They are the bones that are above the thorax and are characterized by having a shape similar to the "s" (italics), in addition to being a long bone, although, in fact, it retains the characteristics of a flat bone. It is one of the components of the shoulder girdle, which is also made up of the scapula. Regarding its development, it is one of the first bone pieces to appear during pregnancy, specifically between the fifth and sixth week; going through different ossification processes; likewise, cartilage creates species of areas in which much more of them are produced, which increases the speed of clavicle formation.
The platysma muscle is the one that houses the clavicle below itself, as well as it is also mixed with muscles such as the deltoid and the trapezius. On the underside of the clavicle, it stands out for having a nutrient hole, in addition to having small rough areas within its surface. It is related to the expansion of some nearby tendons and muscles, such as: the Conoid Ligament, the Subclavian Muscle and the Trapezoid Ligament. As for its edges, they are mostly convex, thick and rough, even so, others are flat and smooth.
Sometimes, their anatomy may be different, being modified by nerves or, in different cases, their development would be affected by the lifestyle that an individual may have, such as working in activities that require high physical effort. In fish, the clavicle was present only in primitive specimens, since today it is almost impossible to be observed in them; in the same way, some mammals do not have this bone piece or have reduced it.
