ANATOMY HNS; Lecture 4, 5 and 6 - Face and Oral cavity, Upper airway and digestive tract, Eye and orbit Flashcards
What are the features observed in the mouth when oral cavity inspection occurs?
Uvula, oropharynx (posterior wall), frontal fold in mouth is palatoglossal and posterior is the palatopharyngeal which when contracted helps with swallowing; palatine tonsil is a lymph node
How do you test vagus nerve function in the oral cavity?
Uvula should move into the midline when saying ‘Ah’ -> if compromised uvula moves away from damaged side
How does the epiglottis aid in swallowing?
Retroflexes to cover the laryngeal inlet to stop you choking on food
How does the hard palate aid in swallowing?
Provides a hard surface on which to push food onto to break it up more easily
What are the features of the oral cavity which can be seen in a midline section?
What are the features of the oral cavity which can be seen in the posterior view?
NB: piriform fossa which is where a lot of fish bones get stuck and it is highly innervated causing a lot of pain
What are the sections of the pharynx?
Nasopharynx, oropharynx, laryngopharynx, superior; middle and inferior constrictors (sensory IX, X (pharyngeal plexus); motor X/xi,) all aiding in swallowing
How does swallowing work?
Lift and retract tongue (styloglossus, intrinsic muscles of tongue), bolus into oropharynx (palatoglossus retraction), close off nasopharynx by raising soft palate, raise larynx which is closed off by epiglottis, peristaltic wave of constrictor muscles, relax cricoharyngeus and open oesophagus
What are the 3 salivary glands?
Parotid (mainly serous) IX which goes through parotid duct, opening upper second molar; submandibular (mainly serous) VII, sublingual (mainly mucous) VII
What are the muscles in the tongue?
Syloglossus, hyoglossus, genioglossus (protraction of tongue), intrinsic muscles -> supplied by CN XII
What are the features of the tongue and surrounding muscles in a sagittal section?
NB: Mylohyoid is the floor of the mouth; submandibular ganglion is PS ganglion involved in saliva secretion
How do you test CN XII and what would you see if there was a lesion on one side?
Stick the tongue out, which should be in the middle and tongue moves toward the side of the lesion, if chronic, the muscle on that side will have atrophied
How is the tongue innervated?
Tactile sensation in the trigeminal nerve; with anterior 2/3rds is taste and facial nerve; and in posterior 1/3rd of tongue both touch and taste is pharyngeal; end of tongue is vagus which is both again
What are the superficial muscles of mastication?
Masseter (zygomatic arch to lat surface of ramus and angle of mandible); temporalis (temporal fossa to coronoid process of mandible)
What nerve supplies the superficial muscles of mastication?
Trigeminal except buccinator muscle which is supplied by the facial muscle
What are the deep muscles of mastication?
Lateral pterygoid -> sphenoid/lat pterygoid plate to neck of mandible; medial pterygoid -> lat pterygoid plate/maxilla/palate to angle of mandible
What is the function of the medial pterygoid?
Elevates, protracts and lateral movement of mandible for chewing
What is the function of the lateral pterygoid?
Depresses and protracts the mandible to open mouth
What is the function of the Masseter muscle?
Elevating mandible allowing forced closure of mouth
What is the function of the Temporalis muscle?
Elevates and retracts the mandible
What is the TMJ?
Articular disc and capsule around the joint -> hinge action on joint, gliding action on articular tubercle when opened a bit more -> anterior dislocation of jaw can be problematic due to the blood supply in the cavity
What is the blood supply to the face area coming off the external carotid artery (some anatomists like freaking out poor medical students)?
Superior thyroid artery, ascending pharyngeal, lingual, facial (big loop so that it doesn’t become tense when opening the jaw causing rupture of the artery), occipital, posterior auricular, maxillary, superficial temporal
What are the 5 main branches of the facial nerve going to the face?
NB: Parotid gland gets innervation from glossopharyngeal NOT from Facial
What is the mandibular nerve?
Inferior alveolar nerve (lies in mandible and emerges out onto chin - called mental nerve), stimulated by toothache; lingual nerve is sensation to ant 2/3rd of tongue, but joins to facial (chorda tympani) nerve
How are the dermatomes organised in the head and neck?
