A herniated disc (also called bulged, slipped or ruptured) is a fragment of the disc nucleus that is pushed out of the annulus, into the spinal canal through a tear or rupture in the annulus. Discs that become herniated usually are in an early stage of degeneration. The spinal canal has limited space, which is inadequate for the spinal nerve and the displaced herniated disc fragment. Due to this displacement, the disc presses on spinal nerves, often producing pain, which may be severe.
https://www.aans.org/en/Patients/Neurosurgical-Conditions-and-Treatments/Herniated-Disc#:~:text=A%20herniated%20disc%20(also%20called,or%20rupture%20in%20the%20annulus.