Intrinsic Muscles of the thoracic limb

Question 1

Deltoideus m.

Answer 1

origin:
Scapular head - spine of the scapula
acromial head - acromion

insertion: deltoid tuberosity of the humerus
action: flex the shoulder joint

Question 2

infraspinatous m.

Answer 2

origin: infraspinous fossa of the scapula
insertion: lateral side of the greater tubercle of the humerus
action: extend or flex the shoulder joint depending on the position of the limb

Question 3

teres minor m.

Answer 3

origin: infraglenoid tubercle and distal third of caudal border of the scapula
insertion: teres minor tuberosity of the humerus
action: flex the shoulder joint, rotate the shoulder laterally, prevent medial rotation when bearing weight

Question 4

supraspinatous m.

Answer 4

origin: supraspinous fossa of the scapula
insertion: greater tubercle of the humerus
action: extend and stabilize the shoulder joint

Question 5

subscapularis m.

Answer 5

origin: subscapular fossa of the scapula
insertion: lesser tubercle of the humerus
action: adduct, extend and medially stabilize the shoulder joint, flex shoulder joint, rotate shoulder medially

Question 6

teres major m.

Answer 6

origin: caudal angle and caudal border of the scapula, caudal surface of the subscapularis m.
insertion: teres major tuberosity of the humerus
action: flex the shoulder joint, rotate the shoulder medially

Question 7

coracobraciallis m.

Answer 7

origin: coracoid process of the scapula
insertion: crest of the lesser tubercle of the humerus
action: adduct, extend and stabilize the shoulder joint

Question 8

tensor fasciae antebrachii m.

Answer 8

origin: fascia covering the lateral side of latissimus dorsi m.
insertion: olecranon
action: extend the elbow

Question 9

Triceps brachii m.

Answer 9

origin: long head: caudal border of the scapula
lateral head: tricipital line
accessory head: neck of humerus
medial head: crest of lesser tubercle

insertion: olecranon
action: Long head: flex the shoulder joint and extend the elbow. Lateral, accessory, medical heads: extend the elbow

Question 10

anconeus m.

Answer 10

origin: lateral supracondylar crest of the humerus, lateral and medial epicondyles of the humerus
insertion: lateral surface of the proximal end of the ulna
action: extend the elbow

Question 11

biceps brachii m.

Answer 11

origin: supraglenoid tubercle of the scapula
insertion: ulnar and radial tuberosities (dog) radial tuberosity (cat)
action: extend the shoulder joint, flex the elbow

Question 12

brachiallis m.

Answer 12

origin: proximal third of the lateral surface of the humerus
insertion: ulnar and radial tuberosities (dog) ulnar tuberosity (cat)
action: flex the elbow