Equine Carpus

Question 1

What carpal bones make up the proximal row of the carpus?

Answer 1

radial, intermediate, accessary, ulnar

Question 2

What carpal bones make up the proximal row of the carpus?

Answer 2

2,3,4 carpal bones Presence of the 1st (30%) and 5th (2%) carpal bone is variable

Question 3

What are the intercarpal joints?

Answer 3

Vertically oriented joints between the carpal bones

Question 4

When flexed which proximal carpal bone moves distally?

Answer 4

Radial bone—immediate is left high (I is high)

Question 5

What bones do the accessory carpal bone articulate with?

Answer 5

Distal aspect of the radius Ulnar carpal bone

Question 6

Accessary carpal bone can be developed from more than one center of ossification and usually ossifies by what age?

Answer 6

6 months

Question 7

There are common normal variations of what carpal bone?

Answer 7

Ulnar

Question 8

What causes this radiolucency?

Answer 8

Incomplete fusion of the epiphysis of radius and styloid process of the ulnar… normal variant

Question 9

What view is most useful for assessing degree of angular deformity?

Answer 9

Dorsopalmar (extended)

Question 10

What deformity is most frequently observed?

Answer 10

Valgus

Question 11

Fusion of the distal radius and ulnar epiphysis should accord when?

Answer 11

3-6 months

The arrow is pointing to the ulnar epiphysis which is normally no fused in this horse at this age…there is incomplete ossification of the carpal bones in this horse.

Question 12

Where do cyst-like lesions occur in the carpus?

Answer 12

Carpal bones

2nd and 4th prox metacarpal bone

Distal radius

Question 13

What is the most common place to see a cyst-like lesion in the carpus?

Answer 13

Ulnar carpal bone

Question 14

Cyst-like lesions in the ulnar carpal bone (with and without an osseous fragment) have been associated with what?

Answer 14

Avulsion of the lateral palmar intercarpal ligament

Question 15

If cyst-like lesions are seen in a foal…one should think what?

Answer 15

Osteomyeolitis should be a rule out.

Question 16

What is a hygroma and where is it usually located on the carpus?

Answer 16

Acquired subcutaneous sac (blunt trauma) - No communication with the joint

Dorsal aspect of the carpal region

Question 17

Swelling on the craniodistal aspect is usually associated with what structure?

Answer 17

Extensor sheath synovitis

Like secondary to injury to: extensor carpi radialis, common digital extensor or long digital extensor.

These can rupture (espically extensor carpi radialis) in foals causing flexure deformity as well as swelling.

The periosteal reaction of the radius is commonly associated with injury of the extensor carpi radialis.

Question 18

Non-painful swelling of the dorsolateral aspect of the carpus may represent this pathology?

Answer 18

Herniation of carpal joint synovial membrane

Contrast study is needed for further evaluation and to differentiate it from a hygroma

Question 19

What are the arrows pointing to?

Answer 19

Intracapsular fat. Showing that there is no joint effusion. B has joint effusion.

Question 20

What joint cavity is separate from other joint cavities in carpus?

Answer 20

Antebrachiocarpal joint.

Question 21

Calcinosis circumpscripta has been reported IN what joints of the carpus?

Answer 21

Antebrachiocarpal

Middle

Question 22

Distention of the flexor carpal sheath is consistent with injurying what structures?

Answer 22

DDF

SFDF

Accessory ligament of the DDF

Idiopathic synovitis.

Fractures of Accessory or palmar fractures of other carpal bones

Question 23

The pictures represents what pathology? The long arrow in A represents what?

Answer 23

This is distal caudal radial physeal exostosis or osteochondroma.

This causes impingment of the DDF causing secondary synovitis.

A is the normal bony prominence of the radius…you need the other osseos shit to make it pathologic.

Question 24

Osseous and osteochondral abnormalities (fractures) are more common in what joint and what side?

Answer 24

Middle carpal joint

Right front limb due to racing counter-clockwise

Question 25

Most common place for osteochondral injuries in thoroughbred and quarterhorses?

Answer 25

Dorsodistal aspect of the radial carpal bone

Question 26

Sclerosis of the carpal bones are commonly associated with what type of inijury?

Answer 26

Chronic, repetitive injury

Question 27

What commonly precedes osteochondral fragments in the radial carpal bone?

Answer 27

focal lucency of the distal aspect of the bone