Scenario 23: The Anatomy of the Head and Neck Flashcards
What is the neurocranium?
Skull cap or calvaria in cranial base and the intracranial region. Formed of frontal, ethmoidal, sphenoidal, occipital and paired temporal and parietal bones
What is the viscerocranium?
Comprimises facial bones in anterior part of cranium. Formed of mandible, vomer, maxillae, inferior nasal conchae, zygomatic, palatine, nasal and lacrimal
Which bone are the styloid and mastoid process of the skull on?
Temporal bone
What is the pterion?
The meeting of frontal, parietal, temporal, and sphenoid bones
What is the lambdoid?
Where the lambdoidal suture meets the coronal suture
What is formed by the frontal bone?
The top of head, forehead and roof of orbits
What is formed by the parietal bone?
Lateral walls and roof of cranium
What is formed by the occipital bone?
Posterior region of the skull
What is formed by the temporal bone?
Inferior lateral walls and floor of cranium
What does the sphenoid bone articulate with?
All cranial bones and palatine, zygomatic, maxillae and vomer facial bones
Where is the ethmoid bone found?
Between orbits, anteromedial floor of the cranium, roof of nasal cavity, medial wall of each orbit and part of nasal septum
What are the features of the ethmoid bone?
Crista galli, cribiform plate, orbital plate, perpendicular plate, ethmoid sinus
What do the palatine bones form?
Hard palate, nasal cavity and eye orbit
What do zygomatic bones form?
Cheekbones, lateral wall of each orbit and the cheeks
What do lacrimal bones form?
Medial wall of each orbit providing passageway for tear duct
Where is the maxilla?
Central part of facial skeleton
Where is vomer found?
Inferior posterior part of nasal septum,
Where is the inferior nasal conchae bone?
Lateral wall of nasal cavity
Where is the mandible?
Entire lower jaw
What are the four main sinuses in the skull?
Frontal, above eyes, ethmoid, along nose, sphenoid, near ear, maxillary, either side of nose
What is the bregma point?
Where coronal suture of the skull meets sagittal suture of the skull
What is the function of skull sutures?
Allow bones to move during birth by acting as an expansion joint. Allow brain to grow. More ossified with age.
Which vertebrae is axis and which is atlas?
Atalas- C1
Axis- C2
Which bones and brain parts are in the anterior cranial fossa?
Frontal bone, ethmoid, lesser wing of sphenoid. Frontal lobe.
Which bones and brain parts are in the middle cranial fossa?
Sphenoid, petrous (of temporal). Temporal lobe,
Which bones and brain parts are in the posterior cranial fossa?
Temporal bone, occipital bone. Cerebellum
What is the sella turnica?
Saddle like prominence crossing midline on superior surface of body of sphenoid where the pituitary gland sits
What passes through the cribiform plate?
CI (olfactory nerve)
What passes through the optic canal?
CII (optic nerve)
What passes through the superior orbital fissure?
CIII (oculomotor nerve) IV (trochlear nerve) VI (abductens) V1 (ophthalmic nerve from trigeminal)
What passes through the foramen rotundum?
V2 of trigeminal (Maxillary nerve)
What passes through the foramen ovalae?
V3 of trigeminal (mandibular nerve)
What passes through the foramen lacerum?
Middle meningeal artery
What passes through the foramen spinosum?
Internal carotid artery
What passes through the inferior auditory meatus?
CVII (facial) and CVIII (vestibulocochlear) nerves
What passes through the jugular fossa?
CIX (glossopharyngeal) CX (vagus) CXI (accessory) nerves
What passes through the hypoglossal canal?
CXII (hypoglossal nerve)
What passes through the foramen magnum?
Spinal cord and vertebral arteries
What are the three layers of meninges?
Dura mater, arachnoid matter, pia mater
What is the dura mater?
The outer layer of meninges, made of collagen fibres acting as a mechanically protective cover
What is the arachnoid matter?
A delicate web of non vascular connective tissue, middle layer of meninges
What is the pia mater?
Continuous with the surface of brain/cord, supports blood supply, forms choroid plexus with ependymal cells
What are the layers of the skull from skin to pia mater?
