M02.02.02 The pons

The pons is a region of the brainstem that plays a vital role in relaying signals between various parts of the brain and spinal cord. It is located below the midbrain and above the medulla oblongata. Here’s an overview of the external and internal anatomy of the pons, including its nuclei and vasculature:

External Anatomy:

• Location: The pons is situated between the midbrain rostrally (superiorly) and the medulla oblongata caudally (inferiorly).
• Size and Shape: It is a larger structure compared to the midbrain and has a bulging appearance.
• Anterior Surface: The ventral (anterior) surface of the pons is marked by transverse fibers known as the pontine basilar sulcus, which separates it from the medulla oblongata.
• Posterior Surface: The dorsal (posterior) surface of the pons forms a part of the floor of the fourth ventricle.

Internal Anatomy:

• Nuclei: The pons contains several important nuclei involved in various functions:
  • Cranial Nerve Nuclei: The pons houses the nuclei of cranial nerves V (trigeminal), VI (abducens), VII (facial), and VIII (vestibulocochlear). These nuclei are responsible for sensory and motor functions of the face, jaw, and hearing and balance.
  • Pontine Nuclei: These nuclei are involved in the coordination of movements, particularly in connection with the cerebellum.
• Ascending and Descending Tracts: The pons contains both ascending and descending nerve tracts that transmit sensory and motor information between the brain and spinal cord.

Vasculature:

• Basilar Artery: The pons receives their main blood supply from the basilar artery, which is formed by the fusion of the vertebral arteries. The basilar artery runs along the anterior surface of the pons and gives rise to multiple branches supplying the structure.
• Pontine Arteries: The basilar artery gives off pontine arteries that penetrate into the substance of the pons to provide oxygenated blood to its internal structures.

Understanding the internal anatomy, nuclei, and vasculature of the pons is crucial for evaluating and managing various neurological conditions. Disruptions in the blood supply to the pons can result in conditions like pontine infarction (stroke), affecting the functions associated with this region. Diagnostic techniques such as MRI or CT scans are used to visualize the pons and identify any abnormalities. Additionally, neurological assessments and evaluation of cranial nerve function help diagnose and manage disorders involving the pons.