Head and neck Flashcards
State the borders of the anterior and posterior triagles of the neck
- Anterior triangle -> ant=midline, post =ant SCM, sup=mandible, floor=vertebrae
- Posterior triangle-> ant=post SCM, post=ant trapezius, inf=clavicle, floor=scalene
State the contents of the anterior and posterior triangles
- Ant = carotid sheath (CCA, IJV, CNX), CNXII, submandibular, thyroid and parathyroid, lymph nodes
- Post = CNXI, subclavian a, EJV, brachial plexus trunks, lymph nodes
Where does the CCA bifurcate?
-C4
What are the advantages of the neck being separated by fascial planes?
-Allows ease of movements of individual compartments, limits infection
Describe the hyoid bone, state its functions and describe the muscles associated with it.
- Horseshoe shaped bone situated at c3 anchored by strap muscles. Elevates and depresses the larynx in order to aid swallowing
- Elevation by suprahyoid muscles -> digastric, stylohyoid, mylohyoid and geniohyoid
- Depression by infrahyoid muscles -> omohyoid, thyrohyoid, sternohyoid and sternothyroid
Name the layers of the neck
- Skin
- Superficial fascia
- Deep Cervical fascia
- Pretracheal fascia
- Carotid sheaths
- Prevertebral fascia
What lies within the deep fascia of the neck?
- SCM
- Trapezius
- Submandibular gland
- Parotid glands
State the layers of the pretracheal fascia and what is contained within this layer. Why is it beneficial that these structures are separated?
- Muscular and visceral layers
- Trachea, oesophagus, thyroid and infrahyoid muscles
- Allow independant movement during swallowing
What are superficial infections like cellulitis limited to the superficial space?
-Cannot cross deep investing fascia
What is the retropharyngeal space? Why is there a danger space within here?
- Area between pretracheal fascia and paravertebral fascia
- Split into two by alar fascia which joins carotid sheath
- Behind alar fascia lies danger space which connects to diaphragm and therefore would allow infections to spread into the thorax
Why would a parapharyngeal abscess be potentially life threatening?
-Could compress the carotid sheath and lead to IVC thrombosis
State the muscles of facial expression, the nerve which innervate them (and its branches), which pharyngeal arch its related to and state 2 diseases which can affect these muscles
- Frontalis, orbicularis oculi, orblicularis oris, zygomatic mj and mn, buccinator
- CNVII (temporal, zygoatic, buccal, mandibular, cervical)
- PhA 2
- Stroke and Bells palsy
State the muscles of mastication, the nerve which innervate them, which pharyngeal arch its related to
- Massater, Temporalis, med and lateral pterygoids
- CNV(3)
- PhA1
What are the branches of the ECA?
- Superior thyroid
- Ascending pharyngeal
- Lingual
- Facial
- Occipital
- Posterior auricular
- Superior temporal
- Maxillary
Name the branches of trigem and state their functions
- Opthalmic ->sensory to forehead, upper eyelids and dorsum of nose
- Maxillary -> sensory to cheeks, wings of nose, upper lip/teeth,hard palate and sinuses
- Mandibular -> sensory to temple, mandible, lower lip/teeth, motor to MoM
What is the most common cause of non-traumatic facial palsy? How does facial palsy present?
- Inflammation of CNVII near exit through stylomastoid foramen
- Total unilateral facial paralysis including forehead, inability to close eyelid, loss of integrity of oral cavity
Describe the pharyngeal arch system
- 5 external buldges which have a mesenchymal core, ectodermal covering and endodermal lining
- In between each arch exteriorly there is a pharyngeal cleft and interiorly there is a pharyngeal pouch
- Undergo extensive modification to become embryonic head and neck
- Each arch as an associated artery, nerve and cartilage bar
State the borders of the sections of the pharynx
- Naso = Back of nasal cavity to soft palate in line with C1
- Oro = soft palate to epiglottis in line with c2/3
- Laryngo = epiglottis to inferior border of cricoid cartilage in line with c3-c6
Briefly describe the formation of the neural tube. What disease occurs when there is defects in neural tube formation?
