Henry Gray (18251861). Anatomy of the Human Body. 1918.
The Ligament of the Neck of the Rib (ligamentum colli costæ middle costotransverse or interosseous ligament).The ligament of the neck of the rib consists of short but strong fibers, connecting the rough surface on the back of the neck of the rib with the anterior surface of the adjacent transverse process. A rudimentary ligament may be present in the case of the eleventh and twelfth ribs.
The Ligament of the Tubercle of the Rib (ligamentum tuberculi costæ posterior costotransverse ligament).The ligament of the tubercle of the rib is a short but thick and strong fasciculus, which passes obliquely from the apex of the transverse process to the rough non-articular portion of the tubercle of the rib. The ligaments attached to the upper ribs ascend from the transverse processes; they are shorter and more oblique than those attached to the inferior ribs, which descend slightly.
Movements.The heads of the ribs are so closely connected to the bodies of the vertebræ by the radiate and interarticular ligaments that only slight gliding movements of the articular surfaces on one another can take place. Similarly, the strong ligaments binding the necks and tubercles of the ribs to the transverse processes limit the movements of the costotransverse joints to slight gliding, the nature of which is determined by the shape and direction of the articular surfaces (Fig. 314). In the upper six ribs the articular surfaces on the tubercles are oval in shape and convex from above downward; they fit into corresponding concavities on the anterior surfaces of the transverse processes, so that upward and downward movements of the tubercles are associated with rotation of the rib neck on its long axis. In the seventh, eighth, ninth, and tenth ribs the articular surfaces on the tubercles are flat, and are directed obliquely downward, medialward, and backward. The surfaces with which they articulate are placed on the upper margins of the transverse processes; when, therefore, the tubercles are drawn up they are at the same time carried backward and medialward. The two joints, costocentral and costotransverse, move simultaneously and in the same directions, the total effect being that the neck of the rib moves as if on a single joint, of which the costocentral and costotransverse articulations form the ends. In the upper six ribs the neck of the rib moves but slightly upward and downward; its chief movement is one of rotation around its own long axis, rotation backward being associated with depression, rotation forward with elevation. In the seventh, eighth, ninth, and tenth ribs the neck of the rib moves upward, backward, and medialward, or downward, forward, and lateralward; very slight rotation accompanies these movements.
The articulations of the cartilages of the true ribs with the sternum are arthrodial joints, with the exception of the first, in which the cartilage is directly united with the sternum, and which is, therefore, a synarthrodial articulation. The ligaments connecting them are:
The Articular Capsules.
The Interarticular Sternocostal.
The Radiate Sternocostal.
The Articular Capsules (capsulæ articulares; capsular ligaments).The articular capsules surround the joints between the cartilages of the true ribs and the sternum. They are very thin, intimately blended with the radiate sternocostal ligaments, and strengthened at the upper and lower parts of the articulations by a few fibers, which connect the cartilages to the side of the sternum.
The Radiate Sternocostal Ligaments (ligamenta sternocostalia radiata; chondrosternal or sternocostal ligaments).These ligaments consist of broad and thin membranous bands that radiate from the front and back of the sternal ends of the cartilages of the true ribs to the anterior and posterior surfaces of the sternum. They are composed of fasciculi which pass in different directions. The superior fasciculi ascend obliquely, the inferior fasciculi descend obliquely, and the middle fasciculi run horizontally. The superficial fibers are the longest; they intermingle with the fibers of the ligaments above and below them, with those of the opposite side, and in front with the tendinous fibers of origin of the Pectoralis major, forming