Head and Neck Flashcards
Where does the neck descend from and to?
The lower margin of the mandible to the suprasternal notch of the manubrium, and upper part of the clavicle.
Where is the investing fascia attached to - superiorly, posteriorly and inferiorly?
Superiorly - lower mandible, mastoid process, superior nucheal line and external occipital protuberance.
Posteriorly - spinous processes and ligamentum nuchae.
Inferiorly - clavicle, acromium and spine of the scapula.
What muscles and glands does the investing layer split?
Muscles - sternocleidomastoid and trapezius.
Glands - parotid and submandibular.
What is the pre-tracheal layer attached to superiorly, and what does it blend to inferiorly?
Attached to the hyoid bone, blending with the fibrous pericardium, in the thorax.
What are the two layers of the pre-tracheal fascia?
Muscular layer - enclosing the infrayoid muscles.
Visceral layer - enclosing the thyroid gland, trachea and oesophagus.
Where does the pre-vertebral fascia extend to and from?
From the base of the cranium to the 3rd thoracic vertebra.
Where does infection within the deep neck spaces often arise from, and why are they not actually spaces?
They arise from the teeth, tissues of the pharynx or sinuses.
They are filled with loose connective tissue.
What can physical compression of a retopharyngeal abscess cause?
Airway issues, due to the close proximity of the trachea.
Why are retropharyngeal abscesses more common in children?
Retropharyngeal lymph nodes atrophy after the age of 3-4.
What is the more common cause of retropharyngeal abscesses in adults?
Penetrating injuries of the pharynx or oesophagus.
How can a goitre cause impedance of venous blood vessels, and what can this present as?
It can extend retrosternally, compressing them.
This means there is an accumulation of blood, causing facial plethora.
What is the Pemberton manoeuvre?
When the arms are raised above the head, there is narrowing of the thoracic inlet, meaning that facial plethora will develop, due to compression of the venous structures by a retrosternal goitre.
What is the main function of the scalene muscles, and what do they form?
Accessory muscles of respiration.
They form the floor of the posterior triangle.
What muscles do the trunks and subclavian vessels pass between?
The anterior and middle scalenes.
What is the function of the buccinator?
Keeping the cheeks taut to prevent food from pooling between the cheeks and teeth.
What are the different muscles that are involved in elevating and depressing the mandible?
Elevating - medial pterygoid, temporalis and masseter.
Depressing - lateral pterygoid and suprahyoids (4).
What do the pterygoid muscles attach to?
They originate from the pterygoid plates, located at the base of the skull.
They insert onto the mandible.
What are the two bellies of the occipitofrontalis, what are they joined by and what are each of their actions?
Occipitalis and frontalis, joined by the epicranial aponeurosis.
Frontalis - attaches to the skin of the eyebrows to wrinkle the skin.
Occipitalis - movement of the scalp.
Where is the orbicular oculi located and what are the two bellies’ role?
Encircling the orbits of the eyes.
Orbital is to protect the eyes by squeezing them tightly.
Palpebral is to close them gently to keep the eyes moist - blinking.
What is the origin and insertion of the orbicularis oris and what is its function?
It arises from the maxilla and mandible, and inserts into the skin and membrane of the lips.
It’s function is to purse the lips together for speech and to seal the mouth closed whilst eating.
What is the origin and insertion of the platysmus, and what is the function?
Arises from the fascia of the anterior chest, inserting into the mandible and overlying subcutaneous tissue.
It function is to tense the skin, and to a small degree, depress the mandible.
What are the cranial nerves of the facial and trigeminal nerves?
Facial - 7.
Trigeminal - 5.
What are the 5 extra-cranial branches of the facial nerve?
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Temporal.
Zygomatic.
Buccal.
Marginal Mandibular.
Cervical.
What is the House-Brackmann’s scale?
A scale used to determine the severity of the facial nerve injuries.
Which branch of the trigeminal nerve innervates the muscles of mastication?
The mandibular division of the trigeminal nerve.
What is the nerve supply to the supra-hyoid and infra-hyoid muscles?
Supra-hyoids - cranial nerves 5 and 7.
Infra-hyoids - cervical nerves (C1-C3), ansa cervicalis.
What is torticollis?
Involuntary contraction of the sternocleidomastoid, causing asymmetrical head/ neck position.
Can be acquired or congenital.
What is the sternocleidomastoid and trapezius innervated by?
Accessory nerve - cranial nerve 11.
What are the borders of the anterior triangle?
Medial - midsagittal line of the neck.
Lateral - anterior border of the sternocleidomastoid.
Superior - inferior border of the mandible.
What are the borders of the posterior triangle?
Posterior - anterior trapezius.
Anterior - sternocleidomastoid.
Inferior - clavicle.
Floor - scalene muscles.
Roof - cervical fascia.
What 3 things are enclosed in the carotid sheets?
Internal jugular vein (laterally), the common carotid artery (medially) and vagus nerve (posteriorly).
What are the contents of the posterior triangle?
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S - Scalene muscles.
P - Phrenic Nerve.
B - Brachial plexus (trunks).
