Uploaded byMehul Tandel
Pons Anatomy
The document outlines the structure and functions of the pons, including its external and internal features, blood supply, and connections to various cranial nerves and the cerebellum. It details the roles of distinct parts of the pons, such as the basilar and tegmentum areas, as well as the pathways for sensory and motor information transmission. It also discusses conditions associated with pons lesions, such as cerebello-pontine syndrome, with specific symptoms resulting from various neural injuries.
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Pons Anatomy
- 1. PONS D r .M e h u l T a n d e l
- 2. Objectives: (1) External featuresof Pons (2) Internal features of Pons– cross sections (1) At the level of Facial Colliculus (2) At the level of Motor & Sensory Nucleus of trigeminal nerve (3) Blood supply with Applied aspects
- 3. Connects the medulla& midbrain Function Transmit information between spinal cord & higher brain regions via neural circuits Relay motor information between cerebral cortex & cerebellum
- 4. PONS PONS M C P Length – 2.5cm External features .. 1. Dorsal & ventral surfaces… - transvereslystriated 2. Basilar sulcus (vertical) .. Lodges Basilar Artery. 3. Dorsal surface forms upper part of floor of 4th Ventricle. 5. Laterally .. Continuous with Middle Cerebellar Peduncle - trigeminal nerve 6. Superior border - 3rd ,4th 7. Inferior border .. With 6th, 7th & 8th C.N. BASILAR GROOVE
- 5. PONS External features Cerebello-pontine angle FacialColliculus Vestibular Area
- 6. MID BRAIN PONS 4th ventricle PONS Posteriorsurface 6th C.N. 7th C.N. 8th C.N. Anterior surface 5th C.N.
- 7. Lower part Upper part Internal features •By 2 sections. • (1) At lower part of medulla Fascial Colliculus • (2) At upper part At motor & Sensory Nucleus of Trigeminal nerve
- 8. • The ponsis divisible into - ventral part (basilar) & dorsal part (Tegmentum). Ventral (basilar) part - The basilar (ventral) part has a uniform structure throughout length of pons. - contains transverse and vertical fibres & Pontine nuclei. (i) Transverse fibres are the pontocerebellar fibres- cross the midline to enter the opposite middle cerebellar peduncle. (ii) The vertical fibres - - Some of them descend from cerebral cortex to end in the pontine nuclei. (corticopontine) - Corticospinal fibres that descend through the pons in to the medulla . - Corticonuclear fibres end in the motor nuclei of cranial nerves mainly of opposite side. Internal = Basilar & Tegmental Part -The basilar (Ventral) part - Uniform structure throughout -Tegmentum (dorsal) part - Differs in upper & lower part of pons.
- 9. C.S. at FascialColliculus
- 10. C.S. of Atmotor & Sensory Nucleus of Trigeminal nerve
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- 13. Ventral(Basilar)PartPons GREY MATTER Pontine nuclei: Afferents- Corticopontine fibres of the same side. Efferents - Pontocerebellar fibres that cross the midline & pass through the middle cerebellar peduncle to enter the cerebellum. (Cortico-ponto-cerebellar pathway) Middle cerebellar peduncle
- 14. WHITE MATTER Longitudinal fibres:-Corticospinal and Corticonuclear (pyramidal) tracts. Transverse fibres:- Pontocerebellar Going to opposite half of cerebellum through middle cerebellar peduncle Ventral(Basilar)PartPons
- 15. Tegmentum of pons(dorsal part) Differs in upper & lower part of pons
- 16. C.S. at FacialColliculus Abducent Nucleus Motor Nucleus of Facial Nerve Internal genu - Facial Colliculus Neurobiotaxis ?
- 17. C.S. at FacialColliculus Superior salivatory Nucleus Lacrimatory Nucleus Nucleus Tractus Solitarius – Upper End
- 18. C.S. at FacialColliculus Vestibular Nucleus Spinal Nucleus & Spinal Tract of V
- 19. Superior Olivary NuclearComplex Principal Superior Olivary Nucleus Accessory Superior Olivary Nucleus Retro - Olivary Nucleus
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- 21. C.S. at FacialColliculus
- 22. C.S. at FacialColliculus
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- 24. C.S. at FacialColliculus Dorsal Cochlear Nucleus Ventral Cochlear Nucleus
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- 26. C.S. of Atmotor & Sensory Nucleus of Trigeminal nerve
- 27. Trigeminal nuclie –Motor & Sensory
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- 29. Trigeminal nuclie –Motor & Sensory
- 30. Trigeminal nuclie –Motor & Sensory Trigeminal Ganglion
- 31. Muscles of Mastication TensorTympani Tensor veli Palatini Ant Belly of Digastric Motor Nucleus Of V Nerve
- 32. Sensory Nuclei OfVth Nerve Spinal Nucleus Pain & Temperature Mesencephalic - Proprioceptive Principal Sensory Touch & Pressure From- Ipsilateral Face 1st Order Neuron
- 33. Sensory Nuclei Of VNerve
- 34. Pain & Temperature SpinalNucleus Of V Nerve
- 35. Efferent: - Ventral trigemino thalamictract (Trigeminal Lemniscus) - Terminate : VPM of Thalamus Nuclie Of V Nerve VPM
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- 40. Efferent – 1.MLF • Intrduction / Definition • Extent • Formation • Function • Applied – MLF Syndrome – Ipsilateral palsy of medial rectus – Contralateral Mononuclear horizontal nystagmus on adduction of eye
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- 42. Efferent – 3.Hair Cells of Macula & Ampullary crest Modulation Of Sensory Input
- 43. Efferent – 4.Spinal Cord
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- 49. Blood supply: Pontine branchof Basilar artery Anterior cerebellar artery Inferior cerebellar artery & Superior cerebellar artery. Venous Drainage Into: Inferior petrosal sinus and Basilar plexus. PONS
- 50. LESION OF PONS: Cerebello– Pontine Syndrome Due to: Acoustic neuroma of vestibular nerve Compress angle
- 51. Cerebello – PontineSyndrome 1. VIII Nerve Persistent tinnitus, Progressive Deafness Nystagmus, Nausea, Vomiting and Vertigo. 2. Cerebellar Lesions Ipsilateral cerebellar signs e.g.,Tremor,Ataxia, Dysmetria (Past Pointing) 3.Spinaltrigeminalnucleusandtract: Ipsilaterallossofpainandtemperaturesensationfromthe face(facialhemianesthesia) 4.FacialNerve: IpsilateralBellsPalsy, Hyperacusis,LossofTaste
- 52. Raymond’s Syndrome =Alternating Abducent Hemiplegia Occlusion of Paramedian branches of Basilar artery 1. 6th Nerve Ipsilateral paralysis of lateral rectus – Internal Squint 2. Pyramidal Tract Contralateral Hemiplegia
- 53. Millard - GublerSyndrome = Alternating Facial Hemiplegia Occlusion of Paramedian branches of Basilar artery 1. 7th Nerve IpsilateralBellsPalsy, Hyperacusis,LossofTaste 2. Pyramidal Tract Contralateral Hemiplegia
- 54. Alternating Trigeminal Hemiplegia 1.5th Nerve - Ipsilateral loss of pain and tepmperature sensation from the face (facial hemianesthesia) - LMN paralysis of masticatory muscles 2. Pyramidal Tract Contralateral Hemiplegia
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