Hip joint
The hip joint is the most powerful joint in the human body. It connects the head of the femur to the acetabulum of the pelvic bone and can withstand 3-8 times your body weight when walking and running.
Bone structures
- Acetabulum (acetabulum) - a deep cup-shaped fossa formed by the fusion of the ilium, ischium and pubis
- The head of the femur is a sphere with a diameter of about 5 cm, covered with cartilage up to 3 mm thick
- Acetabulum (labrum) - a fibrocartilaginous ring that deepens the cavity and creates a “suction cup” effect
The acetabulum covers more than 50% of the surface of the head - significantly more than in the shoulder joint, which provides high stability.
Ligamentous apparatus
Three powerful ligaments strengthen the joint capsule:
- Iliofemoral (Bertini’s ligament) is the strongest ligament in the body, can withstand loads of up to 350 kg
- Pubofemoral – limits abduction and external rotation
- Ischiofemoral – limits internal rotation
Ligament of the head of the femur (teres ligament) runs inside the joint and contains the artery that supplies the head.
Blood supply
The femoral head receives blood from three sources:
- Medial and lateral circumflex femoral arteries
- Artery ligaments of the femoral head
With a femoral neck fracture, the blood supply to the head is disrupted, which leads to avascular necrosis - the main reason for the need for endoprosthetics.
Biomechanics
When standing on one leg, the hip joint experiences a load equal to 2.5 body weight: body weight + strength of the abductor muscles that balance the pelvis. When running, the peak load reaches 8 body weights.
Endoprosthetics
Hip replacement is one of the most successful surgeries in medical history. Modern dentures last 20–30 years. Indications:
- Coxarthrosis stage III–IV
- Hip fracture in the elderly
- Avascular necrosis of the head
Understanding the anatomy of the joint allows the surgeon to correctly install the components of the prosthesis and restore the biomechanics of the limb.
You can study the acetabulum, femoral head and ligamentous apparatus of the hip joint in 3D anatomy atlas Humio - zoom in, rotate and examine every detail.