Which blood supply to the femoral head is most commonly disrupted in intracapsular neck of femur fractures?

Explanation

## Blood Supply to Femoral Head **Key Point:** The medial femoral circumflex artery (MFCA) is the dominant blood supply to the femoral head and is at highest risk of disruption in intracapsular neck of femur fractures. ### Vascular Anatomy The femoral head receives blood supply from two main sources: | Artery | Origin | Course | Risk in NOF Fracture | | --- | --- | --- | --- | | **Medial femoral circumflex artery** | Profunda femoris | Enters capsule posteromedially; supplies medial 2/3 of femoral head | **HIGH RISK** — disrupted in most intracapsular fractures | | **Lateral femoral circumflex artery** | Profunda femoris | Enters capsule anterolaterally; supplies lateral 1/3 of femoral head | Lower risk; less critical | | Obturator artery | Internal iliac | Small contribution via ligamentum teres | Minimal; only in young patients | | Superior gluteal artery | Internal iliac | Supplies greater trochanter and capsule | Not involved in femoral head perfusion | ### Mechanism of Vascular Disruption 1. The MFCA runs along the posterior aspect of the femoral neck within the joint capsule. 2. Intracapsular fractures disrupt the capsule and damage the small branches entering the femoral head. 3. Loss of MFCA supply → femoral head necrosis (avascular necrosis / osteonecrosis). **High-Yield:** Intracapsular NOF fractures have a 10–30% risk of AVN depending on fracture displacement and patient age. Extracapsular fractures do NOT disrupt the MFCA and have negligible AVN risk. **Clinical Pearl:** In young patients, the ligamentum teres artery (branch of obturator artery) may provide a small collateral supply, which is why young patients have a slightly better prognosis for femoral head survival, but MFCA disruption remains the primary concern. **Mnemonic:** **MFCA = Most Frequently Compromised Artery** in intracapsular NOF fractures.