Saddle joints have concave and convex surfaces. Identify a saddle joint of the skeleton.

Choice A reason: Osteocytes are mature bone cells that maintain bone tissue and communicate with other bone cells. They do not actively resorb bone.

Choice B reason: Osteoblasts are responsible for bone formation, not resorption. They synthesize and secrete the bone matrix and aid in mineralization.

Choice C reason: This is correct. Osteoclasts are large, multinucleated cells that break down bone tissue during the process of bone resorption. They release enzymes and acids that dissolve the bone matrix, playing a critical role in bone remodeling and calcium homeostasis.

Choice D reason: Osteogenic cells are stem-like precursors that differentiate into osteoblasts. They do not directly resorb bone but contribute to bone formation.

Choice E reason: Stem cells are undifferentiated cells that can give rise to various cell types, including osteogenic cells. However, they are not directly involved in bone resorption.

Choice A reason: Intercarpal joints are planar joints that allow gliding movements between the carpal bones. They do not have the saddle-shaped surfaces characteristic of saddle joints.

Choice B reason: Metacarpophalangeal joints are condyloid joints that allow flexion, extension, abduction, and adduction. They are not saddle joints.

Choice C reason: Carpometacarpal joints of the phalanges do not exist. Phalanges articulate with metacarpals, not carpals. This option is anatomically incorrect.

Choice D reason: Interphalangeal joints are hinge joints that allow flexion and extension. They do not have the concave-convex structure of saddle joints.

Choice E reason: The carpometacarpal joint of the thumb is the correct answer. It is a true saddle joint formed between the trapezium and the first metacarpal. It allows a wide range of motion, including opposition, which is essential for grasping.