What causes the neck to pop?

Stretching or bending of the neck can cause the neck to pop, according to The New York Times. These motions reduce the pressure on the neck joints, causing the fluid in the joint capsules to release gas and make a popping sound.

Tendons snapping back into place after a movement can also cause the neck to pop, notes the Library of Congress. As the neck moves, the tendons can shift; when the neck returns to a neutral position, the tendons may pop back into place. People with arthritis may also notice noise in the neck joints due to the degraded cartilage.