Head And Neck Flashcards
What does the neurocranium do?
Completely encloses the brain
What does the viscerocranium do?
Produces the face
Where do cranial nerves leave the skull in order to innervate the face?
The front of the skull
Where do cranial nerves leave the skull in order to innervate the neck and below?
Back of the skull
What are the margins of the anterior triangle of the neck?
Inferior margin of mandible
Midline of neck
Anterior margin of sternocleidomastoid
What structures are associated with the anterior triangle of the neck?
Structures crossing between the head and thorax
What are the margins of the posterior triangle of the neck?
Posterior margin of sternocleidomastoid
Anterior margin of trapezius
Clavicle
What structures are associated with the posterior triangle of the neck?
Structures crossing between the thorax/neck and upper limb
List 3 sites where 3 bones of the skull are fused
Bregma, pterion, lambda
What is the lymphatic system comprised of?
Fluid (lymph)
Drainage vessels
Lymphatic tissues - nodes/lymphoid organ
How is tissue fluid formed?
Net filtration of fluid does not equal net reabsorption of fluid.
Tissue fluid in interstitium enters lymphatic capillaries, forming lymph
What does lymph fluid consist of?
Tissue fluid, small proteins, lipids (chylomicrons from gut lymphatics), damaged cells, bacteria, cancer cells
Approximately how much lymphatic fluid is produced per day?
~3-4 litres
How is lymphatic drainage unidirectional?
Valves. Passive constriction (pulsation of artery/muscle contraction). Intrinsic constriction
Describe the order of lymphatic flow
Tissue fluid, lymphatic capillary, lymphatic vessels (afferent), lymph nodes, lymphatic vessels (efferent), lymphatic trunks, lymphatic ducts
Where does the majority of lymph fluid drain into ultimately?
2 main lymphatic ducts which drain into subclavian veins
What lymph drains into the right lymphatic duct?
Right upper quadrant (arm, chest and side of head)
What lymph drains into the left thoracic duct?
Both legs, 1\2 of head, arm
What is lymphoedema?
Abnormal collection of protein rich fluid causing tissue to swell due to compromised lymphatic system
What might cause lymphoedema?
Removal or enlargement of lymph nodes
Infections (e.g. Certain proteins)
Damage to lymphatic system e.g. Cancer treatments
Lack of limb movement (albeit not alone! Muscle contraction assists movement of lymph)
Congenital e.g. Milroys syndrome
List the lymphatic organs
Spleen, thymus, tonsils, lymph nodes
Describe the constitution of a lymph node
Connective tissue structures - tough fibrous outer capsule. Reticular connective tissue inside ‘candy floss’
What cells do lymph nodes contain?
Large collections of lymphocytes (B and T) and macrophages
How does the lymph system help defence against infection?
All substances transported in lymph pass through at least 1 lymph node.
Physical filter
Phagocytic filter
Full of lymphocytes, active and proliferate in response to antigens
What is lymphadenopathy?
Swollen lymph nodes. Very common patient presentation.
What is the difference between in presentation of infective and malignant lymphadenopathy?
Infective - tender, mobile (most common)
Malignant - hard, matted, non-tender
What should you do on a patient presenting with lymphadenopathy?
Comprehensive history, examine area of tissue it drains, if malignancy suspected examine other lymph nodes and body systems
How can lymph nodes be classified?
Regional - drain specific areas (superficial, more readily palpable)
Terminal - receive drainage from number of regional nodes (deep)
What separates superficial (regional) and deep (terminal) lymph nodes?
Investing layer of deep cervical fascia of the neck
What is Waldeyer’s ring?
Annular collection of lymphatic tissue (nodules) surrounding superior pharynx. Consists of ‘tonsils’ - pharyngeal tonsil (adenoids), palatine tonsil X2, lingual tonsil X2
Why is it important to check the supraclavicular lymph nodes?
