The hip is a ball and socket joint and is one of the largest joints in the body. It connects the thigh bone (femur) with the pelvis. The pelvis is made up of three bones being the ilium (rear), the ischium (lower front) and the pubis (located above the ischium).
It is called a ball and socket joint as the end of the thigh bone is made of up a ball-shaped knob called the femoral head that fits into the hip bone in a formed socket called the acetabulum.
The bony surfaces within the hip joint are covered with articular cartilage (a smooth shiny white cushion surface). The cartilage or cushion is kept slippery by the fluid (synovial fluid) – this smooth slippery substance allows the bones in the hip joint to move against each other with ease. Around the hip joint is soft tissue covering known as joint capsule and surrounding this are large ligaments, tendons and muscles. The joint capsule holds the bones in place and prevents dislocation.
A normal hip functions due to the bones being held in place by the joint capsule and allowed to move smoothly and freely due to the articular cartilage and synovial fluid.