- The notochord signals to overlying ectoderm to become neuroectoderm. Neuroectoderm thickens and the edges elevate out of the neural plate and curl towards each other. Fuse to form the neural tube.
- Expanstion of the cranial end produces 3 vesicles named proencephalon, mesencephalon and rhombencephalon which become the forebrain, midbrain and hindbrain respectively.
Where is the facial skeleton derived from?
-Frontonasal prominences and neural crest of PhA1
Describe the derivatives of the 1st pharayngeal arch (artery, nerve, muscles, cartilage, cleft and pouch)
-Artery regresses, nerve is CNV, muscles of mastication, cartilage is meckels and produces the mandible, malleous and incus, cleft forms external auditory meatus and pouch forms middle ear cavity and eustachian tube
Describe the derivatives of the 2nd pharayngeal arch (artery, nerve, muscles, cartilage, cleft and pouch)
- Artery regresses
- CNVII
- Muscles of facial expression
- Reicherts cartilage -> Stapes, styloid process, lessercornu and upper body of hyoid bone
- Cleft -> obliterated by growth of 2PA
- Pouch -> Palatine tonsil
Describe the derivatives of the 3rd pharayngeal arch (artery, nerve, muscles, cartilage, cleft and pouch)
- Artery becomes internal carotid
- Nerve -> glossopharyngeal
- Muscles -> stylopharyngeus
- Cartilage -> greater cornu and lower body of hyoid bone
- Cleft -> Obliterated by growth of 2nd arch
- Pouch -> Thymus and parathyroid gland
Describe the derivatives of the 4th and 6th pharayngeal arch (artery, nerve, muscles, cartilage, cleft and pouch)
- 4th artery = L Arch of aorta, Right Brachiocephalic
- 6th artery -> pulmonary trunk
- Nerve -> Vagus
- Muscles -> Intrinsic muscles of the larynx and epiglottis
- Cartilage -> Thyroid, artynoid and cricoid cartilage
- Cleft -> obliterated by the growth of the 2nd PA
- Pouch -> 4th contributes to parathyroid gland
Describe the function of CNIX
- Innervates stylopharyngeus and provides special sensation to posterior 1/3 tongue
- Provides sensation to external and middle ear,pharynx, tonsils and soft palate
- Carotid bodies and carotid sinus
- Parasymp to parotid (lesser petrosal nerve)
Describe the course of the vertebral arteries
-Arise from the base of the L and R subclavian and ascend through transverse foramina of C1-6 and unite to form basilar artery
Which vessels anastamose to form the circle of willis?
-Basilar and ICA
Which vessels arise from the base of the subclavian?
-Vertebral, thyrocervical trunk and internal thoracic
Give the branches of the thyrocervical trunk
- Ascending and transverse cervical
- Suprascapular
- Inferior thyroid
What is the carotid sinus and carotid body?
- Sinus is a swelling at bifurcation which has baroreceptors for bp
- Body is separate to artery and has peripheral chemoreceptors
What are the boundaries of the carotid triangle in the neck? What is in it? What clinical significance does the catorid triangle bear?
- Sup = posterior digastric
- Lat=anterior SCM
- Med= superior omohyoid
- IJV, CCA bifurcation, Deep LNs and vagus nerve
- Site of central line in IJV, site of carotids for pulse or surgical access, carotid sinus massage
Describe the layers of the scalp? Which layer are the bvs in and why is this significant? Name the vessels of the scalp
- Skin
- Connective tissue dense
- Aponeurosis
- Loose connective tissue
- Periosteum
- The vessels lie in the dense connective tissue which if lacerated holds the vessels open and thus constriction to prevent bleeding is limited
- Supraorbital, supra trochlear, superficial temporal, posterior auricular, occipital
What is the main blood supply to the skull? What is a common cause of rupture? Why is this the case? What type of haemorrhage is produced?
