Head and Neck COPY Flashcards
What are the borders of the anterior triangle of the neck?
Invisible midline (medial) Superior border of sternocleidomastoid (lateral) Inferior border of the mandible (superior)
What are the contents of the anterior triangle?
Trachea
Oesophagus
Thyroid
Carotid sheath
What are the borders of the posterior triangle of the neck?
Inferior border of sternocleidomastoid (medial)
Middle third of the clavicle (inferior)
Medial border of trapezius (lateral)
What are the contents of the posterior triangle?
External jugular vein
Lymph
Brachial plexus
Lung apex
What are the contents of the carotid sheath?
Common carotid artery
Internal jugular vein
Vagus nerve
Deep cervical lymph nodes
What muscle is invested in the superficial fascia?
Platysma
What muscles are invested in the deep fascia of the neck?
Sternocleidomastoid
Trapezius
What are the contents of the pretracheal fascia?
Trachea
Oesophagus
Thyroid
What is the clinical significance of the retropharyngeal space?
The space communicates with the diaphragm and therefore infection or pus build up in this space and lead to mediastinitus.
What are the four suprahyoid muscles?
Diagastric
Mylohyoid
Stylohyoid
Geniohyoid
What are the four infrahyoid muscles?
Thyrohyoid
Sternohyoid
Sternothyroid
Omohyoid
What are the actions of the hyoid muscles?
Suprahyoid muscles elevate the hyoid bone and larynx during swallowing.
Infrahyoid muscles depress the hyoid and larynx during swallowing and speech.
What are the branches of the ECA?
Superior thyroid Lingual Facial Occipital Maxillary Superficial temporal Ascending pharyngeal Posterior auricular
What are the muscles of facial expression?
Occipitofrontalis
Orbicularis occuli
Zygomasticus
Orbicularis oris
What is the innervation to the muscles of facial expression?
Sensory is CN V
Motor is CN VII
What are the muscles of mastication?
Temporalis
Masseter
Buccinator
Pterygoids
What is the innervation of the muscles of mastication?
Sensory and motor innervation is CN V
What are the branches of the Facial Nerve?
Temporal Zygomatic Buccal Mandibular Cervical
What is a pharyngeal arch?
Complex tissue arches involving the brain, CVS and special sensory organs; system of mesenchymal proliferations in the neck region.
What are the three vesicle stages of the brain?
Prosencephalon (forebrain)
Mesencephalon (midbrain)
Rhombencephalon (hindbrain)
What structures are formed from Meckel’s cartilage?
Malleus
Incus
Template for the mandible
What structures are formed from Reichert’s cartilage?
Stapes
Styloid processes
Lesser and upper body of hyoid bone
What nerve is associated with pharyngeal arch 1?
CN V
What nerve is associated with pharyngeal arch 2?
CN VII
What nerve and artery are associated with pharyngeal arch 3?
ICA
CN IX
What nerve and arteries are associated with pharyngeal arch 4?
Arch of the aorta (L) and brachiocephalic (R)
CN X
What nerve and blood vessel is associated with pharyngeal arch 6?
Pulmonary arch
CN X
What structure is associated with the second pharyngeal pouch?
Palatine tonsils formed by epithelial proliferation and colonization with lymphoid precursors
What structures are associated with the third and fourth pharyngeal pouches?
Dorsally the parathyroid glands and ventrally the thymus glands.
What structures are associated with the first pharyngeal pouch?
Tympanic cavity and auditory tube
What are the branches of the brachiocephalic trunk?
Common carotid artery Vertebral artery Internal thoracic artery Thyrocervical trunk Subclavian artery
What is the carotid sinus?
Swelling in the region of bifurcation where baroreceptors are located in the walls of the artery.
What is the carotid body?
Peripheral chemoreceptors that detect arterial pO2 in the region of the carotid sinus.
What factors contribute to excessive bleeding from the scalp?
Artery walls are closely associated with connective tissue limiting vasoconstriction
Opposing pulls of the occipitofrontalis
There are numerous anastomoses
What are the layers of the scalp?
