Ischial Tuberosity

More than 95% of all pressure sores are located on the lower part of the body. The most common sites are the sacral and coccygeal areas, ischial tuberosities, and greater trochanter. 

Hip Disarticulation Amputation Prostheses. The Canadian hip disarticulation prosthesis, introduced in the United States in 1954, is still used almost univers ly today. It consists of a foot, a shank, a prosthetic knee, a thigh, a hip joint/bumper/control strap, and a socket (Fig. 33.16). The hip disarticulation socket is essentially a bucket, providing a seat for the ischial tuberosity, medial-lateral stability, suspension, and support for weight bearing. 

Hemipelvectomy Prostheses. The prosthesis for an individual witfi a hemipelvectomy is similar to that of the hip disarticulation prosthesis. However, the residuum of an individual with a hemipelvectomy no longer contains the ischial tuberosity. The socket must therefore provide distal support solely through the soft tissues. To minimize soft tissue pressures, the socket may extend more proximally using the iliac crest, distal ribs, and gluteal muscles for support. Suspension may be augmented by shoulder straps. This prosthesis is typically endoskeletal so as to minimize the weight of the prosthesis. 

The intertuberous distance is the widest distance between the ischial tuberosities and is also measured in the axial plane. 

The acetabulum is comprised of a large anterior column and a smaller posterior column, together these columns create an inverted Y. The anterior column is comprised of the superior pubic ramus which continues into the iliac blade. The posterior column is shorter and more vertical and extends from the ischial tuberosity into the ileum. In addition to the two columns, there is an anterior and posterior wall which are important in maintaining hip stability (Theumann et al. 2002). 

In the pelvis, avulsion occurs primarily at six sites, which not surprisingly are the sites of the major muscle attachments. The three commonest sites are the anterior superior iliac spine (ASIS) (the origin of sartorius), the anterior inferior iliac spine (AIIS) (the rectus femoris origin) and the ischial tuberosity (the origin of the hamstring group). With these fractures acutely there is a clinical history of severe exertion, followed by pain and reduced function (Wootton et al. 1990) (Fig. 12.23). 

Fig. 12.24. Sites of pelvic avulsion injuries. A, iliac crest (abdominal muscle insertion). B, anterior superior iliac spine (sartorious muscle origin). C, anterior inferior iliac spine (rectus femoris origin). D, greater trochanter (gluteal insertions). Ey Lesser trochanter (illiopsoas). F, ischial tuberosity (hamstring muscle). G, body of pubis and inferior pubic ramus (adductors and gracillis)...

Cycling Friction, thermal injury Bicyclist s nipple secondary to thermal injury rather than mechanical trauma saddle sores any combination of chafing, skin ulceration, furuncles, folliculitis or ischial tuberosity pain in bicyclists... 

A higher ischial tuberosity may indicate an anterior rotation or superior shear of the innominate on the same side. 

The physician places his fist against the ischial tuberosity on the side of the pubic dysfunction. 

The patient is directed to inhale deeply and the physician resists the movement of the patient s ischial tuberosity against his hand. The patient is then directed to exhale completely. 

Ischial —over the ischial tuberosity, known as "weaver s bottom" when enlarged... 

Tender point 2 to 3 inches below the trochanter along posterior shaft of femur over to the ischial tuberosity. 

Ischiogluteal bursitis is commonly found in patients who have a sedentary occupation. It was once called tailor s bottom, because tailors tended to sit all day on hard chair seats. The patient reports pain when they sit on a hard surface. The pain is usually unilateral. Point tenderness is present over the ischial tuberosity and will be relieved when the patient stands up. There will be no x-ray evidence found. An MRl or CAT scan may reveal a thickening of the bursa. The pain can be relieved by an injection of a local anesthetic into the area. The prescription of a non-steroidal anti-inflammatory medication (NSAID), the use of a cushion on the chair, as well as instructing the patienl to stand up for 1 minute every hour while working will relieve the condition. 

This bursa is located at the medial aspect and immediately below the knee joint. It is in relationship to the insertion of the semitendinosus muscie. This muscie has as its origin the ischial tuberosity and its insertion is at the medial aspect of the tibia, just below the knee joint. The other muscles attaching in this area are the sarto-rius and gracilis muscles. 

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