Anterior superior iliac spine (ASIS) is a bony prominence located on the front and top of the pelvis. It is an important landmark in anatomy, as it serves as a reference point for several muscles and ligaments.
Structure
The Anterior superior iliac spine is formed by the union of the ilium and the pubis bones, which make up the pelvis. It is a small, triangular-shaped bone that protrudes from the front of the pelvis and can be easily felt through the skin. It is located on either side of the midline of the body, just below the waist.
Location
The Anterior superior iliac spine is located at the top and front of the pelvis, about halfway between the pubic symphysis (the joint between the pubic bones) and the iliac crest (the top of the ilium bone). It is located just lateral to the pubic bone and just anterior to the iliac crest. It is also located just inferior to the ASIS is the pubic tubercle, which is a small bony prominence that can also be felt through the skin.
Function
The ASIS serves as an attachment point for several muscles and ligaments in the lower body. These include:
- Tensor fasciae latae muscle: This muscle extends from the ASIS to the tibia bone (shin bone) and is responsible for abducting (moving away from the midline) and flexing the thigh.
- Sartorius muscle: This muscle extends from the ASIS to the tibia bone and is responsible for flexing, rotating, and abducting the thigh.
- Rectus femoris muscle: This muscle extends from the ASIS to the patella (knee cap) and is responsible for extending the thigh and flexing the leg.
- Iliotibial band: This band of connective tissue extends from the ASIS to the tibia bone and helps to stabilize the knee joint.
In addition to these muscles, the ASIS also serves as a reference point for several medical procedures, including hip replacement surgery and the injection of medications into the hip joint.
Clinical significance
Clinical significance of the anterior superior iliac spine (ASIS) can be understood through its role in the following conditions:
- Hip pain: The ASIS is a common location for hip pain, particularly in athletes or individuals who engage in high-impact activities such as running or jumping. Hip pain can be caused by a variety of factors, including muscle strains, ligament sprains, and joint inflammation.
- Hip replacement surgery: The ASIS is an important reference point for hip replacement surgery, as it is used to align the prosthetic hip joint with the pelvis. Accurate alignment of the hip joint is critical for proper function and long-term success of the surgery.
- Injection of medications: The ASIS is also used as a reference point for the injection of medications into the hip joint. This is typically done in cases of joint inflammation, such as in the treatment of osteoarthritis.
- Anatomical reference point: In addition to its clinical significance, the ASIS is also an important anatomical reference point for healthcare professionals. It is used to accurately locate and identify other structures in the pelvis, such as the iliac crest and the pubic symphysis.