How can you test function of V1?
Opthalmic division -> touching forehead, nose
How can you test function of V2?
Maxillary division -> On cheek
How can you test function of V3?
Mandibular division -> on chin
What are the conchae (superior, middle and inferior)?
Increase SA to warm the air and expose the air to the immune system to trap pathogen, covered in respiratory epithelium
What are the nasal cavities?
Upper part of resp tract; ant and post regions; contain conchae
What is the function of nasal cavities?
Warm and humidify air, help trap pathogens
Which bones make up the conchae?
x
How is the nasal cavity innervated (olfaction, regions, glands and vascular smooth muscle)?
Olfaction: Olfactory nerve; Trigeminal nerve: V1 anterior region and V2 posterior region; Facial nerve innervates glands (mucous membrane); sympathetic nerves from T1 innervate vascular smooth muscle
What is the blood supply to the nasal cavities?
Internal/External carotid
How is the nasal cavity drained?
Where are the paranasal sinuses located?
Filled with air, decrease weight of skull, help with transmission of sound, acts as a crumple zone for protection of brain
What do the sinuses look like in an x-ray?
NB: maxillary sinus can be easily infected when teeth taken out or when dental abscess occurs
Where do the sinuses drain into?
Into the nasal cavity (lacrima drains into the (nasolacrimal) nasal cavity)
What is the larynx?
Hollow structure composed of cartilages, membrane and muscles
What is the function of the larynx?
Valve and sound producer
What are important cartilages of the larynx?
Laryngeal cartilage, thyroid cartilage, laryngeal prominence
What do the laryngeal cartilages look like?
Thyroid cartilage sits on top of cricoid cartilage, rocking backwards and forwards which can change the tension of the vocal cords (as well as action of muscles)
What are the vocal folds?
Vestibular fold (false vocal fold) and vocal fold (true vocal fold)
What is the rima glottidis?
Opening between the vocal folds
What are the muscles of the larynx?
What are the muscles of the larynx innervated by?
Vagus nerve branches - left recurrent laryngeal nerve when impinged can cause hoarseness of voice and coughing
What happens when the vagus nerve is damaged at the different levels?
x
Which vessels travel with the branches of the vagus nerves?
Int/ext laryngeal nerve travel with superior thyroid artery; recurrent laryngeal nerve travels with inferior thyroid artery. NB: bronchial/oesophageal tumour/swollen mediastinal lymph nodes can cause left recurrent laryngeal blockage/lesion
Which protective mechanisms exist for the airway?
Swallowing, gag reflex, sneezing, coughing
What is the different mechanism for sneezing and coughing?
Main difference is soft palate movement - raised or lowered
What are the different methods in which you can manage the airway?
Chin lift/jaw thrust, oropharyngeal/nasopharyngeal airway, endotracheal intubation, cricoidthyroidotomy, thracheostomy
What is the anatomy of the auditory apparatus?
Purpose to direct the sound
What is the anatomy of the ear?
NB: ear infection can take on forms that can damage the facial nerve as it goes through the ear (which can become damaged in infection or inflammation
What is the facial nerve emergence point?
Lateral surface of brainstem between pons and medulla
What is the motor component of the facial nerve?
Muscles of facial expression, stapedius, digastric (posterior belly), stylohyoid.
What is the sensory component of the facial nerve (smaller, intermediate nerve)?
Taste (ant 2/3 tongue), parasympathetic (lacrimal glands, mucous glands of nasal cavity, hard and soft palates, sublingual and submandibular glands). General sensation from external acoustic meatus and deeper parts of auricle.
What s the pathway of the facial nerve in the ear?
What is the importance of the mastoid bone in infection?
Ear infection can eat away at the bones of the mastoid sinus and cranial cavity, causing infection to move into cranial cavity (brain)
When might the airway be blocked by the tongue?
When unconscious, which could cause death -> muscle tone is required to keep the airway open
What are the airway manoeuvres that can unblock a patent airway?
