Chapter 77: Pelvic Girdle, Hip, Gluteal Region & Thigh

Pelvic Girdle, Hip, Gluteal Region & Thigh anatomy chapter meticulously details the pelvic girdle, the hip joint, and the structures constituting the gluteal region and thigh, emphasizing their profound significance in human locomotion, weight-bearing function, and clinical practice. The skeletal framework of the pelvic girdle is formed by the paired hip bones (ilium, ischium, pubis) and the sacrum, creating a protective and weight-distributing ring with restricted movement, notable exceptions being during female parturition. The hip joint is a highly stable, large ball-and-socket synovial articulation between the femoral head and the acetabulum, acting as an essential mechanical pivot for body movements, including standing and bending. The thigh region is structurally defined by the strong femoral shaft encased in muscle groups residing within anterior, posterior, and medial osteofascial compartments, delineated by the enveloping fascia lata and its septa. The proximal femur is described in detail, including the head, the neck (defined by the neck-shaft angle and the angle of anteversion), and the greater and lesser trochanters, with recognition of specific bone architecture such as trabeculae patterns related to stress and weight transmission, and the clinical importance of ossification timing in relation to conditions like slipped capital femoral epiphysis (SCFE). The structural integrity of the hip is enhanced by strong capsular ligaments, including the robust iliofemoral ligament, which become taut in hip extension, contributing significantly to joint stability. Functionally, muscles are organized into extensors (quadriceps femoris) and flexors (hamstrings), supplied predominantly by the femoral nerve and sciatic nerve, respectively, while the adductors receive supply mainly from the obturator nerve. Clinically critical neurovascular structures traverse this region, notably the femoral artery and its deep branch, the profunda femoris artery, which forms key anastomotic networks for collateral circulation. Biomechanically, maintaining pelvic stability during single-limb stance relies heavily on the hip abductor muscles (gluteus medius and minimus), and failure of this mechanism yields the characteristic Trendelenburg sign. The chapter also covers specific peripheral nerve entrapment syndromes, such as meralgia paraesthetica affecting the lateral femoral cutaneous nerve and the potential involvement of the obturator nerve leading to the Howship-Romberg sign.