Muscle & Skeletal Structures — NEET Biology

Correct answer: B — S1, S3 and S5

The question asks for correct statements concerning the joints and bones of the appendicular skeleton. S1: The appendicular skeleton consists of 126 bones (30 per limb x 4 = 120; pectoral girdle = 2 clavicle + 2 scapula = 4; pelvic girdle = 2 coxal bones = 2; total = 126 bones), connected by various joints. This statement is correct. S2: The articulation between the head of the humerus and the glenoid cavity forms the shoulder joint, which is a *ball and socket* joint, allowing multi-axial movement, not a hinge joint with uniaxial movement. Therefore, S2 is incorrect. S3: The knee joint is indeed a hinge joint, a type of synovial joint, that permits movement primarily in one plane (uniaxial), enabling flexion and extension of the lower leg. This statement is correct. S4: Gliding joints (e.g., between carpals) allow sliding movements, not 'extensive rotational movements'. Wrist articulation involves a combination of joints but gliding joints are for limited sliding. Therefore, S4 is incorrect. S5: The acetabulum, a cavity in the coxal bone (pelvic girdle), articulates with the head of the femur to form the hip joint, which is a ball and socket joint vital for lower limb locomotion. This statement is correct. Thus, statements S1, S3, and S5 are correct.