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Definition
By Gregory R. Waryasz, MD
The acetabulum of the musculoskeletal system is characterized by being the socket component of the hip joint.
It is part of the hip joint. It consists of bone and cartilage tissue once mature.
Its unique structural feature is that it is a large cup-shaped cavity. The bony anatomy of the fusion of the ilium, ischium, and pubis looks like an inverted Y. There are two columns; anterior and posterior. The acetabular rim has a semilunar part that is covered with articular cartilage.
The anterior column is made up of the anterior iliac wing, anterior wall, pelvic brim, and superior pubic ramus.
The posterior column is made up of the superior and inferior sciatic notch, posterior wall, ischial tuberosity, and most of the quadrilateral plate.
The ilium undergoes primary ossification starting and appearing at age 2 months and undergoing fusion at age 15. The iliac crest is a site of secondary ossification starting at age 16 and fusing at age 25. The anterior inferior iliac spine is a site of secondary ossification that starts at age 16 and fuses by age 25. The ilium fuses with the pubis and ischium at the triradiate cartilage at the acetabular dome to form the innominate bone at maturity around age 15 to form the bony acetabulum. The two innominate bones and the sacrum make up the pelvis. The bone of the acetabulum as well as all other bones, muscles, and ligaments of the body are derived of mesodermal origin in the embryo.
The function of the acetabulum is to contain the femoral head and allow for articulation with the femur to move the leg. The acetabulum is important for weightbearing.
Common diseases include fractures, dislocations, and arthritis. Developmental dysplasia of the hip is a congenital condition of displacement of the femoral head from the acetabulum with improper development of the hip joint.
Commonly used diagnostic procedures include clinical history, physical exam, x-ray, MRI, bone scan and CT scan.
It is usually treated with internal or external surgical fixation or non-operative approaches for fractures and fractures. Arthritis can be treated with NSAIDs, steroid joint injections, or DMARDs. Joint replacement is the surgical treatment for arthritis.
References
Elstrom J, Virkus W, Pankovich (eds), Handbook of Fractures (3rd edition), McGraw Hill, New York, NY, 2006.
Koval K, Zuckerman J (eds), Handbook of Fractures (3rd edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.
Lieberman J (ed), AAOS Comprehensive Orthopaedic Review, American Academy of Orthopaedic Surgeons, 2008.
Moore K, Dalley A (eds), Clinically Oriented Anatomy (5th edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.
Wheeless’ Textbook of Orthopaedics: Fractures of the Acetabulum (http://www.wheelessonline.com/ortho/fractures_of_the_acetabulum