Abdominal/thoracic malignancies can present as enlarged supraclavicular nodes. Oversee transport of lymph from thoracic cavity and abdomen
Left: virchows node, abdomen and thorax
Right: midsection chest, oesophagus and lungs
Where does head and neck superficial lymph nodes drain into?
Deep cervical lymph nodes which surround the IJV before then draining via thoracic duct into subclavian vein
Where does lymph drain into the jugulo-digastric node?
Palatine tonsils, oral cavity, posterior 1/3 tongue, pharynx, larynx
Name the major blood vessels of the head and neck
External jugular, internal jugular, common carotid
Does the common carotid artery give off any branches in the neck?
No
What happens to the common carotid artery?
Bifurcates to give the external and internal carotid arteries
Where do the vertebral, internal thoracic and thyrocervical arteries all arise from?
The subclavian artery in the base of the neck
On the right, what do the subclavian and common carotid arteries arise from?
The brachiocephalic trunk
Where do vertebral arteries arise from?
Subclavian arteries
Via where in the neck do the vertebral arteries ascend?
Ascend through the transverse foramina in cervical vertebrae 6 to 1
What arteries supply the brain?
Vertebral arteries, along with internal carotid arteries, enter skull through carotid canal
At approximately what level does the common carotid artery bifurcate?
Approximately level of the superior border of the thyroid cartilage
Where does the internal jugular artery lie?
Lateral to the common carotid, mostly under sternocleidomastoid
What is the carotid sinus?
A swelling at region of bifurcation. Location of baroreceptors for detecting changes in arterial BP
What is the carotid body?
Peripheral chemoreceptors which detect arterial pO2
What is the carotid sheath?
The common carotid artery and internal jugular vein lie within the carotid sheath along with the vagus nerve and deep cervical lymph nodes. The carotid sheath is closely related to the pretracheal, prevertebral and investing layers of deep fascia
What are the contents of the carotid triangle?
Internal jugular vein, bifurcation of common carotid (thus external and internal carotid arteries)
What are the boundaries of the carotid triangle?
Superior - posterior belly of digastric
Lateral - sternocleidomastoid
Medial - superior belly of omohyoid
What is the carotid triangle important for?
The surgical approach to the carotid arteries, or internal jugular vein. Can also access vagus and hypoglossal nerves.
Can feel the carotid pulse (may also be palpate inferiorly)
Carotid sinus massage
What might a carotid sinus massage be used to treat?
Possible treatment for supraventricular tachycardia (location of baroreceptors)
What are the 6 branches of the external carotid artery?
Superior thyroid Lingual Facial Ascending pharyngeal Occipital Posterior auricular
What are the terminal branches of the external carotid artery?
Superficial temporal
Maxillary
What are the major vessels supplying the scalp?
The internal/ophthalmic artery
The external carotid artery
What vessels supply the scalp from the internal/ophthalmic artery?
Supra-orbital artery
Supratrochlear artery
What vessels supply the scalp from the external carotid artery?
Superficial temporal artery
Posterior auricular artery
Occipital artery
What does the scalp consist of?
Skin, dense connective tissue, aponeurosis, loose connective tissue, periosteum
Briefly outline the blood supply to the scalp
Rich blood supply with many aponeuroses. Largely branches of external carotid artery, except supratrochlear and supraorbital arteries (branches of ophthalmic artery) which arise from the internal carotid artery.
Describe the structure of the blood supply to the scalp, and why this can lead to perfuse bleeding
Walls of arteries closely attached to connective tissue, limits constriction (can get perfuse bleeding) Numerous anastomoses (can get perfuse bleeding) Deep lacerations involving epicranial aponeurosis cause perfuse bleeding because of opposing pull of occiptfrontalis
What mostly supplies blood to the skull? What is a consequence of this?
