The Shoulder and Arm (Lecture 8)

Question 1

Serratus Anteriror

Answer 1

Origin: lateral surface of first 8-9 ribs
Insertion: Anterior portion, vertebral (medial) border of the scapula
Action: Protract (abduct) scapula, rotate scapula, hold scapula against thorax
Nerve: Long thoracic nerve
Clinical: Wing Scapula

Question 2

Pectoralis Minor

Answer 2

Origin: Anterior surface of 3rd, 4th, and 5th ribs
Insertion: Coracoid process of scapula
Action: Depresses shoulder while drawing scapula laterally

Question 3

Levator Scapulae

Answer 3

Origin: C1-C4
Insertion: Superior angle (vertebral border) of scapula
Action: Elevate scapula
Nerve: roots C3-C4 and dorsal scapular nerve

Question 4

Rhomboid Minor

Answer 4

Origin: Spines of C7 and T1
Insertion: Vertebral border of scapula
Action: Elevate and adduct scapula
Nerve: Dorsal scapular nerve

Question 5

Pectoralis Major

Answer 5

Origin: clavicle, sternum, costal cartilages, rectus sheath
Insertion: crest, greater tubercle of humerus (lateral lip of bicipital groove)
Action: adduction, flexion, rotation of brachium medially
Nerve: medial and lateral pectoral nerve

Question 6

Latissiumus dorsi

Answer 6

Origin: lumbar aponeurosis (lower thoracic, lumbar, sacral vertebrae)
Insertion: intertubercular groove of humerus
Action: adduction arm downward and backward, medial rotation, extension
Nerve: thoracodorsal nerve

Question 7

Deltoid

Answer 7

Origin: clavicle, acromion, spine of scapula
Insertion: deltoid tuberosity, humerus
Action: middle fibers: abduct brachium, anterior fibers: extend and medially rotate brachium, posterior fibers: flex and laterally rotate brachium
Nerve: axillary nerve

Question 8

Supraspinatus

Answer 8

Rotator cuff tendon
Origin: supraspinous fossa
Insertion: greater tubercle of humerus
Action: lateral rotation humerus, stabilize joint, initiate abduction
Nerve: suprascapular nerve

Question 9

Infraspinatus

Answer 9

Rotator cuff tendon
Origin: infraspinous fossa
Insertion: posterior aspect, greater tubercle of humerus
Action: lateral rotation humerus, stabilize joint
Nerve: suprascapular nerve

Question 10

Teres minor

Answer 10

Rotator cuff tendon
Origin: axillary border, scapula
Insertion: posterior portion, greater tubercle of humerus
Action: rotate brachium laterally
Nerve: axillary nerve

Question 11

Subscapularis

Answer 11

Rotator cuff tendon
Origin: subscapular fossa
Insertion: lesser tubercle of humerus
Action: strong stabilizer of shoulder, medial rotation of brachium 
Nerve: subscapular nerve

Question 12

Teres major

Answer 12

Origin: inferior angle and lateral border of scapula
Insertion: crest of lesser tubercle of humerus (medial lip of bicipital groove)
Action: rotate brachium medially
Nerve: lower subscapular nerve

Question 13

Coracobrachialis

Answer 13

Origin: coracoid process of scapula
Insertion: medial surface of humerus
Action: flexion and adduction arm at shoulder
Nerve: musculocutatenous nerve

Question 14

Biceps brachii

Answer 14

Origin: short head: coracoid process of scapula; Long head: superior glenoid tubercle
Insertion: radial tuberosity and bicipital aponeurosis
Action: flexes forearm; supinates a flexed forearm
Nerve: musculocutaneous

Question 15

Brachialis

Answer 15

Origin: distal anterior half of humerus
Insertion: coronoid process, ulna
Action: flex forearm at elbow
Nerve: musculocutaneous

Question 16

Triceps brachii

Answer 16

Origin: lateral and medial head: posterior aspect of humerus - long head: infraglenoid tubercle of scapula
Insertion: olecranon process of ulna
Action: extend forearm at elbow
Nerve: radial

Question 17

Anconeus

Answer 17

Origin: lateral epicondyle of humerus
Insertion: olecranon process and posterior surface of ulna
Action: extend forearm at elbow
Nerve: radial