Overview
The most cranial muscle of the forearm. In cattle it forms a single belly with a single tendon, which crosses the dorsal surface of the carpus wrapped in a synovial sheath.
Origin
Lateral supracondylar crest of the humerus.
Insertion
Tuberosity of the large metacarpal bone III+IV (tuberositas ossis metacarpalis III), on the dorsal surface of the proximal metacarpus.
Action
Extends the carpus.
Innervation
Radial nerve (n. radialis).
Clinical relevance
Over the dorsal carpus, superficial to its tendon, a carpal hygroma can develop: inflammation of a subcutaneous bursa, common in cattle housed on hard floors. It must be told apart from distension of this tendon sheath and of the carpal joint.