Mostly the middle meningeal artery (thus loss of scalp does not lead to bone necrosis)
Broadly outline the structure of the blood supply to the scalp
Superficial veins generally accompany arteries (superficial temporal veins, occipital veins, posterior auricular veins)
Describe the venous drainage of the scalp
Supraorbital and supratrochlear veins unite at medial angle of eye to form angular vein, which drains into the facial vein. Some deep parts of the scalp in temporal region have veins which drain into the pterygoid venous plexus
Describe the connection between venous drainage of the scalp and curls venous sinuses (possible infection pathway)
Veins of scalp connect to diploic veins of skull through several emissary veins and thus to Duran venous sinuses. Emissary veins are valveless. Infection from scalp can spread to the cranial cavity and affect meninges.
What supplies the double layer of dura mater covering the brain?
Anterior/middle meningeal arteries
What might a fracture at the pterion cause?
MMA, middle meningeal artery, rupture. Supplies skull and dura. Extradural haemorrhage.
Why might a craniotomy be carried out? How?
To gain access to the cranial cavity. Bone and scalp are reflected inferiorly to preserve blood supply.
From were do all superficial arteries of the face arise from?
Arise from external carotid artery, apart from supra-orbital and supratrochlear, which are from internal carotid artery (via opthalamic)
Describe the endothelium rural venous sinuses
Lined spaces between periosteal and meningeal layers of dura. Form at dural septae. Receive blood from large veins draining blood from brain.
Describe sigmoid dural venous sinuses
Continue as the internal jugular veins, leaving the skull through the jugular foramena
What is the cavernous sinus?
A plexus of extremely thin walled veins on upper surface of sphenoid
What, other than the cavernous sinus veins, is in the cavernous sinus?
Internal carotid artery CN III occulomotor CNIV trocholear CN VI abducent 2 branches of trigeminal (CN 1 ophthalmic and CN 2 maxillary)
Describe the connection of the facial veins with cavernous sinus and pterygoid venous plexus
Veins of the face are valveless. At medial angle of eye, facial vein communicates with superior ophthalmic - drains into cavernous sinus.
Deep facial veins drain into pterygoid venous plexus. Infection from facial vein can spread to dural venous sinuses. Infected clot can travel to intercranial venous system
How many pairs of cranial nerves are there?
12
What do the cranial nerves supply?
Structures of the head and neck (+ vagus, which supplies structures in thorax and abdomen also)
What types of nerve may cranial nerves be?
General sensory, special sensory, motor or autonomic
What is the brainstem?
Adjourns the brain to the spinal cord. Continuous with spinal cord caudally.Ascending and descending fibres between brain and rest of body run through it. Location of the majority of cranial nerve nuclei
What does the brainstem do?
Vital role in regulation of cardio-respiratory functions and maintaining consciousness. Ascending and descending fibres between brain and rest of body run through it.
Where are th majority of cranial nerve nuclei located?
In the brainstem
What are the cranial nerve nuclei, as found in the brainstem?
Collections of cell bodies of nerve fibres that make up the whole cranial nerve
What constitutes the brainstem?
Midbrain, pons and medulla
What is cranial nerve 1 called?
Olfactory nerve
What does cranial nerve 1 sense?
Special sensation - smell
How would you test cranial nerve 1?
Test one nostril at a time, smelling salts.
Describe cranial nerve 1
Paired anterior extensions of forebrain, rather than a ‘true’ cranial nerve.
Other than a URTI, what else is a common cause of anosmia (loss of sense of smell)?
Head injury- shearing forces/basilar skull fracture (nerve endings poke through cribform plate)
What is cranial nerve 2 called?
Optic nerve
Describe the route of the optic nerve CN 2
Retina, optic canal, optic chiasm, optic tracts
What does the optic nerve CN2 sense?
Special sensation, vision
How would you test the optic nerve CN2?
Test one eye at a time. Visual tests and pupils
How might you be able to see the optic nerve?
Seen directly with fundoscopy ‘optic disc’
What is cranial nerve 3 called?
Oculomotor nerve
Describe the route of the oculomotor nerve CN3
Route - SOF (superior orbital fissure) - orbit
What cranial nerves originate in the forebrain?
CN 1 and 2
Olfactory and optic nerves
What nerves originate in the midbrain?
