Orbit And Cavernous Sinus CIS

Question 1

Describe parasympathetic innervation of the lacrimal gland

Answer 1

Superior salivatory nucleus sends preganglionic fibers with CNVII, greater superficial petrosal nerve, and vidian n
Fibers synapse in sphenopalatine ganglion (SPG)
Postganglionic fibers from SPG travel via V2 and lacrimal nerve to innervate lacrimal gland

Question 2

Describe sympathetic innervation to lacrimal gland

Answer 2

Sympathetic trunks sends preganglionic fibers to superior cervical ganlgion
Gives rise to deep petrosal nerve and greater superficial petrosal nerve. These fuse to become vidian nerve
Postganglionic fibers also travel through SPG but do NOT synapse

Question 3

Why does your nose run when you cry?

Answer 3

Lacrimal sac which fills with tears is continuous with nasolacrimal duct
Nasolacrimal duct goes through nasolacrimal canal before opening into inferior nasal meatus.

Question 4

47 year old male presents with inability to open right eye. No other neuro symptoms or history of current symptoms or trauma. On physical exam, doc opens patient’s right eye and notes that the right pupil is unreactive to pen light. In what position will his eye be found in when looking straight ahead? Loss of innervation to what muscle causes complete ptosis in this patient?

Answer 4

Down and out (to the right)

Levator palpebre superioris

Question 5

What are the classic signs and reasons of oculomotor nerve palsy?

Answer 5

Downward and outward gaze: due to loss of extraocular muscle innervation. Innervation to SO and LR intact
Dilated pupil: loss of parasympathetic innervation to pupil
Complete ptosis: loss of innervation to levator palpebrae superioris

Question 6

Describe innervation of extra ocular muscles

Answer 6

Superior oblique m: trochlear n (CNIV)
Lateral rectus m: abducens n (CNVI)
Superior rectus, inferior rectus, medial rectus, inferior oblique: oculomotor nerve (CNIII)
SO4, LR6, all the rest 3

Question 7

Looking where are not cardinal signs? Why?

Answer 7

Looking straight up/down

Does not isolate one muscle

Question 8

Describe levator palpebrae superioris and complete ptosis

Answer 8

Levator palpebrae superioris inserts into palpebral fascia and skin of upper lid
Innervated by GSE fibers of oculomotor III nerve
Destruction of III nerve or one of its branches to this muscle results in paralysis of LPS and complete ptosis

Question 9

Mydriasis seen in oculomotor nerve palsy is caused by disruption of what neural pathway?

Answer 9

Parasympathetic fibers to sphincter pupillae muscle

Question 10

Pupillary constriction (sphincter pupillae m) and thickening of lens (near vision, ciliary m) are ___ responses

Answer 10

Parasympathetic

Question 11

Describe what happens if the nerve is injured to the extra ocular muscles?

Answer 11

Levator palpebrae superioris: complete ptosis
Superior rectus: inability to abduct and elevate affected eye
Medial rectus: inability to adduct affected eye
Inferior rectus: inability to abduct and depress affected eye
Inferior oblique: when adducted, cannot elevate affected eye
Superior oblique: when adducted, cannot depress affected eye
Lateral rectus: inability to abduct affected eyed

Question 12

82 year old presents with sign of stroke. With light reflex exam, direct light reflex is intact bilaterally, but there is a loss of consensual light reflex bilaterally. Which area is most likely infarcted in this patient?

Answer 12

Posterior commissure

Question 13

57 year old male presents with insidious onset of persistent cough and malaise. Upon physical exam, doc notes slight ptosis and abnormal pupil finding in right eye. X-ray shows mass in apex of right lung. What is causing his abnormal pupillary finding?

Answer 13

Decrease in sympathetic outflow to dilator pupillae muscle

Question 14

Describe signs and causes of Horner’s syndrome

Answer 14

Signs: triad of slight ptosis, miosis, and anhydrosis
Causes: mass effect (Pancoast tumor), aortic or carotid artery aneurysm, idiopathic or congenital

Question 15

Describe tarsal muscles and partial ptosis

Answer 15

Tarsal muscle (of Muller) is smooth muscle that inserts on tarsal plate of upper lid
Innervated by postganglionic sympathetic fibers (originated at T1)
Damage to nerve causes partial ptosis

Question 16

21 year old female presents for STD panel. She has history of multiple STI’s. On physical exam, doc notes unequal pupil sizes. Blood culture and dark field microscopy revealed Treponema pallidum. Upon eye exam, what findings are expected?

