MOINA of Shoulders and Arms

Question 1

Pectoralis Major

Answer 1

Origin: Clavicle, sternum, and upper six costal cartilages
Insertion: Lateral lip of bicipital groove of humerus
Nerve: Medial and lateral pectoral nerves from brachial plexus
Action: Adducts arm and rotates it medially; clavicular fibers also flex arm

Question 2

Pectoralis Minor

Answer 2

Origin: third, fourth, and fifth ribs
Insertion: coracoid process of scapula
Nerve: medial pectoral nerve from brachial plexus
Action: depresses point of shoulder; if the scapula is fixed, it elevates the ribs or origin

Question 3

Subclavius

Answer 3

Origin: First costal cartilage
Insertion: Clavicle
Nerve: Nerve to subclavius from upper trunk of brachial plexus
Action: depresses the clavicle and steadies this bone during movements of the shoulder girdle

Question 4

Serratus Anterior

Answer 4

Origin: upper eight ribs
Insertion: medial border and inferior angle of scapula
Nerve: long thoracic nerve
Action: draws the scapula forward around the thoracic wall; rotates scapula

Question 5

Trapezius

Answer 5

Origin: occipital bone, ligamentum nuchae, spine of seventh vertical vertebra, spines of all thoracic vertebrae
Insertion: upper fibers into lateral third of clavicle; middle and lower fibers into acromion and spine of scapula
Nerve: spinal part of accessory nerve (motor) and C3 and 4 (sensory)
Action: upper fibers elevate the scapula; middle fibers pull scapula medially; lower fibers pull medial border of scapula downward

Question 6

Latissimus Dorsi

Answer 6

Origin: iliac crest, lumbar fascia, spines of lower six cervical vertebrae, lower three or four ribs, and inferior angle of scapula
Insertion: floor of bicipital groove of humerus
Nerve: Thoracodorsal nerve
Action: Extends, adducts, and medially rotates the arm

Question 7

Levator Scapulae

Answer 7

Origin: transverse processes of first four cervical vertebrae
Insertion: medial border of scapula
Nerve: C3 and 4 and dorsal scapular nerve
Action: raises medial border of scapula

Question 8

Rhomboid Minor

Answer 8

Origin: ligamentum nuchae and spines of seventh cervical and first thoracic vertebrae
Insertion: medial border of scapula
Nerve: dorsal scapular nerve
Action: Raises medial border of scapula upward and medially

Question 9

Rhomboid Major

Answer 9

Origin: second to fifth thoracic spines
Insertion: medial border of scapula
Nerve: dorsal scapular nerve
Action: Raises medial border of scapula upward and medially

Question 10

Muscle: Deltoid

Answer 10

Origin: lateral third of clavicle, acromion, spine of scapula
Insertion: middle of lateral surface of shaft of humerus
Nerve: Axillary nerve
Action: Abducts arm; anterior fibers flex and medially rotate arm; posterior fibers extend and laterally rotate arm

Question 11

Supraspinatus

Answer 11

Origin: supraspinous fossa of scapula
Insertion: greater tuberosity of humerus; capsule of shoulder joint
Nerve: suprascapular nerve
Action: abducts arm and stabilizes shoulder joint

Question 12

Infraspinatus

Answer 12

Origin: infraspinous fossa of maxilla
Insertion: greater tuberosity of humerus; capsule of shoulder joint
Nerve: suprascapular nerve
Action: laterally rotates arm and stabilizes shoulder joint

Question 13

Teres Major

Answer 13

Origin: lower third of lateral border of scapula
Insertion: medial lip of bicipital groove of humerus
Nerve: lower suprascapular nerve
Action: medially rotates and adducts arm and stabilizes shoulder joint

Question 14

Teres Minor

Answer 14

Origin: upper two thirds of lateral border of scapula
Insertion: greater tuberosity of humerus; capsule of shoulder joint
Nerve: axillary nerve
Action: laterally rotates arm and stabilizes shoulder joint

Question 15

Subscapularis

Answer 15

Origin: Subscapular Fossa
Insertion: lesser tuberosity of humerus
Nerve: upper and lower subscapular nerves
Action: medially rotates arm and stabilizes shoulder joint

Question 16

Long Head

Answer 16

Origin: supraglenoid tubercle of scapula
Insertion: tuberosity of radius and bicipital aponeurosis into deep fascia of forearm
Nerve: Musculocuteneous nerve
Action: supinator of forearm and flexor of elbow joint; weak flexor of shoulder joint

Question 17

Short Head

Answer 17

Origin: Coracoid Process of Scapula
Insertion: tuberosity of radius and bicipital aponeurosis into deep fascia of forearm
Nerve: Musculocutaneous nerve
Action: Supinator of forearm and flexor of elbow joint; weak flexor of shoulder joint

Question 18

Coracobrachialis

Answer 18

Origin: coracoid process of scapula
Insertion: medial aspect of shaft and humerus
Nerve: Musculocuteneous nerve
Action: flexes arm and also process of weak adductor

Question 19

Brachialis

Answer 19

Origin: front of lower half of humerus
Insertion: coronoid process of ulna
Nerve: Musculocuteneous nerve
Action: flexor of elbow joint

Question 20

Long Head

Answer 20

Origin: Infraglenoid tubercle of scapula
Insertion: Olecranon process of ulna
Nerve: Radial Nerve
Action: Extensor of elbow joint

Question 21

Lateral Head

Answer 21

Origin: upper half of posterior surface of shaft of humerus
Insertion: olecranon process of ulna
Nerve: radial nerve
Action: extensor of elbow joint

Question 22

Medial Head

Answer 22

Origin: Lower half of posterior surface of shaft of humerus
Insertion: Olecranon process of ulna
Nerve: Radial nerve
Action: Extensor of elbow joint