Trigeminal nerve Flashcards
describe the osteological landmarks, components, course and branches and supply of the trigeminal nerve CNV
what are the divisions of the trigeminal nerve CNV?
- opthalmic CNV1
- maxillary CNV2
- mandibular CNV3
where do the divisions arise from? where is this positioned?
trigeminal ganglion located in Meckel’s cave on the apex of the petrous temporal bone
where does the opthalmic V1 branch exit the skull to the face?
supra-orbital notch (foramen)
where does the maxillary V2 branch exit the skull to the face?
infra-orbital foramen
where does the mandibular V3 branch exit the skull to the face?
mental foramen
what is each arrow of the diagram pointing to?
what are the key anatomical features of the mandible?
- site for muscle attachments (masticatory and facial expression)
- foramina for passage of neurovascular structures - mental foramen, mandibular foramen
- alveolar processes which house teeth and supports the periodontium
what are the different parts of the mandible?
identify where the CNV motor and sensory roots exit the base of the brain and skull? what is this structure called?
CNV exits the brain at the pons
where does the motor nucleus of CNV arise and exit from? what kind of fibres are these?
arises and exits via the pons - special visceral efferent fibres
where do the three sensory nuclei of CNV arise and exit from? what are their names? what kind of fibres are these?
- mesencephalic nucleus of V - midbrain
- chief sensory nucleus of V - pons
- spinal nucleus of V - medulla oblongata
- all exit from the pons
- general somatic afferent fibres
what is the function of each of the sensory nuclei?
- mesencephalic - proprioception
- chief sensory - discriminative touch
- spinal - pain and temperature, and general conscious sensation for the viscera
which branch of the trigeminal nerve CNV is a mixed nerve and which are sensory only?
- CNV1 opthalmic - sensory
- CNV2 maxillary - sensory
- CNV3 mandibular - mixed
where does the opthalmic division CNV1 exit the intercranial cavity?
superior orbital fissure
where does the maxillary division CNV2 exit the intercranial cavity?
foramen rotundum
where does the mandibular division CNV3 exit the intercranial cavity?
foramen ovale
if all three divisions of CNV are affected, what does that suggest?
there is a lesion in the pons (stroke) or at the cranial base (trauma/tumour)
what may happen if the divisions of the CNV are affected in the cavernous sinus?
there is usually evidence of an effect on other nerves (CNVIII and CNIV)
what are the main branches of the opthalmic division CNV1? what does it innervate?
- frontal, lacrimal, nasociliary
- innervates scalp, forehead, conjunctiva, cornea, upper eyelid
describe the course of the opthalmic division CNV1
- pons
- trigeminal ganglion in Meckel’s cave
- lateral wall of cavernous sinus
- superior orbital fissure
- divides into frontal nerve, nasocillary nerve and lacrimal nerve
- supraorbital notch
what does the frontal nerve of CNV1 divide into? where does it innervate?
- supraorbital nerve
- supratrochlear nerve
- innervates skin of vertex, upper eyelid and forehead
what does the lactrimal nerve of CNV1 innervate?
the lacrimal gland, upper eyelid and forehead
what does the nasocillary nerve of CNV1 branch into? where does it innervate?
- long cilliary nerves
- anterior and posterior ethmoidal nerves
- infratrochlear nerve
- innervates skin of medial upper eyelid and root of nose
describe the corneal blink reflex
- eye is poked (stimulus)
- opthalmic nerve (nasociliary branch) carries stimulus to trigeminal sensory nucleus
- signal is relayed to facial motor nucleus
- sends impulses via facial nerve CNVII to the ocularis oculi muscle which closes the eye