Head tilt and chin lift; jaw thrust; airway adjuncts (used to keep the upper airway open when you get tired - e.g. nasopharyngeal tube and oropharyngeal tube); LMA (laryngeal mask airway - gag reflex can be triggered); endotracheal intubation; cricothyroidotomy
What are the problems associated with airway adjuncts?
Oropharyngeal airway -> gag reflex is triggered; nasopharyngeal airway -> nose bleeds and basal skull fracture can be a problem when inserting
What is the best way to maintain a patent airway?
Endotracheal intubation -> Prevents airway soiling as it has a balloon which inflates, keeping substances from entering the lungs/trachea
What are the important features of the larynx?
What are the 5 phases of swallowing?
Oral preparatory phase, oral transit phase; pharyngeal phase I; pharyngeal phase II; oesophageal phase
What is the oral preparatory phase in swallowing (Sensation needed, in/voluntary, CN used)?
Food/liquid chewed and formed into bolus, which is held on centre of tongue -> lip, jaw, tongue and palate sensory and motor function needed (and dentition); VOLUNTARY - uses CN V, VII, IX, X, XII
What are the 12 CN? (Oh,Oh, Oh, to touch and feel very good velvet Ahhhh)
Olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibular, glossopharyngeal, vagus, accessory, hypoglossal
What is the oral transit phase in swallowing (Sensation needed, in/voluntary, CN used)?
Bolus propelled to back of mouth, palate seal entrance to nasal cavity, lip, jaw, tongue and palate sensory/motor function needed; VOLUNTARY - uses CN V, VII, IX, X, XII (OPEN AIRWAY)
What is the pharyngeal phase I in swallowing (Sensation needed, in/voluntary, CN used)?
Triggered when bolus reaches facial arch, palate stays elevated, tongue reacts - to push bolus to pharynx; tongue, palate and laryngeal sensory/motor function needed - REFLEX, with CN IX, X, XII (CLOSED AIRWAY)
What is the pharyngeal phase II in swallowing (Sensation needed, in/voluntary, CN used)?
Bolus propelled through pharynx; tongue, palate and laryngeal sensory motor function needed - REFLEX using CN IX, X, XII (CLOSED AIRWAY by epiglottis, vocal cords and arytenoid action)
What is the oesophageal phase in swallowing (Sensation needed, in/voluntary, CN used)?
Oesophagus opens, airway closed, breath held; bolus propelled through oesophagus - REFLEX CONTROL using IX, X - respiration then resumes with exhalation to clear any food particles away from airway entrance
How is a normal videofluoroscopy carried out?
Barium transit through mouth 1 sec, pharyngeal transit 1-2s, no residue in mouth/pharynx, no spillage from lips into airway
How does an ataxic swallow differ and what can cause it?
Cerebellar haematoma -> uncoordinated tongue reaction to propel food, delayed airway closure so food enters airway, delayed and ineffective cough to clear airway so food aspirated to lungs
How can you fix an ataxic swallow?
Flex neck during swallow, preventing aspiration -> also exercises to increase swallowing speed and strength
How can a lower motor neurone lesion cause impaired swallowing?
E.g. in an excised acoustic neuroma -> ispilateral paresis of pharynx, larynx and tongue means there is weak bolus propulsion (pharyngeal/oral residue) and failed airway closure means aspiration occurs
How can you fix an impaired swallow caused by a lower motor neurone lesion?
Head rotation to direct bolus down strong side of pharynx and increase airway closure -> also exercises to increase tongue and laryngeal muscle strength for 9m
How does Parkinson’s disease affect swallowing?
Difficulty initiating swallow, typical repetitive tongue movements, linked with muscle rigidity, unable to lower back of tongue
How do you treat parkinson’s disease for swallowing?
Active range of motion exercises of lips and tongue
How does a normal swallow/voice work?
Vocal cords adduct to produce voice and to close airway, saliva is cleared in a single swallow and doesn’t accumulate, water swallowed in <1s, no residue in pharynx/trachea
How does an impaired swallow from a severe head injury differ?
Myoclonus from anoxia, brainstem involvement, spastic pharynx and tongue so decreased movement, infrequent swallow 1 per 17 min, ineffective/weak swallow so residue in pahrynx and aspiration of saliva, ineffective cough so unable to clear saliva from airway
How would you treat an impaired swallow due to severe head injury?
