Large Animal Thoracic Limb - Muscles

Question 1

In the horse there is an additional pectoral muscle called the ________ muscle that is considered a component of the deep pectoral musculature.

Answer 1

Subclavius

(Note: this muscle is limited in the ox, which explains the abrupt transition of neck to shoulder in the ruminants compared to a more gradual transition in horses.)

Question 2

What muscle(s) insert(s) on the accessory carpal bone ? (in canine as well)

Answer 2

Ulnaris lateralis & Flexor carpi ulnaris

Question 3

What muscle inserts on the flexor surface of the distal phalanx (coffin bone)?

Answer 3

Deep digital flexor

Question 4

What muscle inserts on the extensor process of the distal phalanx (coffin bone)?

Answer 4

Common digital extensor

Question 5

In the horse, the cleidocephalicus muscle has one part. What is the name of this part ?

Answer 5

Cleidomastoideus muscle

Question 6

In the ox and goat, the cleidocephalicus muscle has 2 parts. Name these two muscle parts.

Answer 6

Cleido-occipitalis and cleidomatoideus

(Note: This muscle forms the dorsal boundary of the jugular groove.)

Question 7

True or False

There is no real significancant difference of the rhomboideus muscle (between canine and large animals) with the exception of Zebu (a.k.a., Braham) cattle, where this muscle is a major contributor to the hump.

Answer 7

True

Question 8

What muscle is this ?

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 (highest part of the horses back).

Answer 8

Serratus ventralis

Question 9

True or False

Unlike the canine there is no acromial vs. scapular parts of the deltoideus in the horse.

Answer 9

True

Question 10

What is this?

A tendinous structure that is prominent in horses, and present though substantially weaker in ruminants. This tendinous structure extends from the biceps brachii m. to the extensor carpi radialis m. and is a component of the passive stay apparatus of the forelimb in the horse.

Answer 10

Lacertus fibrosus

(long tendon of the biceps brachii m.)

Question 11

The tendon of this muscle passes over the tendon of the extensor carpi radialis muscle in horses.

Answer 11

extensor carpi obliquus m.

(don’t need to know)

Question 12

What muscle is this?

In quadripeds, the insertion [of this muscle] is moved caudally so it is a flexor.

Answer 12

ulnaris lateralis

(Note: This makes it the only flexor innervated by the radial nerve) [don’t need to know]

Question 13

What ligament is this?

In the horse, there is an accessory ligament of the superficial digital flexor; extending from the radius to the tendon of the superficial digital flexor. This ligament is a component of the passive stay apparatus.

Answer 13

Proximal check ligament

(aka. accessory tendon/ ligament of the superficial digital flexor m.)

Question 14

What ligament is this?

In the horse, there is an accessory ligament of the deep digital flexor; extending from MC III to the tendon of the deep digital flexor. This ligament is a component of the passive stay apparatus.

Answer 14

Distal check ligament

(aka. accessory tendon/ ligament of the deep digital flexor m.)

Question 15

True or False

In the horse, there are two interossei and it is entirely tendinous.

Answer 15

False

There is only ONE interosseus in the horses

Question 16

In the horse, the interosseus is commonly called the ___________ ___________, and just as in the dog, the interosseus tendon bifurcates and there are two proximal sesamoid bones enveloped in these tendons at the region of the ______ aspect of the metacarpophalangeal joint.

Answer 16

suspensory ligment; palmar

Question 17

There are medial and lateral ________ ________ of the interosseus that obliquely cross the sides of the _____ pastern bone and extend to the ______ surface to unite with the tendon of the common digital extensor m.

Answer 17

extensor branches; long; dorsal

Question 18

What are the names if the three pairs of sesamoidean ligaments ?

Answer 18

straight, oblique, and cruciate.

Question 19

Additionally, the ________ _________ ligaments bind the proximal sesamoids to the distal end of the cannon bone (metacarpophalangeal joint region)

Answer 19

collateral sesamoidean [ligaments]