If the head of the femur is dislocated postero-medially, compression of which nerve is likely to be a result?
## **Core Concept**
The question tests knowledge of hip anatomy and the potential consequences of a postero-medial dislocation of the femoral head on surrounding nerves. The hip joint is innervated by several nerves, but the one most likely to be compressed by a dislocated femoral head is related to its proximity and anatomical relationship.
## **Why the Correct Answer is Right**
The correct answer, , involves understanding that a postero-medial dislocation of the femoral head would likely compress the obturator nerve. The obturator nerve arises from the lumbar plexus (L2-L4), passes through the obturator canal, and provides innervation to the medial thigh muscles. Due to its anatomical location, a postero-medial dislocation of the femoral head could easily compress this nerve.
## **Why Each Wrong Option is Incorrect**
- **Option A:** The sciatic nerve, while a major nerve in the lower limb, is more commonly associated with posterior dislocations of the hip due to its posterior location relative to the hip joint. A postero-medial dislocation might not directly compress this nerve as much as a purely posterior dislocation would.
- **Option B:** The femoral nerve is located anteriorly and is less likely to be compressed by a postero-medial dislocation of the femoral head. It's more associated with anterior hip or thigh trauma.
- **Option D:** The pudendal nerve, primarily involved in pelvic floor function and not directly related to hip joint dislocation consequences in terms of nerve compression.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that femoral head dislocations can have serious complications, including avascular necrosis, and nerve injuries. The obturator nerve's proximity to the hip joint makes it susceptible to injury in hip dislocations, particularly those with a postero-medial direction.
## **Correct Answer:** . obturator nerve