Anatomy & Structural Pathophysiology
The hip is a multi-axial, ball-and-socket synovial joint formed by the articulation between the rounded head of the femur and the acetabular socket of the pelvis[1]. It is designed to accommodate weight-bearing forces while providing multi-directional movement.
Articular Cartilage & Labrum
Hyaline cartilage covers the femoral head and acetabulum to absorb load forces[2]. The fibrocartilaginous acetabular labrum deepens the socket and provides a mechanical seal to stabilize the joint.
Joint Capsule & Ligaments
Strong capsular ligaments (iliofemoral, ischiofemoral, pubofemoral) enclose the articulation to restrict excessive extension and rotation, maintaining passive joint stability.
Periarticular Bursae
Bursae (such as the trochanteric and iliopsoas bursae) minimize friction between bony prominences and overlying tendinous structures during continuous locomotion[3].
Differential Diagnosis by Pain Location
In adult patients, hip discomfort is classified by its anatomical location into anterior (groin), lateral, and posterior regions to aid differential diagnosis[1][5].
Hip Osteoarthritis (OA)
Intra-articularProgressive joint cartilage degeneration leading to narrowing of the joint space, subchondral sclerosis, and osteophyte formation[2]. Characterized by groin pain aggravated by weight-bearing and internal rotation stiffness[4].
Femoroacetabular Impingement (FAI) & Labral Tear
Intra-articularAbnormal anatomical contact between the proximal femur and acetabular rim (Cam or Pincer morphology)[1], often resulting in mechanical tears of the acetabular labrum during repetitive hip flexion.