Long term NBM (nothing by mouth) and tracheostomy
What are the bones of the orbit?
Roof -> orbital plate of frontal bone; floor -> orbital plate of maxilla; lateral wall -> zygoma, greater wing of sphenoid; medial wall -> frontal process of maxilla, lacrimal bone, orbital plate of ethmoid, lesser wing of sphenoid
What is present in the optic canal of the orbital foramina?
Optic nerve (II) (ganglion cell axon going to the cortex), ophthalmic artery
What is present in the inferior orbital fissure of the orbital foramina?
Maxillary nerve (V2), infraorbital vessels
What is present in the superior orbital fissure of the orbital foramina?
Ophthalmic nerve (V1), Oculomotor (III), Trochlear (IV), Abducens (VI), Ophthalmic vessels, sympathetic fibres
What are the orbital foramina?
x
What are the Recti muscles?
Extrinsic eye muscles, 4 recti muscles -> inf, sup, medial, lateral
Where do the recti muscles originate from?
Common tendinous ring at the back of the orbit
Where do the recti eye muscles insert?
Sclera, 5mm behind corneal margin
What innervates the recti muscles?
Inferior, superior and medial (III) and lateral (VI)
What are the oblique extrinsic eye muscles?
2-> inferior and superior
Where do the obliques originate from?
Inferior: orbital surface of maxilla; superior: body of sphenoid
Where do the obliques insert?
Inferior: post/inferior quadrant; superior: post/sup quadrant loops upwards via trochlea
How are the obliques innervated?
Inferior (III), superior (IV)
What is the levator palpebrae superioris?
Muscle of the upper eyelid
Where does the levator palpebrae superioris originate?
Lesser wing of sphenoid
Where does the levator palpebrae superioris insert?
Superior Tarsal plate and skin of eyelid
How is the levator palpebrae innervated?
CNIII and SNS to smooth muscle (Horner syndrome stops SNS innervation so eyelid droops)
What is the different parts of the anatomy of the eye?
Trochlea is a pulley system (sup oblique moves eyeball down and out)
What are the isolated muscle actions of the eye if muscles were just acting on its own?
LR = abducts (away from midline) MR = adducts (towards midline) IO = elevates and abducts SR = adducts and elevator IR = depresses and adducts SO = depresses and abducts
How do you test the isolated muscle actions in a clinical setting?
LR = lateral abduction in eye MR = adduction in eye SO = adduct eye and then look for depression to isolate muscle (in and out)
Which of nerves are present in the orbit?
Optic (ganglion cell axons), Oculomotor (two rami, motor fibres to MR, SR, IR, IO and LPS; parasympathetic fibres with oculomotor nerve), Trochlear (Motor fibres to SO), Abducens (Motor fibres to LR); Ophthalmic V1 branches -> Lacrimal, Frontal (supertrochlear, supraorbital), Nasociliary (branch to ciliary ganglion, ethmoidal, infratrochlear)
What is the ciliary ganglion?
PSNS, preganglionic fibres in inferior ramus of oculomotor, postganglionic fibres in short ciliary nerves, sphincter pupillae and ciliary muscle
What are the blood vessels to the eye?
Ophthalmic artery and ophthalmic veins
What are the different ophthalmic arteries?
Central artery of retina, muscular branches, ciliary, lacrimal, supratrochlear, supraorbital
What are the different ophthalmic veins?
Superior (cavernous sinus - important due to infection) and inferior (pterygoid plexus)
What is the lacrimal system made up of?
Lacrimal gland, lacrimal sac and nasolacrimal duct
What is the lacrimal gland made up of?
Anterolateral superior orbit; PSNS secretomotor fibres (CNVII) from pterygopalatine ganglion via zygomaticotemporal and lacrimal nerves
What is the function of tears and where do they drain?
To keep the eye moist (can indicate problems in CN if eye is dry) -> Drain to medial part of the eye in to the lacrimal sac via the lacrimal canaliculi and into the nasolacrimal duct into the nose
How do you test the corneal reflex?
Place cotton bud on eye and patient should blink. Afferent V1 and then efferent is facial nerve
