The intervertebral disc (IV disc) comprises three components: cartilage end plates, nucleus pulposus, and annulus fibrosus. Degenerative changes can lead to conditions such as disc protrusion and extrusion, where the nucleus can bulge or completely expel through the annulus, often due to factors like poor health, trauma, or biomechanical issues. Assessment and treatment involve evaluating posture, movement, and applying specific tests for cervical and lumbar herniated discs.