A NEET stem naming the 9th or 12th rib pair is testing whether you remember that only the first 7 pairs attach directly to the sternum. Pairs 8–10 are vertebrochondral (false) ribs — they join the 7th rib's cartilage rather than the sternum itself — and pairs 11–12 are floating ribs with no ventral attachment at all (NCERT Class 11 Biology, Chapter 17, page 225). Collapsing this three-way split into a binary true/false memory is a common miss.
The skeletal inventory carries the same trap in numeric form. The human skeleton totals 206 bones, split into an axial set of 80 (skull, vertebral column, sternum, ribs) and an appendicular set built from four limbs of 30 bones each plus the two girdles (NCERT Chapter 17, page 224, page 226). A skull count of 22 (8 cranial + 14 facial) and a vertebral column of 26 units (7 cervical, 12 thoracic, 5 lumbar, plus the fused sacral and coccygeal regions) are the two sub-counts NEET asks for directly.
Joints classify by how much movement they allow, not by whether a question implies movement is the default. Fibrous joints — the sutures fusing the flat skull bones — allow no movement. Cartilaginous joints, like the pubic symphysis or the joints between vertebrae, allow limited movement. Only synovial joints, with their fluid-filled cavity, allow considerable movement (NCERT Chapter 17, page 227). Assuming "joint" implies at least some flex is the trap: a suture is rigid by design.
The six named disorders pair a structure with a cause, and NEET swaps the pairing: tetany is a Ca++-deficiency spasm disorder (not uric acid), osteoporosis tracks falling estrogen and bone mass, and gout is uric acid crystal accumulation in joints (NCERT Chapter 17, page 227). Myasthenia gravis, muscular dystrophy and arthritis complete the six but carry no numeric-swap trap.
Watch out: this dossier's own PYQ pattern is chapter-wide (digestion, breathing, circulation, excretion), not specific to this topic — none of its questions ground this lesson's MCQs or worked example.