The shoulder articulation [articulatio humeri] is one of the most perfect and most movable of joints, the large upper end of the humerus playing upon the shallow glenoid cavity. Like the hip, it is a ball-and-socket joint. It is retained in position much less by ligaments than by muscles, and, owing to the looseness of its capsule, as well as to all the other conditions of its construction and position, it is exceedingly liable to be displaced; on the other hand, it is sheltered from violence by the two projecting processes - the acromion and coracoid. The ligaments of the shoulder-joint are:
The scapula is connected with the clavicle by a synovial joint with its ligaments at the acromio-clavicular articulation; and also by a set of ligaments passing between the coracoid process and the clavicle. So, that we have to consider: the acromio-clavicular articulation, the coraco-clavicular ligaments, the proper scapular ligaments are also best described in this section - viz., the coraco-acromial and transverse.
The sterno-costo-clavicular articulation Class. - Diarthrosis. Subdivision. - Condylarthrosis.
At this joint the large medial end of the clavicle is united to the superior angle of the manubrium sterni, the first costal cartilage also assisting to support the clavicle. It is the only joint between the upper extremity and the trunk, and takes part in all the movements of the upper limb. Looking at the bones, one would say that they were in no way adapted to articulate with one another, and yet they assist in constructing a joint of security, strength, and importance. The bones are nowhere in actual contact, being completely separated by an articular disc. The interval between the joints of the two sides varies from one inch to an inch and a half (2.5-4 cm.).
Before describing the movements of the thorax as a whole, it must be premised that there are some few modifications in the movements of certain ribs resulting from their shape. Thus, the firs rib (and to a less extent the second also), which is flat on its upper and lower surfaces, revolves on a transverse axis drawn through the costo-vertebral and costo-transverse joints. During inspiration and expiration, the anterior extremities of the first pair of costal arches play up and down, the tubercles and the heads of the ribs acting in a hinge-like manner, the latter having also a slight screwing motion. By this movement, the anterior ends of the costal arches are simply raised or depressed, and the sternum pushed a little forward; it may be likened to the movement of a pump-handle.
These articulations at the front of the thorax may be divided into four sets, viz.: The intersternal joints, or the union of the several parts of the sternum with one another. The costo -chondral joints, or the union of the ribs with their costal cartilages. The chondro-sternal joints, or the junction of the costal cartilages with the sternum. The interchondral joints, or the union of five costal cartilages (sixth, seventh, eighth, ninth, and tenth) with one another.
These costo-vertebral articulations (French: articulations costo-vertébrales)consist of two sets: the capitular (costo-central): i.e., the articulation of the head of the rib with the vertebrae and the costo-transverse, or the articulation of the tubercle (of each of the first ten ribs) with the transverse process of the lower of the two vertebrae, with which the head of the rib articulates: i.e., the one bearing its own number, as the first rib with the first thoracic vertebra, the second rib with the second thoracic vertebra, and so on.
The metatarsus (Latin: ossa metatarsalia; French: les métatarses) consists of a series of five somewhat cylindrical bones. Articulated with the tarsus behind, they extend forward, nearly parallel with each other, to their anterior extremities, which articulate with the toes, and are numbered according to their position from great toe to small toe. Like the corresponding bones in the hand, each presents for examination a three-sided shaft, a proximal extremity termed the base, and a distal extremity or head. The shaft tapers gradually from the base to the head, and is slightly curved longitudinally so as to be convex on the dorsal and concave on the plantar aspect.
This website puts documents at your disposal only and solely for information purposes. They can not in any way replace the consultation of a physician or the care provided by a qualified practitioner and should therefore never be interpreted as being able to do so.