Anatomy Flashcards
what are the choanae
posterior nasal apertures. Closed off during swallowing by the soft palate meeting the superior constrictor muscle.
What are the 3 parts of the septum
- Perpendicular plate/extension of the ethmoid bone (where falx cerebri runs forward).
- Septum cartilage
- Vomer bone
Role of the conchae
Increase S.A. of nasal cavity so more efficient at heating and humidifying the air as it passes to the lungs.
What are the conchae made from
superior and middle part of ethmoid bone
What does the superior meatus drain
posterior ethmoidal sinus/cells
What does the middle meatus drain
Via the infundibulum = Frontal sinus.
Via the hiatus semilunaris = Anterior ethmoidal sinus/cells and maxillary sinuses.
What does the inferior meatus drain
nasolacrimal duct
Respiratory epithelium
Pseudostratified columnar ciliated epithelium + goblet cells
How does the mucoperiosteum act to warm air in the nasal cavity
Very rich in blood vessels which swell when increased blood flow and reduce the volume of nasal cavity so make it warmer.
Blood supply of nasal cavity
Ophthalmic artery = upper and front parts of midline septum.
Facial artery = upper hard palate and lower parts of the septum.
Maxillary artery = posterior septum and lateral wall.
Role of sinuses
Lighten skull weight and add resilience to the skull
Maxillary sinus
V thin bone b/w it and upper molars - careful when extracting to avoid fistulas.
High ostium so mucous accumulates before it can be cleared.
Frontal sinus
Drains above maxillary sinus in middle meatus = cross infection
Sphenoidal sinus
Drains into the sphenoethmoidal recess above the superior conchae.
Innervation of the nasal cavity
Infraorbital nerve = skin of the nose, lower eyelid, cheek, top lip.
Post-ganglionic fibers = glands, air sinuses, gingivae
Endothelial structure of the lymph ducts
Overlapping endothelial cells allow fluids to move in but not flow out.
What does the right lymphatic duct drain
The right side of the body, above the waist only.
What does the thoracic duct drain
All of the body apart from right side above the waist.
Where does the thoracic duct empty
Venous blood supply, between the left subclavian and jugular veins.
Superficial lymphatic vessels are found above which muscle
Sternocleidomastoid, and along external jugular.
Lymph nodes that drain into the deep cervical nodes
Pre-auricular, submental and submandibular node.
Lymph nodes that drain to the superficial nodes
Post-auricular and occipital node.
Face lymphatic nodes and areas they drain
Pre-auricular (drains eyelids, cheeks, and part of scalp)
Post-auricular (drains posterolateral scalp)
Submental (drains chin, tip of tongue, bottom lip, floor of mouth, incisors)
Submandibular (face, gingivae, teeth and tongue)
Occipital (posterior scalp and neck)
Which lymphatic nodes drain the scalp
Post-auricular, pre-auricular and occipital
Which lymphatic nodes drain the teeth
Submandibular (apart from incisors which are drained by the submental)
What is the midline raphe (tongue) and why is it important
Impervious lymph border at anterior 2/3 of tongue. Means cancer can’t spread from one side of tongue to the other through the lymph vessels. Deficient at tip and posterior 1/3 of tongue.
Which lymph node drains anterior 2/3 of tongue
Directly = deep cervical nodes Indirectly = submental and submandibular nodes
Which lymph nodes drain posterior 1/3 of tongue
the Jugulodigastric node of the deep cervical chain
Which lymph node drains tip of the tongue
Submental node then to jugulo-omohyoid node
Bones that make up the roof of the orbit
Frontal bone
Lesser wing of the sphenoid bone
Bones that make up the medial wall of the orbit
Lacrimal bone
Ethmoid bone
Maxilla bone
Body of the sphenoid bone
Bones that make up the lateral wall of the orbit
Zygomatic bone
Greater wing of the sphenoid bone
Bones that make up the floor of the orbit
Maxilla bone
Palatine bone
Zygomatic bone
Openings into the orbit
Superior orbital fissure
Optic canal
Inferior orbital fissure
What structures are in the superior orbital fissure
CN 3,4,5 (V1)
Superior ophthalmic vein
What structures are in the optic canal
CN 2 (Optic nerve) Ophthalmic artery
What structures are in the inferior orbital fissure
CN 5 (V2) Inferior ophthalmic vein
Where do all 4 rectus muscles originate from
Annulus of Zinn
What’s a blow-out fracture of the eye and how does it happen
When the force on globe > strength of bones so the globe breaks/bursts through the bony orbit.
