Biology · Locomotion and Movement · NEET
The clavicle (collar bone) belongs to the PECTORAL girdle. NCERT states each half of the pectoral girdle consists of a clavicle and a scapula. The pelvic girdle has NO clavicle at all; it is made only of coxal bones. So if a question mentions clavicle, the answer is always pectoral (shoulder), never pelvic (hip).
The PECTORAL girdle has the glenoid cavity (a depression below the acromion of the scapula) that holds the head of the humerus, forming the shoulder joint. The PELVIC girdle has the acetabulum, the cavity where the three coxal bones fuse, that holds the head of the femur (thigh bone). NEET reverses these to trap you, so memorise: Glenoid = shoulder = arm; Acetabulum = hip = leg.
Each half of the pectoral girdle has 2 separate bones (clavicle + scapula), so the whole pectoral girdle = 4 bones. Each half of the pelvic girdle is a single coxal bone (itself formed by fusion of 3 bones), so the whole pelvic girdle = 2 coxal bones. The key exam point: pectoral bones stay separate, pelvic bones are fused.
Each coxal bone is formed by the fusion of three bones: ilium, ischium and pubis. At their point of fusion lies the acetabulum, which articulates with the thigh bone (femur). Remember the order ilium (upper), ischium (lower-back), pubis (front).
The pelvic girdle carries body weight and joins firmly to the sacrum (axial skeleton), so it is fixed and strong for support. The pectoral girdle attaches loosely, mainly through muscles and the clavicle, which lets the shoulder and arm move freely in many directions. For NEET, link pelvic = weight-bearing/stable, pectoral = mobile.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
No. The scapula belongs only to the pectoral girdle. The pelvic girdle is made of two coxal bones (each a fusion of ilium, ischium and pubis).
The pelvic girdle. It is thick and firmly fixed to the vertebral column to bear the weight of the body, while the pectoral girdle is light and mobile.
The head of the humerus (upper arm bone) fits into the glenoid cavity of the scapula to form the shoulder joint.
The head of the femur (thigh bone) fits into the acetabulum of the coxal bone to form the hip joint.
The collar bone (clavicle) is an arm girdle bone; it is part of the pectoral girdle, not the pelvic girdle.
