VIVA: Anatomy - Head and neck Flashcards
Identify the intracranial structures visible on this model
5/6 to pass:
- Cerebrum
- Medulla
- Pons
- Cerebellum
- Corpus callosum
- Ventricle
Others:
- Spinal cord
- Dura
- Frontal bone
- Parietal bone
- Occipital bone
- Maxilla
- Ethmoid
- Atlas (C1): anterior and posterior arches
- Axis (C2): dens
Describe the anatomy of the Circle of Willis
4/5 to pass
What are the main arteries contributing to the blood supply of the brain?
To pass:
- Vertebral arteries (merging to form the basilar artery)
- Internal carotid arteries
Others:
- Anastamosing via anterior and posterior communicating arteries to form the circle of Willis
What are the main cerebral arteries? Describe which lobes of the brain they supply
Anterior cerebral: frontal, parietal
Middle cerebral: frontal, parietal, lateral temporal
Posterior cerebral: parietal, medial temporal, occipital
Which vessels make up the posterior circulation?
Posterior cerebral
Superior cerebellar
Anterior and posterior inferior cerebellar
Pontine
Describe the venous drainage of the cerebral hemispheres
- Superior cerebral veins drain the superolateral cerebrum to the superior sagittal sinus
- Superficial middle cerebral veins drain the lateral cerebrum to the cavernous sinus
- Inferior cerebral drain the inferior cerebrum to the cavernous and transverse sinuses
- Great cerebral vein (midline vein formed from the paired internal cerebral veins) merges with the inferior sagittal sinus to form the straight sinus
Of the sinuses:
- Straight sinus is formed at the meeting of the great cerebral vein and the inferior sagittal sinus
- Superior sagittal sinus meets the straight sinus at the confluence of sinuses
- Transverse sinus continues bilaterally, curves into sigmoid sinus before exiting jugular foramen becoming the internal jugular vein
- Cavernous sinus drains the ophthalmic veins and is found either side of the sella turcica; drains into superior and inferior petrosal sinuses which empty into internal jugular vein
What motor and sensory areas lie in the distribution of the MCA?
Motor and sensory supply of contralateral body except legs and perineum
Auditory and speech areas
What is the nerve supply to the extraocular muscles? What other structures are supplied by the CN III?
CN III:
- SR, IR, MR, IO
- Levator palpebrae superioris
- Parasympathetic through ciliary ganglion to smooth muscle of sphincter pupillae and ciliary muscle
CN IV:
- SO
CN VI:
- LR
What is the effect of a complete CN III lesion?
“Down and out” position (depressed, abducted)
Ptosis
Mydriasis
Describe the circulation of CSF
3 to pass:
- Formed in epithelial cells of the choroid plexus lining the lateral, third and fourth ventricles
- Lateral ventricles to third ventricle via intraventricular foramen
- Third to fourth ventricle via cerebral aqueduct
- Passes into subarachnoid space and the central canal of the spinal cord via the lateral apertures of Luschka and medial aperture of Magendie
- Most CSF passes into interpeduncular and quadrigeminal cisterns
- Absorbed from subarachnoid space in arachnoid granulations, especially those that protrude into superior sagittal sinus
What are the functions of the CSF?
1 to pass:
- Protects brain from damage by providing cushion effect
- Buoyancy effect to support brain and prevent compression of nerves and vessels
- Role in homeostasis, regulating metabolites surrounding the brain
- Clearance of cellular waste products
- Immune function
What is the major abnormality shown on this CT?
Right-sided subdural with midline shift
Identify some normal structures on this head CT
- Lobes:
- Frontal
- Temporal
- Parietal
- Occipital - Ventricles:
- Lateral ventricle with anterior and posterior horns
- Third ventricle - Basal ganglia:
- Caudate nucleus
- Lentiform nucleus (putamen, globus pallidus) - Thalamus
- Anterior and posterior limbs of internal capsule
- Septum pellucidum
- Falx cerebri
Identify the non-bony features on this CT. Which bony sinuses are shown?
