Head and Neuro Flashcards
1
Q
What structures pass through the superior orbital fissure?
A
- branches of the CNV1 (nasociliary, frontal and lacrimal)
- occulomotor nerve
- trochlear nerve
- abducens nerve
- superior and inferior ophthalmic veins
2
Q
What structures do you pass through to get to the subclavian vein in cannulation?
A
- Skin
- Subcutaneous Fat
- Deep fascia
- Clavicular head of the pectoral is major
- Clavipectoral fascia
- Subclavius
- Subclavian vein wall
3
Q
What structures are at risk of damage in Subclavian Cannulation?
A
Subclavian Artery
Phrenic nerve
Apex of lung
(Only on the left- the thoracic duct)
4
Q
Why may a patient with a brainstem lesion have difficulty swallowing and regurgitate fluid via the nose?
A
The brainstem contains the nuclei for both the glossopharyngeal and the vagus nerve. Therefore injury results in sensory loss of the palate and paralysis of the palatal and pharyngeal muscles. I’m particular, paralysis of the the me at or veli palatine causes failure of closure of the nasopharynx causing reflux into the nasal cavity
5
Q
What structures pass through the foramen magnum?
A
- The medulla oblongata
- meninges
- ascending accessory nerve
- vertebral arteries
- dural veins
6
Q
What muscles attach to the temporal bone?
A
- Temporalis to the squamous portion
- Masseter to the zygomatic portion
- Sternocleidomastoid to the mastoid process
- posterior belly of digastric to the mastoid process
- splenius capitol to the mastoid process
7
Q
Describe the features of the sphenoid bone.
A
Consists of a body, lesser wings, greater wings and Pterygoid process.
The body contains the sphenoid sinus, the sella turcica, the chiasmatic sulcus, and the clinoid processes which attach to the tentorium cerebri
The lesser wing separates the middle and anterior cranial fossa and forms the lateral border of the optic canal as well as the superior border of the superior orbital fissure
The greater wing contains the foramen rotundum, ovale and spinosum
8
Q
What are the borders of the anterior cranial fossa?
A
Anterolaterally- frontal bone
Posterolaterally- limbs of the sphenoid bone
Floor- frontal bone, ethmoid bone and lesser wings of sphenoid
9
Q
What are the contents of the anterior cranial fossa?
A
- The frontal crest is a midline bony ridge which acts as the site of attachment for the falx cerebri which continues to attach to the crista galli
- the cribriform fossa sits on either side of the crista galli and this supports the olfactory bulb
10
Q
What foramina sit in the anterior cranial fossa?
A
- The cribriform plate (transmit olfactory nerve fibres)
- The anterior and posterior ethmoidal (transmit the anterior and posterior ethmoidal nerves, arteries and veins)
11
Q
What are the boundaries of the middle cranial fossa?
A
Anterolateral- lesser wing of sphenoid
Anteromedial- limbus of sphenoid body
Posteromedial- dorsum sellae
Posterolateral- petrous part of the temporal bone
Floor- greater wings of sphenoid and squamous part of temporal bone
12
Q
What are the contents of the middle cranial fossa?
A
- Sella turcica containing the pituitary gland
- temporal lobes sit laterally
13
Q
What are the foramina of the middle cranial fossa?
A
- optic canal
- superior orbital fissure
- foramen rotundum
- foramen ovale
- foramen spinosum
- hiatus of the greater petrosal nerve
- hiatus of the lesser petrosal nerve
- foramen lacerum
14
Q
What are the boundaries of the posterior cranial fossa?
A
Anteromedial- dorsum sellae
Anterolateral- petrous part of the temporal bone
Posterior- squamous part of the occipital bone
Floor- mastoid part of the temporal bone and the condylar, squamous and basilar part of the occipital bone.
15
Q
What are the contents of the posterior cranial fossa?
A
Brainstem
Cerebellum
16
Q
What are the foramina in the posterior cranial fossa?
A
- Internal acoustic meatus
- Jugular foramen
- Foramen magnum
- Hypoglossal canal
17
Q
What structures pass through the optic canal?
A
Optic nerve and ophthalmic artery
18
Q
What structures pas through the foramen rotundum?