- MMA
- Blow to the pterion
- The point of fusion of 4 bones of the skull making it a weak area
- Extradural
What are dural venous sinuses?
- Endothelial lined spaces between the periosteal and meningeal layers of dura mater
- They receive blood from large veins of the brain and drain into IJV
What structures run through cavernous sinus?
- ICA
- CN III, IV, V1,V2 and VI
Why is it clinically significant that face veins are valveless?
-Allows infection to track back into the skull/brain
Where are lymphatics not present?
-cornea/lens, inner ear, bone marrow
Describe how lymph is formed. What is its purpose?
- Balance between hydrostatic and oncotic pressure -> net movement = tissue fluid
- Some small proteins in tissue fluid and cannot re-enter circ -> enter porous lymphatic capillaries and water follows -> now termed lymph
- Allows tissue fluid ot rejoin systemic circ
How can lymphatic channels contribute to disease?
-Can allow spread of malignancy and disease
State the order of lymphatic flow from tissue fluid to rejoin circulation. How is the flow of lymph maintained?
- Tissue fluid -> afferent lymph vessel -> LN -> efferent lymph vessel -> lymphatic trunk -> lymphatic duct -> subclavian artery
- Valves ensure flow is in one direction and passive constriction by muscles and arteries make lymph flow
What is lymphoedema? Give some causes
- Fluid retention and tissue swelling due to a comprimised lymphatic system.
- Removal of LNs, infection, chemo, immobility
What separates superficial and deep cervical LNs? Name the deep LNs, which are of particular importance?
- deep cervical fascia
- Jugulo-digastric (tonsillitis), jugulo-omohyoid, supraclavicular (left is significance of gastric carcinoma)
Describe the structure of a lymph node, state its function. Give 2 differentials of an enlarged lymph node and how you would differ between them
- Connective tissue structure which has a tough fibrous capsule and reticular inside. Several afferent vessels enter and one leaves -> Made of several follicles surrounded by a cortex with a germinal centre
- immune surveillance with macrophages and lymphocytes, filter
- Infection -> tender, smooth, firm and mobile
- Malignancy -> non-tender, hard, craggy and matted
What are neural crest cells?
-Specialised population of cells that originate laterally in the neuroectoderm, become displaced after neural tube fusion and migrate throughout the body
State where the skeletal structures of the face are deived from
- The frontonasal prominence develops into the forehead, nose and filtrum
- The maxillary portion of PhA1 develops into cheeks, lateral upper jaw and lateral upper lip
- The mandibular portion of PhA1 develops into mandible
How are the oral and anal apertures created?
-No mesoderm in these areas means the membranes rupture as no blood supply develops there
Describe the development of the nose
- Thickening of ectoderm on either side of FNP produces 2 nasal placodes
- Nasal placodes sink into nasal pits
- Lateral apsects of the pits raise out of the plane and form medial and lateral nasal prominences
- Expansion of the maxillary prominence drives the nasal prominences close together until the medial prominences fuse
- Also fuses with maxillary prominence forming intermaxillary segment which contains philtrum, 4 inscisors and primary palate
- Nasal septum grows down and fuses with palatal shelves
Describe the formation of the palate
- Primary palate forms from FNP
- Maxillary prominence of PhA1 develops 2 palatal shelves which grown vertically into oral cavity at either side of tongue
- Mandible grows sufficiently large and allows tongue to drop out of the way and the palatal shelves fuse forming the secondary palate
- Primary palate and secondary palate fuse to give definitive palate
How can a cleft lip or palate occur?