What is proptosis
Forward displacement of the globe caused by any bleeding or growth in the orbit. Can cause compression of vessels and nerves here.
What is the role of the tarsal plate
Next to the globe, connective tissue which gives strength and structure.
Which muscles open the upper eyelid
Levator and Muller muscles
Which muscles close the upper eyelid
Orbicularis oculi
Which muscles open the lower eyelid
Lower Muller muscle
Which muscles close the lower eyelid
Orbicularis oculi
What glands are found in the orbit/globe
Meibomian glands - Sebaceous/secretes oil to stop tears evaporating and to lubricate.
Glands of Zeis - secrete oil onto lashes
Gland of Moll - Apocrine/sweat gland onto the skin.
What is the conjunctiva and its functions
Thin translucent mucous membrane over the globe.
Functions =
- Lubrication (goblets cells secrete mucous)
- Physical barrier - immunological defence.
Globe nerve innervations and their functions
CN II - sight, accomodation and pupil reflex
CN III - 4 extra-ocular muscles, upper levator muscle, iris muscles.
CN IV - superior oblique muscle
CN VI - lateral rectus muscle
CN VII - orbicularis oculi muscles, blink reflex
Action and innervation of the superior rectus muscle
CN III
Elevates
Action and innervation of the medial rectus muscle
CN III
Rotates globe medially
Action and innervation of the lateral rectus muscle
CN VI
Rotates globe laterally
Action and innervation of the inferior rectus muscle
CN III
Depresses
Action and innervation of superior oblique muscle
CN IV
Depresses and rotates the eye laterally
Action and innervation of inferior oblique muscle
CN III
Elevates and rotates the eye laterally
Movement of the arytenoids and how this affects phonation
Rotate around verticle axis: Inwards (adduction) and outwards (abduction).
Sliding: Medially (adduction) and laterally (abduction)
Tilting: Backwards (increase tension) and forwards (increase thickness, decrease tension).
Role of the conus elastus
Muscle covering the vocal folds and constrict the larynx vertically from the vocal folds to the cricoid.
Adduction definition
Closing
Abduction definition
Opening
Vocal folds open/close cycle
- –>F F, vocal folds open
What about the vocal folds affects pitch
Length
Tension
Thickness
How can the pitch of a voice be altered
Tilting arytenoids backward or forwards
What happens to overused vocal folds
Hemorrhaging or nodules/growths on them = lower quality of sound.
Laryngeal muscles
Transverse and oblique interarytenoids Posterior cricoarytenoids Lateral cricoarytenoids Thyroarytenoids Cricothyroids Vocalis
Action of lateral cricoarytenoids
Forcefully adduct the arytenoids e.g. during speech
Action of the cricothyroid muscles
Act on the cricothyroid synovial joint to make the initial movements. Move cricoid up, tipping arytenoids backward and increasing tension in vocal folds.
Action of the vocalis muscles
Make fine adjustments. Pad out the vocal folds and move arytenoids forward, decreasing tension in vocal folds.
What nerves innervate the larynx
Recurrent laryngeal nerve and superior laryngeal nerve (branches off vagus nerve)
What does the superior laryngeal nerve supply
Motor to cricothyroid muscles
Sensory to mucosa above vocal folds
What happens if the superior laryngeal nerve is damaged
No cough reflex and hard to regulate pitch of voice.
What does the recurrent laryngeal nerve supply
Motor to all laryngeal musles apart from cricothyroid muscles (bilateral to interarytenoids)
What happens if the recurrent laryngeal nerve gets damaged
Harsh raspy voice bc vocal folds are tensed (due to cricothyroid muscles) and adducted (weak action from interarytenoids due to bilateral innervation)
Muscular tissue of pharynx
3 constrictor muscles (attached to the stylohyoid ligament) and 2 longitudinal muscles (palatopharyngeal and stylopharyngeal). Create a pressure wave to push food down into the stomach.