S - subclavian vessels.
P-O - posterior omohyoid.
A - accessory nerve.
E - external jugular vein.
What runs within the superficial cervical fascia?
The accessory nerve and the external jugular vein.
What is the main complication of a retropharyngeal abscess?
Mediastinitis.
What is the commonest presentation of a facial nerve lesion, and what is the most common aetiology?
Bell’s Palsy.
Viral infection, predominantly herpes virus.
What is the function of the medial and lateral pterygoids, when working together?
To move the mandible side to side.
Which muscles retract and protract the mandible?
Retract - temporalis.
Protract - medial and lateral pterygoids, and partially the masseter.
Outline the action, location and innervation of the digastric muscle.
Outline the action, location and innervation of the omohyoid muscle.
What layer of the scalp are the 5 arteries supplying the scalp found in?
The dense connective tissue layer.
What nerve is the carotid sinus a branch of, and what types of specialised cell does it contain?
The glossopharyngeal nerve.
It contains baroreceptors.
Where is the superior cervical ganglion located?
Posterior to the carotid sheath, at the level of the 2nd and 3rd vertebra.
Which vertebra does the vertebral artery not run through? State what the transverse foramina does transmit.
C7 - instead it runs anterior to the transverse foramen. It only transmits the vertebral vein.
What nerve does the inferior thyroid nerve travel anterior to, and what is its function?
Recurrent laryngeal nerve.
It is a branch of the vagus nerve that gives sensory and motor innervation to the larynx.
What is the intra-cranial drainage into the internal jugular vein?
The sigmoid sinus drains directly into the internal jugular vein.
The cavernous sinus drains into the internal jugular vein via the superior and inferior petrosal sinuses.
Outline the route of the internal jugular vein (IJV) back to the heart.
IJV drains into the subclavian vein, then into the brachiocephalic trunk, then into the SVC and then into the right atrium.
What is the pterygoid venous plexus located within?
The infra-temporal fossa.
Outline the superficial veins that drain intra-cranially.
What 2 veins drain into the external jugular vein?
The superficial temporal vein an the posterior auricular vein.
What do emissary veins do?
Drain extra-cranial veins into the dural venous sinuses.
Where is the carotid body located, and what types of cells does it contain?
Located within the adventitia of the common carotid bifurcation.
It contains chemoreceptors that monitor blood-oxygen concentration. It is also sensitive to pH and blood-carbon dioxide concentration.
What nerve supplies the carotid sinus and carotid body?
Carotid sinus nerve - a branch of the glossopharyngeal nerve - sends signals to the brainstem.
What pathological condition can arise in the superficial temporal artery? Describe it and its main complication.
Temporal arteritis - inflammation of the walls of the artery, leading to them hardening. It can lead to vision loss in the eye due to it giving branches to the retina of the eye.
State the 2 main branches of the maxillary artery and their functions.
Middle meningeal artery which runs behind the pterion, anterior to the periosteum to supply the meninges and skull.
Sphenopalatine artery which supplies the nasal cavity. This is a source for epistaxis (nose bleeds).
What do the following branches of the ECA supply:
- Superior thyroid.
- Lingual.
- Facial.
- Occipital.
- Posterior auricular.
- Maxillary.
- Superficial temporal.
ST - thyroid gland.
L - tongue.
F - main tissues of the face (from behind the mandible to the corner of the eye).
O - posterior scalp.
PA - posterior to the ear to supply the posterior scalp.
M - deep facial structures.
ST - anterior to the ear.
What kind of haemorrhage and shape does a middle meningeal artery laceration cause?
Extradural haemorrhage.
What are the 2 branches of the internal carotid, as it exits the cavernous sinus?
Opthalamic artery, which enters the orbit.
Branches that enter the circle of Willis.
What procedure is performed to remove the atherosclerotic plaque at the bifurcation of the common carotid artery?
Carotid endartectomy.
Where does the IJV begin from, and what is it a continuation from?
Formed at the jugular foramen, as a continuation of the sigmoid sinus.
Why do you use the internal jugular vein, as opposed to the subclavian vein, for insertion a central line?
Less risk of pneumothorax.
What gland do the maxillary and superficial temporal arteries supply blood to?
Parotid gland.
What does the perpendicular plate help to form?
Septum of the nose.
What is the Crista galli an attachment for?
Falx cerebri.
What does the petrous bone house, and how is it adapted for this?
Cochlea and vestibocochlear nerve.
These are delicate so it is extremely hard.
What can ethmoid fractures present with?
CSF rhinorrhoea.
What X-ray view would a zygomatic arch fracture and mandibular fracture be taken in, respectively?
Zygomatic arch - bucket-handle.
Mandibular - OPG = orthopartomogram, which pans round.
What is the boundary between the middle and posterior cranial floors?
The petrous part of the temporal bone.
In what bone is the stylomastoid foramen located, and what does it transmit?
The temporal bone.
It transmits the facial nerve.
What two bones is the jugular foramen formed between?
The occipital and temporal (petrous part) bones.
Outline some regions in which the lymph nodes can be palpable and non-palpable.
