ARTICULACION DE LA CADERA

Hip Joint Anatomy and Function

Overview of the Hip Joint

• The hip joint, also known as the cox of emerald joint, is a crucial mobile joint in the body due to its structure as an endarthrosis within diarthrosis. Its articular surfaces are spherical segments.

Structure of the Femur

• The femur connects the lower limb to the trunk via its proximal epiphysis, which includes a head and neck. The anatomical neck is significant for understanding fracture locations.

• The femur's neck forms an angle with the body called the angle of roulet, approximately 125 to 130 degrees, indicating its orientation.

Articular Surfaces and Features

• The head of the femur comprises two-thirds of a spherical segment with a smooth surface and a radius between 20 to 25 mm, covered by interarticular fibrocartilage.

• A triangular depression on the internal surface serves as an insertion point for the round ligament (fossa capitis). Key muscle insertions include those for iliopsoas on the lesser trochanter and external obturator on the greater trochanter.

Coxal Bone Contributions

• The coxal bone consists of three parts: ileum, pubis, and ischium, forming the acetabular cavity—a concave depression that facilitates hip joint function. This cavity has an acetabular notch interrupted by ischiapuvian notch at its base.

• Only part of this cavity is articular; it features a fatty layer at its bottom termed non-articular portion or phobia acetaguli where ligaments attach.

Ligaments Supporting Hip Joint Stability

• The articular capsule surrounds and stabilizes the hip joint while being reinforced by three key ligaments: iliofemoral (Burton ligament), pubofemoral, and ischiofemoral ligaments—each contributing uniquely to joint stability during movement.

• The iliofemoral ligament originates from specific pelvic structures creating a distinctive shape resembling an open letter B or Y when viewed from certain angles.

• Additionally, there’s an intraarticular round ligament extending from fossa capitis to acetabular cavity's bottom containing blood vessels like acetabular artery essential for nourishment.

Joint Movements and Types

Understanding Joint Types

• The joint discussed is classified as a diarthrosis, indicating it allows for significant movement.

• Inside the diarthrosis, there exists an anarthrosis, which encompasses all possible movements of the joint.

Range of Motion

• The joint can flex and extend up to 120 degrees, showcasing its flexibility.

• It also allows for internal and external rotation, contributing to its versatility in movement.

Additional Movements

• The joint exhibits separation and approximation movements at approximately 90 degrees, further enhancing its functional capabilities.