Intrinsic Muscles of the Canine Thoracic Limb-Proximal

Question 1

Deltoideus

Answer 1

O: spine and acromial process of the scapula
I: deltoid tuberosity of the humerus
A: flex shoulder

Question 2

Infraspinatus

Answer 2

O: infraspinous fossa of the scapula
I: lateral side of the greater tubercle of the humerus
A: laterally stabilizes shoulder, abduct and laterally rotate the shoulder, assist in extension and flexion of shoulder

Question 3

Teres Minor

Answer 3

O: infraglenoid tubercle of the scapula, distal caudal border of the scapula
I: teres minor tuberosity of the humerus
A: laterally stabilizes and rotates the shoulder, flex the shoulder

Question 4

Supraspinatus

Answer 4

O: supraspinatus fossa of the scapula
I: greater tubercle of the humerus
A: laterally stabilizes shoulder, extend the shoulder

Question 5

subscapularis

Answer 5

O: subscapular fossa of the scapula
I: lesser tubercle of the humerus
A: medially stabilizes the shoulder, adduct and extend the shoulder

Question 6

Teres Major

Answer 6

O: caudal angle and caudal border of the scapula, subscapularis muscle
I: teres major tuberosity of the humerus
A: flex shoulder and rotate arm medially

Question 7

Coracobrachialis

Answer 7

O: coracoid process of the scapula
I: crest of the lesser tubercle of the humerus near teres major tuberosity
A: mainly a shoulder stabilizer, can assist in adduction and/or extension of shoulder

Question 8

Tensor Fasciae antebrachii

Answer 8

O: fascia covering the lateral surface of the latissimus dorsi muscle
I: olecranon of the ulna
A: extend elbow

Question 9

Triceps Brachii

Answer 9

O: caudal border of the scapula (long); tricipital line (lateral), neck of the humerus (accessory), crest of lesser tubercle (medial)
I: olecranon of ulna
A: flex shoulder (long) extend the elbow (all heads)

Note: muscle has four heads: long, lateral, medial, and accessory

Question 10

Anconeus

Answer 10

O: lateral supracondylar crest of the humerus, lateral and medial epicondyles of the humerus
I: proximal and lateral aspect of the ulna
A: extend elbow

Question 11

Biceps Brachii

Answer 11

O: supragleniod tubercle of the scapula
I: radial and ulnar tuberosities
A: extend shoulder and flex elbow

Note: tendon of origin passes through intertubercular groove of the humerus, held in place by transverse humeral retinaculum.
Lacertus Fibrosus in horse extends from biceps branchii to extensor carpi radialis- stay apparatus

Question 12

Brachialis

Answer 12

O: proximal and lateral aspect of the humerus
I: radial and ulnar tuberosities
A: flex elow