When are palpable lymph nodes often seen without infections?
Cervical lymph nodes can be palpable in children (28-55%).
What are the locations of the tonsils in the Waldeyer’s ring?
Pharyngeal/ adenoid - nasopharynx.
Tubal - nasopharynx.
Palatine - oral cavity.
Lingual - back of the posterior aspect of the tongue.
What can andenoid tonsil swelling lead to?
Obstruction of nasal breathing.
Snoring.
Blockage of the Eustachian tube, potentially leading to infection in the middle ear.
What is the most common cause of tonsillitis and which tonsils are most commonly seen?
Viral aetiology.
The palatine tonsils, with inflammatory exudate present - this is extensive in streptococcus pyogenes infections.
What do the superficial cervical lymph nodes drain and where are they found, collectively?
They are found in the superficial cervical fascia.
They drain the face, scalp and parts of the tongue.
What do the post-auricular (superficial) lymph nodes drain?
Posterolateral half of the scalp.
What do the submental (superficial) lymph nodes drain?
Inferior and posterior chin.
Floor of the mouth.
Tip of the tongue.
Lower incisor teeth and gums.
What do the occipital (superficial) lymph nodes drain?
Posterior scalp.
What do the pre-auricular and parotid (superficial) lymph nodes drain?
Anterolateral scalp.
Upper half of the face including the eye lids.
Cheeks.
What do the submandibular (superficial) lymph nodes drain?
The centre of the face and cheek.
Teeth and gingivae - gums.
Parts of the anterior tongue.
What lymph nodes can conjunctivitis cause swelling of?
Pre-auricular and parotid superficial lymph nodes.
What drains the different aspects of the tongue?
What are the 3 different deep cervical lymph nodes, where do they all receive drainage from collectively?
Jugulo-digastric.
Jugulo-omohyoid.
Supraclavicular.
They all receive drainage from the superficial lymph nodes.
Where are the jugulo-digastric lymph nodes found and what do they drain, specifically?
Related to the upper third of the internal jugular vein, within the carotid sheath.
They drain the tonsils, tissues of the upper digestive tract, pharynx and part of the tongue.
Where are the jugulo-omohyoid lymph nodes found and what do they drain, specifically?
Associated with the lower third of the internal jugular vein, within the carotid sheath.
Drains part of the tongue, oral cavity, trachea, oesophagus and thyroid gland.
Where are the supraclavicular lymph nodes found and what do they drain, specifically?
They are found within the supra-clavicular fossa, in the posterior triangle.
They drain the deep parts of the thoracic and abdominal cavity.
What is cervical lymphadenitis, and how does it present?
Infection/ inflammation of the lymph nodes.
It presents with unilateral, red, hot lumps in the neck, often with fever. This is due to bacteria within the lymph node.
What is the palpation of lymph nodes with metastatic cancer like?
It is hard, tethered to the surrounding tissues and painless to the patient.
What is the palpation of lymph nodes with lymphoma like?
Rubbery, fast-growing and painless to palpate.
What forms the border between the anterior and middle cranial fossa?
The lesser wings of the sphenoid.
What forms the border between the middle and posterior cranial foramen?
The petrous bone of the temporal bone.
What two pathologies of the thyroid may cause a (off-)midline neck lump?
Malignant or benign neoplasm, forming a nodule or lump within the gland.
Diseases causing diffuse enlargement - goitre, such as Grave’s disease.
What are some pathologies that can cause salivary gland lumps, and which glands are they most common in - where would they be located?
Calculus (stone).
Inflammation or infection.
Neoplasm - benign or malignant.
They are most common in the submandibular or parotid glands.
They would be located in the lateral aspect of the neck.
What are some causes for vascular lumps within the neck, and where would they be located?
How can these be distinguished from other lumps?
Aneurysm of the carotid artery.
Carotid body tumours.
They are found in the lateral aspect of the neck.
They have a pulsating nature and are able to move side to side, not up and down.
What are two possible causes for benign lumps of the skin or subcutaneous tissue?
Lipoma - can be moved around and able to get under it.
Sebaceous cyst.
These can be found anywhere on the neck.
List the 5 possible congenital lesions causing neck lumps, and where would they be seen?
Thyroglossal duct cysts - midline.
Branchial cyst - lateral, in the anterior triangle.
Dermoid cyst - midline.
Laryngocoele - lateral (air filled sac).
Cystic hygroma - lateral, in the posterior triangle.
What are cystic hygromas, what is their aetiology and what is the management?
They are fluid-filled sacs that transilluminate and can be compressed.
They occur in infants/ fetal development due to lymphatic malformation.
They can be treated with surgical excision or drainage.
How do thyroglossal duct cysts present?
They are non-tender, well-defined lumps that are found deep to the cervical fascia.
They therefore moves up with tongue protrusion.
What can thyroglossal ducts complications be, and how are they treated?
They can become inflamed and infected, leading to them becoming painful.
This requires antibiotic treatment and surgical excision.
What arteries run into the subarachnoid space, and what do they form? What do these run alongside?