- Failed fusion of the primary and secondary palate
- Failed fusion of the palatal shelves of secondary palate
- failed fusion of the medial nasal prominences with maxillary prominence (cleft lip)
Describe the development of the eye and its anatomical positioning
- Outpocketings of forebrain become the optic vesicle and grow outwards to make contact with overlaying ectodermal covering
- This contact induces the formation of the lens placode
- Optic vesicle begins to invaginate bringing the lens placode with it
- The two surfaces of the optic vesicle meet and form the optic cup and then the retina
- The lens placode develops into the lens vesicle and then the lens
- Primordia begin on side of head and as facial prominences grow they are pushed into anatomical position
Describe the development of the external ear
- The external auditory meatus comes from the 1st Ph cleft
- The auricles develop from the 1st and 2nd arches which surround the EAM
- Begin development in the neck region and ascend as the mandible grows
What is fetal alcohol syndrome
- Neural crest migration and brain development is extremely sensitive to alcohol
- Produces deformities including underdeveloped jaw, flattened face, smooth philtrum, small palpebral fissures and possible learning or developmental defects
Describe a typical cervical vetebrae
How is C7 different?
Describe atlas and axis and state which movements they make possible
- Bifid spinous process with transverse foramina and large triangle vertebral foramen
- Spinous process not bifid
- Atlas has no vertebral body or spinous process -> yes movement
- Axis has odontoid process to support atlas -> no movement
In an AP plane of the cervical spine from which vertebrae can you see?
What is a burst fracture?
What is a hangmans fracture?
- C3
- Jeffersons fracture -> 2-4 fractures in atlas caused by the occipital condyles being driven into c1 (fall on head)
- Hyperextension of the head on the neck causes a bilateral fracture of C2 and compresses the brainstem
Name the sutures of the skull and the points of joins. Why are they serrated?
What is the mental symphysis?
- Coronal, saggital and lamboid, bregma and lambda
- Allow interlocking of the cranium
- Point of mandible fusion
How is the skull specialised for its function?
- Dense strong flat bones for protection
- Trilaminar structure with the middle bony layer being spongy bone to make it light weight
Which cranial nerves relate to which cranial fossas?
- 1,2 in anterior fossa
- 3-6 in middle fossa
- 7-12 in posterior fossa
What is a consequence of fracture to the ethmoid bone and why?
- Anosia or CSF rhinorrhoea
- Anosia because olfactory fibres run through ethmoid to supply olfactory mucosa
- CSF rhinorrhoea because csf can now leak out if there is also damage to the meninges
How does the neonatal skull differ from adult skull?
- Cranial sutures wide in the neonate spanned by thick connective tissue called fontanelles to allow movement of bones during childbirth
- Temporarily interlock during birthing to protect the brain
Describe the formation of the inner ear
- Otic placodes develop on lateral embryonic head
- Placodes invaginate to form the otic vesicle and pinches off
- Otic vesicle develops into urticle and scaaule. Urticle develops into a duct system -> semi-lunar canals and saccule into membranous labyrinth -> cochlear and both become encased in bone
What nerves supply tensor tympani and stepedius
- T.Tympani -> CNV2
- Stapedius -> CNVII
Describe the development of the middle ear
- Tympanic cavity and eustachian tube develop from 1st pharyngeal pouch
- Elongation distally to make contact with 1st pharyngeal left forms tympanic cavity
- Narrowing proximally forms eustachian tube
Describe to blood supply to the retina. What is a coloboma?
- Choroid fissure is an opening in the optic stalk which allows the hyaloid artery to pass to developing retina and eventually becomes central retinal artery
- Failed closure of the choroid fissure
Which cranial nerves originate in the midbrain?
Which cranial nerves originate in the pons?
Which cranial nerves originate in the medulla oblongata?
- 3/4
- 5,6,7
- 8,9,10,12
Name Cranial nerve I
What type of nerve is it?
Where is it from/to?
What is its function?
- Olfactory
- Sensory
- Olfactory mucosa through cribriform plate to form olfactory bulb to olfactory tract
- Sense of smell
Give 3 major causes of anosmia
- Upper respiratory tract infection
- Trauma (eg fracture cribriform plate damages nerves)
- Meningitis
Name CN II
What type of nerve is it?
Where if is from/to?
What is its function?
- optic nerve
- Sensory
- Retina -> optic chiasm -> optic tract through optic canal then primary visual cortex
- Sight
Name CNIII
What type of nerve is it?
Where is it from/to?