Skin Connective tissue (dense) Aponeurosis Loose connective tissue Periosteum
Explain the blood supply to the scalp and skull:
The skull is supplied by the middle meningeal artery so loss of supply to the scalp does not lead to bone necrosis as the scalp is supplied separately by the superficial temporal artery.
What are dural venous sinuses?
Endothelium-lined spaces between periosteal and meningeal layers of the dura that receive blood from large veins draining the brain.
What structures pass through the cavernous sinus?
Internal carotid artery CN III CN IV CN V1 and V2 CN VI
List the superficial arteries of the face:
Maxillary Middle meningeal Facial Superior and inferior labial Lateral nasal Angular Supratrochlear Supraorbital
What is meant by the lymphatic system?
System of drainage vessels and lymphatic vessels/tissues that returns lymph to the blood circulation.
How is one-directional flow created in the lymphatic system?
Valves
Passive constriction e.g. arterial pulsing
Intrinsic constriction of SMCs when stretched
What are lymph nodes?
Connective tissue structures with a fibrous outer capsule and reticular tissue inside, containing a large number of lymphocytes and macrophages.
What is Waldeyer’s Ring?
Anular collections of nodules surrounding superior pharynx including adenoids, palatine and lingual tonsils.
Name the bones of the skull:
Parietal Occipital Temporal Zygomatic Sphenoid Frontal Maxilla Mandible Ethmoid Lacrimal
Which four bones contribute to the pteryion?
Sphenoid
Parietal
Frontal
Temporal
What is the purpose of skull foramina?
Allow passage of anatomical structures between intracranial and extracranial components.
How is the neonatal skull different to the adult skull?
Adjacent cranial bones are held together by a thick connective tissue matrix.
Fontanelles- wide membranous tissue islands in the vicinity of the bregma and lambda.
Cranial sutures allow for interlocking of bones during the birthing process.
What drives the development of the face?
The expansion of the cranial nerve tube, pharyngeal arches and the sense of organs and palate.
What are neural crest cells?
Specialized population of cells that originates within the neuroectoderm.
What contributes to the embryological development of the nose?
Nasal placodes (thickenings of ectoderm) appear on the FNP and sink to become nasal pits; medial and lateral nasal prominences form on either side of the pits. Maxillary prominences then push the nasal prominences together to fuse in the midline.
Outline the embryological development of the palate:
Intermaxillary segment is composed of the primary palate, philtrum and four incisors.
Secondary palate is derived from the palatine shelves of maxillary prominences that grow downwards into the oral cavity.
Mandible grows large enough to allow for the tongue to drop.
Palatine shelves grow towards each other and fuse in the midline.
Nasal septum develops as a midline downgrowth and ultimately fuses with palatine shelves.
Outline the embryological development of the eyes:
Outpocketings of the forebrain (optic vesicle) form the retina and optic placodes form the lens.
Optic vesicle makes contract with lens placode which then invaginates and pinches off.
Eye primordia are on the side of the head and move to the front of the face as facial prominences grow.
Outline the embryological development of the external ear:
External auditory meatus develops from the first pharyngeal cleft and the auricles and pinna develop from proliferation within the first and second pharyngeal arches.
Outline the development of the internal ear:
Otic placodes invaginate forming auditory vesicles.
What is the role of CN I?
Olfactory- sensory receptor neurones ascend through cribriform plate of the ethmoid bone and form the olfactory bulb for the special sense of smell.
What is the role of CN II?
Optic- sensory, forming the optic nerve that supplies the eye and allows for special sense of sight.
What is the role of CN III?
Oculomotor- moves the eyeball/eyelids and carries parasympathetic fibres that allow for pupil constriction.
What is the role of CN IV?
Trochlear- allows for movement of the eyeball down and in.
What is the role of CN V?
Trigeminal nerve with opthalmic, maxillary and mandibular branches- supplies sensory innervation to the face, motor innervation to the muscles of mastication and is responsible for the afferent branch of the corneal reflex.
What is the role of CN VI?
Abducens- responsible for lateral eye movement.
What is the role of CN VII?
