Lecture on Pontine Lesions

Introduction

• Topic: Pontine Lesions
• Focus: Different types of pontine lesions, their structures, symptoms, and clinical relevance.

Ventral Pontine Syndrome (Millard-Gubler Syndrome)

• Lesion Location: Ventral aspect of the pons (basilar part)
• Structures Involved:
  • Facial nerve fasciculus
  • Abducens nerve fasciculus
  • Corticospinal fibers
• Symptoms:
  • Ipsilateral facial nerve palsy:
    • Causes drooping of the face.
    • Loss of lacrimation and salivation.
    • Loss of taste from anterior two-thirds of the tongue.
    • Loss of sensation from external ear and tympanic membrane.
  • Ipsilateral lateral rectus palsy:
    • Eye deviates medially due to unopposed medial rectus.
  • Contralateral hemiplegia:
    • Paralysis of muscles on the opposite side.

Foville Syndrome

• Lesion includes ventral and part of tegmental area of the pons.
• Structures Involved:
  • Facial nerve
  • Abducens nerve
  • Corticospinal fibers
  • Paramedian Pontine Reticular Formation (PPRF)
• Symptoms:
  • Same as Millard-Gubler Syndrome:
    • Ipsilateral facial nerve palsy
    • Ipsilateral lateral rectus palsy
    • Contralateral hemiplegia
  • Ipsilateral gaze palsy
    • Due to damage to PPRF affecting corrective saccades.

Raymond Syndrome (Ventro-medial Pontine Syndrome)

• Lesion primarily affects the ventral part of the pons.
• Symptoms:
  • Ipsilateral facial nerve palsy
  • Contralateral hemiplegia

Lateral Pontine Syndrome (Marie-Foix Syndrome)

• Lesion affects the lateral aspect of the pons.
• Structures Involved:
  • Corticospinal and corticobulbar fibers
  • Spinal lemniscus
  • Possible middle cerebellar peduncle
• Symptoms:
  • Contralateral hemiplegia
  • Contralateral loss of pain, temperature, crude touch, and pressure sensations
  • Ipsilateral cerebellar ataxia
    • Due to middle cerebellar peduncle involvement.

Blood Supply to the Pons

• Main Artery: Basilar artery and its branches.
• Other Contributors:
  • Anterior Inferior Cerebellar Artery (AICA)
  • Short and long circumferential branches of the basilar artery.
• Clinical Relevance: Knowledge of blood supply helps in understanding the effects of vascular lesions.

Locked-In Syndrome

• Lesion: Bilateral pontine lesion, primarily ventral.
• Effects:
  • Quadriplegia: Due to bilateral corticospinal tract damage.
  • Aphonia: Loss of speech due to corticonuclear tract damage.
  • Bilateral internuclear ophthalmoplegia with horizontal gaze palsy: Involving abducens nuclei and medial longitudinal fasciculus.
  • Reticular formation intact: Patients remain conscious and aware but cannot move or speak.

Conclusion

• Summary of key points about pontine lesions and their clinical presentations.
• Importance of understanding the neuroanatomical basis for diagnosis and treatment.
• Encouragement to review associated videos and reference materials.

Additional Resources

• Links to social media and support platforms for further learning and discussions.