What is its function
- Oculomotor
- Motor and parasympathetic
- From Oculomotor nucleus and edinger-westphal nucleus to most extraocular muscles
- Move eyeball, open eye lid and pupillary constriction
Name the muscles which oculomotor nerve innervates
- Inferior oblique
- Superior, inferior, medial rectus
- Levator palpabrae Superioris
- Pupillae constrictor
What passes through the superior orbital fissure?
-Oculomotor,Trochlear, Abducens, V1, Central retinal artery
How will a complete oculomotor nerve palsy present?
- Down and out pupil
- Ptosis
- Myadriasis (blown pupil)
Name CN IV
What type of nerve is it?
Where is it from/to?
What is its function?
- Trochlear
- Motor
- From trochlear nucleus in dorsal Midbrain to superior oblique of the eye
- Look down and in (Moves the eye down when the eye is adducted)
What structures travel through the cavernous sinus?
- CN III, IV, V(V1/V2) VI,
- Internal carotid artery
Why might someone wih trochlear nerve palsy have a slight head tilt?
-To compensate for the diplopia they are experiencing, especially when walking downstairs as cant look down and in
Name CNV
What type of nerve is it
Where is it from/to
What is its function?
- Trigeminal
- Sensory and motor
- Trigeminal nucleus in the pons, splits into 3 branches (V1/2/3)
- General sensation to the face, muscles of mastication
Through which foramina do the branches of trigeminal nerve travel?
- Opthalmic -> superior orbital fissure
- Maxillary -> foramen rotundum
- Mandibular -> foramen ovale
What is trigeminal neuralgia?
-Sensory hyperactivity of the trigeminal nerve which sends shooting/burning pain along the distribution of the nerve
What does the corneal reflex test?
-Opthalmic branch of trigeminal and temporal and zygomatic branch of facial
Name CNVI
What type of nerve is it?
Where is it from/to?
What is its function
- Abducens
- motor
- From Adbucens nucleus in pons to lateral rectus
- abduct the eye
Name CNVII
What type of nerve is it?
Where is it from/to?
What is its function?
- Facial Nerve
- Special sensory, motor and Parasympathetic
- Facial nucleus in medulla oblongata through internal auditory meatus -> facial canal -> sytlomastoid foramen -> parotid gland -> splits into 5 branches -> temporal, zygomatic, buccal, maxillary, cervical
- Special sensory to anterior 2/3 tongue (chorda tympani), muscles of facial expression, (salivation and lacrimation
Which salivary glands does facial nerve (chorda typani) serve?
- Submandibular
- Sublingual
Through which foramina does facial nerve travel?
-Internal acoustic meatus
What is bells palsy? What is thought to be the most common cause?
- Idiopathic unilateral facial paralysis
- Inflammation at stylomastoid foramen
Name CN VIII
What type of nerve is it?
Where is it from/to?
What is its function?
- Vestibulocochlear (acoustic nerve)
- Sensory
- Cerebellopontine angle branches into cochlear nerve to cochlea and vestibular nerve to semilunar canals (inner ear)
- Hearing(cochlear) and balance(vestibular)
Through which foramina does vestibulocochlear nerve travel?
-Internal acoustic meatus
What is a vestibular schwannoma (acoustic neuroma)?
-benign intracranial tumour of myelin sheath of vestibulocochlear nerve causing sensorineural hearing loss, tinnitus, balance disruptions and rarely facial palsy if the tumour is v large
How do you tell the difference between conductional and sensoryneural hearing loss?
-Rinne and Weber’s
-In Webers test a conduction block will produce a louder sound on affected side, whilst a sensorineural block will be louder on the opposite side
-In rhinnes test a conduction block will be louder through bone on the effected side
Using both tests together to determine the type of block
Name CNIX
What type of nerve is it?
Where is it from/to?
What is its function?
- Glossopharyngeal
- Sensory, Motor and parasympathetic
- From medulla oblongata to tongue, parotid, carotid sinus and stylopharyngeus
- Provides sensation to oropharynx, post 1/3 tongue, carotid sinus body
- Motor to stylopharyngeus
- parasympathetic input to parotid gland
Through which foramen does glossopharyngeal pass?
