The upper end of the femur features two prominences which serve as attachment sites for muscles and ligaments. The larger prominence is called the greater trochanter and projects from the upper side of the femur. The smaller, or lesser, trochanter, projects medially from the side of the femur, just at the neck of the femur.
The head of the femur is a rounded protrusion, covered with articular cartilage, which fits into the acetabulum of the pelvis. This articulation creates a ball-and-socket joint which is both strong while allowing a wide degree of articulation.
The acetabulum is the large, circular cavity in each side of the pelvis which accepts the head of the femur to form the ball-and-socket hip joint. It receives its name from the Latin term for the vinegar cup, which it resembles.
The pelvis creates the basin of the lower abdominal cavity. It is formed by three separate bones which become fused: the ilium, the ischium, and the pubis. The ilium is the broad, wing-like segment which features the wide, slightly concave surfaces of the back and sides of the pelvic girdle. The ischium forms the smaller, lower, portion which bears the weight of the body while sitting. The pubis creates an archway in the front of the basin which allows the urethra, blood vessels, and nerves to pass through the pelvic girdle to the external genitalia and lower body. The pelvis articulates with the sacrum in the back (and thereby connects to the rest of the vertebral column) and to the legs through the ball-and-socket joint formed by the two acetabula of the pelvis and the head of each femur.
Bones
anterior
ligaments
posterior
ligaments