When the growth of one of the bones of the leg or forearm is arrested after separation of its epiphysis while the other bone continues to grow, the foot or hand is deviated towards the side of the shorter one.
Partial separations may be overlooked at the time of the accident and cause trouble later from bending of the bone, as in one variety of coxa vara. The epiphysis at the lower end of the femur may be displaced into the ham and press on the popliteal vessels.
_Treatment._--The general principles which govern the treatment of fractures apply equally to epiphysial separations, the essential being the accurate replacement of the epiphysis.
In _compound separations of epiphysis_, the end of the diaphysis may be pushed through the skin. The entrance of sepsis may prove an obstacle to any operative measure that would otherwise be indicated.
SURGICAL ANATOMY--INJURIES: _Contusions_; _Wounds_; _Sprains_; _Dislocations_--TRAUMATIC DISLOCATIONS: _Causes_: _Varieties_; _Clinical features_; _Treatment_--Compound dislocations--Old-standing dislocations.
#Surgical Anatomy.#--The function of a joint is to permit of the movement of one bone upon another. The articular surfaces are covered with a thin layer of hyaline cartilage, and are retained in apposition by the tension of ligaments and of the muscles surrounding the joint. The articular capsule (capsular ligament) is directly continuous with the periosteum, and is lined by a synovial layer, which at the line of attachment of the capsule is reflected on to the bone as far as the articular cartilage. The synovial layer invests intra-articular ligaments, and is projected into the interior of the joint in the form of loose folds wherever the articulating surfaces are not in immediate contact. The surface of the synovial layer is covered with minute processes or villi, which in diseased conditions may become hypertrophied. The synovia owes its lubricating property to mucin, derived from the solution of the endothelial cells on the free surface of the synovial layer. The opposing surfaces of a joint being always in accurate contact, the so-called cavity is only a potential one. If fluid is poured out into the joint, the synovial layer and the capsule are put upon the stretch, causing discomfort or actual pain, which is partly relieved by slightly flexing the joint. If the distension persists, the ligaments become elongated and the joint unstable.