E-Pearl of the Week: Gates' Rule of 4 of the Brainstem

November 28, 2011


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November 28, 2011

Gates' Rule of 4 of the Brainstem: A Simple Method to Demystify the Brainstem

According to Gates' rule of 4, there are 4 structures in the midline of the brainstem beginning with M: motor pathway or cortical spinal tract, motor cranial nerves (3, 4, 6 and 12), medial lemniscus, and medial longitudinal fasciculus. There are 4 lateral structures beginning with "S" including the spinocerebellar pathways, sympathetic pathway, spinothalamic pathways and sensory nucleus of trigeminal nerve. There are 4 cranial nerves above the pons (1-4), 4 in the pons (5-8), and 4 in the medulla. Knowledge of the rule of 4 makes the teaching and diagnosis of brainstem syndromes less challenging.


  1. Gates P. The rule of 4 of the brainstem: a simplified method for understanding brainstem anatomy and brainstem vascular syndromes for the non-neurologist. Intern Med J. 2005; 35: 263-266.

Submitted by: Tissa Wijeratne

Disclosures: Dr. Wijeratne has nothing to disclose.

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