VMED 5163 - Comparative Osteology and Support Structures - Thoracic Limb

Dorsal scapular cartilage

In ungulates, the dorsal portion of the scapula may be covered by a roughened area which is known as the?

Most other ungulates have an acromion, a protrusion at the distal end of the spine; horses do not have this

What is a major difference between the scapula of the horse and the scapula other ungulates?

Tuber spinae

Which structure is present only in animals lacking an acromion?

This angle defines the reach of the limbs during movement

Why is the slope of the scapula important in horses?

Intermediate tubercle

The specialized structure seen in the humerus of the horse is the ____

Cranial part of greater tubercle of the humerus

Which palpable bony prominence is known as the point of the shoulder?

Even

Artiodactyls bear weight on an (even/odd) number of toes

Perissodactyls

Ungulates which bear weight on an odd number of toes are referred to as?

Unlike in carnivores, the ulna is fused with the radius to varying degrees in ungulates

In terms of bones, what is the major difference between the antebrachium of carnivores and ungulates?

As the lateral styloid process

Because of the difference in confirmation in horses, the styloid process of the ulna should be referred to how?

Rotation of the limb via supination and pronation are not possible

What effect does the fusion of the radius and ulna have on movement in ungulates?

Digit III

Which digit does a horse bear weight on?

Digits III and IV

Which digits do artiodactyl ungulates bear weight on?

Accessory, ulnar, intermediate, radial

Name the proximal row of carpal bones from lateral to medial

The distal row of carpal bones; numbered medial to lateral

Which row of carpal bones is numbered? How are they numbered?

Carpal bone I

Which carpal bone is present as a normal variation in some horses?

In ruminant species, carpal bones II and III are fused, unlike in horses

What major difference between the cow and the horse is seen in the carpal bones?

Metacarpals II, III, and IV

What metacarpal bones are present in the horse?

Metacarpal bones II and IV in the horse; fused to the caudal portion of the cannon bone

Which bones are known as "splint" bones? Where are they located?

Metacarpals III and IV (fused), and V

In ruminants, which metacarpal bones are present?

Palpable prominences at the distal end of splint bones

What are 'buttons' in horses?

More common medially on metacarpal II due to high pressure during movement; the carpal bone above rests solely on the splint bone, unlike on the lateral side

Popped splint lesions are more common on which splint bone? Why is this?

Long pastern

The proximal phalanx is more commonly known as the ___ in horses

Articulation between the cannon bone and long pastern; also known as the metacarpophalangeal joint

The fetlock joint is formed by the articulation of which bones? What is this joint also called?

On the palmar surface of the fetlock

Where are the proximal sesamoid bones located?

The middle phalanx, or P2

Which bone is commonly known as the short pastern?

Distal phalanx, coffin bone

The ___ phalanx, or ___ bone, is embedded within the hoof

Navicular bone

The distal sesamoid bone tends to be an area of issue in horses. What other name is this bone known by?

Short pastern, coffin bone, and navicular bone

The distal interphalangeal joint joins which bones?

Digits II and V; known as dewclaws

Which digits may be present in ruminants, but non-weight-bearing? What are these digits typically known as?

Tendon of infraspinatus m. and tendon of subscapularis m.

The shoulder joint is supported by which structures?

Lateral and medial collateral ligaments; located caudal to the center of rotation

What are the ligaments associated with the elbow? Where are they located?

Radiocarpal, midcarpal, and carpometacarpal joints

Which joints are located within and around the carpus?

Carpometacarpal joint

At which carpal joint is there little to no movement?

At the radoiocarpal joint

The majority of the movement of the carpus occurs where?

The palmar carpal ligament and proximal and distal check ligaments

The carpus is supported by what main structures?

Lateral and medial collateral ligaments

Which ligaments are located at the fetlock joint?

Pastern joint, or proximal interphalangeal joint

The articulation between the long and short pastern bones is known as the ___ (2 names)

Downward energy generated during movement is stored and transmitted up during a swing phase

Describe the spring response of the equine thoracic limb

Suspensory ligament, proximal sesamoids, and distal sesamoidean ligaments

The suspensory apparatus of the pastern joint consists of what structures?

Suspensory ligament

In horses, the interosseous muscle is more commonly known as the?

Intersesamoidean ligament

The distal sesamoidean ligament located between the proximal sesamoids is known as the?

Oblique sesamoidean ligaments

The straight sesamoidean ligament is surrounded by two ___

On the palmar aspect of the pastern joint

Where are the cruciate sesamoidean ligaments located?

Annular ligaments

The ligament which wraps around the palmar surface of the fetlock and proximal sesamoids is a part of this group

A ruminant; there is an acromion present

Which large animal does this scapula most likely belong to? Why?

A horse

What animal would this bone belong to?

Suspensory apparatus of the fetlock

The image represents what structure of the equine forelimb?