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Splenius Insertion
Splenius Capitis: 1) Mastoid process of temporal bone
2) Lateral third of superior nuchal line
Splenius Cervicis: Tubercles of transverse process C1-C3 or C4
Splenius Origin
1) Nuchal Ligament
2) Spinous process C7-T3 or T4
Splenius Innervation
Posterior Rami of Spinal Nerves
Splenius Action
Alone: Laterally flex neck and rotate head to side of acting muscles
Together: Extend head and neck
Illicostalis
Longissimus
Spinalis
Origin
1) Posterior surface of sacrum
2) Sacro-iliac ligaments
3) Posterior part of iliac crest
4) Supraspinous ligament
5) Sacral and inferior lumbar spinous process
Iliacostalis Insertion
(Lumborum, thoracis, cervicis)
1) Lower ribs
2) Cervicle transverse processes
Longissimus Insertion
(Thoracis, cervisis, capitis)
1) Ribs between tubercles
2) Angles to transverse processes in thoracic and cervical regions
3) Mastoid Process
Spinalis Insertion
(Thoracis, cervicis, capitis)
1) Spinous processes in upper thoracic region and to cranium
Semispinalis (Thoracis, cervicis, capitis)
Origin
1) Transverse processes C4-T10
Semispinalis Insertion
1) Occipital bone
2) Spinous processes in upper thoracic and cervical regions, spanning 4-6 segments
Semispinalis Innervation
Posterior Rami of Spinal Nerves
Semispinalis Action
1) Extends head, thoracic, and cervical regions
2) Rotates these contralaterally
Multifidus Origin
1) Posterior surface of sacrum
2) Sacro-iliac ligaments
3) PSIS
4) Aponeurosis of erector spinae
5) Mammillary processes of lumbar vertebrae
6) Transverse processes T1-T3
7) Articular processes C4-C7
Multifidus Insertion
(Thickest in lumbar region)
1) Entire length of of spinous processes of vertebrae, located 2-4 segments superior to origin
Multifidus Innervation
Posterior Rami of Spinal Nerves
Multifidus Action
1) Stabilizes vertebrae during local movements
2) Unilateral contraction rotates to contralateral side
Rotatores (brevis and longus) Origin
1) Transverse processes of vertebrae - best developed in thoracic region
Rotatores Insertion
1) Attach to junction of lamina
2) Transverse or spinous process of vertebrae immediately (brevis) or 2 segments (longus) superior to vertebra of origin
Rotatores Innervation
Posterior Rami of Spinal Nerves
Rotatores Action
1) May function as organs of proprioception
2) Possibly stabilize vertebrae
3) Assist with local extension and rotatory movements of vertebral column
Obliquus capitis superior Origin
1) Transverse process of C1
Obliquus Capitis Superior Insertion
1) Occipital bone between superior and inferior nuchal lines
Obliquus Capitis Superior Innervation
Posterior Rami of C1 (Suboccipital nerve)
Obliquus Capitis Superior Action
Postural muscle act on head directly
Obliquus Capitis Inferior Origin
1) Spinous process of C2
Obliquus Capitis Inferior Insertion
1) Transverse process of C1
Obliquus Capitis Inferior Innervation
Posterior Rami of C1 (Suboccipital nerve)
Obliquus capitis inferior action
1) postural muscle act on head indirectly
Rectus Capitis Posterior Major Origin
1) Spinous process of C2
Rectus Capitis Posterior Major Insertion
1) Lateral part of the inferior nuchal line
Rectus Capitis Inferior Innervation
Posterior Rami of C1 (Suboccipital Nerve)
Rectus Capitis Posterior Major Action
Postural Muscle act on head directly
Rectus Capitis Posterior Minor Origin
1) Posterior tubercle on the posterior arch of C1
Rectus Capitis Posterior Minor Insertion
1) Medial third of inferior nuchal line
Rectus Capitis Posterior Minor Innervation
Posterior Rami of C1 (Suboccipital Nerve)
Rectus Capitis Posterior Minor Action
1) Postural muscle act on head directly
Sternocleidomastoid Origin
1) Lateral surface of mastoid process
2) Lateral half of superior nuchal line
Sternocleidomastoid Insertion
Sternal Head: 1) Anterior surface of manubrium
Clavicular Head: 1) Superior surface of medial third of clavicle
Sternocleidomastoid Innervation
Spinal Accessory Nerve (CN 11), C2, C3
Sternocleidomastoid Action
Unilaterally contraction: Ipsilateral flexion and contralateral rotation
Biaterally: 1) Extends neck at atlanto-occipital joints
2) Flexes cervical vertebrae so that chin approaches manubrium
3) Extends superior cervical vertebrae while flexing inferior vertebrae so chin is thrust forward with head kept level
