Question

The elbow is an example of which type of joint?

a. hinge

b. pivot

c. saddle

d. gliding

Short answer

The correct answer is (a) hinge

The elbow is an example of hinge joint.

Step-by-step solution

Step 1. Introduction

A joint is a point where two bones make contact. Joints can be classified either histologically on the dominant type of connective tissue functionally based on the amount of movement permitted.

The six types of freely movable joint include ball and socket, saddle, hinge, condyloid, pivot and gliding.

Step 2. Explanation for the correct answer

a. hinge

• In hinge joints, the slightly rounded end of one bone fits into the slightly hollow end of the other bone. In this way, one bone moves while the other remains stationary, like the hinge of a door.
• The elbow is an example of a hinge joint.
• The elbow is a hinge joint consisting of three bones, the humerus, the ulna and the radius.

Step 3. Explanation for the incorrect answer

b. pivot

• Pivot joints consist of the rounded end of one bone fitting into a ring formed by the other bone. This structure allows rotational movement, as the rounded bone moves around its own axis.
• An example of a pivot joint is the joint of the first and second vertebrae of the neck that allows the head to move back and forth.

c. saddle

• Saddle joints are so named because the ends of each bone resemble a saddle, with concave and convex portions that fit together. Saddle joints allow angular movements similar to condyloid joints but with a greater range of motion.
• An example of a saddle joint is the thumb joint, which can move back and forth and up and down, but more freely than the wrist or fingers.

d. gliding

• The gliding joint is a synovial joint built between two bones that meet on flat articular surfaces allowing sliding or gliding motion.
• Example of a gliding joint is the wrist joint.