Anatomy

Question 1

Name the bones of the orbits from lateral and medial.

Answer 1

Zebras Prance Solemnly From Edinburgh Market, Loudly Neighing

zygomatic, palatine, sphenoid, frontal (most superior), ethmoid (middle), maxilla (most inferior), lacrimal, nasal

Question 2

Name the components of the eyelid (muscles and glands). Name the function of these muscles.

Answer 2

Levator palpabrae superioris (LPS), with slips of orbicularis oculi in between most superficial.
Slip of smooth muscle behind (superior tarsal, Muller’s muscle) connecting to tarsal gland

Question 3

Name the function and innervation of the three eyelid muscles.

Answer 3

Superior tarsal - sympathetic, raises eyelid
LPS - CN III, raises eyelid
Orbicularis oculi - CN III, closes eyelids

Question 4

Describe how the lacrimal system works.

Answer 4

Lacrimal gland located superolaterally. Drains to lacrimal duct (canaliculi, puncta, sac) draining through nasolacrimal duct to the nasopharynx.

Question 5

Name the three layers of the eye, their contents, and the segments of the eye.

Answer 5

Outer fibrous - sclera, cornea (plus limbus)
Middle vascular - uvea - iris, choroid, ciliary body
Inner retinal - retina, macula, optic disc
Anterior segment - cornea to iris (chambers - anterior is the same, posterior is iris to suspensory ligaments)

Question 6

Briefly describe the vasculature of the eye.

Answer 6

Superior and inferior ophthalmic veins join to drain into cavernous sinus. Central retinal vein drains directly

Question 7

Name the muscles of the eye (7) and their innervation.

Answer 7

LR6 SO4 AO3
lateral rectus CN VI, superior oblique CN IV, all others CN III
(other muscles: medial, superior, inferior rectus, inferior oblique, LPS)

Question 8

Name the muscles responsible for the following eye movements:

• abduction, adduction
• elevation, depression
• superomedial/lateral
• inferomedial/lateral

Answer 8

• LR (ab), MR (add)
• SR, IO (elevation), IR, SO (depression)
• SR (sup med), IO (sup lat)
• IR (inf med), SO (inf lat)

Question 9

Name cranial nerves 2, 3, 4, 5 (plus the branches), 6, and 7.

Answer 9

optic, oculomotor, trochlear, trigeminal (V1 ophthalmic, V2 maxillary, V3 mandibular), abducens, facial

Question 10

Name the main ganglia surrounding the eye’s nerve network and the primary nerves involved.

Answer 10

Ciliary ganglion (III, short ciliary nerve)
Trigeminal ganglion (V, where three branches diverge)
Pterygopalatine ganglion (CN V2, maxillary)

Question 11

Describe the corneal (blinking) reflex.

Answer 11

cornea to V1 -> trigeminal nucleus/pons -> CN VII causing a blink by the orbicularis oculi

Question 12

Describe the vestibulo-ocular reflex.

Answer 12

Uricular, saccular, and/or ampullary nerves -> vestibular nucleus -> CN III, IV, VI to stabilize eye when head is turned (balance in the ear controlling the eye)

Question 13

Describe the oculo-cardiac reflex.

Answer 13

Long ciliary, short ciliary (via ciliary ganglion) -> trigeminal nucleus -> CN X to produce bradycardia

Question 14

Describe the pupillary light reflex.

Answer 14

light -> ipsilateral CN II -> midbrain -> bilateral CN III -> parasympathetic contraction (sphincter pupillae)

Question 15

Describe the difference between near and far vision in terms of muscle/ligament contractions and innervations.

Answer 15

Near: muscle contracted, slack ligs, thick lens. Parasymp contraction causes contracted pupil
Far: muscle slack, ligaments tense, thin lens. Lack of parasymp innervation causes dilated pupil

Question 16

What is the consensual response?

Answer 16

When light is shone in one eye, it produces constriction in the other (bilateral action of CN III).

