Flashcards in Head And Neck Session 8 Deck (44):
What is seen in a patient with complete oculomotor nerve palsy proximal to the ciliary ganglion?
Down and out pupil, ptosis, dilated pupil and loss of accommodation reflex
What is seen in a patient with complete oculomotor nerve palsy distal to the ciliary ganglion?
Down and out pupil, ptosis but not pupillary involvement
What is the anatomical oculomotor nerve proper?
Pure somatic efferent nerve that supplies all extra ocular muscles including LPS but excluding lateral rectus and superior oblique
Where is the origin of the anatomical oculomotor nerve proper?
Oculomotor nucleus in the midbrain
What are the important anatomical landmarks of the anatomical oculomotor nerve proper?
Cavernous sinus, uncus, tentorial notch, superior orbital fissure
What is the uncus?
Part of the temporal lobe
What is the tentorial notch?
Infolding of dura mater
What happens to the anatomical oculomotor nerve proper between the superior orbital fissure and tendinous ring of the orbit?
Divides into superior (dorsal) and inferior (ventral) branches
Which other cranial nerve is the oculomotor nerve closely associated with?
What is indicated by a patient presenting with unilateral pupil dilation, loss of accommodation reflex but normal oculomotion and palpebral fissure?
Damage to Edinger-Westphal nucleus fibres spare the anatomical oculomotor nerve proper
Why is the clinically examined oculomotor nerve different form the anatomical oculomotor nerve proper?
Close proximity of parasympathetic fibres means they are often implicated in CNIII damage
Why is the pupil dilated in complete palsy of CNIII proximal to the ciliary ganglion?
Sphincter pupillae is dennervated and intact sympathetics cause unapposed dilator pupillae action
Where does the clinical examined oculomotor nerve arise from?
Edinger-Westphal nucleus in midbrain
Which nerve is the longest cranial nerve carrying sensory, motor and autonomic fibres from the superior cervical ganglion?
Where does the ophthalmic branch of the trigeminal nerve originate?
What is the function of the ophthalmic branch of the trigeminal nerve?
Purely sensory to the skin of upper eyelid, eyebrow, forehead, nose, cornea conjunctiva, lacrimal gland, ciliary body, iris, mucous membrane of nasal cavities and meninges
What are the branches of the ophthalmic branch that arise after it has passed through the superior orbital fissure?
Supratrochlear, supraorbital, lacrimal, infratrochlear, external nasal
Where does the maxillary branch of the trigeminal nerve arise from?
What is the function of the maxillary branch of the trigeminal nerve?
Purely sensory to the skin of the lower eyelid, side of nose, upper lip, cheek, nasal cavities, upper teeth and their gums
What branches are formed after the maxillary branch and passed through the foramen rotundum?
Infraorbital, zygomatic official and zygomaticotemporal
Where does the mandibular branch of the trigeminal nerve arise from?
Sensory from trigeminal ganglion, motor from 5th nerve motor nucleus in pons
What branches are formed after the mandibular branch passes through the foramen ovale?
Auriculotemporal, buccal and mental
How is the mandibular branch of the trigeminal nerve tested clinically?
Move jaw against resistance
What components form the facial nerve?
Somatic and visceral efferents with special and general sensory afferents
Which other cranial nerve does the facial nerve later join the afferents of?
Describe the somatic motor portion of the facial nerve.
Arises in facial motor nucleus in pons, forms large motor root, travels along facial nerve
What forms the nervous intermedius that travels with the greater petrosal nerve?
Autonomic fibres from the superior salivatory nucleus
What does nervous intermedius supply?
Lacrimal, submandibular, sublingual, nasal and palatine glands
What forms the sensory root in the pons (nucleus solitarius)?
Sensory fibres of facial nerve and primary sensory neurones in geniculate ganglion
What does the special sensory portion of nervous intermedius provide?
Taste to anterior 2/3 of tongue and soft palate
What does the general sensory portion of nervus intermedius provide?
Sensation to auricle of ear via the trigeminal nerve
What is the origin of the facial nerve?
Oculomotor nucleus in the midbrain
Where is the cranial exit of the facial nerve?
What are the anatomical landmarks of the facial nerve?
IAM, petrous portion of temporal bone and facial canal
Which are the targets of the facial nerve found in the middle ear along the length of malleus?
Chorda tympani and anterior 2/3 of tongue
What are the targets of the branches from the pterygopalatine ganglion?
Lacrimal gland and nasal and oral cavity mucous membranes
What are the targets for the fibres from the submandibular ganglion?
Sublingual and submandibular glands
What are the targets of the fibres that pass through the stylomastoid foramen?
Effector organs, parotid sheath and gland
What is Redlich-Obersteiner's zone?
Boundary between CNS and PNS where Schwann cell myelin meets oligodendrocyte myelin therefore is a point of higher risk of neurovascular compression
What are the branches of the facial nerve that arise in the parotid gland?
Temporal, zygomatic, buccal, mandibular, cervical
What are the clinical signs of complete CNVII palsy?
Facial asymmetry with the following on the affected side: loss of naso-labial fold, lacrimation, oral and nasal secretomotor function, complete upper eyelid ptosis, loss of blink reflex, stasis of tears, oral incompetence
Why can most people with complete CNVII palsy frown?
Frontalis muscles are bilaterally innervated and bilateral damage is rare
How does Bell's palsy differ from any other complete CNVII palsy in terms of symptoms?
Usually temporary (