Skin of scalp, periosteum, bone of skull, periosteal and meningeal layers of dura mater, potential subdural space, arachnoid, subarachnoid space, pia mater
What forms the middle meningeal artery and where does it supply?
Branch of maxillary artery which is a terminal branch of the external carotid artery. Supplies dura mater and calvaria
What are the parts of the brain?
Frontal lobe, parietal lobe, occipital lobe, temporal lobe, cerebellum, diencephalon (thalamus, hypothalamus, 3rd ventricle), brainstem (mid brain, pons, medulla oblongata)
What is the falx cerebri?
Fold of dura mater in longitudinal fissure which separates cerebral hemispheres
What is the falx cerebelli?
Fold of dura mater which separates cerebellar hemispheres
What is the tentorium cerebelli?
Extension of dura mater separating the cerebellum from the inferior partition of the occipital lobes
What are the branches of the circle of Willis?
Anterior, posterior and middle cerebral arteries, superior cerebellar artery, anterior and posterior communicating arteries, ophthalmic artery, basilar artery with potine arteries
What are the dural venous sinuses?
Spaces between periosteal and meningeal layers of dura containing venous blood
Name the dural venous sinuses
Superior and inferior sagittal sinuses, straight sinus, cavernous sinus, superior and inferior petrosal sinuses, transverse and sigmoid sinuses
How would an extradural, or epidural, haemorrhage occur?
Common following blow to head which ruptures middle meningeal artery, between dura of skull
How would a subdural haemorrhage occur?
Vein crossing subdural space bursts and blood builds up between dura mater and arachnoid.
Where would a subarachnoid haemorrhage occur?
Between arachnoid and pia mater
Where do the 1st and 2nd ventricles open up into the 3rd?
Via the inter ventricular foramen (of Monro)
Where is the 3rd ventricle?
Sitting between the two halves of diencephalon connected to 4th ventricle by cerebral aqueduct
Where is the 4th ventricle?
Lies in the posterior parts of pons and medulla and expands inferoposteriorly
What are the divisions of the trigeminal nerve and what are their functions?
Ophthalmic nerve- sensory forehead and upper nose
Maxillary nerve- sensory cheek and upper lip
Mandibular nerve- sensory to temple and jaw, motor to mastication muscles
What is the course of the inferior alveolar nerve?
A branch of the mandibular nerve, it enters through the mandibular bone through the mandibular foramen. Branches off as the inferior dental plexuses.
Describe the course of the facial artery
Branch of external carotid artery, has torturous course across face ending as angular artery at the medial side of the eye. The transverse facial artery runs just above the parotid duct and is a branch of the superficial temporal artery
What is the course of the facial vein?
Commences at the side of the root of the nose as a direct continuation of the angular vein. Lies behind facial artery. Receives blood from external palatine vein and joins anterior branch of retromandibular vein forming common facial vein which drains into internal jugular
Which facial muscles raise the eyebrows?
Epicranius: frontalis and occipitalis
Which facial muscle blinks and closes the eyes?
Orbicularis oculi
Which facial muscle closes and protrudes lips?
Orbicularis oris
Which facial muscle flattens cheek against teeth?
Buccinator
Which facial muscle raises the corner of the mouth?
Zygomaticus
Which facial muscle draws mouth downwards?
Platysma
What are the branches of the facial nerve (CVII)?
Temporal, zygomatic, buccal, marginal mandibular, cervical
What is Bell’s palsy?
Facial paralysis due to swelling of CVII causing ptosis, drooping and dry mouth, impaired taste
Which nerves terminate into the parotid gland?
Terminal branches of VII
What does the scalp contain?
Skin, Connective tissue dense, Aponeurosis- occipito-frontalis, Loose connective tissue and Periosteum
What is the cutaneous innervation of the scalp?
Vi supraorbital nerve, Viii auriculotemporal nerve, C2 greater and lesser occipital nerves
What is the arterial supply of the scalp?
Superior orbital artery, superficial temporal artery, occipital and posterior auricular arteries
What may cause Panda eyes?
Trauma to the back of the head causing blood to pool in the eyelids via loose connective tissue of the scalp
What is in the vestibule of the oral cavity?
Teeth and mucosal inner lining of cheeks and lips
Where is the oral cavity proper?
