The pons (sometimes pons Varolii after Costanzo Varolio) is a structure located on the brain stem. It is rostral to the medulla oblongata, caudal to the midbrain, and ventral to the cerebellum. In humans and other bipeds this means it is above the medulla, below the midbrain, and anterior to the cerebellum.
The pons relays sensory information
between the cerebellum
; aids in relaying other messages in the brain; controls arousal, and regulates respiration (see respiratory centres
). In some theories, the pons has a role in dreaming
Anatomy of the pons
The "knob-like" process (Basal pons) is 2 centimeters long and located on the anterior (front) of the brainstem. It is formed of nerves that travel from one side (left or right) to the other. Most other fibres in the brainstem travel up and down.
The posterior (back) surface of the pons forms part of the wall of the fourth ventricle of the brain.
Most blood to the pons is supplied by pontine arteries. These are small arteries that branch off the basilar artery of the Circle of Willis. Blood also comes from the anterior inferior, and superior cerebellar arteries.
There are two main domains in the pons for control of respiration:
Cranial nerve nuclei
A number of cranial nerve
nuclei are present in the pons:
- Central pontine myelinosis, a demyelination disease that causes difficulty with sense of balance, walking, sense of touch, swallowing and speaking to mention just a few symptoms. In a clinical setting it is often associated with transplant. Undiagnosed it can lead to death or 'locked in' syndrome.