Type: Intrinsic, Manus

Origin: Proximal metacarpus and distal carpal bones

Insertion: Proximal sesamoid bones (4 total—2 per digit) and extensor tendons (via extensor branches)

Function: Suspensory apparatus preventing fetlock hyperextension; supports fetlock during stance.

THE ACTIVE SUSPENSORY LIGAMENT

Unlike the horse where the Interosseous Medius is entirely tendinous and purely 'ligamentous,' the bovine Interosseous III & IV (fused) retains significant fleshy, contractile muscular tissue throughout life, making it both muscle and ligament.

METACARPAL GROOVE POSITION: Lies in the palmar groove of the fused Mc III/IV (cannon bone), deep to the DDF tendon but superficial to the bone.

SESAMODEAN BRANCHES: At the fetlock, divides into tendinous bands attaching to:
• Two axial proximal sesamoids (interdigital side)
• Two abaxial proximal sesamoids (outer sides of each digit)

EXTENSOR BRANCHES (CRITICAL): Sends five total branches. Most importantly, sends tendinous slips dorsally to join the Common Digital Extensor and Lateral Digital Extensor tendons. Also sends an axial band through the interdigital space to join extensor apparatus.

ACTIVE VS. PASSIVE ROLE: Because it retains muscular components, the bovine interosseous provides active contractile support to the fetlock, not just passive suspension. This suggests cattle rely more on tonic muscle contraction than horses do for prolonged standing, explaining why cattle tire more quickly from prolonged standing on hard surfaces.

CHECK LIGAMENT FUNCTION: Acts as the proximal check ligament, limiting fetlock hyperextension (sinking) during the stance phase when the animal bears 60% of body weight on the forelimbs.