The vertebral arteries and internal carotid artery, forming the cerebral arteries.
The cerebral veins also run in this space which drain into the dural venous sinuses.
Describe the 3 layers of the meninges.
Pia mater - a microscopically thin layer that adheres completely to the brain, following the sulci (dips) and gyri (bumps).
Arachnoid mater - this is a soft, fibrous translucent membrane.
Dura mater - formed of a periosteal layer which is lines the inner table of the calvaria and the meningeal layer which is on the inner aspect. There is only a single layer that surrounds the spinal cord, not 2 like with the brain.
What is between the dura and the arachnoid mater, and why is this the case?
There is a potential space between them, and the CSF within the subarachnoid space pushes the arachnoid mater against the dura mater.
What is the tentorial notch, and what goes through it?
Space that is formed between the inner surfaces of the tentorium cerebelli.
The brainstem traverses through.
What do the superior and inferior petrosal sinuses run between?
Superior petrosal sinus is between the cavernous sinus and the transverse sinus.
Inferior petrosal sinus is between the cavernous sinus and the sigmoid sinus.
What dural venous sinus is formed between the junction of the falx cerebri and tentorium cerebelli? What does it drain into and what drains into it?
The straight sinus, which drains into the confluence of the sinuses.
The inferior sagittal sinus drains to this.
Where are the cavernous sinuses located?
In the middle cranial fossa, either side of the body of the sphenoid.
What do the bridging and emissary veins run between, respectively?
Bridging veins from the dural venous sinuses to the cerebral veins of the subarachnoid space.
Emissary veins from the scalp into the dural venous sinuses.
What is the clinical appearance of an extradural haemorrhage?
Rupture of a meningeal artery (often middle) due to significant head trauma (often at the pterion), leading to bleeding within the space between the periosteal dura mater and calvaria. Consciousness can be lost for seconds to minutes before waking up and behaving normal for around an hour - lucidity period. They then rapidly deteriorate in neurological function, due to compression of the intra-cranial contents.
What is the radiographical appearance of an extradural haemorrhage?
A lentiform appearance due to blood pooling between the inner table of the skull and the periosteal layer of the dura mater.
Periosteum cannot be adhered away from the suture lines due to the strong adherence.
What is the clinical appearance of an subdural haemorrhage, and who does this occur in more often?
A head injury incurs, leading to rupture of the bridging vein, usually at the point where it crosses the dura mater. Venous pooling occurs within the subdural space, between the dura mater and arachnoid mater. They can initially be unconscious or not, and after they often complain of a headache. The rate of deterioration is much slower.
Due to cortical shrinkage of the brain, there is increased pressure of the bridging veins in the elderly.
What is the radiographical appearance of an subdural haemorrhage - why?
Crescent shaped appearance due to blood filling one half of the hemisphere of the brain.
What is the clinical appearance of an subarachnoid haemorrhage?
Trauma to the head or spontaneous rupture of a blood vessel, due to aneurysm - a branch of the circle of Willis.
Blood leaks into the subarachnoid space, between the arachnoid mater and pia mater, mixing with the CSF and irritating the meninges.
It is sudden and often fatal.
How are subarachnoid haemorrhage’s diagnosed?
CT head imaging - the faster it is done, the greater the chance of being able to see the haemorrhage.
Lumbar puncture - if a prolonged period has passed, then haemoglobin degradation product test will be done.
What pathology seen in the skin can cause lumps on the scalp?
Sebaceous cysts.
Haematoma.
Why do superficial cuts to the scalp bleed so profusely?
The dense connective tissue inhibits the vessels from vasoconstricting, leading to an increase in blood loss.
Why can there be avulsion of more than one layer of the scalp when hair becomes trapped and pulled out?
The skin and epicranial aponeurosis are strongly adhered to the dense connective tissue, meaning that they all get pulled off together.
What is the function of the loose connective tissue of the scalp?
Allows for movements in all directions.
It contains emissary veins which drain the scalp to the dural venous sinuses.
Where can the spread of blood go to if the laceration is to the depth of the loose connective tissue?
It can track under the epicranial aponeurosis, under the obicularis oculi, leading to bruising over the orbits.
It can also lead to intracranial infections due to the bacteria spreading into the dural venous sinuses via emissary veins.
Why do deep lacerations gape, and how are they treated?
The epicranial aponeurosis pull each side of the laceration apart.
The aponeurosis must be sutured first and then the superficial structures.
What is the usual shape of the motor and sensory neurones?
Motor - unipolar.
Sensory - pseudounipolar.
What is the cephalic flexure?
The neuraxis flexing at the level of the midbrain.
Outline where the rostral, caudal, ventral and dorsal aspects of the brain would appear, in normal topography.
What is the forebrain formed of and how does it split?
It is formed of the cerebrum and the diencephalon.
It splits into the left and right hemispheres.
What is the diencephalon formed from, and what are their functions?
Thalamus - directs sensory information from the peripheries to the brain for perception.
Hypothalamus - endocrine function.
What is the function of the cerebellum and where is it found?
It is part of the CNS that is involved in co-ordination and balance.