CN 3 and 4
Oculomotor and trochlear nerves
What type of sensation does the oculomotor CN3 sense?
Motor/autonomic (parasympathetic)
What muscles does CN3 oculomotor innervate?
4/6 ocular muscles
How would you test the function of the oculomotor CN3 nerve?
Inspection of eyelid and pupils. Eye movements. Pupillary light reflexes
How might a person with CN3 oculomotor nerve lesion present?
Present with diplopia (double vision). Eye in ‘down and out’ position with severe ptosis +/- pupillary dilation.
What might cause a CN3 oculomotor nerve lesion?
Raised intercranial pressure (tumour/haemorrhage), aneurysm (posterior communicating artery), cavernous sinus thrombosis. Diabetes/hypertension (pupil sparing).
What is the cavernous sinus?
Split between the dura and other membranes. Dura lined cavity containing many veins, nerves and internal carotid artery.
What is CN4 called?
Trochlear nerve
What is key about the route of CN4 trochlear nerve
The longest intracranial route of all CNs. Only CN to arise from dorsal aspect of the brainstem.
What type of sensation does the CN4 trochlear nerve transmit?
Motor to extra ocular muscles only
How would you test CN4 trochlear nerve?
Eye movements
How might a CN4 trochlear nerve lesion present?
Rare and subtle, often can correct with slight tilt of head. Diplopia, worse on downward gaze e.g. When reading, walking downstairs.
What might commonly cause a CN4 trochlear nerve lesion?
Head injury, or any cause of raised intercranial pressure. Congenital palsies (children)
What is CN5 called?
Trigeminal nerve
Describe the route of the CN5 trigeminal nerve
Pons - superior orbital fissure - foramen rotundum - foramen ovale
What sort of innervation does the CN5 trigeminal nerve do?
Motor/sensory
Muscles of mastication
Main sensory nerve of face
How would you test the trigeminal CN5 nerve?
Test sensation to face
Test muscles of mastication
What is neuralgia ?
Intense pain to light touch
Which cranial nerves originate in the pons?
CN 5,6,7 and 8
Trigeminal, abducens, facial and vestibulocochlear
What is CN6 called?
Abducens nerve
What route does the abducens nerve CN6 take?
Pons - superior orbital fissure
What sort of innervation does the abducens nerve do?
Motor, to one muscle (lateral vectus)
How do you test the function of abducens CN6?
Eye movements
In what circumstances is abducens nerve CN6 susceptible to injury?
Raised intercranial pressure, e.g. Due to bleed/tumour
How would a patients with a CN6 abducens nerve lesion present?
Diplopia
What is CN7 called?
Facial nerve
Describe the route of CN7 facial nerve
Pons - internal acoustic miatus - petrous temporal bone - stylomastoid foramen
What sort of innervation does CN7 facial nerve do?
Motor/sensory/autonomic
Muscles of facial expression.
Taste (anterior 2/3 of tongue)
Parasympathetic to lacrimal and salivary glands
How might you test the function of CN7 facial nerve?
Test muscles of facial expression
Taste not formally used often
What is ‘bells palsy’
Facial nerve palsy
What might cause facial nerve ‘bells’ palsy?
Parotid tumours
What nerve has the facial nerve got a close relationship with?
Vestibulocochlear nerve
What is CN8 called?
Vestibulocochlear nerve
Describe the route of the vestibulocochlear nerve CN8
Pons - internal acoustic miatus
What sort of innervation does the vestibulocochlear nerve CN8 do?
Special sensory (hearing/balance)
How would you test the vestibulocochlear nerve CN8?
Hearing
Rinne’s and Weber’s tests
How might a patient with vestibulocochlear nerve CN8 lesion present?
Hearing loss. Vertigo/tinnitus, acoustic neuroma (benign tumour)
What is CN9 called?
Glossopharyngeal nerve
Describe the route of CN9 glossopharyngeal nerve
Medulla - jugular foramen
What nerves originate in the medulla?
