Question

this is an example of a _______. ball - and - socket joint pivot joint saddle joint hinge joint scapula humerus

Explanation:

The shoulder joint, where the head of the humerus (ball - like structure) fits into the glenoid cavity of the scapula (socket - like structure), is a ball - and - socket joint. It allows for a wide range of motion in multiple directions. Pivot joints allow rotation around a single axis, saddle joints have a concave and convex surface interaction, and hinge joints allow movement like a door hinge (flexion and extension). The depicted shoulder joint is not any of these other types.

Answer:

A. ball - and - socket joint