Femur Anatomy

Femur Structure

• The femur is the longest bone in the body and the only bone in the thigh.
• Divided into three areas: proximal, shaft, and distal.

Proximal Area

• Forms the hip joint with the acetabulum of the pelvis.
• Consists of a head, neck, and two bony processes (greater and lesser trochanters).
• The head articulates with the acetabulum to form the hip joint.
• The neck connects the head of the femur to the shaft.

Greater Trochanter

• The most lateral palpable projection of the bone.
• Originates from the anterior aspect, just lateral to the neck.
• Site of attachment for many muscles in the gluteal region, such as gluteus medius, gluteus minimus, and piriformis.

Lesser Trochanter

• Smaller than the greater trochanter.
• Projects from the posteromedial side of the femur, just inferior to the neck-shaft junction.
• Site of attachment for the iliopsoas.

Intertrochanteric Line

• A ridge of bone that runs in an inferomedial direction on the anterior surface of the femur.
• Connects the two trochanters together.
• Site of attachment for the iliofemoral ligament and the hip joint capsule.

Intertrochanteric Crest

• A ridge of bone that connects the two trochanters together.
• Located on the posterior surface of the femur.
• Has a rounded tubercle on its superior half, called the Quadrate tubercle.

Shaft of Femur

• Descends in a slight medial direction.
• Brings the knees closer to the body's center of gravity, increasing stability.
• A cross-section of the shaft in the middle is circular but flattened posteriorly at the proximal and distal aspects.

Distal End of Femur

• Presence of medial and lateral condyles, which articulate with the tibia and patella to form the knee joint.
• Medial and lateral condyles are rounded areas at the end of the femur.
• The posterior and inferior surfaces articulate with the tibia and menisci of the knee, while the anterior surface articulates with the patella.

Patella (Knee-cap)

• Located at the front of the knee joint, within the patellofemoral groove of the femur.
• Classified as a sesamoid type bone due to its position within the quadriceps tendon.
• Largest sesamoid bone in the body.

Bony Landmarks of Patella

• Patella has a triangular shape, with anterior and posterior surfaces.
• Apex of patella is situated inferiorly and connected to the tibial tuberosity by the patellar ligament.
• Base forms the superior aspect of the bone and provides attachment area for the quadriceps tendon.

Functions of Patella

• Has two main functions:
  • Leg extension: Enhances power that quadriceps tendon can exert on the femur, increasing efficiency of the muscle.
  • Protection: Protects the anterior aspect of the knee joint from physical trauma.