A
Maxillary nerve (CNV2)
19
Q
What structures pass through the foramen ovale?
A
The mandibular nerve (CNV3)
20
Q
What structures pass through the foramen spinosum?
A
The middle meningeal artery and vein
And the meningeal branch of CNV3
21
Q
What passes through the internal acoustic meatus?
A
The facial nerve, the vestibulocochlear nerve and the labyrinthine artery
22
Q
What passes through the jugular foramen?
A
- glossopharyngeal
- descending accessory
- vagus
- inferior petrosal and sigmoid sinus
- internal jugular vein
23
Q
What passes through the foramen magnum?
A
Vertebral arteries
Medulla and meninges
Ascending accessory nerve
Dural veins
Anterior and posterior spinal arteries
24
Q
Which cranial nerves arise from the cerebrum?
A
The olfactory and optic nerves
25
Which cranial nerves arise from the midbrain?
The trochlear
The occulomotor arises from the junction between the midbrain and the pons
26
Which cranial nerves arise from the pons?
The occulomotor nerve arises from the midbrain-pontine junction.
The trigeminal arises from the pons
The abducens, facial and vestibulocochlear from the pontine-medulla junction
27
Which cranial nerves arise from the medulla?
CNIX, CNX, CNXI, CNXII
28
What is the function and path of the olfactory nerve?
Function: special senses:smell
Olfactory sensors in the nasal epithelium assemble into olfactory nerves which penetrate the cribriform plate in the anterior cranial fossa. They travel via the olfactory bulb to the olfactory tract (inferior frontal lobe)
29
What is the function and path of the optic nerve?
Function: special sensory: site.
The optic nerve is technically an extension of cranial matter as it is surrounded by the meninges.
It starts at the retinal ganglion cells and travels via the optic nerve through the optic canal in the sphenoid bone.
It enters the cranium in the middle cranial fossa where the two nerves unite to form the optic chiasm.
It then passes via the optic tract to the lateral geniculate nucleus in the thalamus and then via the optic radiation to the visual cortex.
30
What is the function and path of the occulomotor nerve?
Function: motor to levator palpebrae, medial&superior&inferior rectus and the inferior oblique muscles of the eye.
Also has parasympathetic fibres to the ciliary ganglion.
Path: emerges from the midbrain and passes inferior to the posterior communicating artery via the cavernous sinus. It exits the skull via the superior orbital fissure.
31
What might cause CNIII palsy?
- raised ICP
- PCA aneurysm
- cavernous sinus thrombosis
- trauma
32
What are the symptoms of a CNIII palsy?
Ptosis, “down and out” eye, dilated pupil
33
Describe the function and path of the trochlear nerve?
Function: innervates the superior oblique muscle of the eye
Originates from the midbrain and runs in the subarachnoid space into the cavernous sinus and exits the skull via the superior orbital fissure.
34
What are the branches of the trigeminal nerve?
The trigeminal nerve originated from the pons. The sensory root forms the ganglion and splits into V1,V2,V3.
The motors root passes inferiorly and gives fibres to V3.
V1= opthalmic
V2 = maxillary
V3 = mandibular
35
What are the terminal branches or CNV1?
The frontal, lacrimal and nasociliary.
The lacrimal branch also carries parasympathetic fibres from the pterygopalatine ganglion to innervate the lacrimal gland.
36
What are the terminal branches of CNV3?
This is the mandibular division of the trigeminal nerve?
Terminal branches are: auriculotemporal, buccal, inferior alveolar, lingual
37
What are the functions of CNV3?
Sensory: sensation to the floor of the oral cavity, external ear, lower lip, teeth and gums, and anterior 2/3 of the tongue.
Motor: muscles of mastication (temporalis, pterygoids, masseter), anterior belly of digastric, myelohyoid, tensor veli palatini, tensor tympani
Parasympathetic:
- carries fibres from the submandibular ganglion (CNVII) via the lingual nerve
- carried fibres from the otic ganglion (CNIX) to the parotid gland with the auriculotemporal nerve
38
What are the functions of the facial nerve?