Bony sinuses (need 2/3):
- Ethmoid
- Sphenoid
- Mastoid
What is the blood supply of the cerebellum?
Vertebral arteries -> basilar artery -> posterior cerebral
Anterior and posterior inferior cerebellar arteries
Superior cerebellar artery
Identify the anatomical features on this CT through the base of the skull
Bones (2/4 to pass):
- Temporal
- Occiput
- Sphenoid
- Nasal
Sinuses (2/4 to pass):
- Mastoid air cells
- Sphenoid sinus
- Ethmoid
- Nasal cavity
Intracranial (3/5 to pass):
- Fourth ventricle
- Cerebellum
- Vermis
- Temporal lobe
- Pons
Describe the posterior circulation of the brain
Vertebral arteries (originating from subclavian arteries) give off posterior and anterior inferior cerebellar then unite at caudal border of pons to form basilar artery
Basilary artery ascends to superior border of pons, giving off superior cerebellar artery, and terminates by dividing into the two posterior cerebral arteries
Posterior communicating arteries join the posterior cerebral arteries to the middle cerebral arteries (and hence the anterior circulation)
What areas of the brain do the main arteries of the posterior circulation supply?
Vertebral arteries: cranial meninges, cerebellum
Basilary arteries: brainstem, cerebellum and cerebrum
Posterior cerebral arteries: inferior aspect of cerebral hemispheres and occipital lobe
Posterior communicating arteries: optic tract, cerebral peduncle, internal capsule and thalamus
Demonstrate the areas supplied by the middle cerebral artery and describe the function of these areas
Lateral surfaces of both cerebral hemispheres excluding the anterior part of the frontal lobe and the occipital lobe, and including the basal ganglia but not the thalamus
Function includes motor and sensory supply of contralateral body except legs and perineum, and speech centres (Broca and Wernicke’s)
Identify the extraocular muscles on this model
All to pass:
- Superior rectus
- Inferior rectus
- Medial rectus
- Lateral rectus
- Superior oblique
- Inferior oblique
Describe the actions of the extraocular muscles
5 described to pass:
- SR: elevate, adduct, medially rotate
- IR: depress, adduct, laterally rotate
- MR: adduct
- LR: abduct
- SO: depress, abduct, medially rotate
- IO: elevate, abduct, laterally rotate
What nerves supply the extraocular muscles?
CN III:
- SR, IR, MR, IO
CN IV:
- SO
CN VI:
- LR
How are the actions of the extraocular muscles tested clinically?
LR, SR and IR tested in abduction
MR, IO and SO tested in adduction
What extraocular muscles make the eye look directly up?
IO and SR (SO and IR make eye look directly down)
What is the effect of a CN IV lesion?
Loss of SO innervation
Inability to look down when looking inward (e.g. walking down stairs, reading)
Extorsion (compensate by tilting head to opposite shoulder)
Describe the structures of the eye using the model
Vitreous body
Lens
Anterior and posterior chambers (with aqueous humour)
Iris
Pupil
Describe the structure of the walls of the eyeball
Fibrous: cornea, conjunctiva, sclera
Vascular: choroid, ciliary body, iris
Nervous: retina, optic disc, macula
Describe the pupillary light reflex arc
Light hits retina
Impulse travels down optic nerve -> pretectal nucleus -> both Edinger-Westphal nuclei -> parasympathetic fibres of CN III to ciliary ganglion
Short ciliary nerve -> sphincter pupillae
Dilator pupillae -> cervical sympathetics via internal carotid artery -> CN V1 -> nasociliary nerve -> long ciliary nerve
Describe the formation and drainage of aqueous humour
Produced by ciliary processes (capillary diffusion)
Enters posterior chamber
Passes through pupil to anterior chamber
Filters through iridocorneal angle to Canal of Schlemm
Drains into anterior scleral veins
Demonstrate on the model the arterial supply to the face
Facial artery:
- Arises from the external carotid artery and contacts the submandibular gland, then hooks over mandible anterior to masseter, before taking a tortuous course to the medial angle of the eye
Transverse facial artery:
- Arises from the superficial temporal artery, and anastamoses with the facial artery
Demonstrate the branches of the facial nerve on the model
Five branches (3/5 to pass):
- Temporal
- Zygomatic
- Buccal
- Marginal mandibular
- Cervical
Exits base of skull at stylomastoid foramen
What is the function of the facial nerve?