Facial- responsible for motor innervation of muscles of facial expression, special sensory innervation to the anterior 2/3 of the tongue (via chorda tympani) and parasympathetic innervation to the salivary and lacrimal glands.
What is the role of CN VIII?
Vestibulocochlear nerve- sensory innervation to the inner ear to allow for sense of balance and hearing.
What is the role of CN IX?
Glossopharyngeal- provides sensation to the oropharynx, carotid sinus and posterior third of the tongue and motor innervation to the stylopharyngeus muscle and carries parasympathetic fibres to the parotid gland. Also responsible for the afferent limb of the gag reflex.
What is role of the CN X?
Vagus- provides sensation to the laryngopharynx and the ear, motor innervation to the muscles of the pharynx and larynx and parasympathetic innervation to the heart, lungs and GIT. Also responsible for the efferent limb of the gag reflex.
What is the role of CN XI?
Spinal accessory- motor innervation to the sternocleidomastoid and trapezius.
What is the role of CN XII?
Hypoglossal- provides motor innervation to the intrinsic muscles of the tongue.
What are the four key ganglia of the parasympathetic nervous system in relation to the head and neck?
Ciliary ganglion (associated with CN III) Pterygopalatine ganglion (associated with CN VII) Submandibular ganglion (associated with CN VII) Otic ganglion (association with CN IX)
What are the key nuclei of the parasympathetic nervous system in relation to the head and neck?
Edinger-Westphal nucleus (Ciliary ganglion)
Superior salivatory nucleus (Pterygopalatine and Submandibular ganglia)
Dorsal Motor Vagal Nucleus
Explain the relationship between blood vessels and the sympathetic supply to the head and neck region:
Sympathetic fibres hitch-hike on the internal and external carotid arteries to reach their destinations and are therefore vulnerable to damage from blood vessel pathology.
What structures are supplied by the superior cervical ganglion?
Sweat glands Pupillary dilation Levator palpaebrae superioris Nasal glands Salivary glands
What structures are supplied by the middle cervical ganglion?
Lower larynx
Trachea
Hypopharynx
Upper oesophagus
What bones contribute to the orbit?
Frontal Sphenoid Ethmoid Zygomatic Maxilla Lacrimal
What muscles move the eyeball?
Superior rectus (III) Superior oblique (IV) Medial rectus (III) Inferior rectus (III) Inferior oblique (III) Lateral rectus (VI)
What are the clinical features of an oculomotor nerve palsy?
Ptosis
Diplopia
Pupillary dilation
“Down and out” position
What is the blood supply to the eye?
Opthalmic artery from the ICA
Superior opthalmic vein to the cavernous sinus
What are the features of thyroid eye disease (NOSPECS)?
No symptoms Only signs Soft tissue involvement e.g. lid oedema Proptosis Extraocular muscle involvement Corneal ulceration Sight loss (optic neuropathy)
What is a RAPD?
Relative afferent pupillary defect- observed using the swinging-flashlight test whereupon patient’s pupils constrict less (appear to dilate) when a bright light is swung from the unaffected to the affected eye. (Seen in orbital cellulitis).
Where is the middle ear found?
Within the petrous temporal bone.
What is the role of the tympanic muscles?
Stapedius and tensor tympani act to dampen movements of the tympanic membrane in order to prevent sound being too loud.
What are the components of the inner ear?
Cochlea, vestibule, semicircular canals
How is pressure equalised in the middle ear?
Eustachian tube
Communication posteriorly with mastoid air cells
What are the auditory ossicles and what is their role?
Malleus, incus and stapes act to communicate soundwaves transmitted from the tympanic membrane to the cochlea.
What structures of the vestibular compartment contribute to balance?
Utricle- detects up/down
Saccule- detects forwards/backwards
Semicircular canals- detect rotation
Outline how sound waves are transmitted into afferent nerve impulses:
Stapes communicates with the oval window and moves fluid within the cochlea. This leads to movement of the basilar membrane hair cells (cupula) which generates nerve impulses.
What structures make up the nose?
Nasal bone, nasal septum
Septal cartilage
Major and minor alar cartilages
What is the nasal septum?