What are the 4 layers of tissue making up the pharyngeal wall
- Areolar CT (buccopharyngeal fascia containing nerve and venous plexus).
- Muscular tissue.
- Fibrous tissue (attaches pharynx to the base of the skull and medial pterygoid plates).
- Mucosa (respiratory = upper, remainder = SSE).
During swallowing, how does the mouth get closed off
Tongue moves up and meet hard palate
During swallowing, how does the nasal cavity get closed off
- Superior constrictor muscle moves down to meet the soft palate
- LVP and TVP move the soft palate up
- Uvula moves up
During swallowing, how does the laryngeal opening get closed off
- Hyoid bone and thyroid cartilage move up and forward (due to the action of geniohyoid and constrictor muscles) so epiglottis flops down and covers the opening.
- Arytenoid cartilages move forwards and medially (due to the action of the laryngeal muscles) to close of the glottis using the vocal folds.
CN I (5 points)
- Olfactory nerve
- Foramen = Cribriform plate of the ethmoid bone
- Enters = Nasal cavity
- Sensory
- Olfactory epithelium, allows for the sense of smell
CN II
- Optic nerve
- Foramen = optic foramen / canal
- Enters = orbit
- Sensory
- Retina (vision) and a part of the accommodation and pupil reflexes.
CN III
- Oculomotor
- Foramen = Superior orbital fissure
- Enters = Orbit
- Motor
- Target = eye and eyelid muscles internal and external.
CN IV
- Trochlear
- Foramen = Superior orbital fissure
- Enters = orbit
- Motor
- Target = superior oblique muscle of the eye
CN V1
- Opthlamic branch of trigeminal
- Foramen = Superior orbital fissure
- Region entered = orbit
- Sensory
- Skin and mucosa at and above orbit
CN V2
- Maxillary branch of Trigeminal
- Foramen = Foramen rotundum
- Target = Pterygopalatine fossa
- Sensory
- Skin and mucosa from orbit to mouth e.g. palate, nasal cavity.
CN V3
- Mandibular division of Trigeminal
- Foramen = Foramen ovale
- Enters = Infratemporal fossa
- Mixed
- Targets = M to M of M and mylohyoid and other head/neck muscles. S to skin and mucosa from mouth to chin and anterior 2/3 of tongue.
CN VI
- Abducens
- Foramen = Superior orbital fissure
- Enters = orbit
- Motor
- Target = lateral rectus muscle
CN VII
- Facial
- Foramen = Internal acoustic meatus. Exits at stylomastoid foramen.
- Enters = Temporal bone
- Mixed
- M = muscles of facial expression and head/neck muscles. S = taste to anterior 2/3 of tongue
CN VIII
- Vestibulocochlear
- Foramen = internal acoustic meatus
- Enters = Temporal bone
- Sensory
- Targets = balance and hearing
CN IX
- Glossopharyngeal
- Foramen = Jugular foramen
- Enters = Middle ear/infratemporal fossa
- Mixed
- Targets = M to stylopharyngeus muscle and parotid gland. S to the pharynx, middle ear, auditory tube and taste to posterior 1/3 of the tongue
CN X
- Vagus nerve
- Foramen = Jugular foramen
- Mixed
- M to pharynx, larynx, soft palate and thorax. S to larnx.
CN XI
- Accessory nerve
- Foramen = jugular foramen / formamen magnum
- Enters = neck
- Motor
- Targets = sternocleidomastoid and trapezius muscles
CN XII
- Hypoglossal nerve
- Foramen = Hypoglossal canal
- Enters = neck
- Motor
- All tongue muscles apart from palatoglossus (CN X)
Damage to CN III (and test)
Diplopia, lateral squint and dilated pupils.
Test = see if the patient can follow pen across all visual fields.
Damage to CN II
Damage to optic tract = complex visual loss
Damage at optic chiasm = loss of temporal fields
Damage to optic nerve = blindness in that eye
Damage to CN VII
If after middle ear, taste and lacrimation are intact but facial expression lost on that side.
