Locomotion and Movement: NEET PYQ, 2018–2026

Answer: (A)

Principle: bone is continuously remodelled, and osteoporosis occurs when bone resorption outpaces bone formation, lowering bone mass and density. Its main consequence is increased fracture risk. The disorder is common in older people and postmenopausal women, where declining estrogen speeds up bone loss. Keep it distinct from disorders of the joint itself, such as arthritis and spondylitis.

Answer: (B)

Principle: hyaline articular cartilage is avascular, so its cells must obtain oxygen and nutrients by diffusion. Apply: in a synovial joint, the synovial fluid bathes the cartilage surfaces and supplies nutrients by diffusion. The distractors assign blood vessels, bone marrow or lymph roles that the avascular cartilage does not have.

Answer: (A)

Principle: ribs are classified by how their ventral ends attach. True ribs (pairs 1 to 7) attach directly to the sternum by their own costal cartilages. False ribs (pairs 8 to 10) do not reach the sternum directly; their cartilages join the cartilage of rib 7 and so reach the sternum indirectly. Floating ribs (pairs 11 and 12) have no ventral attachment at all. Application: the sternal group is pairs 1 to 10 (7 true plus 3 false), so 10 pairs. The floating group is pairs 11 and 12, so 2 pairs. Note that the dorsal attachment to vertebrae is the same for all 12 pairs, so it does not distinguish the groups; the question depends only on the ventral ends.

Answer: (D)

The joint between the carpals is the standard example of a gliding joint, one of the kinds of synovial joint. The others named in NCERT are the ball and socket, hinge, pivot and saddle joints.

Answer: (C)

Principle: rheumatoid arthritis is an autoimmune inflammatory disease of synovial joints. The immune system attacks the synovial membrane, which thickens and invades cartilage and bone. Clues here are symmetric involvement of small joints and autoantibodies. Gout (uric acid crystals) and osteoarthritis (non-inflammatory wear of cartilage) are the other common joint disorders and do not fit the autoimmune picture. Synovial fluid normally reduces friction, so its excess is not the primary cause of this damage.

Answer: (B)

Principle: the adult skeleton has 206 bones, divided into the axial skeleton (80) and the appendicular skeleton (126). The appendicular skeleton includes the limbs and their girdles. The pectoral girdle is made of the clavicle and scapula on each side, giving 4 bones. The pelvic girdle is made of the hip bones (os coxae) on each side. In the adult each os coxae is a single fused bone formed from the ilium, ischium and pubis, so the pelvic girdle has 2 bones. Application: 4 + 2 = 6. Students who lose marks here usually either forget the pelvic girdle or count the three fusing components of the hip bone separately, which is valid for a child's skeleton but not for an adult.

Answer: (B)

The human skeleton has 206 bones. The axial skeleton, along the main axis of the body, has 80: the skull, vertebral column, sternum and ribs. The appendicular skeleton, the limbs with their girdles, has the other 126.

Answer: (A)

A skeletal muscle fibre is formed in development when many single-nucleated myoblasts fuse into one long, multinucleated cell. The fibre keeps those nuclei, which is why it is large and can synthesise the proteins needed for many myofibrils. Nuclei do not divide with contraction, and the contractile machinery (actin, myosin, sarcomeres) is not separately encoded in the sarcoplasm. Remember: the multinucleate condition is a developmental fusion event, not a feature of the contraction cycle.

Answer: (B)

Principle: joints are classified by the shape of their articulating surfaces and the movement they allow. A pivot joint has a peg of bone rotating within a ring. At the atlanto-axial joint, the dens of the axis projects upward into the ring formed by the anterior arch of the atlas and the transverse ligament, so the atlas rotates on the axis. This produces the rotation of the head, like shaking the head 'no'. The atlas-occipital joint is different: it is a condylar joint allowing nodding. So the atlas-axis joint is a pivot joint, and the correct answer is pivot joint.

Answer: (A)

Muscle contraction needs ATP at two points: hydrolysis powers the myosin power stroke, and binding of fresh ATP is needed for myosin to release actin. Without ATP after death, the cross-bridges cannot break, so the muscle remains locked in a rigid state.