CN 9, 10, 11, 12
Glossopharyngeal, vagus, spinal accessory, hypoglossal nerves
What type of innervation does the glossopharyngeal CN9 nerve do?
Special sensory - taste posterior 1/3 of tongue
General sensory - soft palate, tonsils, oropharynx, tympanic membrane. Carotid body and sinus
Autonomic - parotid gland
Motor - 1 muscle, stylopharyngeus
Mostly sensory!
How would you test CN9 glossopharyngeal nerve?
Gag reflex (sensory limb), taste not often formally tested Tested in conjunction with CNX
What is CN 10 called?
Vagus nerve
Describe the route of CNX vagus nerve
Medulla - jugular foramen - carotid sheath - neck
What sort of innovation does the vagus nerve do?
General sensory - laryngopharynx, larynx mainly (also small part of ear
Motor - muscles of soft palate, pharynx, larynx
Autonomic - parasympathetic to thoracic and abdominal viscera
(Special sensory)
How would you test the vagus nerve CNX?
Noting speech, swallow, cough, gag reflex (efferent limb)
What is a common sign if there is an isolated lesion of CNX vagus nerve?
Deviation of uvula when soft palate elevated.
Injury to recurrent laryngeal nerve branch can cause hoarseness and dysphonia
What is CN 11 called?
Spinal accessory nerve
Describe the route of the accessory CNXI nerve
Medulla - jugular foramen
What sort of innervation does the spinal accessory CNXI nerve do?
Motor - sternocleidomastoid, trapezius
How would you test the spinal accessory nerve CNXI?
Shrug shoulders, turn head against resistance
When would the spinal accessory nerve CN11 be susceptible to injuries?
Runs down through neck in posterior triangle. Susceptible to injury here e.g. Lymph node biopsies, stab wound
What else contributes to the spinal accessory nerve, other that’s the cranial root?
Receives spinal rootlets from upper 5/6 cervical segments. Ascend up foramen magnum to join cranial root.
What is CN12 called?
Hypoglossal nerve
Describe the route of CN 12 hypoglossal nerve
Medulla - hypoglossal canal
What sort of innervation does the hypoglossal CN 12 nerve do?
Motor only
Muscles of the tongue
How would you test function of CN 12 hypoglossal nerve?
Inspection or movement of tongue
How would nerve lesion to CN12 present?
Damage to CN12 causes weakness and atrophy of the tongue muscles on ipsilateral side
What cranial number is the hypoglossal nerve?
CN XII
CN 12
What cranial number is the spinal accessory nerve?
CN XI
CN 11
What cranial number is the vagus nerve?
CN X
CN 10
What cranial number is the glossopharyngeal nerve?
CN IX
CN 9
What cranial number is the vestibulocochlear nerve?
CN VIII
CN 8
What cranial number is the facial nerve?
CN VII
CN 7
What cranial number is the abducens nerve?
CN VI
CN 6
What cranial number is the trigeminal nerve?
CN V
CN 5
What cranial number is the trochlear nerve?
CN IV
CN 4
What cranial number is the oculomotor nerve?
CN III
CN 3
What cranial number is the optic nerve?
CN II
CN 2
What cranial number is the olfactory nerve?
CN I
CN 1
What is the autonomic nervous system a part of?
The peripheral nervous system
Where is the central control of the autonomic nervous system?
The hypothalamus
What does the autonomic nervous system control?
Body functions not under conscious control
Maintains and fine tunes internal environment, accelerator and brake.
Describe the layout of the autonomic nervous system
Preganagloinic neurone, ganglion, postgangloinic neurone
What might the target tissues for the autonomic nervous system be?
Smooth muscle, cardiac muscle, glands
What might also be called ‘visceral efferent/motor’?
The autonomic nervous system
Where do the sympathetic nerves arise from?
The thoracolumbar spinal cord T1 to L2
Where do the parasympathetic nerves arise from?