What does the facial nerve supply + what are the branches
Branches = Temporal, Zygomatic, Buccal, Mandibular, Cervical.
Muscles = Zygomaticus, Buccinator, Frontalis, Orbicularis Oculi and Oris, Lip depressors and elevators.
Secretomotor nerves to Lacrimal, Submandibular and Sublingual glands.
Taste to anterior 2/3 of tongue (Chorda Tympani)
Damage to CN VIII (and test)
Damage to cochlear or nerve = sensorineural hearing loss.
Test = high f tuning fork near the ear and if still not heard, on mastoid process. If only heard on mastoid process = conductive hearing loss only.
What does CN IX supply
M = stylopharyngeus and to the parotid gland S = mucosa of the pharynx, posterior 1/3 of the tongue, middle ear and auditory tube.
Damage to CN IX
No gag reflex
What does CN X supply
M = muscles of the pharynx (constrictor muscles and palatopharyngeus), larynx (and soft palate S = mucosa of the larynx
Damage to CN X (and test)
Damage to muscles of the palate (dysarthria/speaking problems), pharynx (dysphagia/problems swallowing) and larynx (dysphonia/problems making sounds).
Test = see if the patient can cough strongly and soft palate raises symmetrically when speaking.
Testing CN XII
See if the patient can stick out tongue without it deviating to one side.
3 things unique about the TMJ
- The R and L synovial joints are connecting by bone so move together.
- Articular surfaces of the joint are covered in fibrocartilage.
- Articular disc separates the cavity into 2.
The ligaments found around the TMJ
Tempromandibular/ lateral ligament
Sphenomandibular ligament
Stylomandibular ligament
Borders of the posterior triangle (neck)
Clavicle, posterior border of sternocleidomastoid and anterior border of trapezius
Where does the external jugular vein drain blood from
Outside of skull, deep parts of face
What can make the external jugular vein stand out
Valsalva’s maneuver (forced exhalation against resistance) and increased vena cava/central venous pressure e.g. due to right-sided heart failure.
The infrahyoid muscles
Thyrohyoid
Omohyoid (inferior and superior bellies)
Sternothyroid
Sternohyoid
Innervation of the infrahyoid muscles
Ansa Cervicalis from Cervical spinal nerves 1-3
Function of the infrahyoids
Depress the larynx and hyoid bone after swallowing
What does the carotid sheath contain
internal jugular vein
Common Carotid artery
Vagus nerve
What does the superior thyroid artery supply and what does it branch off
Branches off the eternal carotid and supplies the superior anterior aspect of the thyorid
What does the inferior thyroid artery supply and what does it branch off
Branches off the thyrocervical artery (from the subclavian) and supplies the inferior posterior aspect.
Why are tumours in the thyroid area v dangerous
Because they can compress the oesophagus or trachea
Borders of the anterior triangle (neck)
Anterior side of sternocleidomastoid, mandible and midline of neck.
What does the ansa cervicalis supply and which nerves does it branch off
Supplies the infrahyoid muscles and geniohyoid.
Branches of the cervical spinal nerves 1-3 (part of the cervical plexus)
Main branches of CN V1
Frontal branch
Lacrimal branch
Nasociliary branch
Main branches of the cervical plexus and which nerves is it made up of
Made from Cervical spinal nerves 1-4
Main motor branches = ansa cervicalis and phrenic nerve (C3,4,5 keep the diaphragm alive)
Sensory branches = auricle nerve, transverse cervical nerves.
How to do an emergency cricothyroid stab/tracheotomy
Incision between the thyroid and cricoid cartilages and insert a tube.
What are the suprahyoid muscles
Mylohyoid muscle
Geniohyoid muscle
Stylohyoid muscle
Digastric muscle (anterior and posterior bellies)
The action of the suprahyoid muscles
Elevate the hyoid bone during swallowing.
Borders of the submandibular triangle
Anterior belly and posterior belly of digastric muscle and mandible.
Anatomy of the submandibular gland and its duct
Deep part hooks around posterior margin of the mylohyoid muscle.
