Function: lateral rotation of scapula

raises arm from 90 degrees to over the head

innervation: spinal part of accessory nerve (CN XI)

function: elevates the scapula

innervation: dorsal scapular nerve; C5

function: retract and help hold scapula in place

innervation: dorsal scapular nerve; C5

function: primary abductor of arm, raises arm from 10 degrees to 90 degrees

innervation: axillary nerve; C5 & C6

function: abducts arm 5-10 degrees; used to lift heavy weight off floor

innervation: suprascapular nerve; C5 & C6

function: laterally rotates humerus 

innervation: suprascapular nerve; C5 & C6

function: externally/laterally rotates humerus

innervation: axillary nerve; C5 & C6

function: medially/interally rotates the humerus

innervation: upper and lower subscapularis nerves; C5 & C6

function: internal/medial roation of humerus; extends humerus

innervation: lower subscapularis nerve; C5 & C6

function: protracts/holds scapula to the body; elevates the scapula

innervation: long thoracic nerve; C5 C6 C7

function: extends humerus ("swimmer's muscle"); internal/medial rotation of humerus; adducts arm

innervation: thoracodorsal nerve; C5 C6 C7