Question

Articulating surfaces have both concave and convex regions; surface of one bone fits the complementary surface of another

A. Saddle joint
B. Ball-and-socket joint
C. Condyloid joint
D. Gliding joint

Answer 1

Saddle joints have both concave and convex regions, enabling bones to fit together. An example is the first carpometacarpal joint, which provides the thumb the ability to move in different planes.

Step-by-step explanation:

Saddle joints have both concave and convex regions on their articulating surfaces, allowing the surface of one bone to fit the complementary surface of another. An example of a saddle joint is the first carpometacarpal joint between the trapezium and the first metacarpal bone at the base of the thumb, which gives humans their opposable thumbs. Therefore, the correct answer is A. Saddle joint.