Veterinary Gross Anatomy

DISTAL SESAMOID

Ox

• The distal sesamoid is otherwise called as  os navicularis. 
• It is placed behind the second inter-phalangeal articulation. It presents two surfaces, two borders and two extremities .
• The dorsal face is articular, faces upward and forward and presents two facets for the second phalanx.
• The volar or flexor surface is broader and in life is covered by fibro-cartilage for the play of the deep flexor tendon.
• The proximal border is grooved for ligamentous attachment.
• The distal border bears a small facet about its middle for the os pedis. The extremities are rounded.

Sheep and Goat 

• The number similar to that of an ox.
• The flexor surface of the distal sesamoid forms a shallow groove not divided by a ridge.

Horse

• The distal sesamoid is shuttle shaped and longer, with narrow extremities.

Pig

• One distal sesamoid for each chief digit.
• Absent in accessory digits.

Dog 

• The distal sesamoids are cartilaginous.

Rabbit

• Distal sesamoids are present in the inter-phalangeal joints.

Fowl

• They are absent