Extrinsic Muscles Of The Forelimb

Question 1

Superficial pectoral

Answer 1

Origin: first 2-3 sternobrae and raphe
Insertion: greater tubercle of humerus
Action: adduct limb and prevent abduction

Question 2

Deep pectoral

Answer 2

Origin: sternum, raphe, fascia
Insertion: lesser + greater humerus tubercle
Action: pull trunk cranially + extend shoulder, draw limb caudally + flex shoulder + adduct limb

Question 3

Brachiocephalicus

Answer 3

Origin: clavicular intersection, neck
Insertion: distal end of humerus
Action: advance limb, draw head + neck laterally

Question 4

Omotransversarius

Answer 4

Origin: transverse wing of atlas
Insertion: distal part of spine of scapula
Action: advance limb, flex neck laterally

Question 5

Trapezius

Answer 5

Origin: raphe + supraspinatus ligament
Insertion: spine of scapula
Action: elevate and abduct the forelimb

Question 6

Latissimus dorsi

Answer 6

Origin: ribs
Insertion: teres major tuberosity and tendon
Action: draw free limb caudally - flex shoulder

Question 7

Rhomboideus

Answer 7

Origin: occipital bone, raphe, spinous processes T1-T7
Insertion: dorsal border if scapula
Action: elevate forelimb and draw scapula against trunk

Question 8

Serratus ventralisb

Answer 8

Origin: C3-C7 and T1-T8
Insertion: scapula
Action: support trunk and depress scapula