Regarding the blood supply and innervation of the hip joint, all of the following are true EXCEPT:

Explanation

## Hip Joint Vascular and Nerve Supply ### Correct Statements **Key Point:** The hip joint has a rich sensory innervation from multiple nerves: - **Femoral nerve** (L2–L4): anterior and medial aspects - **Obturator nerve** (L2–L4): medial and posterior aspects - **Superior gluteal nerve** (L5–S1): posterior and superior aspects This multimodal innervation explains why hip pathology can present with referred pain in the knee or groin. **High-Yield:** The **medial circumflex femoral artery (MCFA)** is the dominant blood supply to the femoral head in adults. It arises from the profunda femoris artery, passes medially around the femur, and gives off lateral epiphyseal branches that penetrate the femoral neck to supply the femoral head. This vessel is at critical risk in femoral neck fractures, especially intracapsular fractures, leading to avascular necrosis (AVN). **Clinical Pearl:** The lateral circumflex femoral artery (LCFA) also arises from the profunda femoris artery, supplies the greater trochanter, and contributes medial epiphyseal branches to the femoral head. However, it is less critical than the MCFA for femoral head perfusion. ### The Incorrect Statement The obturator artery is **NOT** the primary blood supply to the femoral head. Instead: | Artery | Origin | Role in Femoral Head Supply | Clinical Significance | |--------|--------|------------------------------|------------------------| | **Medial circumflex femoral** | Profunda femoris | **PRIMARY** supply to femoral head (lateral epiphyseal branches) | At risk in femoral neck fractures; AVN if disrupted | | **Lateral circumflex femoral** | Profunda femoris | Secondary supply to femoral head (medial epiphyseal branches) | Less critical but contributory | | **Obturator artery** | Internal iliac | Supplies ligamentum teres artery (small, inconstant); negligible in adults | Clinically insignificant for femoral head perfusion | **Mnemonic:** **MCF = Main** (medial circumflex femoral is the dominant supply); **LCF = Less** (lateral circumflex is secondary); **OA = Obsolete** (obturator artery is negligible in adults). **Warning:** Confusion between MCFA and obturator artery blood supply is a classic exam trap. The obturator artery's role is minimal in adults and does NOT become the primary supply even in special circumstances.