It is found at the back of the brainstem.
What is the significance of the anatomical position of the foramen magnum?
It is the point at which the brainstem is found above and the spinal cord is found below.
Where are the cell bodies and nuclei found, within the forebrain?
Cortex of the brain - grey matter, also containing unmyelinated axons and glial (support) cells.
What is the function of the sulci and gyri?
To increase the surface area of the grey matter.
What do the central sulcus, lateral fissure and parieto-occipital sulcus split?
Central sulcus - separates the frontal lobe from the parietal lobe.
Lateral fissure - separates the temporal from the parietal and frontal lobes.
Parieto-occipital sulcus - splits the parietal and occipital lobes, can only be seen medially.
What is the structure and function of the corpus collosum?
It is formed of bundles of axons that allows for communication between hemispheres.
What separates the two lateral ventricles of the brain?
Septum pellucidum.
What is the function of the frontal lobe?
What is the function of the temporal lobe, and is there any difference between the functions in the left and right sides?
Does occur in both hemispheres, just dominant in one over the other.
What is the function of the parietal lobes?
Somatosensory perception.
Spatial awareness.
Body image.
What is the function of the occipital lobe?
Visual perception.
What is the function of the pre- and post-central gyri?
Pre-central = primary motor cortex.
Post-central = primary somatosensory cortex.
What are the functions of the 3 parts of the brainstem, and what is its overall function?
Midbrain - eye movement coordination and pupillary response to light.
Pons - feeding, sleep and consciousness.
Medulla - cardiovascular and respiratory function.
The sensory and motor pathways run up and down through the brainstem.
Where do the motor pathways become spinal nerves, and what from?
Explain how they control certain sides of the body.
Upper motor nerves, with their cell bodies in the primary motor cortex, descends through the brain and decussates at the level of the medullary pyramids, where they synapse onto spinal nerves.
What is a lower motor neurone?
The motor fibres of the spinal nerve - PNS.
How do cranial nerves with motor function decussate?
The upper motor neurone, from the primary motor cortex, decussate at the level of the cranial nerve nuclei.
If the upper motor neurone is lost, what happens to some of the cranial nerves?
They have a back-up cortical input from the ipsilateral motor cortex.
How can there be injury to the neurones within the forebrain or brainstem, that connect to the spinal nerves?
There can be tumours that compress the neurones during their pathway.
A stroke can occur.
What are the mixed, sensory, and motor cranial nerves?
State where they arise from.
What is the commonest cause for anosmia, and how does this occur?
Common cold or upper respiratory tract infections lead to swelling of the tissues, inhibiting the chemicals from reaching the olfactory nerves.
What is the olfactory mucosa?
The olfactory receptors, which are within the epithelium of the superior aspect of the nasal cavity.
How could a tumour cause anosmia?
A frontal lobe tumour could compress the olfactory bulb or tract.
What medical conditions are associated with olfactory nerve complications?
Parkinson’s disease.
Alzheimer’s disease.
What stimulates the generation of action potentials for the optic nerve to pass on signals?
Photons.
What are the clinical findings of examinations of optic nerve lesions?
What can some fibres of the optic tracts terminate at?
Some fibres communicate with the brainstem, giving information about light intensity to control pupil size.
Most continue on the visual pathway, to the occipital lobe.
How can the optic nerve be compressed?
If there is an increase in intracranial pressure, the optic nerves can be compressed against the free tentorial edge.
If there is a pituitary tumour then the optic chiasm can be compressed.
What is the difference in appearance of injury to the optic nerve or optic chiasm, and why?
Optic nerve - visual symptoms or blurring on the affected side.
Optic chiasm - visual disturbances in both eyes as the optic nerve neurones cross here. Bitemporal hemianopia.
What opening in the cranial floor do CNS III, IV and VI pass through?
The superior orbital fissure.
What two smooth muscles does the CN III - oculomotor nerve - supply, and what are their functions? State which afferent fibres supply which.
Sphincter pupillae - found in the iris to constrict the pupil size. Visceral afferents (parasympathetic).
Ciliary body - controls the size of the lens of the eye. Visceral afferents (parasympathetic).
What skeletal muscles does the CN III - oculomotor nerve - supply, and what are their functions? State which efferent afferent supply which.
All extra ocular muscles, except 2 - eye movements.
Levator palpebrae superioris - keeps the eyelid retracted.
These are supplied by the somatic (motor) afferent fibres.
What kind of herniation causes oculomotor nerve lesions?
Uncul (tectorial) herniation.
Which artery is at risk of aneurysm, causing an oculomotor nerve lesion?
Posterior communicating artery.
What muscle is supplied by the trochlear nerve?
Superior oblique muscle.
Which muscle is supplied by the abducens nerve, and what is the abnormal eye position with lesions?
Lateral rectus muscle - meaning that there is medial deviation of the eye.
What is the importance of the route of the abducens nerve, when considering pathology?
Compression is likely due to the upward trajectory, as it runs along the clivus.
This can lead to stretching of the CN.
What is the function of the cerebellar tonsils, and where are they located?