-Jugular foramen
Name CNX
What type of nerve is it?
Where is it from/to?
What is its function?
- Vagus nerve
- Sensory, motor and parasympathetic
- From medulla oblongata to everywhere
- Provides sensation to laryngopharynx, ear
- Provides motor supply to muscles of pharynx and larynx
- parasympathetic input to heart, lungs, GI tract
Through which foramen does the vagus nerve pass?
-jugular foramen
Name CNXI
What type of nerve is it?
Where is it from/to?
What is its function?
- Accessory spinal nerve
- Motor
- Spinal roots C1-C5 to SCM and trapezius
- Innervates SCM and trapezius
Through which foramina does accessory spinal nerve pass?
-Through foramen magnum into the cranium then through the jugular foramen back out
Name CNXII
What type of nerve is it?
Where is it from/to?
What is its function?
- Hypoglossal nerve
- Motor
- Hypoglossal nucleus in medulla oblongata to tongue
- Extrinsic and intrinsic muscles of the tongue
Through which foramen does hypoglossal travel?
-hypoglossal canal
Where does the sympathetic input to the head come from?
- Thoracolumbar outflow of spinal cord
- Spinal preganglionic neurones synapse in sympathetic trunk at superior, middle and inferior cervical ganglia. Post ganglionic neurones then hitchhike on ICA, inferior thyroid artery and vertbral arteries into the head where they use cranial nerve to reach their target destination
What are the sympathetic functions in the head?
- Sweat glands
- dilator pupillae
- Smooth muscle
- Salivary glands
Describe the parasympathetic outflow in the head
-3 pairs of parasympathetic nerves synapse onto 4 ganglia within the head:
Oculomotor -> ciliary ganglion ->short ciliary nerves -> Sphincter pupillae
Facial -> Pterygopalatine ganglion -> greater petrosal -> lacrimal gland
Facial -> submandibular ganglion -> chorda tympani ->salivary glands
Glossopharyngeal -> otic ganglion -> lesser petrosal ->parotid gland
Describe the boundaries of the orbit
- Superoir = Frontal and sphenoid
- Medial =ethmoid, lacrimal sphenoid and maxillary
- Inferior = maxillary and zygomatic
- Lateral = zygomatic and sphenoid
- Apex = optic canal
What is a blow out fracture?
- Caused by a sudden increase in intraorbital pressure ie blow to the orbit causing fracture of the thin medial/inferior wall leading to herniation of the contents into maxillary sinus
- Often the inferior rectus becomes trapped and pt unable to look up
Describe the layers of the eyeball
1) outer layer consisting of sclera, cornea, conjunctiva
2) middle vascular layer consisting of iris, choroid, ciliary body
3) inner layer consisting or vitreous humor and retina
What is open angle glaucoma?
- Blockage of the trabecular meshwork causing fluid to accumulate between cornea and iris
- Increases intraorbital pressure causing compression of optic nerve
- Progressive painless visual loss
What is closed angle glaucoma?
- Sudden blockage of the drainage of aqueous humor by the lens being forced against the iris
- Painful vision loss
Describe the chambers of the eye
- Posterior segment from lens to optic canal
- Anterior segment from cornea to lens -> split into anterior chamber from cornea to iris and anterior chamber from iris to lens
What are cataracts?
-Hardening and flattening of the lens producing an inability to focus light as it scatters across the lens
What is the difference between central retina artery occlusion and central retinal vein occlusion?
- Artery produces quick painful vision loss
- Vein produces slow painless vision loss
What is the difference between a meibomian cyst and a sty?
- Meobomian cyst is a painless swelling due to infection of tarsal gland
- Sty is a painful infection of ciliary gland
What is orbital cellulitis?
-inflammtion of the orbit often caused by staph aureus which causes pain and discharge, loss of vision and maybe inability to open eye due to swelling
Describe the innervation of two sides of tympanic membrane
- external ear = V3
- Middle ear = glossopharyngeal
What is a pinna haematoma?
