Hip bone

Study entry

Parts

A large, flat bone formed by the fusion of three bones: ilium (above), ischium (behind and below) and pubis (in front and in the middle). The three meet at the acetabulum, joined by Y-shaped cartilage until adolescence; fusion begins at 15–17 years and ends between 20 and 25. The obturator foramen lies between the pubis and the ischium.

Joints

Hip (the acetabulum with the head of the femur); sacroiliac (the auricular surface of the ilium with the sacrum); pubic symphysis (the symphysial surface with the pubis of the other side).

Palpation

Iliac crest (especially the anterior third), anterior superior iliac spine, iliac tubercle, pubic tubercle and body of the pubis, and ischial tuberosity (with the thigh flexed). The posterior superior iliac spine lies at the bottom of a skin dimple, about 4 cm from the midline.

Clinical

The iliac crest, near the posterior superior spine, is a site from which bone marrow or bone for grafting is taken.

Source: cap. 7, «Huesos del miembro inferior: hueso coxal» (ilion, isquion, pubis, foramen obturado, acetábulo) y «Anatomía de superficie de la cintura pélvica y el fémur»

Clinical correlation

Avulsion fractures of the hip bone

A fracture of the hip bone is a fracture of the pelvis (see ch. 6). The expression «hip fracture», on the other hand, is usually used loosely for the head, neck or trochanters of the femur. In an avulsion, a sudden sprint or braking (sprinting, kicking, hurdling, basketball, martial arts) makes the tendon pull off a piece of the bone where it attaches. It happens at the prominences of muscle attachment: anterior superior iliac spine (sartorius), anterior inferior iliac spine (rectus femoris), ischial tuberosity (hamstrings) and ischiopubic rami.

Related clinical cases

• Avulsion fractures of the hip bone

Other structures in this region

• Femur
• Patella
• Tibia
• Fibula
• Talus
• Calcaneus
• Navicular
• Cuboid