Space between upper and lower dental arches filled by the tongue
What forms the boundaries of the oral cavity?
Maxilla and palatine form roof, maxilla and mandible form anterior boundary, floor and posterior walls are formed by soft tissue
Where is the soft palate?
Is suspended from the posterior border of the hard palate as a free margin from which the uvula hangs
Which muscles form the floor of the oral cavity?
Mylohyoid muscles and medial geniohyoid muscles, diagastric muscles externally
What is the vermillion border?
The transitional zone between mucous membrane and skin of lips
How many of each type of tooth is there?
3 pairs of molars, 2 of premolars, 1 of canines, 2 incisors in upper and lower jaw makings 32 total
Which nerve supplies the mucous membrane of the roof of the oral cavity?
Branches of maxillary nerve
Which nerve supplies the mucous membrane of the lateral walls and floor of the oral cavity?
Branches of mandibular nerve (lingual)
Which nerve supplies the muscles of the lateral of the oral cavity?
Facial nerve
Which nerve supplies the muscles of the floor of the oral cavity?
Geniohyoid- C1
Mylohyoid and diagastric belly- mandibular branch of trigeminal
Which nerve supplies teeth?
Alveolar branches of the maxillary and mandibular (upper and lower respectively)
What is the function of the tongue?
Mastication, taste, deglutination, articulation and oral cleansing
What are the extrinsic muscles of the tongue?
Palatoglossus, styloglossus, hypoglossus, genioglossus
What are the intrinsic muscles of the tongue?
Superior and inferior longitudinal transverse and vertical muscles of the tongue
What is the innervation of the muscles of the tongue?
CXII- hypoglossal nerve
What is the sensation of the anterior 1/3 of the tongue?
Lingual nerve
What is the sensation of the posterior 1/3 of the tongue?
Glossopharyngeal nerve
Which nerve supplies taste to the tongue?
Chorda tympani nerve (CVII)
What is the arterial supply of the tongue?
Lingual artery from external carotid branching into dorsal lingual artery, deep lingual artery and sublingual artery
What is the venous drainage of the tongue?
Dorsal lingual veins drain dorsum and side of tongue into lingual vein into external jugular
Deep lingual vein begins at the apex of the tongue and runs posteriorly beside lingual frenulum to join the sublingual vein which joins facial vein
What are the lymphatics of the tongue?
Anterior to vallate papillae the tongue is drained into central and marginal lymph vessels. Posterior 1/3 is drained by posterior lymph vessels ultimately draining into nodes around the sternocleidomastoid
What is the purpose of the nose and nasal cavity?
Airway to respiration, moistens and warms inspired air, filters air to remove foreign particles, houses olfactory receptors, resonating chamber for speech
What is the epithelial lining of the nasal cavity?
Pseudostratified ciliated columnar epithelium with goblet cells
What is present in the lamina propria of the nasal cavity?
Serous and mucus acni glands which form sticky sheet for particles to stick to
What separates oral and nasal cavities?
Hard palate
What is the function of the conchae?
Increase tuber lance of inspired air and increases contact between air and mucosa
What is the function of the para nasal sinuses?
Empty secretions into nasal cavity
What is the sensory supply of the nasal cavity?
Branches of maxillary and opthalmic
Name the cranial nerves in order.
I- olfactory II- optic III- oculomotor IV- trochlear V- trigeminal VI- abducens VII- facial VIII- vestibulocochlear IX- glossopharyngeal X- vagus XI- accessory XII- hypoglossal
What does the olfactory nerve do?
Smell
What does the optic nerve do?
Visual fields and pupillary reactions
What does the occulomotor nerve do?
Extra ocular movements
What does the trochlear nerve do?
Motor to superior oblique muscle of eye
What does the trigeminal nerve do?
Facial sensation, voice and speech, corneal reflexes, jaw movement
What does the abducens nerve do?
Extra ocular movements
What does the vestibulocochlear nerve do?
Hearing and balance
What does the glossopharyngeal nerve do?
Swalling, palate elevation, gag reflex, gustation, voice and speech
What does the accessory nerve do?
Shrug shoulders, turn head
What does the hypoglossal nerve do?
Voice and speech, move tongue
Which cranial nerves are located n the anterior portion of the brain?