-Collection of blood between cartilage adnd perichondrium which leads to avascular necrosis
Which are children predisposed to otitis media?
-Eustachian tubes are narrower, shorter and more horizontal which predisposed to dysfunction leading to infection
Why does tympanic retraction occur in otitis media? When will it buldge outwards? What are common causes of otitis media?
- Negative pressure within the middle ear
- Otitis media with effusion (glue ear) secondary to a prolonged negative pressure
- Haemophilus, streptococcus pneumoniae, staph
Give 3 complications of otitis media
- Perforation of tympanic membrane
- Mastoiditis
- Bells palsy
What are grommets and when are they used?
- Small ventilation tubes inserted into tympanic membrane to equate middle ear pressure
- Recurrent otitis media
What is a cholesteatoma?
-Accumulation of dead skin cells within middle ear forming a nectrotic mass which erodes middle ear structures and bone
Briefly describe how the vestibular system contributes to balance
- Has areas of gelatinous matrix with stereocilia inside
- During movement the fluid in the labyrinth moves the sterocilia to provide the sensation of moving up, down or side to side
Name 2 problems with the vestibular system causing balance issues
- Benign Positional Paroxysmal Vertigo
- Meniere’s disease -> Vertigo, hearing loss, tinnitus and aural fulless
What structures make the nose? What is the name of the exit into nasophaynx? What epithelia lines the nose and sinuses?
- Nasal bone, septal cartilage, alar cartilage
- Chonae
- Pseudostratified ciliated columnar with goblet cells
Name the turbinates and their passages. State the function
- Mix and humidify air, increase SA
- Superior, middle and inferior turbinates and corresponding meatus
- Nasolacrimal to inferior meatus
- All sinuses to middle meatus except posterior ethmoidal which goes to superior meatus
Which sinuses are present at birth and which develop?
- Frontal is not present
- Maxillary, sphenoid and ethmoid present at birth and enlarge
Describe the blood supply to the nose, why is it so rich?
- To warm and humidify air
- Contributions from facial, maxillary (sphenopalatine) and opthalmic arteries (anterior and posterior ethmoidal)
- Kiesselbachs area -> common site of rupture due to many anastamoses
What are the sites of epistaxis? Who does it occur in? Describe the management steps
- Posterior at sphenopalatine (10%)
- Anterior at kiesselbachs area (90%)
- Small children or elderly
1) Simple compression of cartilage with elevated and a topical vasoconstrictor for 30 mins
2) insert gauze
3) Silver nitrate cauterization
4) Nasal Packing -> anterior then posterior
5) Arterial Ligation or embolisation
How could an infection spread from the nasal cavity to anterior cranial fossa? to middle ear? to paranasal sinuses? to conjunctiva?
- Foramen cecum or cavernous sinus
- Eustachan tube
- Through meatus
- Nasolactimal duct
Which nuclei does facial nerve arise from? Which branches from which nucleus?
- Facial motor nucleus in pons -> motor branches
- Nucleus solitarus in pons -> sensory afferents of chorda tympani
- Superior salvitory nucleus -> Parasympathetic nerves to pterygopalatine ganglion (greater petrosal) and submandubular ganglion (parasymp of chorda tympani)
Which branches come off facial nerve intracranially?
-Nerve to stapedius, greater petrosal and chorda tympani
What is the oral vestibule? What is the oral cavity proper?
- Lips to teeth
- Teeth to palatophayngeal arch
To which bones are the muscles of the soft palate attached? Name these muscles. Which nerve innervates them?
- Palatine, vomer and pterygoid plates of sphenoid
- Levator veli palatini, tensor veli palitini, palatopharyngeus, palatoglossus
- Sensory is CNIX and motor is CNX
Name the extrinsic muscles of the tongue
-Genioglossus, styloglossus, hyoglossus and palatoglossus
What supplies general and special sensation to the tongue
- Anterior 2/3 general = v3, special = chorda tympani
- Posterior 1/3 = glossopharyngeus for both
What is walders ring?