Perpendicular plate of ethmoid bone, vomer, palatine bone and septal cartilage.
What are the openings into the nasal cavity?
Sphenopalatine foramen, incisive foramen, foramen cecum
What arteries anastamose at Kiesselbach’s area?
Greater palatine artery (ECA) Anterior ethmoidal artery (ICA) Sphenopalatine artery (ECA) Posterior ethmoidal artery (ICA) Superior labial artery (ECA)
What is the venous drainage of the nasal cavity?
Cavernous sinus, facial vein and pterygoid plexus in the infratemporal fossa.
What is the sensory innervation to the nasal cavity?
Opthalmic and maxillary branches of the trigeminal nerve.
What are the paranasal sinuses?
Paired mucous-membrane-lined out-pocketings of the nasal cavity.
How is the maxillary sinus related to dental pain?
The first two molars communicate with the floor of the maxillary sinus and superior alveolar nerve.
What is the oral vestibule?
Everything that lies outside of the teeth but inside the lips and cheeks.
What makes up the hard palate?
Palatine processes of the maxilla and the palatine bone (horizontal plate and pyramidal process) where the muscles of the soft palate are attached.
What are the muscles of the soft palate?
M. uvulae M. levator veli palatini M. tensor veli palatini M. palato pharyngeus M. palato glossus
What is the motor innervation to the muscles of the soft palate?
All muscles etc. M. tensor veli palatini are supplied by CN X.
What nerve supplies the intrinsic muscles of the tongue?
CN XII
What muscles make up the extrinsic muscles of the tongue?
Styloglossus
Genioglossus
Hyoglossus
What actions are the intrinsic muscles of the tongue responsible for?
Superior longitudinal- curves sides of the tongue upwards
Transverse- protrustion of the tongue
Vertical- flattens and broadens the tongue
Inferior longitudinal- brings sides of the tongue down
What is the sensory innervation to the tongue?
Posterior third - CN XII
Anterior two thirds- CN V (general) and CN VII (special)
What is the temperomandibular joint?
Articulation between the cranium and the mandible at the mandibular fossa, articular tubercle and head of the mandible.
What is special about the shape of the disc at the TMJ?
Irregular shape allows poorly aligned bones to fit (upper surface is concavo-convex, lower surface is concave and the disc is thinner centrally).
What are the supporting structures of the TMJ?
Stylomandibular ligament
Temperomandibular ligament
Sphenomandibular ligament
Joint capsule
How does the sphenomandibular ligament prevent joint dislocation?
It remains at a constant length and tension for all positions of the joint.
Outline the process of opening the mouth:
Condyles are pulled forwards by lateral pterygoids;
chin is pulled down and back by diagastric muscles.
Outline the process of closing the jaw:
Posterior fibres of the temporalis retract the mandible;
the rest of the temporalis, the masseter and medial pterygoid muscles help to elevate the mandible.
What movements are produced by the two synovial cavities of the TMJ?
Superior cavity produces translation
Inferior cavity produces rotation
Where is the infratemporal fossa located?
Lies below the middle cranial fossa and deep to the zygomatic arch behind the maxilla.
What are the muscular contents of the infratemporal fossa?
Lower part of the temporalis, the medial and lateral pterygoids
What are the nerve contents of the infratemporal fossa?
Mandibular nerve (V3) which branches into the auriculotemporal, inferior alveolar, lingual and buccal branches; chorda tympani (VII) and the otic ganglion.
What are the arterial contents of the infratemporal fossa?
Maxillary artery (ECA), middle meningeal artery and superficial temporal artery.
What are the venous contents of the infratemporal fossa?
Pterygoid venous plexus, maxillary and middle meningeal veins.
What cranial openings are found in the infratemporal fossa?
Foramen ovale, foramen spinosum, alveolar canal, inferior orbital fissure and pterygomaxillary fissure.
Where can you find the pituitary gland?
The sella turcica
What are the two components of the pituitary gland?
The infundibulum is an outgrowth of the forebrain neuroectoderm towards the pharynx to form the posterior pituitary.