I, II, III, IV
Which cranial nerves are located in the pons?
V, VI and VII
Which cranial nerve arises in the inner ear?
VIII
Which cranial nerves attach to medulla oblongata?
IX, X, XI and XII
Which cranial nerves are afferent only?
Olfactory, optic, vestibulocochlear
Which cranial nerves are efferent only?
Occulomotor, trochlear, abducens, accessory, hypoglossal
Which cranial nerves are mixed?
Trigeminal, facial, glossopharyngeal, vagus
What is the course of the olfactory nerve?
Enter olfactory bulb forming olfactory tract
What is the course of the optic nerve?
Begins deep to optic disc and exits through optic canal and enter middle cranial fossa to form the optic chasm
Which muscles does the oculomotor nerve control?
All extraocular muscles and levator palpebrae supiois
Where does the abducens nerve run?
Arises in pons and supplies lateral rectus muscle after passing through superior orbital fissure
Where are the temporal and infra temporal regions?
Superior and inferior to zygomatic arch
What are the borders of the infratemporal fossa?
Lateral- ramus of mandible
Medial- lateral pterygoid plate
Anterior- posterior aspect of maxilla
Posterior- tympanic plate, mastoid and styloid
Superior- inferior surface of greater wing of sphenoid
Inferior- medial pterygoid muscle meets mandible
What is the contents of the infra temporal fossa?
Inferior part of temporalis, lateral and medial pterygoid muscles, maxillary artery, pterygoid nervous plexus, mandibular, inferior alveolar, lingual, buccal and chorda tympani nerves and optic ganglion
Which joint allows mastication?
Synovial joint between mandible and temporal bone (TMJ)
What articulates at the TMJ?
The head of the mandible and the articular tubercle of the temporal bone and mandibular fossa. These surfaces are covered in fibrocartilage
What movements are possible at the TMJ?
Hinge movement in lower compartment of joint between stationary disc and moving condyle
Gliding movement in upper compartment of joint between moving disc and stationary fossa
What movements is the mandible capable of?
Depression, elevation, lateral excursions (L and R) protrusions and retraction
What are the muscles of mastication?
Masseter, temporalis, medial and lateral pterygoid
What is the function of masseter?
Elevates mandible and can retrude mandible. Acting alone can move mandible to the same side.
Where does masseter run?
From zygomatic arch to lower margin of mandible covering most of ramus
Where does temporalis run?
Side of skull and coronoid process of mandible arising from temporal bone and fascia
What is the function of temporalis?
Maintains normal mandibular position, elevates and retrudes mandible, ipslateral excrusion
Where are medial and lateral pterygoids found?
Occuy infratemporal fossa
What is the function of the medial pterygoid?
Elevate and protrude mandible, contralateral excrusion
What is the function of the lateral pterygoid?
Protrude and depress mandible, contralateral excrusion
What is the function of the suprahyoid muscle?
Forms floor of mouth and raises hyoid bone and larynx when mandible is stable
What is the function of the infrahyoid muscle?
Depresses hyoid bone and larynx in swallowing
How can we breathe and chew at the same time?
Bilateral contraction of palatoglossus muscles narrows oropharygeal isthmus and posterior part of tongue covers the gap so food is not inhaled
Describe the swallowing reflex
Soft palate is raised by levator muscles and tensed by tensor muscles, superior constrictor contracts and closes nasopharynx from oropharynx. Suprahyoid muscles raise larynx to force the epiglottis over the laryngeal opening. Middle and inferior constrictors contract and push bolus into stomach. Aryepiglottic and transverse arytenoid muscles contract reducing size of laryngeal inlet. Vocal vestibular folds close.
What are the carotid sheaths?
Tubes of fascia lying bilaterally on the neck which contain the common carotid artery, internal jugular vein and vagus nerve
What are the features of the atlas?
Foramen transversarium, vertebral foramen and dens foramen with dens facet, anterior and posterior arches, with tubercles, lateral masses and a groove for the vertebral artery
What are the features of the axis?
Bifurcating spinous processes, lamina, vertebral foramen, dens, atlas facet, inferior articular process, transverse process and superior articular facet
Describe the deep fascia of the neck
Superficial investing layer and deeper layer ensheathing the structures lying within the investing layer.
