Structure And Location Of The Hip Bone's Acetabular Notch

Description

Acetabular notch (incisura acetabuli) occupies the inferior margin of the acetabulum on the os coxae, interrupting the otherwise continuous acetabular rim. Superior to the notch, the horseshoe-shaped lunate surface (facies lunata) forms the articular socket for the femoral head, while the nonarticular acetabular fossa lies centrally and slightly medial within the cup. From this fixed lateral perspective on the pelvic girdle, the notch is seen as an inferior gap between the anterior and posterior horns of the lunate surface, positioned distal to the acetabular roof and medial to the prominent rim where the acetabular labrum attaches. Small. But anatomically loaded. Surgeons and educators focus on the acetabular notch because it is the point where the transverse acetabular ligament bridges the gap, completing the ring of the acetabular labrum and influencing how the femoral head is constrained in flexion and rotation. The notch also relates to the ligament of the head of the femur (ligamentum teres), which courses toward the acetabular fossa and can carry the acetabular branch of the obturator artery (with variable contribution from the medial circumflex femoral system), a detail that matters in pediatric hip vascularity and in discussions of avascular necrosis risk. In acetabular fractures involving the inferior rim or in pincer-type femoroacetabular impingement addressed with rim trimming, recognizing the notch and adjacent horn anatomy helps you describe fracture lines, resection limits, and labral attachment sites without ambiguity. Use this illustration in pelvic and hip modules for gross anatomy and orthopedics, in surgical education materials for hip arthroscopy and total hip arthroplasty orientation, and in publisher graphics explaining acetabular labrum continuity at the transverse acetabular ligament. Anatomical accuracy verified by SciePro's Medical Advisory Board.