Secretions travel in Wharton’s duct
Branches of the external carotid artery
Some attendings like freaking out potential medical students. SALFOPMS Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior Auricular Maxillary Superficial temporal
Damage to the cervical sympathetic chain
Drooping of eyelid, no sweating/flush skin, constricted pupil = Horner’s syndrome
What is the modiolus
Place at the corner of the mouth where 8 muscles meet.
What are the branches of the facial nerve and which branches supply the muscles of facial expression.
Temporal - frontal, orbicularis oculi Zygomatic - orbicularis oculi Buccal - buccinator, orbicularis oris, zygomaticus Mandibular - mentalis Cervical
The action of Masseter/ the deep and superficial part features
Closes mouth by elevating jaw. Has many origins so can retract and protrude jaw too. Deep part is more muscular and more for closing (verticle fibres). Superficial is more tendonous (for opening). Diff angels so the max force can be exerted through the whole range of movements.
Action of Temporalis
Closes jaw by elevating and retracting mandible. Weaker action than masseter.
Action of the Lateral Pterygoid
Opens mouth by protruding jaw - moves articular disc and condyle forward
Action of the Medial Pterygoid
Closes mouth by elevating jaw. Also protrudes jaw.
Origin of the buccal nerve, its path and what it supplies
From V3
Pierces masseter but doesnt supply it and enters mouth
Sensory to lower buccal and gingival mucosa.
Motor to lower temporalis and pterygoid muscles.
What does the mylohyoid nerve branch off and what does it supply?
Branch off V3, inferior alveolar nerve.
Supplies mylohyoid muscle and anterior belly of digastric muscle.
Order of branching off V3
Mandibular nerve Buccal nerve (with branches to M of M) Auriculotemporal nerve Lingual nerve (with Chorda Tympani) Inferior alveolar nerve (with mylohyoid, inferior dental and mental nerve branches)
What does the inferior alveolar artery supply and what does it branch off.
Mandible, chin, lower teeth, mylohyoid muscle
What nerves can be found at level of bifurcation of common carotid into external and internal
Hypoglossal and Glossopharyngeal
What happens at the germinal centres of lymph nodes
Cells proliferate and mutate and differentiate
What are the 4 types of tonsils and type of epithelium.
Lingual tonsils (SSE) Palatine tonsils (SSE) Adenoids (Respiratory epithelium) Tubal tonsils (respiratory epithelium)
What does the internal carotid artery supply
Goes directly to the brain
What vessel runs over the sternocleidomastoid muscle
External jugular vein
What is the role of the thyroid Isthmus
Connects the 2 lobes of the thyroid
What is the shape of the thyroid cartilage
A ring, incomplete posteriorly. Articulates w the cricoid cartilage anteriorly inferiorly.
What is the shape of the cricoid cartilage
Complete ring, bigger and flatter posteriorly.
Features of cervical vertebrae
Tranverse foramen
Bifid spinous process
Small body
Masseter
Origin = Zygomatic arch and process
Insert = Ramus, angle of the mandible and lateral surface of the coronoid process.
Action = elevates mandible (has many origins so can also protrude and retract mandible).
CN V3.
Temporalis
Origin = Temporal fossa
Insert = Coronoid process (down to retromolar fossa)
Action = Elevates and retracts mandible
CN V3.
Lateral Pterygoid
Origin = Lateral surface of lateral pterygoid plate
Insert = Articular disc and neck of condyle
Action = Protrudes mandible so opens the mouth.
CN V3
Medial Pterygoid
Origin = Medial surface of lateral pterygoid
Insert = Inner surface of angle of mandible
Action = Elevates mandible and protrudes.
CN V3
Jaw movements
Biting/insicing = Protrude jaw so incisors meet
Mastication = Depress mandible via infra and suprahyoid muscles. Lateral and medial excursion to allow cuspal contact.
Speaking
Limits of movements when yawning.
Lateral Excursion of mandible
- Lateral pterygoid on balancing side contracts to move mandible to working side.
- Temporalis on working side contracts so working side moves back slightly and balancing side moves medially.
TMJ movements
Some rotation around the axis of the condyle Anterior movement (condylar guidance) onto the articular eminence.
Role of the articular disc
- Joins lateral pterygoid to the lateral joint surface
- Pulled forward by lateral pterygoid when the condyle moves forward onto the articular eminence so packs the joint and stabilizes it.