They coordinate voluntary movement of the distal part of the limbs.
They appear on the inferior aspect of the cerebellum, protruding downwards.
What is the function of the midline vermis and cerebellar peduncles?
Midline vermis - splits the cerebellum into left and right. Controls trunk musculature.
Cerebellar peduncles - connect the cerebellum to the brainstem.
What condition is optic neuritis associated with?
Multiple sclerosis.
What are the neurosensory cells for the optic nerve?
Cones and rods.
What movement of the eye is affected by a trochlear nerve injury?
Difficulty moving the eye down and out.
What are cranial nerve lesions?
How do they present on each side of the body?
Disease/ injury involving the nuclei of the cranial nerve, within the brainstem, or with the cranial nerve outside of the CNS.
Lesions to the cranial nerve on one side of the body will lead to palsy on that side of the body.
What type of conditions can cause symptoms on the opposite side of the body, why?
Injuries within the CNS, such as strokes and intracranial pressure increases.
This is because the neurones supplying the cranial nerves, within the brain are yet to decussate.
What are the sensory innervations of the trigeminal nerve?
The skin and tissues of the face, parts of the scalp, the surface of the eye and some deep facial structures.
Anterior 2/3rds of the tongue.
What deep facial structures does the trigeminal nerve supply?
Orbital structures, the nose and nasal cavity, the paranasal air sinuses and parts of the oral cavity.
What is the motor innervation of the trigeminal nerve?
Muscles of mastication.
How is the trigeminal nerve examined?
Light touch in the dermatomes of Va, Vb and Vc, on either side of the face with the patients’ eyes closed.
Ask the patient to tense the jaw and feel for the tension in the temporalis and masseter, also get the patient to wiggle jaw side to side for the pterygoids.
Corneal reflex.
What is the corneal reflex, and what is it testing for within the trigeminal?
Both eyes are open and touching of the cornea of one of the eyes causes both eyes to close.
The opthalamic division of CN V senses the touch, which sends impulses to the brain, stimulating the facial nerve to respond - motor (obicularis oculi, closing the eyes).
What are some causes of trigeminal nerve lesions?
Trigeminal herpes zoster.
Trigeminal neuralgia.
Orbital and mandibular fractures - distal branches.
Posterior cranial fossa tumours.
Brainstem infarcts/ lesions.
What determines where trigeminal herpes zoster will infect?
The division in which the herpes zoster virus travels down from the trigeminal ganglion determines where the virus will be seen.
What is trigeminal neuralgia?
Compression of the trigeminal ganglion from an aberrant blood vessel (deviated from its normal path), causing electric shock-like pain in the region of the affected division.
What foramina do each of the branches of the trigeminal nerve pass through?
Opthalamic - superior orbital fissure.
Maxillary - foramen rotundum.
Mandibular - foramen ovale.
What are the branches of the opthalamic division of the trigeminal nerve, and what are their functions?
Lacrimal - sensation of the lacrimal glands.
Frontal - gives sensation to skin around the eyes, via the supraorbital and supratrochlear nerves.
Nasociliary - sensation to the eyeball and dorsum of the nose.
What is Hutchinson’s sign?
Trigeminal herpes zoster where the is involvement of the tip of the nose, increasing the risk of the eyeball being involved, as there is communication via the nasocilliary branch. Scarring due to vesicle formation there leads to visual defects.
What are the branches of the maxillary division of the trigeminal nerve, and what are their functions?
Infraorbital nerve - runs through the infraorbital foramen, giving sensation to the lower eyelid and cheek.
Superior alveolar nerve - gives sensation to the upper jaw, teeth and the gums.
How can the infraorbital nerve be damaged?
Orbital blow-out fractures, where it runs through the floor of the orbit.
What are the branches of the mandibular division of the trigeminal nerve, and what are their functions?
Motor branch supplying the muscles of mastication.
Lingual nerve - sensation to the anterior 2/3rds of the tongue.
Inferior alveolar nerve - travels within the mandible, giving sensation to the teeth and gums of the lower jaw, and from the skin of the chin (mental nerve).
Auriculotemporal nerve - innervates the temporal-mandibular joint and the side of the head.
What nerve can mandibular fractures put at risk?
Inferior alveolar nerve.
What is the functions of the facial nerve?
Motor - muscles of facial expression and stapedius.
Parasympathetic - lacrimal, nasal and salivary glands.
Taste - anterior 2/3rds.
What foramen does the facial nerve pass through to emerge through the base of the skull?
Through the internal acoustic meatus and then through the stylomastoid foramen.
What are the 3 intra-petrous branches of the facial nerve, and what are their functions?
Greater petrosal nerve - carries parasympathetic innervation to the lacrimal and nasal glands.
Nerve to stapedius.
Chorda tympani - taste of the tongue and parasympathetic innervation of the salivary gland.
How can the facial nerve be damaged?
Lesions around the internal acoustic meatus.
Posterior cranial fossa tumours.
Basal skull fractures, involving the petrous bone.
Middle ear disease.
Facial nerve palsy - Bell’s palsy, Ramsay-Hunt Syndrome.
