Muscles of the Superficial Back

Question 1

Trapezius

Answer 1

origin: external occipital protuberance of the skull, C1-T12 spinous processes
insertion: medial margins of the clavicle (upper fibers), acromion (middle fibers), scapular spine (lower fibers)
innervation: subtrapezial nerve plexus (CN XI2 and C3 and C4 ventral rami)
action: elevation, depression, retraction and superior rotation of the scapula

Question 2

Levetator Scapulae

Answer 2

origin: : C1-C4 transverse processes
insertion: medial border of scapula (above spine)
innervation: dorsal scapular nerve ( also 3rd and 4th cervical spinal nerves)
action: elevation and inferior rotation of the scapula

Question 3

Rhomboid Minor

Answer 3

origin: spinous processes of C7 and T1
insertion: medial border of the scapula (at the spine)
innervation: dorsal scapular nerve
action: retraction and inferior rotation of the scapula

Question 4

Rhomboid Major

Answer 4

origin: spinous processes of T2-T5
insertion: medial border of the scapula ( below the spine)
innervation: dorsal scapular nerve
action: retraction and inferior rotation of the scapula

Question 5

Latissimus Dorsi

Answer 5

origin: spinous processes of T6 to L5, iliac cres, thoracolumbar fascia
insertion: intertubercular groove of Humerus
innervation: Thoracodorsal nerve
action: extension, adduction and medial rotation of the arm