Motor: muscles of facial expression, posterior belly of digastric, stylohyoid, stapedius
Sensory: taste to anterior 2/3 or tongue
Parasympathetic:
- fibres to submandibular ganglion (saliva formation)
- fibres to the pterygopalatine ganglion (tear production)
39
What is the path of the facial nerve?
The facial nerve arises from the pontine-medulla junction as motor and sensory branch.
They exit the cranium via the internal acoustic meatus, the roots then enter the facial canal where they fuse.
Whilst still in the facial canal it gives off the greater petrosal nerve, nerve to the stapedius and the chorda tympani.
It then exits the facial canal via the stylomastoid foramen where it runs anterior to the external ear. It gives off the nerve to the posterior belly of digastric, the posterior auricular and the nerve to the stylohyoid. It then passes into the parotid gland.
The terminal branches are: Temporal, Zygomatic, Buccal, Marginal Mandibular, Cervical
40
List the branches of the facial nerve, and what do they innervate?
1. Greater petrosal (parasympathetic fibres to the lacrimal gland)
2. Nerve to the stapedius
3. Chorda tympani (taste to anterior 2/3 of tongue and give parasympathetic fibres to the submandibular/sublingual gland)
4. Posterior auricular (sensory)
5. Nerve to the posterior belly of the digastric
6. Nerve to the stylohyoid
7. Temporal (frontalis, obicularis occuli, corrigate supercilli)
8. Zygomatic (orbicularis occuli, zygomaticus major)
9. Buccal (buccinator, orbicularis ori)
10. Marginal mandibular (depressor labii inferioris, depressor anguli oris, mentalis)
11. Cervical (platysma)
41
What may cause damage to the facial nerve?
Intracranial: infection in the middle ear, Bells palsy, SOL, stroke
Extracranial: parotid gland tumour, surgery, parotid infection, herpes
42
What symptoms may you get in facial nerve palsy?
Reduced salivation, loss of taste, ipsilateral hyperacuisis, reduced tear production.
Paralysis of the nerves of facial expression
43
Describe the path of the Vestibulocochlear nerve?
Arises at the pontine-medulla angle. Exits the cranium via the internal auditory meatus.
44
What are the functions of the glossopharyngeal nerve?
- Nerve to the stylopharyngeus causes elevation of the pharynx in swallowing and speech
- Carotid sinus nerve
- Tympanic nerve (sensation of the inner ear)
- Pharyngeal - sensation of the oropharynx
- Lingual - taste and general sensation of the posterior 1/3 of the tongue
- tonsillar branch innervates the palatine tonsils
- parasympathetic supply to the parotid gland via the otic ganglion
45
Describe the path of the vagus nerve.
The vagus nerve arises from the medulla and exits the skull via the jugular foramen.
In the neck it travels via the carotid sheath.
The right passes anterior to the subclavian, the left passes between the carotid and subclavian.
Branches in the neck:
- Pharyngeal
- Superior laryngeal
- Recurrent laryngeal
It then enters the thorax and passes into the abdomen via the oesophageal hiatus
46
What are the branches of the internal carotid in the neck?
None
47
What level does the carotid artery bifurcate?
C4
48
What are the intracranial branches of the internal carotid?
The opthalmic artery, the posterior communicating artery, anterior choroidal artery, anterior cerebral and the middle cerebral artery
49
Describe the course and branches of the vertebral arteries.
They arise from the subclavian artery, ascend via the transverse processes of the cervical vertebra and enter the cranium via the foramen magnum.
They give off the meningeal branch, the anterior and posterior spinal arteries and the posterior inferior cerebella
50
Where is the cavernous sinus and what are the boundaries?
Located in the middle cranial fossa, on either side of the sella turcica.
Borders:
Anterior: superior orbital fissure
Posterior: petrous part of the temporal bone
Medial: body of the sphenoid
Lateral: meningeal layer of the dura mater
Floor: endosteal layer of dura in the greater wing of the sphenoid
51
What are the contents of the cavernous sinus?
Occulomotor nerve
Trochlear Nerve
Opthalmic nerve
Maxillary Nerve
Abducens Nerve
Internal carotid artery
52
Where does the cavernous sinus receive drainage from?
