Espiral AtlasIschial tuberosity
tuber ischiadicum
Study entry
Description
A large, rough prominence where the body of the ischium meets the ramus.
Relations
It bears the body's weight when sitting; tendinous origin of muscles of the posterior region of the thigh.
Palpation
Easy at the bottom of the buttock with the thigh flexed; with the thigh extended, the gluteus covers it.
Source: cap. 7, «Huesos del miembro inferior: hueso coxal» y «Anatomía de superficie»
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.
Ischial bursitis
Repeated microtrauma with hip extension in the seated position (cycling, rowing) exceeds the capacity of the sciatic bursa to cushion, and it becomes inflamed by friction against the ischial tuberosity. The pain is over the bursa and gets worse with the gluteus maximus; in the chronic form it may calcify. Because the ischial tuberosities bear the weight in sitting, debilitated people, especially poorly cared-for paraplegics, can have pressure ulcers there.
Injury of the hamstring muscles
Hamstring strain (stretch or tear) is common in running, jumping, baseball, basketball, rugby and soccer; it happens twice as often as that of the quadriceps. Violent effort can pull off part of the proximal attachments on the ischial tuberosity. Fibers and vessels rupture and a hematoma forms, contained by the fascia lata, which works like a stocking. It hurts so much that the athlete falls and writhes. Insufficient warm-up favors it. Forced flexion of the hip with the knee extended, as in a kick, can pull off the piece of the tuberosity where the biceps femoris and the semitendinosus attach.
Related clinical cases
- Avulsion fractures of the hip bone
- Ischial bursitis
- Injury of the hamstring muscles