A&p Lab Test 2

Front 1

trapezius

Back 1

origin - occipital bone (protuberance)

insertion - clavicle

function - raises or lowers shoulders and shrugs them

nerve supply - spinal accessory; second, third and fourth cervical nerves

Front 2

rhomboid major

Back 2

origin - T1-T4

insertion - scapula (medial border)

function - retracts, rotates, and fixes the scapula

nerve supply - dorsal scapular nerve

Front 3

rhomboid minor

Back 3

origin - C6-C7

insertion - scapula (medial border)

function - retracts, rotates, elevates and fixes the scapula

nerve supply - dorsal scapular nerve

Front 4

latissimus dorsi

Back 4

origin - vertebrae (spines of the lower thoracic, lumbar and sacral), ilium (crest), lumbodorsal fascia

insertion - humerus (intertubercular groove)

function - extends the arm and adducts the arm posteriorly

nerve supply - thoracodorsal nerve

Front 5

teres major

Back 5

origin - scapula (lower part, axillary border)

insertion - humerus (upper part, anterior surface)

function - assists in extension, adduction, and medial rotation of the arm

nerve supply - lower subscapular nerve

Front 6

teres minor

Back 6

origin - scapula (axillary border)

insertion - humerus (greater tubercle)

function - rotates the arm outward

nerve supply - suprascapular nerve

Front 7

biceps brachii

Back 7

origin - scapula (supraglenoid tuberosity, coracoid)

insertion - radius (tuberosity at the proximal end)

function - flexes the supinated forearm, supinates the forearm and hand

nerve supply - musculocutaneous nerve

Front 8

triceps brachii

Back 8

origin - scapula (infraglenoid tuberosity), humerus (posterior surface - lateral head above the radial groove; medial head, below)

insertion - ulna (olecranon)

function - extends the lower arm

nerve supply - radial nerve

Front 9

sternocleidomastoid

Back 9

origin - sternum, clavicle

insertion - temporal bone (mastoid process)

function - flexes head and neck, one muscle alone, rotates head toward opposite side; spasm of this muscle alone or associated with trapezius called torticollis, or wryneck

nerve supply - accessory nerve

Front 10

deltoid

Back 10

origin - clavicle, scapula (spine and acromion)

insertion - humerus (lateral side about halfway down - deltoid tubercle)

function - abducts the arm, assists in flexion and extension of the arm

nerve supply - axillary nerve