1. The descriptive anatomy of the tendinous component of the subclavius muscle is amplified.

2. The subclavius tendon comprises a shorter, medial pars libera, continuous with a longer, narrower, more lateral pars paramuscularis. This last may be prolonged further laterally by two or three tendinous fasciculi.

3. Both parts of the subclavius tendon are constant. By tenodesis they provide, on the average, one and a half to two inches of material eminently suitable for employment in the functional replacement of a damaged costo-clavicular ligament.