The biceps and the triceps are the major muscles of the upper arm. Both muscles take origin from the humerus itself but also have an origin on the scapula; both insert on the forearm, namely, the radius and ulna respectively. Distally, both muscles are susceptible to overuse and strain, and may rupture or avulse from their insertions. Rupture of the biceps and triceps are most commonly due to increased eccentric force through a degenerated tendon. Common proximal biceps conditions include tendonitis, subluxation and rupture of the long head of the biceps tendon, which takes origin from the supraglenoid tubercle of the scapula (and is therefore primarily a shoulder muscle). Proximal triceps disease is rare.
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