Lab 6

Question 1

Pectoralis major

Answer 1

Origin: Clavicular and sternocostal head

Insertion: lateral lip of the bicipital groove on humerus

Innervation: Medial and lateral pectoral nerve

Main actions:
Clavicular head- shoulder flexion from an extended position
Sternal head- shoulder extension from a flexed position

Question 2

Pectoralis Minor

Answer 2

Origin: Anterior and superior surfaces of rib 3, 4 and 5

Insertion: coracoid process of scapula

Innervation: Medial pectoral nerve

Main actions: Protraction of scapula

Question 3

Subclavius

Answer 3

Origin: Rib 1

Insertion: groove on inferior surface of middle 1/3 clavicle

Innervation: nerve to subclavious

Main actions: depresses clavicle when the upper limb is moving

Question 4

Serratus Anterior

Answer 4

Origin: external lateral surfaces of first 8 ribs

Insertion: anterior surface of medial border of scapula

Innervation: long thoracic nerve

Main actions: scapular protraction, scapular upward rotation

Question 5

Trapezius (Clasp)

Answer 5

Origin: external occipital crest, Ligamentum nuchae

Insertion:
Upper- fibres to the posterior clavicle
Middle- fibres run horizontally to the acromion process of scapula
Lower- fibres ascend to the scapular spine

Innervation: Accessory nerve

Main actions:
Upper- scapular elevation and upward rotation
Middle- scapular retraction
Lower- scapular depression and upward rotation

Question 6

Latissumus Dorsi

Answer 6

Origins: Posterior iliac crest, lower 3 or 4 ribs

Insertion: Floor of bicipital groove (under armpit)

Innervation: Thoracodorsal nerve

Main actions: Shoulder medial rotation and shoulder adduction

Question 7

Levator Scapulae

Answer 7

Origin: C1 to C4 transverse process

Insertion: superior portion of medial border of scapula

Innervation: dorsal scapular nerve

Main actions: Scapular elevation

Question 8

Rhomboid Minor (on top of major)

Answer 8

Origin: C7 and T1 spinous process

Insertion: Medial end of scapular spine at medial border of scapula

Innervation: Dorsal scapular nerve (on back)

Main actions: Scapular retraction

Question 9

Rhomboid Major

Answer 9

Origin: T2 to T5 spinous processes

Insertion: Medial border of scapula

Innervation: Dorsal scapular nerve

Main actions: scapular retraction (same as minor)

Question 10

Deltoid (clasp)

Answer 10

Origin:
Anterior portion of lateral 1/3 clavicle
Lateral portion of acromion process
Inferior edge of scapular spine

Insertion: Deltoid tuberosity of humerus

Innervation: Axillary nerve

Main actions: abduction of shoulder

Question 11

Rotator Cuff (SITS)

Answer 11

4 Muscles
Supraspinatus
Infraspinatus
Teres Major

Subscapularis

Question 12

Supraspinatus

Answer 12

Origin: Supraspinous fossa of the scapula

Insertion: superior portion of greater tubercle of humerus

Innervation: Suprascapular nerve

Main actions: Abduction of the shoulder

Question 13

Infraspinatus

Answer 13

Origin: infraspinous fossa of the scapula

Insertion: middle portion of greater tubercle of humerus

Innervation: suprascapular nerve

Main actions: lateral rotation of the shoulder

Question 14

Teres Minor

Answer 14

Origin: mid-portion of lateral border of scapular

Insertion: inferior portion of greater tubercle of humerus

Innervation: axillary nerve

Main action: lateral rotation of the shoulder

Question 15

Subscapularis

Answer 15

Origin: subscapular fossa of the scapula

Insertion: lesser tubercle of the humerus

Innervation: upper and lower subscapular nerve

Main actions: shoulder medial rotation

Question 16

Teres Major

Answer 16

Origin: Posterior surface of inferior angle of scapula

Insertion: Medial lip of bicipital groove

Innervation: lower subscapular nerve

Main actions: Shoulder medial rotation

Question 17

Biceps Brachii

Answer 17

Origins: Long head-supraglenoid tubercle of scapula
Short head- coracoid process of scapula

Insertion: radial tuberosity

Innervation: musculocutaneous nerve

Main actions: radio-ulnar supination

Question 18

Brachialis

Answer 18

Origin: anterior humerus 1/3 down shaft

Insertion: ulnar tuberosity

Innervation: musculocutaneous nerve

Main actions: elbow flexion

Question 19

Coracobrachialis

Answer 19

Origin: coracoid process of scapula

Insertion: medial shaft of humerus

Innervation: musculocutaneous nerve

Main actions: shoulder flexion

Question 20

Triceps brachii (3 heads/origins)

Answer 20

Origins:
Long head- infraglenoid tubercle of the scapula
Lateral head- distal to greater tubercle
Medial head- deep, halfway down the numeral shaft

Insertion: olecranon process of ulna

Innervation: Radial nerve

Main actions: elbow extension

Question 21

Anconeus

Answer 21

Origin: lateral epicondyle of the humerus

Insertion: olecranon process of ulna

Innervation: radial nerve

Main action: elbow extension