The Pons

Question 1

What is the largest part of the brainstem

Answer 1

The pons

Question 2

Describe the embryonic derivation of the pons

Answer 2

The pons develops from the embryonic metencephalon (part of the hindbrain, developed from the rhombencephalon), alongside the cerebellum.

Question 3

Where is the Pons located

Answer 3

In the anterior part of the posterior cranial fossa

Question 4

Anatomical relations of the pons

Answer 4

Posteriorly – the cerebellum, separated by the fourth ventricle.
Inferiorly – the medulla oblongata.
Superiorly – the midbrain lies immediately above the pons.

Question 5

Describe the pontomedullary junction

Answer 5

The pontomedullary junction is an important anatomical landmark defined by the angle between the lower border of the pons and the superior border of the medulla.

Question 6

Describe the cranial nerves that originate from the ventral surface of the pons

Answer 6

Cranial nerve V: trigeminal – originates from the lateral aspect of mid pons
Cranial nerve VI: abducens – originates from the pontomedullary junction, close to the midline
Cranial nerve VII: facial – originates from the cerebellopontine angle, the more lateral aspect of the pontomedullary junction.
Cranial nerve VIII: vestibulocochlear – originates laterally to the facial nerve.