-Ring of lymphatic tissue consisting of palatine tonsils, adenoids, tubal tonsils and lingual tonsils
Describe the TMJ. Which ligaments support it?
- Unstable synovial joint formed by the mandible head and temporal bone. It has 2 cavities separated by fibrocartilage which allows the joint to fit together as the bones are poorly aligned.
- Temperomandibular ligament and 2 accessory ligaments (sphenomandibular and stylomandibular)
What prevents anterior and posterior displacement of the TMJ?
- Ant = articular tubercle
- Post = Posterior glenoid tubercle
What passes through foramen spinosum?
-MMA
How does the TMJ move?
-In 2 planes:
Translation -> Jaw slides forward in superior cavity -> lateral ptertgoids
Rotation -> Jaw moves down and back -> digastric
-Rotation and then translation to open mouth
-Retraction (temporalis) then elevation (temporalis, masseter and m.pterygoid)
What is the infratemporal fossa?
- Irregular shaped cavity behind maxilla and zygomatic arch, just below middle cranial fossa
- Contains lower temporalis and pterygoids, CNV3, chorda tympani and otic ganglion, maxillary artery-> MMA, pretygoid plexus
Where is the pituitary gland located?
-In the sella tercica in the middle cranial fossa underneath the hypothalamus
Describe the embryological development of the pituitary
- Posterior pituitary developes from the infundibulum outpouching of forebrain which grows down towards the pharnyx
- Concurrently an outpocketing of ectoderm from the oropharynx of the stomatoduem gorws upwards and becomes the anterior pituitary. The outpocketing is called Rathkes pouch
- Ossification of the cranium pinches off rathke’s ouch separating it from pharynx
Describe the embryological development of the tongue
-The primordia of the tongue receives a component from each pharyngeal arch:
2 lateral swellings form from 1PhA
3 medial swellings form from all the arches -> Tuberculum (Ph1), Cupola (2+3), Epiglottal (4+6)
-The lateral swellings overgrow tuberculum and the 3rd arch grows over 2nd in cupola
-Apoptosis occurs and frees the tongue from the oral cavity floor leaving the lingual frenulum
-Myogenic precursors migrate from occipital somites to form the intrinsic and extrinsic muscles of the tongue
Describe the embryological development of the thyroid
- Primordia begins in floor of pharynx between tuberculum and cupola
- Foramen cecum is the passageway through which the thyroid descends as a bi-lobed diverticulum connected by an isthmus
- It remains connected to the tongue by the thyroglossal duct which eventually closes after birth
- Follicular cells are derived from thyroid diverticulum
- Parafollicular cells from 4th Ph pouch
Describe some thyroid abnormalities as a result of development
- Thyroglossal cyst/fistulae
- Ectopic thyroid tissue
From where does the palatine tonsil get its blood supply?
-Tonsillat branch of facial artery
Describe the musculature of the pharynx
-3 pharyngeal constrictors which overlap each other and attach to the thyroid cartilage anteriorly and posterially my the median raphe
Describe the sensory and motor innervation to the pharynx
- Sensory = naso ->V2, oro->IX, layngo->XII
- Motor = X, XII
What is the epithelia on either side of the epiglottis?
- Lingual surface = stratified squamous
- Laryngeal surface = psuedostratified ciliated columner with goblet cells
What is the fuction of the cricothyroid muscles?
-Stretch and tense vocal cords via artynoid cartilage
What is a stroboscopy?
-Camera through the nose to view the larynx
Describe the layers of the vocal cords
- Stratified squamous
- Reinkes space
- Vocal ligament
- Vocalis muscle
Give 3 causes of a horse voice
- Layngeal SCC
- Tyroid disease
- Neuropathic (diabetes)
- Oesophageal cancer
- Apical lung cancer
What 2 nerves innervate the muscles of the larynx?
-Superior and recurrent laryngeal nerve