What are the attachments of the deep fascia of the neck?
Inferiorly it attaches to the spine and acromion process of the scapula and the manubrium sterni of each side. Superiorly it attaches to the external occipital protuberance, superior nuchal line and mastoid process
Where does the deep fascia of the neck split?
Between the mastoid process and ramus of the mandible to enclose the parotid gland
What is the pre vertebral fascia of the neck?
A tough membrane covering the anterior aspect of the flexor muscles extending from the base of the skull to the body of T3
What is pre tracheal fascia?
Delicate fascia surrounding thyroid gland
What is in the posterior triangle of the neck?
Accessory nerve, 4 superficial branches of the cervical plexus, external jugular vein, sternocleidomastoid muscle
What is in the anterior triangle of the neck?
Suprahyoid muscles, infrahyoid muscles, cervical plexus and vagus and hypoglossal nerves. Common carotid artery which branches at the level of the hyoid into internal and external carotid branches. Anterior jugular veins.
Where do the posterior divisions and cervical spinal nerves supply?
Extensor muscles of vertebral column and skin and posterior parts of scalp and neck
Where do the anterior divisions and cervical spinal nerves supply?
Form cervical and brachial plexuses
Where does the superficial phrenic nerve supply?
Skin of anterior and lateral parts of neck and side of head
Where does the deep phrenic nerve supply?
Muscles of anterior and lateral parts of neck and side of head
What are the cutaneous branches of the cervical plexus?
Lesser occipital, great auricular, accessory, transverse nerve of the neck, supraclavicular
What is the lymphatic drainage of the neck?
Efferent vessels form jugular trunk which enters the thoracic duct on left and right. All drains to cervical nodes.
Where is the pharynx?
Extends from cranial base to lower border of cricoid cartilage where it becomes continuous with the oesophagus. Lies behind the nasal, oral and laryngeal cavities
What is the lining of the pharynx?
Mucosa
Where is the nasopharynx?
Above the soft palate and behind the nose
What are the walls of the nasopharynx?
Soft palate is the floor and the superior constrictor muscle forms the major part of the posterior wall. On the lateral wall is the opening of the pharyngotympanic and behind is the adenoid tonsil (a small mass of lymph tissue)
Where is the oropharynx?
Behind the soft palate communicating anteriorly with the oral cavity
What lies between palatoglossal and palatopharyngeal arches?
Palantine tonsils
Where is the laryngoopharynx?
Part of pharynx lying adjacent to the where the larynx projects up into it ending at C6
What are the 4 muscular layers of the pharynx?
Mucosal coat, submucosa (tough fibrous coat anchors pharynx to base of skull), muscular coat (5 pairs of muscles form an outer semicircular, 2 inner longitudinal muscles) areolar coat covering the exterior of the pharynx (buccopharyngeal fascia)
What is the function of the 3 constrictor muscles?
Contract sequentiality as peristaltic waves during swallowing
What is the motor supply of the pharynx?
Pharyngeal branch of vagus nerve except stylopharyngeus which is glossopharyngeal
What is the sensory supply of the pharynx?
Glossopharyngeal mostly, soft palate and roof of the pharynx is by maxillary nerve. Vagus supplies the pharyngeal inlet.
What is the arterial supply of the pharynx?
Ascending pharyngeal, superior and inferior thyroid, facial and maxillary arteries
What is the venous drainage of the pharynx?
Veins form a plexus on the pharynx which communicates with the pterygoid plexus
What is the lymphatic drainage of the pharynx?
Many lymph vessels pass to deep cervical lymph nodes but some posterior ones enter the neutropharyngeal ducts which lie between pre vertebral and buccopharyngeal fasciae
What is in the external layer of the muscles of the pharynx?
Superior, middle and inferior pharyngeal constrictor
What is in the internal layer of the muscles of the pharynx?
Palatopharyngeus, salpingopharyngeus, stylopharyngeus,
What is the function of the internal layer of pharyngeal muscles?
Elevate pharynx and larynx in speaking and swallowing
Where does the larynx lie?
From the base of the tongue to the trachea (C3-6). The inlet lies behind the posterior 1/3 of the tongue.