Opthalmic veins, central retinal vein, pterygoid plexus, facial vein, sphenoparietal sinus, superficial middle cerebral vein
53
Where does the cavernous sinus empty into?
The superior and inferior petrosal sinus. Which in turn empty into the jugular vein
54
What is cavernous sinus thrombosis?
Formation of a clot in the cavernous sinus (normally due to infection). It causes peri-orbital oedema, ptosis, photophobia and typically CNVI palsy (although it can also cause CNIII, CNV1, CNV2 or CNIV as well)
55
What is the most common organism causing cavernous sinus thrombosis?
Staph A
56
Describe the dural venous system of the brain?
Unpaired:
Superior sagittal sinus
Inferior sagittal sinus
Straight sinus
Occipital sinus
Intercavernous sinus
Paired:
Transverse sinus
Superior and Inferior petrosal sinus
Cavernous sinus
Sigmoid sinus
The superior sagittal sinus drains into the confluence of sinus, along with the straight sinus (which is the confluence of the great cerebral vein and the inferior sagittal sinus.
The confluence of sinus then split to drain into the transverse sinus which drains into the sigmoid sinus.
The sigmoid sinus and the inferior petrosal drain into the IJV.
57
What are the main sulci of the cerebrem?
Central sulcus - separates the frontal and parietal lobes
Lateral sulcus - separates the frontal/parietal from the temporal lobe.
The lunate sulcus -groove in the occipital cortex
58
What are the main gyri of the brain?
Precentral gyrus = primary motor cortex
Postcentral gyrus = primary sensory cortex
Superior temporal gyrus = sound processing
59
What are the layers of the meninges?
Dura: outer, thicker fibrous layer.
Arachnoid: has villi that project through the dura into the dural venous sinus emptying CSF
Pia mater: invests brain and spinal cord
60
What are the folds of the dura?
1. Falx cerebri (attaches the crista galli - tentorium cerebella) It contains the superior sagittal sinus and the inferior sagittal sinus.
2. Tentorium cerebella (attaches to the clinoid processes)
3. Flax cerebelli - separates the lobes of the cerebelli.
4. Diaphragm sellae - over the pituitary fossa
61
What is Broca's area?
This is the motor element of speech, located in the frontal lobe of the dominant hemisphere
62
What is the function of the dural folds?
Contains the venous sinus.
Also prevents rotational injury of the brain.
63
What cancers metastasise to the brain?
Lung, breast, bowel, melanoma and renal cell
64
What are the primary brain cancers?
Glioblastoma: often have early spread. Macroscopically with ill-defined mass with necrosis and haemorrhage.
Anaplastic Astrocytoma
Meningioma: normally resectable, rubbery round lobulated mass with calcifications and spindle sheets.
65
What is the difference between the primary and secondary head injury?
Primary: at the point of damage.
i.e. contusions, axonal injury
Secondary: damage due to complications such as haemorrhage, herniation, hypoxia, oedema, ischaemia.
66
What is Cushing's reflex?
Hypertension and bradycardia due to raised ICP.
67
What are the features of the extradural haematoma?
Convex haematoma on CT
Raised ICP
Lucid interval
68
What is the classic cause of an extradural haematoma?
Due to rupture of the middle meningeal artery, classic of when a # pterion (confluence of frontal, parietal, temporal and sphenoid bone)
69
How would you manage a sub-arachnoid haemorrhage?
Nimodipine
VP shunt
Monitoring (due to rebleed rate which is highest in the first two weeks)
70
Complications of a subarachnoid haemorrhage?
Rebleed
Low Na (due to cerebral salt wasting)
Vasospasm
Hydrocephalus
Seizure
Arrythmia
71
What would a total anterior circulation infarct cause?
Hemiparesis and hemi sensory loss
Honomynous hemianopia
Higher cognitive dysfunction.
72
What would a middle cerebral infarct cause vs anterior cerebral?
Middle: contralateral Sx in upper extremity
Anterior: contralateral Sx in lower extremity
73
What is a lacunar infarct?
This is an infarct in the perforating arteries around the internal capsule, thalamus and basal ganglia.
