Orbit and nasal cavity Flashcards
What are the bones of the nasal cavity
Nasal bones, maxillae, frontal bone and septum
What are the cartilages that form the nasal cavity
- Lateral
- Major alar
- Septal
What are the three projections of the internal lateral wall and what is their purpose?
- Superior conchae
- Middle conchae
- Inferior conchae
- help direct flow of air through nose
What does the nasal cavity open into?
Nasopharynx
Arterial supply of the nose
Branches from ophthalmic and maxillary
Nerve supply of nose
Olfactory nerve, ophthalmic(v1 and maxillary v2) trigeminal vein
Where are olfaction receptors located
- Epithelium lining the roof and walls of the nasal cavity
How does olfaction occur
- Epithelium secretes a mucus fluid, odoriferous gases are dissolved into the fluid and then detected by the olfactory nerves
What is anosmia
Partial or complete loss of sense of smell
What are paranasal sinuses
- Paranasal sinuses are air filled extensions of the nasal cavity
Where do the paired frontal sinuses drain into?
- Each one opens into anterior part of the middle nasal meatus through which the frontonasal duct which traverses the anterior part of the ethmoid labyrinth
What are ethmoidal cells
- Ethmoidal cells are invaginations in the ethmoid bone and drain into middle meatus(if anterior, or middle) or superior meatus(if posterior)
What do the sphenoidal sinuses in sphenoid bone drain into?
- Sphenoidal sinuses drain into spheno-ethmoidal recess
Where do paired maxillary sinuses drain into?
- Middle meatus
What is the notch on the frontal bone for?
- Cutaneous nerve
What are the three layers of the eye?
Outer fibrous - Sclera and cornea
Vascular - iris
Inner - retina
How do eyes develop
- Optic stalk grows out and lens vesicle grows in
What are the 7 extraocular muscles surrounding the globe of the eye and therefore responsible for moving it?
- Levator palpebrae superioris(elevates the eyelid)
- Superior oblique
- Superior rectus
- Medial rectus
- Lateral rectus
- Inferior rectus
- Inferior oblique
What are the three different axes for rotation of the eye
- Anteroposterior (lateral-medial rotation)
- Transverse axis (elevation-depression)
- Vertical axis (abduction-adduction)
What does the superior rectus do?
- Active in elevation of the eye(also inwards)
- Also draws it towards midline(adduction)
- Top of the eye
What does the inferior rectus do?
- Bottom of the eye
- Active in depression of the eye(also inwards)
What does the medial rectus do?
- Adduction
What does the lateral rectus do?
- Abduction
What does the superior oblique do?
- Attached to the superior part of the eye
- Down and outwards directional movement
What does the inferior oblique do?
- Attached to the inferior part of the eye
- Upwards and out directional movement
What is the type of innervation provided by cranial nerve 3 - oculomotor
- Somatic motor(general somatic efferent) to extra-ocular muscles(except-superior oblique and lateral rectus) and (general visceral efferent-parasympathetic) via cillary nerves to cillary body and sphincter pupillae
Effect of parasymp and smp on the eye
- Parasymp constricts eye
- Symp dilates eye
What is the type of innervation provided by cranial nerve 4 - trochlear
- Somatic motor(general somatic efferent) to superior oblique
What is the type of innervation provided by cranial nerve 6 - abducent
- Somatic motor(general somatic efferent) to lateral rectus
What nerves are compromised when specific eye movements are impaired?
CN 3, 4 and 6
What nerve is likely to be compromised when the pupil is dilated
- CN 3
What nerve is likely to be compromised in ptosis(drooping or falling of upper eyelid)?
- CN 3
Damage to what nerve can cause an abnormal pupil reflex?
- CN3
What are the main nerves supplying the eye
- CNII, III, IV, V1, VI, VII
Blood supply for the eye
- Ophthalmic
- Infra-orbital
- Cerebral
What nerve can be damaged by an aneurysm of cerebral artery?
- CN3
What nerve can be damaged by an orbital fracture
- CN4
What nerve can be damaged by an cavernous sinus lesion?
- CN6
What does the lacrimal apparatus consist of?
- Lacrimal gland(two parts, orbital and palpebral)
What does the lacrimal gland secrete lacrimal fluid into?
- Lacrimal papilla
- Lacrimal sac
- Inferior meatus via nasolacrimal duct
Nerve supply to the lacrimal gland
- Parasympathetic - secretomotor(via facial VII)
- Sympathetic - vasoconstrictive(superior cervical ganglion, via internal carotid)