Motor supply to the face (needed to pass): muscles of facial expression, digastric, stylohyoid and stapedius
Parasympathetic supply to submandibular, sublingual and lacrimal glands
Taste to anterior 2/3 of tongue
Somatic sensory to external auditory canal
What is the sensory nerve supply of the face?
Trigeminal nerve with branches (2/3 needed to pass):
- Ophthalmic
- Maxillary
- Mandibular
Demonstrate the walls of the orbit on this XR and name the bones that form them
Roof: orbital part of frontal bone *, lesser wing of sphenoid
Medial: ethmoid * with contributions from frontal process of maxilla, lacrimal and sphenoid
Lateral: frontal process of zygomatic *, greater wing of sphenoid
Floor: maxilla *, zygomatic, palatine
*needed to pass
Demonstrate the position of the infraorbital nerve on this XR
Region of infraorbital foramen/notch
What structures does the infraorbital nerve innervate?
Skin of cheek*
Skin and oral mucosa of upper lip*
Upper medial teeth (premolars, canines, incisors)*
Skin of lateral nose
Skin/conjunctiva of inferior eyelid
Anteroinferior nasal septum
Mucosa of maxillary sinuses
*needed to pass
Identify the bones visible on this XR
Frontal*
Maxilla*
Zygoma*
Mandible*
Nasal
Sphenoid
Ethmoid
Lacrimal
Vomer
*needed to pass
Identify the sinuses on this XR
3/4 to pass:
- Frontal
- Maxillary
- Ethmoid
- Mastoid
Demonstrate the muscles of facial expression as seen on this photograph
3/4 needed to pass:
- Orbicularis oculi
- Orbicularis oris
- Zygomaticii
- Buccinator
Demonstrate the muscles of mastication
Medial and lateral pterygoids
Masseter
Temporalis
Describe the course of the facial nerve
Exits through stylomastoid foramen near origin of digastric
Divides into superior and inferior divisions before entering the posteromedial surface of the parotid gland, within which it forms pes anserinus and divides into five branches (temporal, zygomatic, buccal, marginal mandibular, cervical)
Identify and name some facial muscles innervated by the facial nerve
Temporal: frontalis, auricularis
Zygomatic: orbicular oculi, zygomaticus major and minor
Buccal: buccinator, nose, upper lip
Mandibular: orbicularis oris, depressor anguli oris
Cervical: platysma
Demonstrate the features of this bone
Body*
Angle*
Ramus*
Condyle* (includes head and neck)
Coronoid process*
Pterygoid fossa
Mandibular notch
Lingula
Mylohyoid groove
Submandibular fossa
Sublingual fossa
Symphysis
Mental protuberance
Alveolar processes
Mental tubercles
Digastric fossa
Mental spines
*4/5 of these plus one other
Which nerve passes within this bone? Demonstrate the entry and exit points
Inferior alveolar nerve
- Enters mandibular foramen (within mandible supplies mandibular teeth)
- Exits mental foramen as mental nerve (supplies skin and mucous membranes, lower lip, skin of chin)
What nerve does the inferior alveolar nerve arise from?
