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 ethe 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
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
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
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)
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
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)
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
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