TMJ dislocation and how to fix it
When the condyle overshoots the articular eminence. Can only happen anteriorly (there’s bone medially and the lateral pterygoid muscle laterally).
Can be fixed by applying downwards and backward force onto the mandible (needs to be done quickly or using muscle relaxants to stop them spasming or locking the jaw in place).
TMJ dysfunction
Mostly due to over-closing e.g. grinding teeth.
Meningeal Arteries - origin, foramen, location, supply
Branch off the maxillary artery (from the external carotid)
Foramen spinosum
Located in the extradural space and they mostly supply the cranium bones.
The Mater’s
Dura Mater
Arachnoid Mater
Pia Mater
About the dura mater
One layer tightly bound to the cranium and one to the arachnoid mater.
Venous sinuses can be found here.
Creates the dural folds.
About the arachnoid mater
Covers the pia mater. Has extensions which run into the pia mater through the subarachnoid space.
About the pia mater
Thin layer, very tightly associated with the brain.
Dural folds and their functions
Stabilise and support the brain.
Falx Cerebri = Between the cerebrum hemispheres
Falx Cerebelli = Between the cerebellum hemispheres
Tentorium Cerebelli = between the cerebrum and cerebellum hemisphere.
Extradural space and consequences of a haemorrage here
A potential space above the Dura Mater containing the meningeal arteries.
As the dura mater is v tightly associated with the cranium, a hemorrhage here can’t spread so causes a localized coning and increase in intracranial pressure. This can force the brain down and put pressure on the brain stem = v dangerous.
Subarachnoid space and consequeces of a haemorrage here
A real space, containing brain arteries, nerves and CSF (which reduces the brains apparant weight and cusions it).
Slower raise in intracranial pressure as the fluid can spread so less dangerous.
Venous drainage of the cranium
Venous blood drains into venous sinuses which follow the path of the dural folds and eventually drain into the internal jugular vein.
How do the venous sinuses connect to deep and superficial veins?
Via the orbit, pterygoid and pharyngeal venous plexuses and the emissary veins.
What are emissary veins and what problems are associated with them?
Veins that exit the cranium into the nasal sinuses. Have no valves so blood and infections can travel up the brain too.
Role of the Circle of Willis
Connects the internal carotid and vertobrobasilar systems.
Provides an alternative blood supply if there’s damage in one of the other vessels.
What does the anterior cerebral artery supply and what happens if it gets damaged?
Supplies the medial part of the frontal lobe.
Damage = Loss of M and S function to opposite leg.
What does the middle cerebral artery supply and what happens if it gets damaged?
Supplies the lateral part of the hemisphere (apart from occipital lobe)
Damage = Loss of M and S function to opposite arm and side of the face (and speech).
What does the posterior cerebral artery supply and what happens if it gets damaged?
Supplied the medial and inferior part of the occipital and temporal lobe and visual cortex.
Damage = Blindness one 1 side of visual field.
Different types of strokes
Ischemic and hemorrhagic stroke
Ischemic stroke
A blocked brain artery. Brain function lost after the point of blockage.
Hemorrhagic stroke
Trauma, aneurysm etc can cause a tear in a brain artery (blood is toxic to brain tissue). Short-term effects are normally worse than long-term effects and function can return as mass of blood clot decreases.
Functions/benefits of CSF
Cushions and protects the brain.
Lightens the apparent weight of the brain.
Carries nutrients and hormones to the brain.
Takes metabolic waste products away from the brain.
Embryology time frame
Pre embryonic stage = 0-2.5 weeks
Embryonic stage = 2.5-8 weeks
Fetal stage = 8 weeks - 9 months
Post fertilization/early embryonic events
Gastrulation
Neurulation
Development of the pharyngeal arches
Gastrulation
Epiblast and hypoblast totipotent cells in the inner cell mass (surrounded by placental cells).
Epiblast cells move down and invaginate, pushing the hypoblast cells out the way.
3 embryonic/germ layers = Ectoderm, mesoderm and endoderm.
Neurulation
- Another germ layer = Ectomesderm (derived from ectoderm but has properties of mesoderm)
- Ectoderm thickens in the middle to form the neural plate.
