Horse coffin and hoof abnormalities

Question 1

What is Navicular syndrome in horses?

Answer 1

It’s a chronic degenerative condition where inflammation and degeneration of the navicular bone and it’s surrounding tissues occurs, it cause lameness bilaterally in the forelimbs.

Question 2

What are the surrounding tissues of navicular bone?

Answer 2

Navicular bone (the bone has a flexor side which contain fibrocartilage which facilitate the movement of DDFT), navicular bursa (located between the bone and DDFT), the bone is connected with the 3rd pastern via distal sesamoidean impar ligament and with 2nd pastern with collateral sesamoidean ligament (T ligament).

Question 3

Explain enthesophyte.

Answer 3

Formation of a bony parts at a ligament or tendon

Question 4

What happens to the navicular bone in navicular syndrome?

Answer 4

1. The bone undergo focal loss of the medullary architecture with subsequent synovial invagination and medullary sclerosis.
2. The fibrocartilage in the flexor side of the bone is damaged and cause traumatic fibrillation of the DDFT and subsequent adhesion between the bone and the tendon.
3. Enthesophyte formation on the proximal and distal border of the bone

Question 5

How to diagnose navicular disease?

Answer 5

1. Radiography: radiolucent circular appearance with radiolucent tract (stem) giving the shape of a lollipop (characteristic appearance of degenerative condition in the navicular bone).
2. Nerve block: Palmar nerve block (heel block) will alleviate the lameness and confirm the diagnosis of navicular syndrome.
3. MRI

Question 6

How to treat navicular syndrome?

Answer 6

1. Rest
2. Medical management:
   - Phenylbutazone (use it with caution because of adverse effects on renal GIT)
   - COX-2 Selective as Firocoxib
3. Shoeing with raised heel (wedge pads or wedge shoe)
4. Injection of corticosteroid in the coffin joint (effective in 1/3 of horses for 2 months) or in the navicular bursa (effective in 80% of horses for 4 months)
5. Last resort (palmar nerve neurectomy)

Question 7

What is the periosteum?

Answer 7

It’s the connective tissue that surrounds a bone

Question 8

Explain pyramidal disease (buttress foot)

Answer 8

It’s traumatically induced disease where periostitis of the extensor process of coffin bone happens due to fracture causing inflammation and bulging of the coronary band.

Question 9

What do you know about clubfoot?

Answer 9

upright angle of dorsal aspect of hoof
use oxytetracycline in mild case is advised

causes: excessive carb (energy) diet
genes
trauma
djd
unbalanced mineral diet
overeating
excessive exercise

treatment: desmotomy of accessory ligament of DDFT (aka inferior check ligament)