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thoracoappendicular muscle; origin, first costal cartilage; insertion, inferior surface of acromial end of clavicle; action, fixes clavicle or elevates first rib; nerve supply, subclavian from brachial plexus.
Etymology: L, sub + clavicula
a short muscle of the chest wall. It is a small cylindric muscle between the clavicle and the first rib and arises in a short thick tendon from the junction of the first rib and its cartilage under the clavicle. It inserts into the groove on the inferior surface of the clavicle between the costoclavicular and conoid ligaments. The subclavius is innervated by a special nerve from the lateral trunk of the brachial plexus, which contains fibers from the fifth and sixth cervical nerves. It acts to draw the shoulder down and forward. Compare pectoralis major, pectoralis minor, serratus anterior.
subclavius(sŭb-klā′vē-ŭs) [″ + clavis, key]
A tiny muscle from the first rib to the undersurface of the clavicle.