epifysiala

Epifysiala is a term used in some anatomical vocabularies to denote the epiphyses, the rounded ends of long bones that participate in joint formation with adjacent bones. In the growing skeleton, epiphyses are connected to the shaft by areas that allow growth and are separated from the diaphysis by the epiphyseal plate.

Anatomy: Proximal and distal epiphyses are the ends of long bones. They are composed largely of cancellous (trabecular) bone, surrounded by a thin cortical shell, and often contain red bone marrow. The articulating surfaces are covered by articular (hyaline) cartilage to reduce friction and distribute load.

Development: In children, the epiphyses are separated from the diaphysis by the epiphyseal (growth) plate, a layer of cartilage that enables longitudinal bone growth. As growth ceases in adolescence, the growth plate ossifies, leaving an epiphyseal line as evidence of prior growth.

Clinical relevance: Injury or disease affecting the epiphysis or growth plate can disrupt bone growth and joint function. Physeal (growth plate) injuries in children are commonly classified by the Salter-Harris system. Epiphysical disorders, such as Legg-Calvé-Perthes disease affecting the femoral head, or degenerative conditions like osteoarthritis in later life, illustrate epiphysis involvement in clinical practice.

Etymology and usage: The name derives from Greek epi-, upon, and physis, growth. In English and many languages, epiphysis (plural epiphyses) is the standard term, with epifysiala representing a language-specific form used to describe the same structures.