Thoracic Comparisons

Question 1

Deep pectoral - dog vs. horse

Answer 1

horse has an additional pectoral muscle, SUBCLAVIUS MUSCLE, that is considered a component of the deep pectoral musculature

Question 2

Brachiocephalicus - horse - ox and goat

Answer 2

Horse: cleidocephalicus has only one part - cleidomastoideus

Ox and goat: Cleidocephalicus has 2 parts - cleidooccipitalis and cleidomatoideus

this muscle forms the dorsal boundary of the jugular groove

Question 3

Rhomboideus

Answer 3

no real significance with the exception of zebu cattle, where this muscle is a major contributor to the hump

Question 4

Serratus Ventralis

Answer 4

large and strong, but if damaged, support of the forelimb is lost

Myopathy and muscle damage results in “flying scapula” in ruminants (and potentially horses) where the dorsal border of the scapula rises above the withers

Question 5

Deltoideus

Answer 5

not divided in the horse, as the horse lack an acromion; therefore, no acromial vs. scapular parts of the deltoids in the horse

Question 6

Biceps Brachii

Answer 6

Lacertus Fibrosus - (long tendon of biceps brachia) is a tendinous structure that is prominent in horses and present though substantially weaker in ruminants . This tendinous structure extends from the biceps brachia to the extensor carpi radials and is a component of the passive stay apparatus of the forelimb in the horse

Question 7

Extensor carpi radialis

Answer 7

in the horse, the tendon of this muscle passing over the tendon of the extensor carpi radialis

Question 8

superficial digital flexor

Answer 8

accessory ligament of the superficial digital flexor (proximal check ligament) extending from the radius to the tendon of the superficial digital flexor - ligament is a component of the passive stay apparatus

Question 9

Deep digital Flexor

Answer 9

accessory ligament of the deep digital flexor (distal check ligament) extending from MC III to the tendon of the deep digital flexor (stay apparatus)

Question 10

Interosseus

Answer 10

Horse: Suspensory ligament, similar to the dog, the interosseus tendon bifurcates and there are two proximal sesamoid bones enveloped in these tendons at the region of the palmar aspect of the metacrarpophalangeal joint.

Medial and lateral extensor branches of the interossues - obliquely cross the sides of the long pattern bone and extend to the dorsal surface to unite with the tendon of the common digital extensor

there are three pairs of sesamoidean ligaments: straight, oblique and cruciate

collateral sesamoidean ligaments bind the proximal sesamoids to the distal end of the cannon bone