Upload
drpratik-mistry
View
27
Download
1
Embed Size (px)
Citation preview
INTRODUCTION• Pons means
“bridge” connect midbrain and hind brain
• Extent• Relations: ventrally
and dorsally• Laterally connected
with middle cerebellar peduncle
EXTERNAL FEATURES
• VENTRAL SURFACE: Sulcus basilaris Laterally continue with
MCP Show transverse ridges
and grooves because of ponto-cerebellar fibres
Ponto-medullary junction attachment to 6th, 7th, 8th CN
Cerebello-pontine angles
EXTERNAL FEATURES
• DORSAL SURFACE: Form upper part of floor
of 4th ventricle above medullary stria
Facial colliculus formed by
Vestibular area Locus ceruleus
(substantia ferruginea)
BASILAR PART• Traversed by
longitudinal & transverse fibres and scattered pontine nuclei
• Longitudinal fibres
• Transverse fibres
• Nuclei pontis and their role
TEGMENTAL PART• Traversed by number of ascending and
descending tracts• Contain decussation of trapezoid body, nuclei of
6th, 7th, 8th and 5th cranial nerves• Also has pontine reticular formation• Described in two parts:1. At the level of facial colliculus2. Above the level of facial colliculus
AT THE LEVEL OF FACIAL COLLICULUS
• Necklace of ascending tracts
• Medial lemniscus• Trigeminal
lemniscus• Spinal lemniscus• Trapezoid body• Nucleus of
trapezoid body and superior olivary nuclear complex
AT THE LEVEL OF FACIAL COLLICULUS• Dorsally, motor
nucleus facial nerve
• Abducent nucleus• neurobiotaxis• Superior
salivatory nucleus
• Nucleus of spinal tract of 5th CN
• Central tegmental tract
AT THE LEVEL OF FACIAL COLLICULUS• Dorso-laterally
• Middle cerebellar peduncle
• Ventral & dorsal cochlear nuclei
• Ant. Spino-cerebellar tract
• Part of inferior cerebellar peduncle
• Vestibular nuclei
ABOVE THE LEVEL OF FACIAL COLLICULUS• Smaller cavity of
4th ventricle bounded by
• Ant. Spino-cerebellar tract
• Middle cerebellar peduncle with motor and sensory roots of 5th nerve
ABOVE THE LEVEL OF FACIAL COLLICULUS• Motor nucleus of
5th nerve• Principal sensory
nucleus of 5th nerve – touch & pressure
• Mesencephlic nucleus of trigeminal nerve – proproiceptive fibres from muscles of mastication & TM Joint