Parotid malignancy.
What is the function of the vestibulocochlear nerve?
Innervates the cochlear for hearing.
Innervates the vestibular system for balance.
What do patients present with, with a vestibulocochlear nerve injury and how can these patients be examined?
Presents with hearing loss with or without tinnitus; dizziness/ vertigo.
Tested with bedside hearing tests such as a whisper or finger rub. Can also perform a tuning fork test.
How can the vestibulocochlear nerve be damaged?
Vestibular schwannoma and other posterior cranial fossa tumours.
Occlusion of labyrinthine artery.
Petrous bone fractures.
What is the route of the glossopharyngeal and vagus nerves?
Medulla.
Run through posterior cranial fossa.
Exit through jugular foramen.
Enter into carotid sheath:
- CN IX exits carotid sheath proximally.
- CN X continues down length of neck.
What is the function of the glossopharyngeal nerve?
Sensation of the oropharynx/ tonsils, and the middle ear cavity.
Gives sensation and taste to the posterior 1/3rd of the tongue.
Parasympathetic innervation to the parotid gland.
Afferent nerve fibres from the carotid sinus and carotid body.
Why may the glossopharyngeal nerve not be classed as a purely sensory nerve?
It gives a small contribution to the muscles of the pharynx.
These innervations join with the vagus nerve to form the pharyngeal plexus.
What is the function of the vagus nerve?
Gives motor function to the muscles of the larynx/ pharynx, including the soft palate.
Sensation to the larynx/ laryngopharynx.
Parasympathetic innervation of gut, cardiac and airway tissues.
Sensation to the parts of the external ear.
What may patients present with CN X nerve lesions?
Difficulties with speech.
Changes in voice.
Difficulty swallowing.
Weak cough.
How can you test for CN X lesions?
Speech and cough.
Asking the patients to open their mouth and say ‘ahhh’ to see if the soft palates elevate on both sides - uvula pulled to one side if one vagus nerve is injured.
Swallowing.
How can you test for CN IX and X lesions?
Gag reflex - touching the oropharynx on both sides. The sensation is by CN IX and motor by CN X.
How can CN IX and X be damaged?
Recurrent laryngeal nerve can be damaged by thyroid pathology or surgery, as well as superior thorax/ mediastinal pathology.
Pathology of the carotid sheath.
Posterior cranial fossa tumours.
Fractures to the base of the skull, involving the jugular foramen.
Medullary brainstem lesions, such as strokes.
What is the common and differing routes of the accessory and hypoglosal nerves?
Common - arise from the medulla (and spinal nerves for CN XI) and run through the posterior cranial fossa. Enter into carotid sheath.
Different:
- Hypoglossal exits and travels towards the tongue. Initially through hypoglossal canal.
- Accessory exits and heads towards the posterior triangle. Initially through jugular foramen.
What is the function of the hypoglossal nerve?
Innervates the muscles of the tongue for movements and protrusion.
How is the hypoglossal nerve examined?
Movements of the tongue from side to side.
Protrusion of the tongue can lead to deviations of the tongue, towards the side innervated by the damaged nerve.
What are some causes for hypoglossal nerve lesions?
Surgery or pathology involving the internal or external carotid arteries.
Posterior cranial fossa tumours.
Motor neurone disease.
Ischaemia of the brainstem, where the hypoglossal nucleus lies.
How is the accessory nerve tested for?
Turn the head (SCM) and shoulder shrug (trapezius) against resistance.
What are some causes for accessory nerve injuries?
Surgery, injury or pathology involving the posterior triangle.
Posterior cranial fossa tumours.
Fractures of the base of the skull, involving the jugular foramen.
What do the pharyngeal arches make up, in the embryo?
The lateral walls of the embryonic pharynx.
What does the first pharyngeal cleft become?
The external auditory meatus.
What is the external ear formed from?
Swellings of the first and second pharyngeal arch.
What is the relationship between the sizes of the pharyngeal arches?
The first is the largest, and they get progressively smaller.
What is the cartilaginous bar of the first pharyngeal arch known as?
Meckel’s cartilage.
What does the Meckle’s cartilage give rise to?
The mandible, malleus (hammer) and incus (anvil).
What do the 4th and 6th arches give rise to?
The thyroid, arytenoids and cricoids.
What are the cranial nerves associated with each of the pharyngeal arches?
What does the facial skeleton arise from?
The frontonasal prominence and the first pharyngeal arch.
What is the muscular derivative of the first pharyngeal arch?
Muscles of mastication.
What is the muscular derivative of the second pharyngeal arch?
Muscles of facial expression.
What is the muscular derivative of the third pharyngeal arch?
Stylopharyngeus - muscle of the pharynx.
What is the muscular derivative of the fourth and sixth pharyngeal arch?
What is the derivative of the first pharyngeal pouch?
Pharyngotympanic (Eustachian) tube and middle ear cavity.
What is the derivative of the second pharyngeal pouch?
Palatine tonsil.
What is the derivative of the third pharyngeal pouch?
Inferior parathyroid.
Thymus.