The brainstem
What does the sympathetic autonomic nervous system innervate? (4 tings)
Smooth muscle of blood vessels, eye lid (tarsal muscle) and iris (dilator pupillae)
Sweat glands
Arrector pili muscles (hair follicles)
DECREASES secretions from salivary and lacrimal glands
What does the parasympathetic autonomic nervous system innervate? (3 tings)
Smooth muscle of iris (sphincter pulillae) and ciliary body (controls thickness of lens) Lacrimal glands (tears) Salivary and mucosal glands
Describe the chain via which the sympathetic nerves innervating the head and neck get there
Arise from spinal cord Sympathetic chain Cervical ganglion Hitch hike onto blood vessels (carotid plexus) Target tissues
What smooth muscle is innervate do by the sympathetic autonomic nervous system?
Smooth muscle in eyelid and iris (dilator)
Smooth muscle in blood vessel walls
Arrector pills muscles of hairs
Sweat glands
What are the carotid arteries and lung apex important anatomical relations to?
Sympathetic nerves innervating the head and neck
Pathology in the carotid arteries or lung apex may cause anatomical dysfunction where else?
In the eye and face
What is horners syndrome?
Mitosis, partial ptosis, +/- anhydrosis
Interruption of sympathetic nerve supply to head and neck. Possible diagnosis relate to anatomical relations of sympathetic nerve on its route from spinal cord to head (apex of lungs, carotid artery dissection)
What might cause horners syndrome? (Mitosis, partial ptosis, +/- anhydrosis)
Interruption of sympathetic nerve supply to head and neck. Possible diagnosis relate to anatomical relations of sympathetic nerve on its route from spinal cord to head (apex of lungs, carotid artery dissection)
What is the origin of the sympathetic nerves in the head and neck?
Spinal cord T1 to L2
Mostly T1 and T2
What ganglia are a part of the sympathetic nervous system of the head and neck?
In cervical portion of sympathetic chain
Superior cervical ganglion
Middle cervical ganglion (structures in neck and chest)
Upon what do the sympathetic nerves of the head and neck hitchhike on?
Blood vessels
Very distally join branches of CN 5
What are the effector tissues of the sympathetic nerves of the head and neck?
Eye (dilator pupillae)
Eye lid (superior tarsal muscle)
Smooth muscle
Sweat glands (+salivary and lacrimal glands DECREASING secretions)
Describe the response of the sympathetic nerves of the head and neck
‘Fight or flight’
Pupillary dilation, assists lid retraction, vasoconstriction, sweating
Describe the route taken by the parasympathetic nerves supplying the head and neck
Arise from brainstem Hitchhike onto one of 4 CNS Ganglion Hitchhike onto branches of CN 5 Target tissue
List the 4 ganglions used by parasympathetic nerves supplying the head and neck
Edinger Westphal
Superior Salivary
Inferior Salivary
Dorsal Motor
What do the parasympathetic nerves in the head and neck innervate?
Smooth muscle of iris (constrictor) and ciliary body (controls lens)
Mucosal glands in nasal/oral mucosa/resp tract
Salivary and lacrimal glands
List some signs of parasympathetic CN 7 lesions
Pathology at of before geniculate ganglion may involve all parasympathetic functions carried out within CN7
Pathology after genticulate ganglion will not involve greater oetrosal nerve (lacrimal gland spared)
Describe the route taken by parasympathetic CN3 oculomotor
Brainstem (EWN) para. Fibres emerge with CN3 fibres
Hitchhike on CN3. Preganglionic
Ciliary ganglion. Post ganglioninc hitchhike on small branches from V1/Va
Eye ciliary body pupillae sphincter
Describe the route taken by the parasympathetic CN9 glossopharyngeal
Jugular foramen Tympanic nerve Tympanic plexus Lesser petrosal nerve - Foramen ovale Optic ganglion (in infratemporal space) Branch of CN V3 Parotid gland
What does the parasympathetic CN 9 nerve do? (Parotid gland)
Motor to stylopharyngeus
Sensory from oropharynx, tonsils
Taste and general sensation (posterior 2/3 tongue)
Sensory branches to carotid body/sinuses