How to Draw Pons Cross-section ?

Pons in latin, refers to a “bridge”. Pons varolli is a part of brain-stem, that links thalamus with medulla oblongata. The cross-section of pons is similar to the midbrain as described earlier but few things must be kept in mind:

  1. The orientation of lemnisci in midbrain is more or less vertical, but in pons it is horizontal.
  2. Cranial nerve III and IV arises from midbrain and mainly Cranial nerve V, VI, VIII and VIII arises from pons.
  3. Cerebral aqueduct lies in midbrain and 4th ventricle lies in pons.

Earlier, we imagined transverse section of the midbrain as an inverted striped face of red-eyed demon. Similary, we will use the analogy of an “inverted face of a human” to draw the cross-section of pons.

pons mnemonic

Now, let’s label the structures shown above:

  1. Hair = Transverse pontine fibers
  2. Eye = Corticospinal and Corticonuclear tracts
  3. Ear = Middle cerebellar peduncle
  4. Stripes = Lemnisci
    • Medially: Medial lemniscus
    • Middle: Trigeminal lemniscus medially and Spinal lemniscus laterally
    • Lateral: Lateral lemniscus
  5. Bridge of nose = Raphe nucleii
  6. Ala of nose = Medial Longitudinal Fasciculus
  7. Mole = Facial nerve motor nucleus (In caudal pons)
  8. Moustache = Cranial nerve nucleii
    • Medial most = CN VI or Abducens nerve (In caudal pons)
    • Middle = CN V or Trigeminal nerve – motor and sensory (In rostral pons)
    • Lateral most = CN VIII – Superior vestibular nucleus (In rostral pons)
  9. Lips = Periventricular gray
    • Contains locus coeruleus
  10. Open mouth = 4th ventricle
  11. Chin = Superior cerebellar peduncle

Now, let’s look at the real picture:

pons cross-section

You can compare with your own face to learn the pons. Wasn’t that easy? Leave comments below 🙂 .

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