What are the 26 bones of the spine called?

Correct Answer: B

Rationale: The human spine, or vertebral column, consists of 26 individual bones in children (33 before some fuse in adulthood), collectively called vertebrae. These include 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused into the sacrum), and 4 coccygeal (fused into the coccyx). Ribs protect the chest, skull bones form the head, and pelvic bones support the lower body, making 'vertebrae' the correct answer.

Correct Answer: B

Rationale: The diaphysis is the long, cylindrical shaft of a long bone, primarily compact bone, providing strength. The epiphysis is the end, the endosteum lines the interior, and the periosteum (misspelled here as 'periosteium') is the outer membrane, making 'diaphysis' the correct answer.

Correct Answer: C

Rationale: Osteons (or Haversian systems) are the cylindrical units of compact bone, containing lamellae, a central canal, and osteocytes. Lamellae are layers within osteons, canaliculi are channels, and trabeculae are in spongy bone, making 'osteons' the correct answer.

Correct Answer: C

Rationale: Intramembranous ossification forms bone directly from fibrous connective tissue membranes, as in flat skull bones. Hematopoiesis makes blood cells, endochondral ossification uses cartilage, and remodeling reshapes bone, making 'intramembranous ossification' correct.

Correct Answer: D

Rationale: The appendicular skeleton includes limbs and girdles. The coxal bone (hip) is part of the pelvic girdle, thus appendicular. Cranium, ribs, and sternum are axial skeleton components, making 'coxal bone' correct.