trochanter

Trochanter is an anatomical term for a large, prominent bony projection. In humans, it most often refers to structures on the proximal femur, where two principal trochanters are present: the greater trochanter and the lesser trochanter.

The greater trochanter is a large, lateral projection on the upper part of the femur, above the neck. The lesser trochanter is a smaller projection on the posteromedial aspect near the junction of the neck and shaft. The region between and around these trochanters includes important surface features such as the intertrochanteric line (anterior) and the intertrochanteric crest (posterior), as well as the trochanteric fossa on the greater trochanter.

Trochanters serve as major sites for muscle attachment. The gluteus medius and gluteus minimus attach to the greater trochanter, contributing to hip abduction. The iliopsoas inserts at the lesser trochanter, playing a key role in hip flexion. A group of short external rotators also attach around the greater trochanter area, supporting lateral rotation of the hip.

Clinical relevance includes trochanteric fractures, which occur in the proximal femur and are particularly common in older adults. The term also encompasses intertrochanteric fractures, which occur between the greater and lesser trochanters, as well as avulsion injuries in which tendon or muscle pulls off a fragment of bone at the trochanter.

Although the femur is the most well-known example, the term trochanter is used in human and veterinary anatomy to describe similar prominences on other bones in various species, serving as key attachment points for muscles and ligaments.