Navicular

Question 1

Three radiographic views to evaluate the navicular bone and what is best evaluated on each view

Answer 1

Lateral
-impart ligament can avulse at its attachment site on the distal border of the flexor surface

Dorso65*proximal-palmarodistal oblique (D65Pr-PaDiO) (Collimated DP oblique)

• invaginations of the distal border
• there should be no more than seven

Palmaroproximal-palmarodistal oblique (PaPr-PaDiO) (skyline)

• Flexor surface and trabecular bone
• small crescent lucency in the saddle Ridge of the navicular bone is present in 50 percent of normal horses
• with bursitis or tendonopathy subtle flattening of the flexor surface will occur

Question 2

Name the four surfaces of the navicular bone

Answer 2

Proximal border, distal border, articular surface, flexor surface

Question 3

Navicular syndrome

Etiology

Clinical signs –3

Radiographic signs – 3

Answer 3

Unknown

• Unilateral or bilateral for Limb lameness
• Sensitivity to hoof testers across heel or frog
• Resolve with Palmer digital nerve block

– Increase in size number or abnormal shape of synovial invaginations
– Sclerosis of trabecular bone (medullary cavity)
-enthesiopathy of collateral sesamoidean and impar distal sesamoidean ligaments

Question 4

Two ligaments that attach on the navicular bone

Answer 4

Collateral sesamoidean ligament

Impar distal sesamoidean ligament

Question 5

Gold standard for evaluating navicular syndrome

Answer 5

MRI

Question 6

Fractures of the navicular bone common when…

Not to be confused with two other things

Answer 6

Bones are significantly weakened by degenerative change

– Gas artifacts
– Bipartite and multipartite navicular bones

Question 7

Penetrating foreign body of the heel or frog region can affect… (5)

Procedure to help diagnose

Answer 7

DDFT, digital tendon sheath, navicular bursa, navicular bone, DIPJ

Fistulogram – sterile Iodinated contrast or flexible metallic probe