Superficial Back Muscles

Trapezius Insertion (3)

1. Lateral 1/3 clavicle 2. acromion 3. scapular spine

Latissimus dorsi Origin (3)

1. spinous processes of T7-L5 2. Sacrum connected by the thoracolumbar facia 3. iliac crest

Origin of Trapezius (4)

1. superior nuchal line (ridge found on posterior aspect of occipital bone) 2. external occipital protuberance (inion) 3. spinous processes C7-T12 4. ligamentum nuchea ( ligament that attaches trapezius to cervical region)

Trapezius Innervation

Cranial nerve XI (Spinal Accessory)

Latissimus dorsi action (3)

Extend, adduct and medially rotate humerus

Latissimus dorsi insertion

Intertubercular sulcus of humerus (on proximal anterior side of humerus)

Intermediate Back Muscle Action

Primarily proprioception (possibly respiratory function as well)

Rhomboid Major Origin

Spinous process T2-T5

Innervation of most deep back muscles

dorsal (posterior) rami of spinal nerves

Innervation of Rhomboids (major and minor) and levator scapulae

dorsal scapular nerve (levator scapulae also innervated with cervical nerves)

Levator scapulae action

elevates scapula

Actions of trapezius (4)

elevation, depression and rotation of scapula and scapular retraction

Deep Back Muscle Action

extend and rotate vertebral column, postural muscles

Rhomboid Minor Insertion

medial scapular border (at spine)

Rhomboid Major Insertion

medial scapular border (inferior to spine)

Levator scapulae insertion

medial scapular border (superior to the spine)

Superficial Back Muscle Action

move upper extremity (scapular and humeral attachments)

Rhomboid Major action

retracts/elevates scapula

Rhomboid minor action

retracts/elevates scapula

Rhomboid Minor Origin

spinous process C7-T1

What other muscle is also innervated with cranial nerve XI?

sternocleidomastoid

Latissimus dorsi innervation

thoracodorsal nerve

Levator scapulae origin

transverse processes C1-C4

Innervation of (most) superficial and intermediate back muscles

ventral (anterior) rami of spinal nerves