Which bone is a paired irregular bone which articulates with the maxilla, also known as the cheekbone?

Correct Answer: C

Rationale: The zygomatic bone, a paired irregular bone, articulates with the maxilla and forms the cheekbone, contributing to the orbit’s structure. The palatine forms the palate, and the lacrimal is a small orbital bone, neither being the cheekbone.

Correct Answer: A

Rationale: The interosseous membrane, a flexible ligament, connects the ulna and radius along their lengths, stabilizing them and allowing pronation/supination. 'Intraosseous' implies within a bone, not between.

Correct Answer: C

Rationale: The fovea capitis is a small pit in the femoral head where the ligamentum teres attaches, anchoring it in the acetabulum. Other options are different femoral features (e.g., trochanters are projections).

Correct Answer: A

Rationale: The skeletal system is divided into the axial skeleton (skull, vertebral column, thoracic cage; 80 bones) and the appendicular skeleton (limbs, girdles; 126 bones), totaling 206 bones in adults. B refers to bone shapes, C to bone tissue types, and D to joint/connective tissue types—none are the main divisions.

Correct Answer: A

Rationale: The vertebral column is sequenced top-down: cervical (7), thoracic (12), lumbar (5), sacral (5, fused), coccygeal (4, fused). The thoracic region, with rib attachments, lies directly below the cervical region in the upper back.