Summary Neuro week 3

Week 3 – Brainstem & cranial nerves

General functions of parts of brainstem

- Discrimination of tone & sound recognition
Midbrain - Vision
- Light reflex
- Movements of eyes
- Maintenance of awake state
Pons - Connects cerebrum & cerebellum
- Muscle movements of face
- Hearing & spatial orientation
- Balance
Medulla - Movements of tongue
- Sensation from head & neck area


Anatomy of the brainstem

- Lies upon the basal part of the occipital bone

- Largely covered by the cerebellum

I. Dorsal aspect of brainstem

- Viewed by removing the cerebellum (& cutting the peduncles)

- From the bottom upwards:

1. Medulla

 Dorsal median sulcus
o Marks the midline of the brainstem
o Continuous with the spinal cord
 Fasciculi gracilis & cuneatus
o Dorsal columns pass from the SC > through the fasciculi > terminate in the nucleus gracilis & cuneatus
(Gracile & cuneate tubercles)
 In rostral medulla, the central canal of the SC
opens into the floor of the 4th ventricle
 Floor of the 4th ventricle
o Shallow rhomboid depression
o Caudal 1/3 of floor
 Made up by the medulla
o Rostral 2/3 of floor
 Made up by the pons
o Widest at the ponto-medullary junction
 In this region, the lateral recess
extends to the lateral margin of
the brainstem
 Lateral apertures are at the ends
of the lateral recesses
 Passage of CSF from the
4th ventricle to the sub-
arachnoid space