An elderly woman was admitted with a fracture of the neck of right femur which failed to unite. On examination an avascular necrosis of the head of femur was noted. The condition would have resulted most probably from the damage to –
**Core Concept**
Avascular necrosis (AVN) of the femoral head occurs due to a lack of blood supply, leading to bone tissue death. This condition often results from a disruption of the blood supply to the femoral head, which is primarily provided by the medial and lateral circumflex femoral arteries.
**Why the Correct Answer is Right**
The most common cause of AVN in the context of a femoral neck fracture is damage to the medial circumflex femoral artery. This artery branches off from the profunda femoris artery and supplies the femoral head through the retinacular branches. When the femoral neck is fractured, the medial circumflex femoral artery is often damaged, leading to a loss of blood supply to the femoral head. This can cause AVN, which is a common complication of femoral neck fractures that fail to unite.
**Why Each Wrong Option is Incorrect**
**Option A:** The lateral circumflex femoral artery is also an important supplier of blood to the femoral head, but it is less commonly damaged in femoral neck fractures.
**Option B:** The inferior gluteal artery primarily supplies the gluteus maximus muscle and is not a primary supplier of blood to the femoral head.
**Option C:** The superior gluteal artery supplies the gluteus medius and minimus muscles and does not provide a significant blood supply to the femoral head.
**Clinical Pearl / High-Yield Fact**
In cases of femoral neck fractures, the risk of AVN is higher if the fracture is displaced or if there is a significant delay in surgical intervention. Early diagnosis and treatment of AVN can improve outcomes, but prevention through accurate fracture reduction and stable fixation is key.
**Correct Answer:** A. Damage to the medial circumflex femoral artery.