74
What would a posterior cerebral artery infarct?
Contralateral hemianopia and macular sparing.
75
What would an infarct of the vertebrobasilar artery cause?
This is an infarct of the brainstem causing ataxia, gait disorder and CN lesions.
76
What is lateral medullar syndrome?
Infarct of the posterior inferior cerebellar artery.
Causes nystagmus, dysphagia, ipsilateral CN palsy, ipsilateral facial numbness and contralateral sensory loss, ipsilateral horners syndrome
77
What is SIADH?
Confusion, lethargy and nausea and vomiting.
Causes a hyponatraemia, increased urinary Na, decreased serum osmolality.
78
What is diabetes insipidus?
Transient low ADH after pituitary surgery, causing a low urinary sodium and a hypernatraemia.
79
How do you manage diabetes insipidus?
Desmopressin
80
Describe the ventricular system in the brain?
Lateral ventricles drain into the third ventricle via the foramen of Monroe.
The third ventricle sits between the R and L thalamus, it has supra-optic recess above the optic chiasm.
The CSF drains via the aqueduct of sylvius into the fourth ventricle which is situated at the junction of the medulla and the pons.
The CSF then drains into subarachnoid space via the foraemen of Luschka and foramen of magendie.
81
Where is CSF produced?
The choroid plexus (which is in the ependymal cells of the lateral, 3rd and 4th ventricles).
82
Where does CSF drain?
Via the arachnoid villi which is projection of arachnoid mater into the dural sinus
83
What is hydrocephalus?
Abnormal accumulation of CSF in the cerebral cavity cisterns and ventricles.
84
What is cerebral perfusion pressure?
MAP - ICP
(Normally >50mmHg)
85
How can you classify hydrocephalus?
Primary Communicating: due to slowed resorption in the arachnoid granulations due to SAH or over production.
Primary Non-communicating: due to block in the outflow due to space occupying lesions or choroid plexus papilloma.
Secondary:
Due to increased CSF after loss of brain tissue (also known as normal pressure hydrocephalus)
86
Causes of hydrocephalus?
Congential: Dandy Walker syndrome, arachnoid malformation
Acquired: SOL, trauma, SAH, meninges
87
Why is determining the difference between primary communicating and primary non-communicating important?
Communicating lumbar puncture is theraputic, in non-communicating it is contra-indicated as it may cause tonsillar herniation.
88
How do you manage hydrocephalus?
Primary communicating: lumbar puncture, acetazolamide, furosemide.
Primary non-communicating: VP shunt, endoscopic 3rd ventricle fenestration.
89
What are the complications of a VP shunt?
- Shunt obstruction
- Subdural haematoma
- Infection
- Low pressure state
90
Where is the pituitary gland?
Located in the sella turcica of the sphenoid bone
91
Where is the hypothalamus?
the hypothalamus sits at the base of the 3rd ventricle above the optic chiasm.
It is connected to the pituitary gland via the pituitary stalk.
92
What does the anterior pituitary secrete?
ACTH, TSH, FSH, LH, Prolactin
93
What does the posterior pituitary secrete?
ADH, Oxytocin
94
What may a functional pituitary tumour cause?
Acromegaly
Cushing's
Prolactinoma
HyperthyroidismW
95
What is the investigation of choice for pituitary tumour?
MRI
96
What is the management of a pituitary tumour?
Transphenoidal surgical resection, radiotherapy and dopamine agonists.
97
What are the layers of the scalp?
Skin
Connective tissue
Epicranial aponeurosis
Loose connective tissue
Periosteum
98
What is the arterial supply of the scalp?
Branches of the external carotid:
- Temporal
- Posterior auricular
- Occipital
+ branches of the opthalmic artery.
99
What is the innervation of the scalp?
Trigeminal:
- Supratrochlear + supraorbital from V1
- Zygomaticotemporal from V2
- auriculotemporal from V3
Cervical:
- lesser occipital (C2)
- greater occipital (C2)
- greater auricular (C2/C3)
100
What is an abscess?
A localised collection of pus surrounded by granulation or fibrous tissue
101
What is a cerebral abscess?