Question 17

Name the production site of CSF and its flow.

Answer 17

Produced in the choroid plexus of the lateral ventricles of the brain.
Drains to 3rd ventricle (via interventricular foramina of Monroe), to the 4th (via cerebral aqueduct of Sylvius)
CSF then drains to the subarachnoid space (via foramen of Luschka) and the venous sinuses to SVC.

Question 18

What is the main difference between blood and CSF (in terms of contents)?

Answer 18

CSF
> : H2O, Na+, Cl-, HCO3-
< : protein, glucose, K+

Question 19

Which two conditions may arise as consequences of raised ICP?

Answer 19

Hydrocephalus, papilloedema

Question 20

Name the layers of the cornea, and tear film.

Answer 20

(external) epithelium, Bowman’s, stroma, Descemet’s, endothelium (internal).
- —
(external) lipid, aqueous, mucous (internal).

Question 21

Which four things must occur for a sight to be perceived?

Answer 21

Light must fall on visual receptors, light must be regulated (e.g. to prevent bleachout), signals must be transduced to electrical stimuli, and these must reach the brain.

Question 22

Describe the organisation of the photoreceptors in terms of cells from the receptors to the nerve.

Answer 22

Direction of impulse: photoreceptor (cell body, synaptic foramina) -> bipolar cells -> ganglion cells
Light impulse travels ‘through these’ to the photoreceptors and the signal goes ‘backward’
Horizontal cells (feed to photoreceptor / bipolar; amacrine to bipolar / ganglion

Question 23

Name and describe the meningeal layers.

Answer 23

Dura mater (hard mother) - tough exterior layer, splits into periosteal and meningeal layers to envelop dural venous sinuses
Arachnoid mater (spidery mother) - contains many trabeculae ('spidery' legs) and granulations (outpouchings)
Pia mater (faithful mother) - completely surrounds the brain

Question 24

Name and describe the two meningeal spaces.

Answer 24

Subdural space - potential, source of haemorrhage

Subarachnoid space - actual space, contains circulating CSF

Question 25

Name and describe the two primary infoldings of dura mater in the cranium.

Answer 25

Falx cerebri - medial, splitting the two hemispheres | Tentorum cerebelli - inferolateral of the falx cerebri, separating the cerebrum from the cerebellum

Question 26

Describe how cranial nerves II, III, IV, and VI may be damaged as they traverse the cranium.

Answer 26

II (optic) - outpouchings of the CNS tract, meaning it contains subarachnoid space. increased ICP can cause pressure on the optic disc (papilloedema) III (oculomotor) - medial temporal lobe herniation damages the (outer) parasympathetic nerves (first); pupil becomes 'down and out' IV (trochlear) - long intracranial course, if damaged can affect superior oblique (SO) meaning the eye cannot move inferomedially (diplopia) VI (abducens) - exits between pons and medulla, travels through subarachnoid space to petrous ridge (where it is most susceptible to damage). Can damage LR; eye can't move laterally in medial plane

Question 27

Name the contents of the superior orbital fissure.

Answer 27

Live Frankly To See Absolutely No Insult - lacrimal portion of CN V1 - frontal portion of CN V1 - trochlear (CN IV) - superior portion of CN III - abdeucens (CN VI) - nasolacrimal portion of V1 - inferior portion of CN III

Question 28

Name the foramina through which the cranial nerves (excluding II - IV, V1, and VI) exit the cranium.

Answer 28

CN I (olfactory) - cribriform plate of the ethmoid bone CN V2 - foramen rotundum CN V3 - foramen ovale CN VII - internal acoustic meatus, stylomastoid foramen CN VIII - internal acoustic meatus CN IX - XI - jugular foramen (with inferior petrosal and sigmoid sinuses) CN XI also passes through the foramen magnum with the spinal cord and vertebral arteries CN XII - hypoglossal canal

Question 29

Name the four main paranasal sinuses and name their drainage.

