Which of the following muscles is primarily responsible for the flexion of the forearm at the elbow joint?

A. Pivot joint:Pivot joints permit rotational movement around a single axis (for example the atlantoaxial joint) but have limited overall range compared with multiaxial joints.
B. Saddle joint:Saddle joints allow biaxial movement (for example the thumb carpometacarpal joint) and provide greater motion than a hinge but less than multiaxial joints.
C. Ball-and-socket joint:Ball-and-socket joints (such as the shoulder and hip) allow multiaxial movement including flexion/extension, abduction/adduction, and rotation, providing the greatest range of motion.
D. Hinge joint:Hinge joints permit movement primarily in one plane (flexion and extension), giving a more limited range compared with ball-and-socket joints.

A. Saddle joint: Saddle joints allow biaxial movement (e.g., thumb carpometacarpal joint) but do not permit movement in all directions.
B. Pivot joint: Pivot joints allow rotation around a single axis (e.g., atlantoaxial joint) and therefore do not provide multiaxial movement.
C. Hinge joint: Hinge joints permit movement primarily in one plane (flexion/extension) like the elbow and do not allow movement in all directions.
D. Ball-and-socket joint: Ball-and-socket joints (for example the shoulder and hip) permit multiaxial movement including flexion/extension, abduction/adduction, and rotation, allowing the greatest directional range.