What is the derivative of the fourth pharyngeal pouch?
Superior parathyroid.
C-cells (parafollicular) of the thyroid.
What are the 5 building blocks of the development of the face?
Frontonasal prominence.
Two maxillary prominences.
Two mandibular prominences.
What does the frontonasal prominence form?
Forehead, bridge of the nose, upper eyelids and the centre of the upper lip - philtrum.
Label the following diagram.
What is the self-cleaning function of the external acoustic meatus?
Desquamatisation - dead squamous epithelium - migrate laterally out from the tympanic membrane.
What is tympanosclerosis?
Hardening of the tympanic membrane giving the appearance of white plaques, which is from healed trauma, that give no hearing deficits.
Describe the physiology of hearing.
What is the presentation of cholesteatoma?
Red lesion at the attic (pars flaccida) of the tympanic membrane.
Foul-smelling discharge.
Progressive hearing loss.
Secondary symptoms due to the destruction of other tissues.
What are the signs and symptoms of acoustic neuroma?
Describe Rinne’s test.
Describe Weber’s test.
What is transmitted through the optic canal, superior orbital fissure and inferior orbital fissure?
What can be seen on a CT scan of an orbital blowout fracture?
Orbital contents prolapsing and bleeding into the maxillary sinus.
Soft tissues and muscles trapped in the fracture site.
What is the orbital septum and what is its function?
A thin fibrous sheet originating from the orbital rim, that is continuous with the tarsal plate (dense connective tissue).
It acts as a barrier against infection spread, from the superficial eye, into the orbital cavity.
What does the levator palpebrae superioris insert into?
Orbital septum and tarsal plate.
What is a stye, its cause and treatment?
What is a meibomian cyst, its cause and treatment?
What is the limbus?
The junction between the sclera and cornea.
What is the production and drainage of aqueous humour?
What is central retinal artery occlusion, its presentation and presentation on ophthalmoscopy?
An embolic occlusion within the central retinal artery.
It is sudden loss of vision in one eye that develops over a few seconds and is painless.
The underlying choroid layer remain perfused but insufficient for the retina, causing ischaemia. This makes the retina appear pale, accentuating the macula, forming a cherry-red spot.
What can some refractive causes of decreased visual acuity, anterior to the retina be?
What can leukocoria be a sign of?
Retinal blastoma - ocular malignancy, seen in children.
Label a retinal artery, retinal vein, optic disc and macula on the following.
What is the primary resting gaze, and how does this relate to the different axes?
Primary resting gaze is where the position of the eyes is straight ahead, at rest, due to the equal and opposite actions of the extra-ocular muscles.
The orbital axes is at an acute angle to the visual axes.
What are the causes of an abducens nerve injury?
What are the clinical features of a trochlear nerve injury?
Elevated and adducted eye.
Vertically displaced diplopia.
Worsening diplopia when walking down stairs or reading due to looking down - superior oblique is lost and so the angle difference between the visual axes increases.
Possible head tilt to compensate for the loss of intortion.
What are the borders of the parotid gland?
What do the palatine tonsils lie between?
The palatoglossal arch and the palatopharyngeal arch.
Describe the pharyngeal phase of swallowing.
What is the oral phase of swallowing?
What is the oesophageal phase of swallowing?
Identify the frontal, ethmoid air and maxillary sinuses on the facial X-ray.
State what the black line is pointing to and why.
Increased fluid level due to blood pooling here as there is an orbital blowout fracture.
Identify the maxillary sinus ostium, the middle conchae and middle meatus.
What is circled in red?
Ethmoid air cells.
On a CSF sample with blood, what is seen?
Halo sign.
What does the nasal cavity run from and to?
Runs from the nares to the choanae.
What are the 5 arteries of the medial wall of the nasal cavity, and where do they arise from?
Ophthalmic artery gives rise to:
- Anterior ethmoid artery.
- Posterior ethmoid artery.
Maxillary artery gives rise to:
- Greater palatine artery.
- Sphenopalatine artery.
Superior labial artery (from the facial artery).
Label the following diagram.
What is the framework of the laryngeal inlet?
Describe the cough reflex.
What is pointed to in this X-ray?
Yellow - coronal sutures.
Red - lamdoid sutures.
Blue - middle meningeal artery impression on the skull.
What is seen on this X-ray?
Sagittal suture.
What abnormality is seen on this X-ray?
Fracture of the maxilla is not seen but may be there as could be blood pooling in the maxillary sinus.
Could be acute sinusitis.
What abnormality is seen on this X-ray?
State the tissue which is most likely to be compromised.
Inferior rectus muscle most likely to be involved.
What abnormality is seen in this X-ray?
Black eyebrow sign, signifying gas in the orbit.
What abnormalities can be seen on this MRI?
Basal skull fractures.
What abnormality is seen on this X-ray?
Jefferson fracture - burst fracture of the atlas.
What is seen in this X-ray?
Spondylolisthesis - C6 vertebra fracture-dislocation of the pars interarticularis.
Label the required lobes and ventricles of the brain MRI.
Label the required lobes and ventricles of this MRI.