Mandibular nerve (V3)
Describe the features of the temporomandibular joint
2 needed to pass:
- Bones: condyle of mandible, articular tubercle, mandibular fossa
- Disc: separates superior synovial cavity (gliding in/out) and inferior synovial cavity (hinge up/down)
- Postglenoid tubercle and temporomandibular (lateral) ligament
- Stylomandibular and sphenomandibular ligaments
Describe the mandibular attachments of the muscles of mastication
2 needed to pass:
- Temporalis: temporal fossa to medial coronoid and anterior ramus
- Masseter: maxillary process and zygomatic arch to angle and lateral ramus
- Lateral pterygoid: greater wing sphenoid and lateral surface lateral pterygoid plate to joint capsule, disc and pterygoid fossa on neck of mandible
- Medial pterygoid: medial surface lateral pterygoid plate and tuberosity of maxilla to medial ramus below foramen
What movements is the mandible capable of at the TMJ?
3 needed to pass:
- Protraction/retraction
- Depression/elevation
- Side-to-side
Which factors contribute to the stability of the TMJ?
Shape of TMJ
Occlusion of teeth
Stylomandibular ligament
Sphenomandibular ligament
Joint capsule
Muscles of mastication
Can you demonstrate where the muscular attachments to the mandible would be?
4 needed to pass:
- Masseter
- Temporalis
- Lateral pterygoid
- Medial pterygoid
- Mylohyoid
- Digastric
- Depressors of the face (labii inferioris, anguli oris)
Which nerves run on or within the bony mandible?
Inferior alveolar/mental nerve (branch of V3)
Plus one other of:
- Auriculotemporal nerve (branch of V3)
- Nerve to mylohyoid (branch of inferior alveolar)
- Mandibular branch of facial nerve
Show the course of the inferior alveolar nerve on this mandible and explain why it is prone to injury
Early large branch of mandibular trigeminal after it exits foramen ovale
Runs on surface of inside mandible ramus to mandibular foramen* (gives off nerve to mylohyoid)
Passes inferior and anterior through bone in alveolar canal, close to roots of third molar* supplying all lower teeth and exits as mental nerve from mental foramen* anterior/superior
Prone to injury as close relationship to bony mandible - at risk during fracture
If the lingual nerve is damaged, what deficits would you expect?
Anterior 2/3 of tongue: taste and somatic sensory loss* (via chorda tympani)
Loss of secretory function (submandibular salivary glands)
Sensory loss to floor of mouth and/or gums
*needed to pass
Which bones make up the orbital rim?
2/3 needed to pass:
- Frontal
- Zygomatic
- Maxilla
Describe the course of the infraorbital nerve
Entrance into the orbit via inferior orbital fissure
Traverses infraorbital groove and canal in orbital floor
Emerges via infraorbital foramen
What structures pass through the superior orbital fissure?
CN III*
CN IV*
CN VI*
Superior ophthalmic nerve (CN V1)
Sympathetic fibres
Ophthalmic veins
*needed to pass
Identify the sensory supply to the pinna. What other nerves supply the ear and canal?
Greater auricular nerve (C2) supplies cranial surface and lower half
Auriculotemporal nerve (from V3) supplies upper half and most of the meatus
Others (2/4 needed to pass):
- Lesser occipital
- Vagus
- Glossopharyngeal
- Facial nerve for the tympanic membrane
Identify the bones and sutures of the cranial vault
Bones:
- Frontal
- Parietal
- Occipital
- Temporal
- Sphenoid
Sutures:
- Coronal
- Sagittal
- Lambdoid
What are the major bony compartments within the base of skull and what are the major bones forming them?
Identify all 3 fossae plus * major bone in each:
- Anterior cerebral fossa: frontal *, ethmoid, lesser wing of sphenoid
- Middle cerebral fossa: sphenoid, squamous temporal laterally, contains sella turcica
- Posterior cerebral fossa: occipital, dorsum sella of sphenoid
Identify the various foramina in the base of skull
Identify 5 foramina to pass:
- Cribiform plate
- Optic canal
- Superior orbital fissure
- Foramen lacerum
- Foramen rotundum
- Foramen ovale
- Foramen spinosum
- Internal acoustic meatus
- Foramen magnum
- Jugular foramen
- Hypoglossal canal
- Condylar canal
- Mastoid foramen
What structures pass through the foramen magnum?