What is the function of the larynx?
Acts as an air passageway linking pharynx with trachea, also acts as a sphincter to prevent food entering trachea and as an organ of phonation
Which cartilages support the larynx?
Thyroid, cricoid and epiglottis cartilages, and the paired arytenoid, cuneiform and corniculate
Describe the thyroid cartilage
Largest cartilage, 2 plates joined anteriorly in the mid line. Forming Adam’s apple in males.
Describe the cricoid cartilage
Immediately below the thyroid cartilage at C6, encircles larynx
Describe the epiglottis cartilage
Fibroelastic cartilage, lies behind hyoid bone posterior to tongue.
Describe the arytenoid cartilage
2 pyramidal cartilages which lie on posterior lamina of cricoid cartilage and articulate with it.
Describe the corniculate cartilage
2 tiny elastic cartilages sitting atop of the arytenoid cartilages extending their length
Describe the cuneiform cartilage
Found in epiglottic folds
What is the thyrohyoid membrane?
A fibroelastic sheet joining the inferior surface of the hyoid bone and the superior aspect of thyroid cartilage
Where do the vocal ligaments run?
Elastic fibres running from vocal processes of arytenoid to the thyroid cartilage
Where do the vestibular ligaments run?
From lateral borders of arytenoid cartilages to the internal lamina of the thyroid cartilage
Where do the aryepiglottic ligaments run?
Pass upwards from apices of arytenoid cartilages to the lateral border of the epiglottis
Where does the quadrangular membrane run?
From aryepiglottic ligament to ventricular ligament
Where does the cricothyroid membrane run?
Fills space between vocal cords and cricoid cartilage
What are the extrinsic muscles of the larynx?
Supra and infrahyoid muscles
What are the intrinsic muscles of the larynx?
Posterior, lateral and transverse cricoarytenoid muscles, vocalis, cricothyroid
What is the function of the intrinsic muscles of the larynx?
Opens rims to allow passage of air in and out, close vestibule and rims glottides during swallowing to prevent aspiration of food. Control the tension in vocal cords for phonation.
What is the motor supply of the larynx?
Intrinsic muscles supplied by laryngeal branches of the vagus nerve, external branches supply cricothyroid, rest by recurrent laryngeal
What is the sensory supply of the larynx?
Vagus nerve sensory to larynx, internal laryngeal nerve supplies mucus membrane above the vocal fold, recurrent laryngeal supplies below this.
What is the arterial supply of the larynx?
Superior and inferior thyroid arteries, superior gives off internal laryngeal branch, inferior gives inferior laryngeal branch
What is the venous drainage of the larynx?
Superior and inferior thyroid veins
What is the lymph drainage of the larynx?
Above the vocal folds drains to upper deep cervical lymph nodes, below to lower deep cervical lymph nodes
How does phonation happen?
Vocal folds are adducted to obstruct air flow, pressure builds up until it forces the folds apart so the air can escape. The air is converted to series of puffs at a frequency decided by sub glottal pressure, mass and tension of vocal ligaments. This determines the pitch.
How are vowel sounds formed?
Continuous flow of air through the oral cavity, tongue and lips modify the sound of this
What divides the subclavian artery into 3 parts?
The scaleus anterior muscle
What is the course of the vertebral artery?
Arises from subclavian and goes through the foramen of C1-6, winding round the atlas to enter through the foramen magnum. It forms the basilar artery by uniting with the vessel from the opposite side.
What is the course of the thyrocervical trunk?
Arises from subclavian, divides into inferior thyroid, supra scapular and transverse cervical branches.
What is the course of the costocervical trunk?
Arises from subclavian and divides into superior intercostal and deep cervical arteries.
What is the course of the common carotid artery?
Divides into internal and external branches at upper border of thyroid cartilage
What is the course of the internal carotid artery?
Continues through neck to reach skull at carotid canal. Inside the skull it supplies brain.
Where does the inferior thyroid artery supply?
Inferior part of thyroid giving muscular branches and pharyngeal and inferior laryngeal branches
Where does the transverse cervical artery supply?
Trapezius
Where do the deep cervical arteries supply?
Muscles of neck and anastomose with the vertebral and occipital arteries
