of atlas (C1)

obliquus capitis superior insertion

occipital bone inferior to nuchal lines, superior to rectus capitis posterior major

obliquus capitis superior action

Bilateral: extension of AOJ, Unilateral: Lateral Flexion of AOJ

obliquus capitis superior innervation

suboccipital nerve, dorsal ramus of C1

obliquus capitis inferior origin

spinous process of axis (C2)

obliquus capitis inferior insertion

Transverse process of C1

obliquus capitis inferior action

Bilateral: extension of AAJ, Unilateral: ipsilateral rotation of the AAJ

obliquus capitis inferior innervation

suboccipital nerve, dorsal ramus of C1

AAJ and AOJ

Atlanto Axial Joint, Atlanto Occipital Joint

Trapezius origin

Medial aspect of superior nuchal line and external occipital protuberance, ligamentum nuchae, spinous processes of C7-T12 vertebrae

trapezius insertion

Posterior-superior edge of the lateral third of the clavicle; acromion and spine of the scapula

Trapezius Action

Upper part: elevates and retracts scapula, causes ipsilateral side-bending of the head (lateral flexion) and contralateral rotation, Middle part: retracts scapula (prime mover for this action), Lower part: depresses and retracts scapula Lower and upper parts: upwardly rotate the scapula

Trapezius Innervation

Accessory nerve

latissimus dorsi origin

Spinous processes of (T6) T7-T12 and thoracolumbar fascia, crest of the ilium, median sacral crest, ribs 9-12, thoracolumbar fascia, inferior angle of the scapula (variable)

latissimus dorsi insertion

Floor of the intertubercular (bicipital) groove of the humerus

latissimus dorsi action

Causes depression at the

scapulothoracic joint by pulling the humerus and

scapula inferiorly. Actions on the UE will be discussed later

latissimus dorsi innervation

Thoracodorsal nerve

(a.k.a. Middle subscapular nerve) (C6- C8)

rhomboid major and minor origin

Ligamentum nuchae, Spinous processes of C7-T4 (T5)

rhomboid major and minor insertion

Medial border of the scapula

rhomboid major and minor action

Retracts and downwardly rotates, and elevates the scapula

rhomboid major and minor innervation /Dorsal scapular nerve (C4-C5)

levator scapulae origin

Transverse processes of C1-C4 vertebrae

levator scapulae insertion

Superior angle and upper part of medial border of scapula

upper part of medial border of scapula

levator scapulae action

Elevates and downwardly rotates scapula, causes

ipsilateral side-bending

(lateral flexion) of the

neck

rotates scapula, causes ipsilateral side-bending (lateral flexion) of the neck

levator scapulae innervation

Dorsal scapular nerve (C4-C5)