Diaphysis in the context of "Metaphysis"

An epiphysis (from Ancient Greek ἐπί (epí) 'on top of' and φύσις (phúsis) 'growth'; pl.: epiphyses) is one of the rounded ends or tips of a long bone that ossify from one or more secondary centers of ossification. Between the epiphysis and diaphysis (the long midsection of the long bone) lies the metaphysis, including the epiphyseal plate (growth plate). During formation of the secondary ossification center, vascular canals (epiphysial canals) stemming from the perichondrium invade the epiphysis, supplying nutrients to the developing secondary centers of ossification. At the joint, the epiphysis is covered with articular cartilage; below that covering is a zone similar to the epiphyseal plate, known as subchondral bone. The epiphysis is mostly found in mammals but it is also present in some lizards. However, the secondary center of ossification may have evolved multiple times, having been found in the Jurassic sphenodont Sapheosaurus as well as in the therapsid Niassodon mfumukasi.

The epiphysis is filled with red bone marrow, which produces erythrocytes (red blood cells).

The long bones are those that are longer than they are wide. They are one of five types of bones: long, short, flat, irregular and sesamoid. Long bones, especially the femur and tibia, are subjected to most of the load during daily activities and they are crucial for skeletal mobility. They grow primarily by elongation of the diaphysis, with an epiphysis at each end of the growing bone. The ends of epiphyses are covered with hyaline cartilage ("articular cartilage"). The longitudinal growth of long bones is a result of endochondral ossification at the epiphyseal plate. Bone growth in length is stimulated by the production of growth hormone (GH), a secretion of the anterior lobe of the pituitary gland.

The long bone category includes the femora, tibiae, and fibulae of the legs; the humeri, radii, and ulnae of the arms; metacarpals and metatarsals of the hands and feet, the phalanges of the fingers and toes, and the clavicles or collar bones. The long bones of the human leg make up nearly half of adult height. The other primary skeletal component of height are the vertebrae and skull.

The medullary cavity (medulla, innermost part) is the central cavity of bone shafts where red bone marrow and/or yellow bone marrow (adipose tissue) is stored; hence, the medullary cavity is also known as the marrow cavity.

Located in the main shaft of a long bone (diaphysis) (consisting mostly of spongy bone), the medullary cavity has walls composed of compact bone (cortical bone) and is lined with a thin, vascular membrane (endosteum).