Difference between revisions of "Cranial Nerves - Anatomy & Physiology"

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[[Image:brainstemcranialnervespyramids.jpg|thumb|right|150px|The brainstem, cranial nerves and pyramids. © BioMed Archive.]]
 
[[Image:brainstemcranialnervespyramids.jpg|thumb|right|150px|The brainstem, cranial nerves and pyramids. © BioMed Archive.]]
  
Cranial nerves are those nerves which arise from the brain and brain stem rather than the spinal cord. Nerves arising from the spinal cord are the [[Nervous System - PNS - Anatomy & Physiology|peripheral nerves]]. There are 12 cranial nerves, although the trigeminal nerve (V) has '''3 branches'''. These are:
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Cranial nerves are those nerves which arise from the brain and brain stem rather than the spinal cord. Nerves arising from the spinal cord are the [[PNS Structure - Anatomy & Physiology|peripheral nerves]]. There are 12 cranial nerves, although the trigeminal nerve (V) has '''3 branches'''. These are:
  
 
'''Opthalmic (V1)'''
 
'''Opthalmic (V1)'''

Revision as of 15:04, 14 August 2009



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()Map NERVOUS AND SPECIAL SENSES (Map)



The brainstem, cranial nerves and pyramids. © BioMed Archive.

Cranial nerves are those nerves which arise from the brain and brain stem rather than the spinal cord. Nerves arising from the spinal cord are the peripheral nerves. There are 12 cranial nerves, although the trigeminal nerve (V) has 3 branches. These are:

Opthalmic (V1)

Maxillary (V2)

Mandibular (V3)

A summary of the cranial nerves is shown below:


Nerve Attatchment to brain Exit Foramen Fibre Type Location of cell bodies Distribution
I - Occulomotor Olfactory bulb Cribriform plate SVS Olfactory epithelium Olfactory epithelium
II - Optic Optic chiasma Optic canal SSS Retina Retina
III - Occulomotor Midbrain Orbital fissure and Round Foramen GSM + GVM Nuculi III

parasympathetic nuculi III

Extraoccular mm.

Constrictor pupulli

IV - Trochlear Midbrain (dorsal) Round Foramen GSM Nuc IV Dorsal oblique mm.
V - Trigeminal Pons V1 - Orbital fissure

V2 - Round Foramen and Orbital Fissure

V3 - Oval Foramen

V1 - GSS

V2 - GSS

V3 - SVM

V1 - Trigeminal gangion

V2 - Trigeminal ganglion

V3 - Nuculi V

V1 - Eye region

V2 - Upper jaw inc. teeth

V3 - mm. of arch 1

VI - Abducens Medulla oblongata Orbital fissure GSM Nuc IV Dorsal oblique mm.
VII - Facial Medulla oblongata Stylomastoid foramen SVM + GVM + SVS Nuc III

(Taste - gleniailate ganglion)

mm. of arch 2

Submaxillary and sublingual glands

Rostral 2/3 taste

VIII - Vestibulocochlear Medulla oblongata Inner accoustic meatus SSS Vestibular ganglion Maculae and cristae
IX - Glossopharyngeal Medulla oblongata Jugular foramen G/S V M/S Ganglia IX - SVM

Nuculi ambiguous - mm. arch 3

Carotid gland

Caudal 1/3 taste mm. of arch 3

Carotid body

X - Vagus Medulla oblongata Jugular foramen GVM + SUM + GVS + GSS Ganglion X - (amongst others) Thoracic and abdominal organs

mm. of arches 4-6 Pharynx and larynx External ear

XI - Accessory Medulla oblongata Jugular foramen GSM Cervical spinal cord Trapezius m. etc
XII - Hypoglossal Medulla oblongata Hypoglossal canal GSM Medulla nuculi XII Tongue mm.

Cranial Nerve Fibre Types

Cranial nerves are best explained by function:


  • General Somatic Motor (GSM)

Motor cortex —→ Motor nuculi —→ Muscle


  • General Visceral Motor (GVM)

Brainstem —→ Parasympathetic nuculi —→ Parasympathetic ganglion —→ Gland etc


  • "Branchial motor" - Special Visceral Motor (SVM)

Motor cortex —→ Motor nuculi —→ Muscle


  • General Somatic Sensory (GSS) and General Visceral Sensory (GVS)

Sensory cortex —→ Thalamus —→ Trigeminal nuculi —→ Trigeminal ganglion —→ Skin etc


Special sensory fibres (SSS + SVS):

Smell SVS

Priform cortex —→ Olfactory tubercle —→ Olfactory Bulb —→ SMELL


Vision SSS

Occipital cortex —→ Thalamus MGN —→ Rostral colliculus/Retinal ganglion cell —→ Bipolar cell —→ VISION


Hearing/Balance SSS

Temporal cortex —→ Thalamus MGN —→ Caudal colliculus and hindbrain —→ Spiral ganglion —→ HEARING


Taste SVS

Sensory cortex —→ Thalamus —→ Hindbrain (VII, IX, X) —→ Ganglion —→ TASTE