Fine structure of the pons

Question 1

I. What are the characteristics of the pons?

Answer 1

1. Spinal tract + spinal trigeminal nucleus + trigeminal lemniscus
2. Medial lemiscus
3. Corticospinal tract

Question 2

II. Which nuclei appear in the caudal part of the pons?

Answer 2

1. Facial motor nucleus appears, which is rostral to the nucleus ambiguus
   -> Axon makes a loop before leaving to form facial nerve
2. Abducens motor nucleus appears, which is just rostral to the hypoglossal nucleus
   -> Axons runs ventrally to leave at near ventral midline => lateral rectu
3. Inferior salivatory nucleus appears dorsal to facial nucleus
   => Axon descend and join glossopharyngeal nerve
   => terminate in otic ganglion -> innervate the parotid gland
4. Superior olivary nucleus is relay nuclei of acoustic system
   => Axons ascend as lateral lemniscus -> terminate in midbrain inferior colliculi

Question 3

II. he rostral part of the pons
1. Which tracts appear in the tegmentum pontis, rostral part of the pons?

Answer 3

1. Medial lemniscus, the ascending tracts & lateral lemniscus course in tegmentum pontis (dorsal portion)
2. Reticular formation is also in tegmentum pontis