CLAVICLE (Lat. eh/Ocala, a little key, dim. of c(oris, key). or CoLLAR-BoNE. A long bone. curved somewhat like the italic letter f, and placed at the upper and anterior part of the thorax, in a nearly horizontal position. in connection with the scapula or shoulder-blade, the clavicle forms the shoulder, and is the only bony connection between the upper extremity and the trunk. The inner extremity of the c•av icle articulates with the sternum (breast-bone) and the cartilage of the first rib, while the outer extremity articulates with the scapula. The range of motion in the clavicle is extensive— especially in a vertical direction—and the vari ous movements of the arm are in this way read ily accommodated. In the female the clavicle is smoother, slender, and presents a less marked curve. The length, also, is slightly less, and the position more nearly horizontal. Manual labor, which brings the shoulder into constant exer cise, renders the clavicle thicker and tougher, and therefore in right-handed people the right clavicle shows greater development.
qince the clavicle favors the lateral movements of the upper extremities, we do not find it in animals whose fore limbs are used only for pro gression; but it is present in almost all animals whose anterior extremities are clawed and used for prehension.
The clavicle is frequently fractured by direct violence, and also by indirect force, as in falling upon the hand. Dislocations are of less frequent occurrence.
Ossification of the clavicle begins very early— even as soon as the thirteenth day. according to Beclard—and at birth this process is almost com plete. Consult: Cray. Awl/only, edited by Pick 18J3) holden, Human Osteology (Sew York, 18S5).