A long bone is made up of three parts: the epiphysis, diaphysis and the metaphysis. A long bone is a cylindrical elongated bone as seen in the femur, or thigh bone; and the humerus, or upper arm bone. An epiphysis is one of the rounded ends of the long bones of the body which makes up a joint.
The diaphysis is the middle section of the long bone. This is where the metaphysic is located. The metaphysic is a widened area just below the epiphysis in which the growth plate is found. A growth plate, also called the physis, is the area which allows for bone growth during childhood. The growth plate ossifies, or hardens into bone once development is complete, somewhere between the late teen years and early twenties.
The epiphyses are covered with an articular cartilage and filled with red bone marrow. The articular cartilage is a hard but flexible form of connective tissue which assists in the support and movement of the joints. Red bone marrow is a tissue located within the bone which produced red blood cells, white blood cells and platelets.
Red blood cells are responsible for the transportation of oxygen. White blood cells, also called leukocytes, protect the body against foreign substances such as infections. Platelets, or thrombocytes, are a vital part of the blood which regulated hemostasis, or the stopping of blood flow from a damaged blood vessel.
The epiphysis, as with any other portion of the long bone, can sustain damage. A slipped capital epiphysis, for example, is a fracture resulting in a break in the union of the bone’s growth plate. This break in the bone can cause the rounded ends to slip onto the metaphysis. This condition can cause hip pain and dysfunction. Pain can also be experienced in the hip or groin, thigh or knee.
Treatment for this condition is the prevention of further displacement of the end of the long bone into the shaft or diaphysis and stabilization of the bone to achieve proper healing and possible closure of the growth plate. This is accomplished through a time of non-weight bearing, immobilization through casting, and possible internal fixation of the bone. Internal fixation is a procedure where the bone epiphysis is fastened together through a series of pins or screws.