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Policy#: 529-331

Title: ANIMAL USE PROCEDURE: Cervical Dislocation

Effective: 8/19/2021


Related Policies and Guidance

This policy does not address the use of cervical dislocation for emergency euthanasia in the field.  See guidance on "Euthanasia of Wildlife in Emergency Situations” (

As a laboratory-specific animal training procedure, it is the responsibility of the PI to ensure that all personnel receive the appropriate training and maintain documentation for the laboratory-specific training in their lab, per Policy 529-251: Policy on Training of Animal Users ( 

Cervical dislocation of ANESTHETIZED animals

Cervical dislocation of anesthetized animals is an acceptable method of euthanasia for small rodents (<200 g), immature rabbits (< 1 kg), bats and similar small species, and does not require a specialized scientific justification.  In heavier rats and rabbits, the greater muscle mass in the cervical region makes manual cervical dislocation physically more difficult; accordingly, it should be performed only with mechanical dislocators or by individuals who have demonstrated proficiency in euthanizing heavier animals.

Investigators must provide details of the anesthesia used (chemical, dose, volume and route of injection), as well as clear methods for determining adequate depth of anesthesia prior to either decapitation or cervical dislocation.

Cervical dislocation of UNANESTHETIZED animals

Cervical dislocation of unanesthetized animals can only be approved for small rodents (<200 g), immature rabbits (< 1 kg), bats and similar small species, and with the following conditions:

  • A scientific justification explaining why anesthesia cannot be used must be provided in the AUP.
  • The protocol must include a description of the procedure, including the criteria used to assess the success of the procedure.
  • The protocol must state that individuals being trained in this procedure will practice on anesthetized animals until the trainer is confident in the trainee’s competence in this procedure.

Example procedure description

  1. Restrain the rodent in a normal standing position on a firm, flat surface and grasp the tail (in some cases the hind limbs may be grasped more easily) with one hand.
  2. Place a solid rod-shaped object (e.g., pen), or the thumb and first finger of the other hand against the back of the neck at the base of the skull.
  3.  To produce the dislocation, quickly push forward and down with the hand or object restraining the head while pulling backward with the hand holding the tail.

Performing the procedure on a surface that the animal can grip may make it easier to gain access to the base of the skull because rodents often stretch themselves forward when held by the tail.

The effectiveness of dislocation can be verified by separation of cervical tissues. When the spinal cord is severed, a 2-4 mm space will be palpable between the occipital condyles and the first cervical vertebra. Occasionally, however, the dislocation occurs between thoracic vertebrae. Check closely to confirm respiratory arrest and when possible verify, by palpation, that there is no heartbeat.


Approved: 10/6/2008; latest revision 7/19/2021