Nerve: Spinal accessory nerve (IX) and twigs from C3 and C4

Origin: External occipital protuberance, superior nuchal line, ligamentum nuchae, spinous processes of C7-T12

Insertion: Anterior border of spine of scapula, acromion and lateral 1/3 of posterior border of clavicle

Action: adducts and rotates scapula; upper part elevates scapula; lower part depresses scapula

Nerve: Thoracodorsal nerve

Origin: Spinous processes of T6-T12, thoracolumbar fascia, crest of ilium and lower 3 or 4 ribs

Insertion: Floor of intertubercular groove of humerus

Action: Extends & adducts arm; rotates arm medially

Nerve: Nerve to levator scapulae

Origin: Transverse process of C1-C4

Insertion: Posterior lip of medial border of scapula

Action: Elevates scapula and inclines head laterally

Nerve: Dorsal scapular nerve

Origin: Spinous processes of T2-T5

Insertion: Posterior lip of medial border of scapula

Action: Adducts scapula

Nerve: Dorsal scapular nerve

Origin: Spinous processes of C7-T1

Insertion: Root of spine of scapula

Action: Adducts scapula

Nerve: Intercostal nerves T2-T5

Origin: Ligamentum nuchae and spinous processes of C7-T3

Insertion: Superior border of ribs 2-4

Action: Elevate ribs (proprioceptive?)

Nerve: Intercostal nerves T9-T12

Origin: Spinous processes of T11-L2

Insertion: Inferior border of ribs 8-12

Action: Depress ribs (proprioceptive?)

Nerve: segmentally by dorsal rami of spinal nerves

Origin: Broad tendon from iliac crest, sacrum and lumbar spinous processes

Insertion: Angle of ribs and cervical transverse processes

Action: Unilaterally - lateral flexion of vertebral column; Bilaterally - extend vertebral column

Nerve: Segmentally by dorsal rami of spinal nerves

Origin: Broad tendon from iliac crest, sacrum and lumbar spinous processes

Insertion: Posterior medial aspects of ribs and transverse processes of thoracic and cervical vertebrae

Action: Unilaterally - lateral flexion of vertebral column; Bilaterally - extend vertebral column

Nerve: Segmentally by dorsal rami of spinal nerves

Origin: Spinous processes from lower thoracic and lumbar vertebrae

Insertion: Spinous processes on upper thoracic and cervical vertebrae

Action: Unilaterally - lateral flexion of vertebral column; Bilaterally - extend vertebral column

Nerve: Segmentally by dorsal rami of spinal nerves

Origin: Ligamentum nuchae and spinal processes of C7-T3

Insertion: Mastoid process of temporal bone and superior nuchal line of occiput

Action: Laterally flex/rotate head

Nerve: Segmentally by dorsal rami of spinal nerves

Origin: Spinal processes of T2-T6

Insertion: Transverse processes of C1-C3

Action: Laterally flex/rotate neck

Nerve: Segmentally by dorsal rami of spinal nerves

Origin: Transverse processes of C4-T12

Insertion: Superior nuchal line of occiput

Action: Extend head and neck

Nerve: Suboccipital (Dorsal ramus C1)

Origin: Spinous process of C2

Insertion: Lateral inferior nuchal line of occiput

Action: Extend and rotate head

Nerve: Suboccipital (Dorsal ramus C1)

Origin: Posterior tubercle of C1

Insertion: Medial inferior nuchal line of occiput

Action: Extend and rotate head

Nerve: Suboccipital (Dorsal ramus C1)

Origin: Transverse process of C1

Insertion: Occiput between nuchal lines

Action: Extend and rotate head

Nerve: Suboccipital (Doral ramus C1)

Origin: Posterior tubercle of C2

Insertion: Transverse process of C1

Action: Rotate neck