A localised collection of pus surrounded by granulation tissue and reactive astrocytes. The surrounding brain tissue will have a perivascular infiltrate (mainly lymphocytes)
102
What may cause a cerebral abscess?
Normally secondary to encephalitis, which may be due to a spread of infection from the paranasal sinuses, middle ear or cavernous sinus
Or via haematogenous spread from endocarditis
103
How would a cerebral abscess present?
Meningism, headache, fever, altered mental state, seizures, focal neurological sign
104
What are the common pathogens that may cause a cerebral abscess?
Bacterial: strep, staph and bacteriodes
Fungi: aspergillus and cryptococcus
Protozoa: toxoplasma and entomeaba
105
What are the risk factors for developing a cerebral abscess?
Immunocompromised
Foreign travel
IVDU
Diabetes/smoker
Recurrent sinusitis
Dental infection
106
What are the boundaries of the orbit?
Roof: frontal bone and lesser wing of the sphenoid
Floor: maxilla, palatine and zygomatic bone
Medial: ethmoid, lacrimal and sphenoid bon.
Lateral: zygomatic bone and greater wing of the sphenoid
107
What are the pathways into the orbit?
Optic canal (transmits optic nerve)
Superior orbital fissure (lacrimal nerve, frontal and nasociliary, CNIII, CNIV, CNVI, paired ophthalmic veins)
Inferior orbital fissure (zygomatic branch of V2)
Other small openings include the nasolacrimal canal, and supraorbital and infraorbital foramen
108
What are the extraoccular muscles innervated by the occulomotor nerve?
- Levator palpebrae superioris:
Originates on the lesser wing of the spehnoid and attaches to the tarsal plate of the eyelid. Acts to elevate the eyelid.
- The Superior rectus, inferior rectus, medial rectus.
All originate from the common tendinous ring at the base of the orbit and attach to the sclera of the eyeball.
- The inferior oblique attach from the orbital floor and attaches to the sclera posterior to the lateral rectus.
109
What is the extra-occular muscle innervated by the trochlear nerve?
The superior oblique: From body of the sphenoid, via the trochlea and attaches posterior to the superior rectus.
Acts to depress, abduct and medially rotate the eyeball
110
What is the extra-occular muscles innervated by the abducens?
Lateral rectus muscle
111
What are the layers of the eyeball?
1. Fibrous layer = contains the sclera and cornea.
This provides the shape and support and provides attachment for the occular muscles and refracts light.
2. Vascular= contains the choroid (CT and blood vessels), the ciliary body (smooth muscle controlling shape of aqueous humor) and the iris (circular structure muscle to control pupil).
3. Inner = retina.
112
How would you differentiate between an UMN and LMN lesion of the facial nerve?
UMN are forehead sparing
113
What are the differentials for facial nerve palsy?
UMN:
- stroke
- subdural haematoma
- MS
- SOL
LMN:
- otitis media
- cholesteatoma
- neoplasm of parotid
- trauma of the temporal bone
- iatrogenic (mastoid or parotid surgery)
- ramsay hunt
114
What is Bells palsy?
Painless LMN facial nerve palsy. Causes hyperacuisus, inability to close eye, metallic taste and decreased lacrimation.
Need soral steroids and eye care.
85% will recover
115
What are the poor prognostic factors in Bells Palsy?
Complete palsy for over 3 weeks.
Age over 50
Associated pain
HTN
DM
Pregnancy
116
What is ramsay hunt syndrome?
This is a herpes zoster infection causing a CNVII palsy.
Causes pain, CNVII palsy, tinnitus, vertigo and hyperacuisis.
May have vesicles in the concha, anterior 2/3 of the tongue and or soft palate
117
How do you treat Ramsay hunt syndrome?
Needs prednisiole and aciclovir
118
What is an aneurysm?
Localised permanent dilatation of the vascular tree over 1.5x the normal diameter?
119
What are the risk factors for Berry Aneurysms?
CT disorders
PCKD
Family Hx
Smoking
HTN
Atherosclerosis
Cocaine use
Age
Female
120
Where is the most common site of a berry aneurysm?
At the anterior communication artery.