Answer 29

(superior - inferior) Frontal (middle meatus, semilunar hiatus) Ethmoidal air cells - posterior (superior meatus) - middle (middle meatus, ethmoidal bulb) - anterior (middle meatus, semilunar hiatus) Sphenoid (sphenoethmoidal recess) Maxillary (middle meatus, semilunar hiatus) - the nasolacrimal duct drains into the inferior meatus

Question 30

There are nine laryngeal cartilages (3 unpaired, 3 paired). Name them.

Answer 30

Unpaired (epiglottis, thyroid, cricoid) | Paired (arytenoids, upon which sit the much smaller corniculate and cuneiform cartilages)

Question 31

Describe the rich arterial supply to the nose, and name the area where the arteries converge.

Answer 31

Anterior ethmoidal, posterior ethmoidal (both from ophthalmic artery), sphenopalatine (internal maxillary), greater palatine (descending palatine), superior labial (from facial) Little's area (aka Kiesselbach plexus)

Question 32

Name the key aspects of the temporal bone.

Answer 32

``` squamous and petrosal portions zygomatic process (mandibular fossa inferior), mastoid process, auricular tubercle, external acoustic meatus, and styloid process ```

Question 33

Name the aspects of the ossicular chain, the two middle ear muscles, and how the inner ear works to produce stimuli for sound.

Answer 33

tympanic membrane -> malleus -> incus -> stapes - tensor tympani (V3, which supplies muscles of mastication) attaches the Eustachian tube to malleus - stapedius (VII, temporal bone to stapes) oval window -> scala vestibuli (perilymph), round the helicotrema to the scala tympani) -> round window The perilymph stimulates hair cells on the organ of Corti Cochlear nerve + vestibular nerve = cochleovestibular nerve (CN VIII).

Question 34

Name and describe the key components of the vestibular system.

Answer 34

Otoliths - saccule (vertical acceleration), utricle (horizontal acceleration) Semicircular canals (indicate angular movement) - anterior SCC (sagittal) - lateral SCC (axial) - posterior SCC (coronal)

Question 35

Name the key anatomy seen on otoscopy.

Answer 35

Orientate with cone of light at 5 o'clock. Superior - pars flaccida, with posterior and anterior fold Malleus - long downward projection almost in midline Incus - seen more to the side Umbo - inward projection at the centre Annulus - outside ring Pans tensa - inferior part

Question 36

Describe the key branches of the facial nerve as it passes through the temporal bone, then through the pterygopalatine ganglion, and how dysfunction can manifest in a patient.

Answer 36

Temporal part of CN VII exists between the internal acoustic meatus and stylomastoid foramen. During this course, it - synapses at the geniculate ganglion - gives branches to the stapedius, and the greater petrosal and chorda tympani branches Consider the course of these branches; - greater petrosal synapses in the PPG, travelling via the zygomatic nerve (e.g. through V1/2) to supply the lacrimal duct, mucosa of the ant 2/3 tongue (supplying parasympathetic; the deep petrosal nerve joins it to supply sympathetic innervation and form the vidian nerve) - chorda tympani travels through the middle ear, then joins V3 - inferior to the stylomastoid foramen, CN VII supplies FACIAL MUSCLES ONLY Therefore, the pathology allows consideration of where the nerve is affected.

Question 37

Name the intrinsic laryngeal muscles and their primary function in moving the vocal cords.

Answer 37

Arytenoids - adduct vocal cords Lateral cricoarytenoids - adduct vocal cords Posterior cricoarytenoids - abduct vocal cords Thyroarytenoids - relaxes the vocal cords (e.g. lower pitch) Cricothyroids - tenses the vocal cords (e.g. higher pitch)

Question 38

The anterior neck muscles are centred around the hyoid and their names are based on their attachment to other structures. Name the 4 main suprahyoid and 4 main infrahyoid muscles.

Answer 38

