How many bones does the adult human body have?

Correct Answer: B

Rationale: The adult human skeleton typically consists of 206 bones. This number accounts for the fusion of certain bones (e.g., sacrum, coccyx) that occurs after infancy, when the count is higher (around 270). 210 is close but slightly over, while 180 and 126 are significantly under the standard count.

Correct Answer: A

Rationale: Most cranial bones (e.g., frontal, parietal, occipital) are flat, providing a broad, protective shield for the brain. Irregular bones (e.g., sphenoid, ethmoid) exist in the skull, but flat bones predominate in the cranium.

Correct Answer: A

Rationale: The mandible (lower jaw) is the only movable bone of the skull, articulating at the temporomandibular joint for actions like chewing. The hyoid, while in the neck, is not part of the skull and doesn’t move in the same context.

Correct Answer: B

Rationale: The vertebral arch, posterior to the body, consists of two pedicles (attaching to the body) and two laminae (flat plates forming the arch’s roof). Processes (e.g., spinous, transverse) project from the arch but are not its core components.

Correct Answer: B

Rationale: The scapula (shoulder blade) is triangular, with a broad base superiorly and an apex inferiorly, optimizing muscle attachment and shoulder mobility. It’s neither rectangular nor square.