A facial bone that is not paired is the

Correct Answer: C

Rationale: The vomer is a single, midline facial bone forming part of the nasal septum. Maxillae, lacrimals, and nasals are paired bones, while the vomer is unpaired, making it the correct choice.

Correct Answer: D

Rationale: The os coxa (hip bone) comprises the ilium, ischium, pubis, acetabulum (socket), and obturator foramen. The capitulum is a feature of the humerus, not the os coxa.

Correct Answer: A

Rationale: The sphenoid bone lacks a styloid process. The temporal bone has a styloid process (near the ear), and the ulna and radius have styloid processes at their distal ends in the wrist.

Correct Answer: B

Rationale: The periosteum is a dense connective tissue membrane covering the outer surface of bones, aiding in growth, repair, and attachment. The pericardium surrounds the heart, perichondrium covers cartilage, and endosteum lines the medullary cavity—only periosteum fits the description.

Correct Answer: B

Rationale: Vertebrae are classified as irregular bones due to their complex, unique shapes that don’t fit the long, short, or flat categories. Long bones (e.g., femur) are elongated, flat bones (e.g., sternum) are thin, and short bones (e.g., carpals) are cuboidal—vertebrae match none of these.