Rathke’s pouch is an outpocketing of the ectoderm of the stomatodeum that pinches off during development of the sphenoid bone to form the anterior portion of the pituitary.
Outline the contribution of each of the pharyngeal arches to the tongue:
2 lateral lingual swellings from PhA1 3 median lingual swellings: - tuberculum impar PhA1 - cupola PhA2, 3 and 4 - epiglottal swellings PhA4
Outline how the intrinsic muscles of the tongue become innervated by the hypoglossal nerve:
Myogenic precursors migrate from the occipital somites bringing CN XII innervation with them.
Where would you find the primordium of the thyroid gland?
Between the tuberculum impar and cupola
Where is the point of origin for the descent of the thyroid gland?
Foramen cecum (point of the sulcus terminalis of the tongue)
What is the thyroglossal duct?
Connects the thyroid gland to the tongue and may leave a remnant on the pyramidal lobe.
What are the features of Di George Syndrome? (CATCH-22)
Congenital heart disease Abnormal facies Thymic aplasia Cleft palate Hypocalcaemia (no parathyroid glands) 22q chromosome deletion
What are the features of CHARGE syndrome?
Coloboma (hole in an eye structure) Heart defects Atresia of the choanae Retardation Genital hypoplasia Ear defects
At what vertebral levels are each of the pharyngeal regions found?
C1- nasopharynx
C2-3- oropharynx
C3-6- laryngopharynx
What is the motor innervation to the pharynx?
CN X, IX, XII, VII
What is the sensory supply to each of the pharyngeal regions?
Nasopharynx- Maxillary branch of trigeminal
Oropharynx- IX (glossopharyngeal)
Laryngopharynx- XII (hypoglossal)
What epithelium is found within the pharynx?
Nasopharynx- respiratory ciliated stratified squamous
Oropharynx and Laryngopharynx- stratified squamous
Name the muscles of the pharynx:
Superior constrictor
Middle constrictor
Inferior constrictor
Outline the stages of the process of swallowing:
Tongue and suprahyoid muscles pull the hyoid and larynx up
Soft palate elevates and closes the nasopharynx
Superior constrictors contract
Middle and inferior constrictors move bolus
Cricopharyngeus relaxes (opens oesophagus)
What is the blood supply to the pharynx?
Superior thyroid
Ascending pharyngeal
Ascending and descending palatine
Lingual, facial and maxillary arteries
Pharyngeal venous plexus
What is Killian’s dehiscence?
Weak area between the inferior constrictor muscle and cricopharyngeus muscle that is a common site of development of a posterior diverticulum.
What are the three areas of the larynx?
Supraglottis- from the inferior surface of the epiglottis to the vestibular folds
Glottis- vocal cords and 1cm inferiorly
Subglottis- from below the glottis to the lower border of the cricoid surfaces (C6)
What is the blood supply to the larynx?
Supplied by superior and inferior laryngeal arteries from the thyroid arteries, and the superior and inferior laryngeal veins.
What is the nervous supply to the larynx?
Superior laryngeal nerve pierces the thyrohyoid membrane and the recurrent laryngeal nerves run in the tracheo-oesophageal grooves.
What is the motor innervation to the intrinsic muscles of the larynx?
All are CN X apart from the cricopharyngeus which is supplied by the external laryngeal nerve.
What are the three cartilages associated with the larynx?
Thyroid cartilage
Cricoid cartilage
Arytenoid cartilage
What is the function of the arytenoid cartilages?
Paired cartilages involved in vocal cord movement as it is the site of attachment for the intrinsic muscles of the larynx.
What are the piriform fossae?
Fossae lateral to the epiglottis that act as funnels to move food down to the oesophagus.
What is the vallecula?
Depression between the tongue base and epiglottis.
What are the layers of the vocal cords?
Stratified squamous epithelium
Reinke’s space (for vibration)
Vocal ligaments
Vocalis muscle
What muscles are responsible for movements of the vocal cords?
Abduction- posterior cricoarytenoid muscle
Adduction- lateral cricoarytenoid muscle