- Crease along the axis of the neural plate
- Neural folds/plate move together and fuse = neural tube
- The merged neural folds separate from neural tube = neural crest/epidermis.
- Neural crest cells move to mesoderm and differentiate into diff types of cells.
The fate of the 4 embryonic germ layers
Ectoderm = Hair, the epidermis. Mesoderm = Skeleton, muscles Endoderm = Epithelium Ectomesoderm = CNS, PNS
The 4 (out of 6) embryonic pharyngeal arches all contain ?
Arch bone/cartilage
Arch muscle
Arch cranial nerve
Arch artery
Embryonic pharyngeal arch 1
CN V
Muscles of mastication
Meckel’s cartilage (= mandible, malleus and incus)
Embryonic pharyngeal arch 2
CN VII
Muscles of facial expression
Styloid process, part of the hyoid bone, Stapes
Embryonic pharyngeal arch 3
CN IX
Stylopharyngeus
Hyoid bone
Embryonic pharyngeal arch 4
CN X
Laryngeal and soft palate muscles
Laryngeal cartilages
Laryngeal muscles and their innervation
Interarytenoids Posterior cricoarytenoid Lateral cricoarytenoid Cricothyroid Thyroarytenoids Vocalis All supplied by CN X (recurrent and superior laryngeal nerves)
Interarytenoids
Adduct the vocal folds
Recurrent laryngeal
Thyroarytenoids
Move the arytenoids forward, relaxing the vocal folds. Makes the initial movements.
Recurrent laryngeal
Posterior cricoarytenoids
Abduct the vocal folds
Recurrent laryngeal
Cricothyroid
Acts on the cricothyroid synovial joint to move the cricoid up so it tilts the arytenoids backward and tenses the vocal folds.
Superior laryngeal.
Vocalis
Pads out the vocal folds and moves the arytenoids forward, relaxing the vocal folds.
Recurrent laryngeal
What does the recurrent laryngeal nerve innervate
M to all the laryngeal muscles (apart from cricothyroid)
What does the superior laryngeal nerve innervate
M to the cricothyroid muscle.
S to laryngeal mucosa up to the vocal folds.
What are the pharyngeal muscles and their innervation?
Superior, middle and inferior constrictor muscles (CN X/pharyngeal plexus)
Stylopharyngeus (CN IX)
Palatopharyngeus (CN X/pharyngeal plexus)
What are the soft palate muscles and their innervation
LVP (CN X)
TVP (CN V3)
Palatoglossus (CN X)
Palatopharyngeus (CN X)
The action of the soft palate muscles
Palatoglossus/pharyngeus elevate the pharynx and larynx.
LVP and TVP elevate and tense the soft palate.
Muscles of the tongue and their innervations.
Extrinsic: Palatoglossus Genioglossus Styloglossus Hyoglossus
Intrinsic: Superior longitudinal Inferior longitudinal Transverse Verticle
All supplied by CN Xii apart from palatoglossus (CN X)
Palatoglossus
Elevates the posterior tongue / depresses the soft palate.
Styloglossus
retract the tongue and elevates the sides
Hyoglossus
Depresses the tongue and sides of the tongue and retract tongue
Genioglossus
Many actions e.g. protrusion and depression
Inferior and superior longitudinal tongue muscle action
Curl apex of tongue down (inferior) / up (superior)
Transverse tongue muscle action
Narrow and increase the depth of tongue.
Verticle tongue muscle action
Flatten and lengthen the tongue.
Attachments of the constrictor muscles
All attach to the pharyngeal raphe at the midline.
Superior = pharyngeal tubercule
Middle = stylohyoid ligament/hyoid bone
Inferior = thyroid cartilage
Venous drainage of the brain
Via the sinuses and then to the internal jugular vein.
Superior sagittal sinus
Inferior sagittal sinus
Straight sinus, transverse sinus, sigmoid sinus
Ventricles in the brain
Lateral ventricle (main big one) 3rd and 4th ventricles (joined by the aqueduct)
Type III la forte fracture complications
Can disrupt cranial floor so the brain is open to the outside via nose so can get infected.