Medulla/brainstem*
Vertebral arteries
CN XI
*needed to pass
Describe the innervation of the tongue
Motor: hypoglossal (except palatoglossus by pharyngeal plexus)
Somatic sensory: sensation to anterior 2/3 tongue via lingual nerve
Special sensory: taste to anterior 2/3 of tongue via chorda tympani
Describe the motor and sensory distribution of the trigeminal nerve
Motor:
- Muscles of mastication* (lateral and medial pterygoid, masseter, temporalis)
- Mylohyoid
- Anterior belly of digastric
- Tensor tympani
- Tensor veli palatini
Sensory:
- Skin of face and anterior scalp*
- Eyelids, cornea, conjunctiva
- Nose and mucosa of nasal cavity
- Paranasal sinuses
- Ear
- Mouth, lip, gingiva and palate
- Tongue (taste to anterior 2/3)
- Dura of anterior and middle cranial fossa
Other:
- Distributes postsynaptic parasympathetic fibres of head to their destinations
*needed to pass + 1 other motor and 4 other sensory
Which nerve branch would you anaesthetise before repairing a lower lip laceration?
Mental nerve, branch of mandibular (V3)
Describe the ventricular system of the brain
Lateral ventricles (with anterior, posterior and inferior horns) open into third ventricle via interventricular foramen
Third ventricle (slit-like between diencephalon halves) continues as cerebral aqueduct posteroinferiorly and connects to fourth ventricle
Fourth ventricle (pyramid-shaped, posterior part of pons and medulla) tapers and is continuous with the central canal
Outline the flow of CSF in the brain
CSF secreted by choroid plexuses* in ventricles
Drains into subarachnoid space from fourth ventricle via medial and lateral apertures
Then passes to multiple cisterns in the subarachnoid space*
*needed to pass
What are the branches of the trigeminal nerve?
Ophthalmic: supratrochlear, infratrochlear, external nasal, lacrimal
Maxillary: zygomatic, infraorbital
Mandibular: auriculotemporal, buccal, mental, lingual
Using the model, demonstrate the main features of the larynx
Thyroid cartilage*
Cricoid cartilage*
Epiglottic cartilage*
Cricothyroid membrane*
Vocal cords*
Epiglottic vallecular
Arytenoid cartilages
Cuneiform and corniculate cartilages
What is the motor supply of the larynx?
Inferior laryngeal nerve is a continuation of the recurrent laryngeal nerve and innervates all muscles except the cricothyroid (which is innervated by the superior laryngeal nerve)
Both are branches of CN X
Identify the features of this bone
C2 or axis* features:
- Body
- Dens*
- Superior and inferior articular facets
- Lamina
- Pedicle
- Transverse process
- Transverse foramen
- Bifid spinous process
- Vertebral foramen
*needed to pass + 4 others
Describe the joints between C1 and C2
- 2x lateral atlanto-axial joints:
- Synovial joints with lax capsule
- Between inferior articular facet of atlas and superior articular facet of axis on either side - 1x medial atlanto-axial joint:
- Synovial joint
- Between anterior arch of C1 and dens
- Pivot joint
Which ligaments stabilise the joints between C1 and C2?
