Interosseous muscles
Musculi interossei
Definition
Origin: Proximal end of metacarpals.
Insertion: Proximal sesamoid bones.
Function: Flexion of manus or proximal support of the fetlock in horses and ruminants.
Description:
The interosseous muscles are muscular structures covering the palmar aspect of the manus. They are muscular in carnivores and pigs but tendinous in horses and adult ruminants.
In carnivores: Carpal bones II-V give rise to four tendons that, later integrate with the proximal sesamoid bones and the common digital extensor.
In ruminants: Single origin divides into five branches that support standing digits axially and abaxially.
Horses: Medial, middle (functional), lateral interossesous muscles are present; the middle is also called suspensory ligament. It is a strong tendinous band, which arises from the proximal end of the cannon bone and the distal row of the carpal bones. It bifurcates to reach proximal sesamoid bones, further extending to common digital extensor tendon.
References
König, H. E., & Liebich, H. (2020). Veterinary anatomy of domestic animals: Textbook and Colour Atlas. Thieme.
