Comprehensive Osteology of the Femur

1. Introduction to the Femur

The femur is the longest, heaviest, and strongest bone in the human body. Located in the thigh, it transmits weight from the pelvis to the tibia. Its morphology is designed for both stability and locomotive power.

2. Proximal Extremity

The proximal end consists of the Head, Neck, and the Greater and Lesser Trochanters.

• The Head: Smooth and spherical, it articulates with the acetabulum. The fovea capitis is a small pit for the ligamentum teres, providing a pathway for the artery of the ligamentum teres.
• The Neck: Measuring about 5 cm, it connects the head to the shaft at an angle of ~125 degrees (angle of inclination).
• Trochanters: The Greater Trochanter serves as an insertion point for the gluteus medius and minimus, while the Lesser Trochanter is the primary insertion for the iliopsoas muscle.

3. The Femoral Shaft (Corpus Femoris)

The shaft has a slight anterior bow. The most critical feature is the Linea Aspera on the posterior surface. This prominent ridge provides a site of attachment for the adductor group of muscles and the short head of the biceps femoris.

4. Distal Extremity

The distal end features two massive condyles:

• Medial and Lateral Condyles: Articulate with the tibia to form the knee joint.
• Intercondylar Fossa: A deep notch between the condyles that houses the anterior and posterior cruciate ligaments (ACL and PCL).

5. Clinical Correlates

• Hip Fractures: Commonly occur at the femoral neck in elderly patients with osteoporosis. This can lead to avascular necrosis due to damage to the medial circumflex femoral artery.
• Slipped Capital Femoral Epiphysis (SCFE): Seen in adolescents, where the femoral head slips relative to the neck.

6. Review Questions

1. Which ligament attaches to the fovea capitis?
2. What happens to the angle of inclination in Coxa Vara?
3. Which artery provides the primary blood supply to the femoral head?