Question

Which of the following definitions BEST describes a saddle joint?

A. Each of the joint surfaces has both a concave and convex surface.
B. One joint surface is concave and the other surface is convex.
C. Each of the joint surfaces is relatively flat.
D. One joint surface fits like a peg in the hole of the opposite joint surface.

Answer 1

A saddle joint is a type of synovial joint where the articulating surfaces have a saddle shape. It allows movement in different planes and is primarily found at the base of the thumb. Saddle joints are functionally classified as biaxial joints.

Step-by-step explanation:

A saddle joint is defined as a type of synovial joint where both articulating surfaces have a saddle shape, with one surface concave and the other convex. This allows the bones to fit together like a rider sitting on a saddle. A primary example of a saddle joint is the first carpometacarpal joint at the base of the thumb, which enables thumb movement in different planes. Saddle joints are functionally classified as biaxial joints.