Cranial Nerves Flashcards
Where does the 1st cranial nerve pass through ?
Cribriform Plate
Where are the receptors for the olfactory nerve found ?
In the Olfactory Epithelium
What type of nerve fibres does the 1st cranial nerve carry ?
Special Sensory - Smell
What might an increase in CSF cause in the eye ?
Papilloedema
What type of nerve fibres does the 2nd cranial nerve carry ?
Special Sensory - Vision
Where does the 3rd cranial nerve emerge ?
Ventral Midbrain
Which nerve pass out of the Superior Orbital Fissure ?
3, 4, 5-V1 and 6
Which cranial nerves carry parasympathetic fibres ?
3, 7, 9 and 10
If there was a problem with the 3rd cranial nerve what signs would there be on examination ?
- Ptosis
- Eye down and out
- Pupil would be dilated
What fibres does the 3rd nerve carry ?
- Somatic motor to the Extraoccular muscles and eyelid
- Autonomic motor to the Spincter Pupillae and Ciliary Body muscle
Where does the 4th cranial nerve emerge from ?
Dorsal part of the midbrain
What fibres does the 4th nerve carry ?
Somatic motor to the Superior Oblique
What symptoms would patient get if 4th nerve wasn’t functioning ?
- Diplopia
- Eye moves up and and out
Where does the 6th cranial nerve emerge ?
Pontomedullary junction
What fibres does it carry ?
Somatic motor to lateral rectus
Signs/symptoms of 6th cranial nerve palsy ?
- Eye deviates medially
- Diplopia
Where does the 5th cranial nerve emerge
The surface of the pons
What does V1 innervate and what fibres does it carry ?
General sensory from the forehead, scalp, eyelid, cornea, nose and sinuses
What reflexes are lost when CN 5 is damaged ?
Corneal and Jaw reflexes
Where does V2 pass through ?
Foramen Rotundum
Where does V3 pass through ?
Foramen Ovale
What does V2 innervate and what fibres does it carry ?
General sensory from the maxilla, maxillary teeth, nose, sinuses , lip, palate and the TMJ
What pathology which involves excruciating pain can occur if CN 5 is damaged ?
Trigeminal neuralgia
What does V3 innervate and what fibres does it carry ?
General sensory from the mandible, TMJ, low lib, mandublar teeth and the tongue (anterior 2/3rds).
Somatic motor to the muscles of mastication e.g. Temporalis, Masseter, Lateral and Medial Pterygoids.
What other muscles does V3 innervate ?
Anterior part of Digastric, Tensor Veli Palatini and Tensor Tympani.
Where does the facial nerve emerge from ?
Pontomedullary junction
What nerves pass through the Internal Acoustic Meatus ?
Facial and Vestibulocochlear
What is the course of the facial nerve ?
Through the IAM, Facial Canal and out of the Stylomastoid Foramen.
What does the facial nerve innervate and what fibres does it carry ?
- Somatic motor to the muscles of facial expression, stapedius and posterior belly of digastric.
- Autonomic motor to submandibular, sublingual and lacrimal glands.
- Special sensory from the anterior 2/3rds of the tongue via the Chorda Tympani.
- General sensory from the external acoustic meatus
What pathology occurs when the facial nerve is damage ?
Bell’s palsy
What are the signs of Bell’s Palsy ?
- Cannot close eyelids
- Can’t smile
- Can’t purse lips
- Cannot wrinkle forehead
Where does cranial nerve 8 arise from ?
Pontomedullary junction
What fibre type does CN 8 carry ?
Special Sensory - Hearing and Balance
What happens when CN 8 is damaged ?
- Vertigo
- Tinnitus
- Deafness
- Nystagmus
Which nerves exits via the jugular foramen ?
9, 10 and 11
What fibres does CN 9 carry ?
- Special sensory from the posterior 1/3rd of the tongue.
- General sensory from the posterior 1/3rd of the tongue and to the middle ear.
- Autonomic motor to the parotid gland
- Visceral sensory from the carotid body and sinus
- Somatic motor to the Stylopharyngeus
What occurs when CN 9 is damaged ?
Loss of gag reflex
Loss of taste to the posterior 1/3rd of the tongue
Which CN’s emerge from the medulla ?
9, 10, 11 and 12
What fibres does CN 10 carry ?
- Special sensory from the epiglottis and palate (Taste).
- General sensory from the external acoustic meatus.
- Visceral sensory from many organs
- Autonomic motor to muscles of bronchi, gut and heart.
- Somatic motor to pharynx and larynx.
What troubles would a patient have if pharyngeal and laryngeal branches of vagus were damaged ?
Difficulty swallowing and speaking.
What fibres does CN 11 carry ?
Somatic motor to SCM and Trapezius
What actions would be affected in CN 11 was damaged ?
Patient wouldn’t be able to turn head against resistance or shrug shoulders.
Where does the hypoglossal nerve pass out of the skull ?
Hypoglossal canal
What fibres does Hypoglossal carry ?
Somatic motor to the muscles of the tongue
What nerve is vulnerable to damage during a tonsillectomy ?
Hypoglossal nerve
What signs would patient present with who had a damage CN 12 ?
Wasting and paralysis of affected side of tongue. Tongue would deviate to affected side.
If cranial 5 and 8 are dysfunctioning where would the problem be likely to be at ?
Pontomedullary junction
If there are unusual signs that don’t make sense on examination what should you think ?
Chronic or malignant meningitis
If there are just motor signs what should you think ?
Myasthenia Gravis
What are the causes of dilated pupils ?
- Young
- Dark room
- Cocaine overdose
- Mhdriatic eye drops
What are the causes of constricted pupils ?
- Elderly
- Opioid overdose
- Mitotic eye drops
- Bright lighting
What condition present with mitosis ?
Horner’s syndrome
What microvascular problems will cause painful palsies ?
Hypertension and diabetes
What are the causes of nystagmus ?
- Vestibular system dysfunctioning
- Tumours
- Toxins
What is trigeminal neuralgia ?
If you have trigeminal neuralgia, even mild stimulation of your face such as from brushing your teeth or putting on makeup may trigger excruciating pain.
How do we treat trigeminal neuralgia ?
Carbamazepine
Is Bulbar palsy an UMN or LMN palsy ?
LMN - Due to lesions in the IC
Is Pseudo-bulbar palsy an UMN or LMN palsy ?
UMN - Due to lesions in the medulla
Which conditions is Bulbar palsy seen in ?
MND and Polio