Suprahyoid: - digastric - myohyoid ('molar teeth' to hyoid) - stylohyoid (styloid process of temporal bone to hyoid) - geniohyoid (genio = chin, so mandible to hyoid) ------------------------- Infrahyoid: - sternohyoid (sternum, directly to hyoid) - thyrohyoid (thyroid cartilage to hyoid) - omohyoid (omo meaning shoulder, to hyoid) - sternothyroid (sternum to thyroid cartilage)

Question 39

Describe how the vagus nerve (CN X) supplies the larynx and name its primary branches.

Answer 39

- superior laryngeal branch; gives off internal and external branches. the internal branch supplies the supraglottis - recurrent laryngeal branch (left; aortic arch. right; subclavian vein) passes through the thyroid and trachoesophageal groove to become the inferior laryngeal nerve after it passes the inferior constrictor muscle. It supplies all laryngeal muscles EXCEPT THE CRICOTHYROIDS

Question 40

Name the components of Waldeyer's ring.

Answer 40

Palatine tonsil ('the' tonsils), pharyngeal tonsil (adenoid), and lingual tonsil (tongue)

Question 41

Name the four muscles of mastication, their function, and their joint innervation.

Answer 41

Temporalis, medial pterygoid (closes jaw) Masseter, lateral pterygoid (opens jaw) All innervated by the mandibular branch of the trigeminal nerve (V3)

Question 42

Name the tongue muscles and their innervation, along with the pharyngeal muscles (2 layers, 3 muscles each)

Answer 42

Palatoglossus (CN X), styloglossus, genioglossus, and hyoglossus (CN XII) Layers - outer circular, inner longitudinal - superior, middle, outer constrictors - stylo-, salpingo-, palatopharyngeal

Question 43

Name the muscles of the soft palate.

Answer 43

Palatoglossus, musculus uvulae, tensor veli palatini, levator veli palatini

Question 44

Name the main supplies of the glossopharyngeal nerve. Which muscle does it supply?

Answer 44

Parotid gland (via otic ganglion) Palatine/lingual branches (palate, tongue) Carotid sinus (conveying information from the chemo- and baroreceptors from the carotid bodies) The only muscle supplied by CN IX is the stylopharyngeus.

Question 45

What is formed from the first pharyngeal arch?

Answer 45

CN V Meckel cartilage - incus, malleus, mandible, squamous portion of temporal bone, maxilla, and zygomatic bone External acoustic meatus, middle ear

Question 46

What is formed from the second pharyngeal arch?

Answer 46

CN VII Reichart cartilage - stapes, styloid process, stylohyoid, lesser horn of hyoid, upper hyoid body Palatine tonsil

Question 47

What is formed from the third pharyngeal arch?

Answer 47

CN IX (stylopharyngeus) Greater horn of hyoid, lower hyoid bone Inferior parathyroid glands, thymus

Question 48

What is formed from the fourth and sixth pharyngeal arches?

Answer 48

``` 4th: CN X (superior laryngeal branch) Superior parathyroids, ultimobranchial body (which forms the thyroid and C-cells) 6th: CN X (recurrent laryngeal branch) ```

Question 49

Name the key aspects of the pharyngeal arch.

Answer 49

cleft (outer, ectoderm), mesenchyme (main body), pouch (inner, endoderm). The mesenchyme contains a cartilage, artery, and nerve.

Question 50

Describe the embryology of the tongue.

Answer 50

Develops in the 4th week by two lateral and one midline swelling. The anterior mucosa is derived from CN V3 (first arch) and the posterior by CN IX (third arch), while occipital somites develop into myoblasts and are supplied by CN XII.

Question 51

Describe the embryology of the palate.

Answer 51

Nasal pits deepen and penetrate into mesenchyme with forward growth of the frontonasal prominence. They are connected to the intermaxillary segment by nasal fins, which develop into the nasal sac. The cavities develop and communicate with the oral cavity via primitive choanae. Right and left palatal shelves fuse centrally, expanding anterior and posterior to form the incisor foramen