- Cruciate or cruciform ligament*:
- Made up of STRONG transverse ligaments across atlas behind dens (with bursa in between), and WEAKER vertical bands from back of body of axis posterior to dens to basi-occiput (bypass atlas)
- Holds dens in position and prevents pressure from dens on medulla - Alar ligaments x2:
- From sides of dens to edge of foramen magnum
- Strong and limit rotation
- With weak apical ligament from apex of dens to foramen magnum - Tectorial membrane:
- Continuation of posterior longitudinal ligament
- From back of body of axis to anterior half of foramen magnum
- Lies in front of dura
*needed to pass + 1 other
Using the model, demonstrate the main features of the larynx
- Thyroid cartilage*
- Cricoid cartilage*
- Arytenoid cartilages
- Epiglottic cartilage*
- Epiglottic vallecula
- Cuneiform and corniculate cartilages
- Crico-thyroid membrane*
- Vocal cords*
What is the motor supply of the larynx?
Larynx is innervated by the superior and inferior laryngeal branches of the vagus nerve (CN X):
- Inferior laryngeal nerve is a continuation of the recurrent laryngeal nerve* and supplies all intrinsic muscles except one*
- Cricothyroid is supplied by the superior laryngeal nerve
*needed to pass
On the model, identify the structures of the larynx
- Cartilages:
- Thyroid*
- Cricoid*
- Epiglottis*
- Arytenoids
- Corniculate
- Cuneiform - Ligaments:
- Cricothyroid membrane*
- Thyrohyoid
- Vocal cords* - Muscles:
- Cricothyroid
- Cricoarytenoid - Spaces and folds:
- Vallecula*
- Aryepiglottic folds
- Piriform recess
- 5/6 to pass + 2 others
What is the innervation of the larynx?
Supplied by vagus nerve (CN X):
- Inferior laryngeal nerve (terminal branch of recurrent laryngeal nerve*) supplies all intrinsic muscles of larynx except cricothyroid, and provides sensation below cords
- External laryngeal nerve (branch of superior laryngeal nerve) supplies cricothyroid muscle
- Internal laryngeal nerve (branch of superior laryngeal nerve) provides sensation above cords
*needed to pass
What is the result of an injury to the recurrent laryngeal nerve?
- Hoarse voice
- Stridor if bilateral due to inability to abduct cords (posterior cricoarytenoids are only abductors)
Identify the venous structures in this photo
4 to pass:
- SVC
- Right brachiocephalic vein
- Left brachiocephalic vein
- Subclavian vein
- Internal jugular vein
- Inferior thyroid vein
Identify the nerves in this photo
3 to pass:
- Phrenic nerve
- Right vagus nerve
- Right recurrent laryngeal nerve
- Left vagus nerve
- Sympathetic trunk
What is the difference between the course of the right and left recurrent laryngeal nerves?
- Right hooks around subclavian artery
- Left hooks around aorta
- After looping, they ascend in tracheoesophageal groove to supply the intrinsic muscles of the larynx (except cricothyroid)
What are the boundaries of the anterior triangle of the neck?
- SCM
- Mandible
- Midline of neck
SCM has been removed in this photo. Where is the internal jugular vein? Describe its course
- IJV originates as continuation of sigmoid sinus
- Contained in carotid sheath*
- Lies lateral and ventral to artery
- Passes deep to SCM* and two heads of SCM (sternal and clavicular)
- Joins subclavian vein* posterior to sternal end of clavicle*
- Forms brachiocephalic vein*
*needed to pass
What major structures are at risk during insertion of an IJ line?
2 to pass:
- External carotid artery
- Common carotid artery
- Vagus nerve
- Other nerves
- Lung
- Trachea
- SCM
- Thyroid
- Thoracic duct
What are the contents of the carotid sheath?
- Common carotid artery * (with division into internal and external carotid)
- Internal jugular vein *
- Vagus nerve *
- Cervical lymph nodes, carotid sinus nerve, sympathetic nerve fibres
*needed to pass
Describe the course of the left common carotid artery
2/3 to pass:
- Arises from arch of aorta
- Ascends into carotid triangle, within carotid sheath, CCA medial to IJV
- Divides into internal and external carotid arteries at the level of the superior border of the thyroid cartilage
