Final answer:
The acetabulum is the deep socket in the pelvis that holds the head of the femur, creating the hip joint. It is deepened by the acetabular labrum and is supported by several ligaments, providing stability for the joint.
Step-by-step explanation:
The deep socket that holds the head of the femur to form the hip joint is known as the acetabulum. This structure is part of the pelvis and is crucial for the stability and weight bearing capability of the hip joint. The acetabulum is further deepened by the acetabular labrum, which is a ring of cartilage that provides a better fit and stability for the head of the femur.
Additionally, the hip joint is reinforced by several strong ligaments, such as the iliofemoral, pubofemoral, and ischiofemoral ligaments, which spiral around the head and neck of the femur and are tensioned especially when the body is upright, contributing to the hip's stability. Inside the joint capsule, there is a ligament called the ligament of the head of the femur, which is not as supportive but contains an artery essential for blood supply to the femoral head.