Answer 16

Pupil does not constrict with light but constricts when an object is brought toward the eyes

Question 17

Describe Argyll-Robertson pupil

Answer 17

Result of syphilis infection
Pupils are unreactive to light but constrict during accommodation
Due to destruction of pretectum
*Prostitute’s eye: accommodating but unreactive**

Question 18

Described accommodation

Answer 18

Cortically-mediated response: frontal eye field, corticotectal fibers, Edinger-Westphal and oculomotor nuclei
Triad of accommodation: convergence of gaze, pupillary constriction, thickening of lens
Near vision

Question 19

Describe Holmes-Adie pupil

Answer 19

Tonically slow reacting pupil to light
Normal response to accomodation
Usually caused by inflammation residual from infection or lesion of ciliary ganlgion

Question 20

17 year old male presents to ED after being slammed in the face during batting practice. On physical exam, patient was conscious, and neuro exam was WNL. He had swelling and erythema on lateral aspect of orbito-zygomatic region. Doc pages for emergency surgery. What vessel is most likely damaged?

Answer 20

Arterial Circle of Iris

Question 21

What is hyphema?

Answer 21

Presence of blood in anterior chamber of eyeball usually due to trauma and rupture of great arterial circle of the iris.
Usually represents a serious medical condition

Question 22

Describe subconjunctival hemorrhage

Answer 22

Usually due to rupture of deep pericorneal plexus

Bleeding is restricted to subconjunctival tissue or bulbar fascia

Question 23

Describe conjunctivitis

Answer 23

Brick-red inflammation or irritation of conjunctiva
Usually more noticeable at fornices
When touched, redness does not fade, and vessels are movable
Vessel involved: superficial pericorneal plexus

Question 24

25 year old male is brought to ED after being ejected from car in MVA. CT rules out brain hemorrhage. CT reveals a facial fracture involving orbital floors bilaterally and reveals a misaligned maxilla. Otolaryngologist, plastic surgeon, and maxillofacial surgeon are paged for consult. What type of fracture does this patient present with?

Answer 24

Le Fort 3

Question 25

Describe Le Fort 1 classification of maxillary fractures

Answer 25

Horizontal maxillary fracture, separating teeth from upper face
Fracture line passes through alveolar ridge, lateral nose, and inferior wall of maxillary sinus

Question 26

Describe Le Fort 2 classification of maxillary fractures

Answer 26

Pyramidal fracture, with the teeth at the pyramid base, and nasofrontal suture at its apex
Fracture passes through alveolar ridge, lateral walls of maxillary sinuses, inferior orbital rim, and nasal bones

Question 27

Describe Le Fort 3 classification of maxillary fractures

Answer 27

Craniofacial disjunction

Fracture line passes through nasofrontal suture, maxillo-frontal suture, orbital wall, and zygomatic arch

Question 28

Describe blow out fractures (orbital floor fractures) clinical findings

Answer 28

Enophthalmos: due to increased orbital volume (posterior displacement of eye)
Diplopia: due to extraocular muscle entrapment
Orbital emphysema: especially when fracture is into adjacent paranasal sinus
Malar region numbnss: due to injury to inferior orbital nerve

Question 29

58 year old female goes to urgent care when “everything just when dark” in right eye. Onset was abrupt and painless. HPI reveals Hx of atherosclerotic disease. Neuro exam normal besides complete vision loss in right eye. There is a cherry red macula seen on fundoscopic exam. Occlusion of what artery would most likely cause this patient’s presentation? Why?

Answer 29

Central retinal artery

Question 30

41 year old female presents to PCP after suffering “lightning like” pain in her cheek area after brushing her teeth. Pain is unpredictable and lasts only seconds before subsiding. No remarkable medical history. When showing distribution of pain, she points to her left preauricular and temporal area. Which nerve supplies sensory innervation to area affected in this patient?

Answer 30

Mandibular nerve

Question 31

Describe trigeminal neuralgia (tic douloureux)

Answer 31

Chronic pain condition that affects CNV
Classic form causes extreme, sporadic, sudden burning or shock-like facial pain that lasts from a few seconds to as long as two minutes per episode
Intense flashes of pain can be triggered by vibration or contact with cheek like brushing teeth, eating, drinking, talking, etc

Question 32

Describe branches and exit of ophthalmic nerve (V1)

Answer 32

(All sensory)

Nasociliary
Frontal (supratrochlear and supraorbital)
Lacrimal

Exits superior orbital fissure

Question 33

Where does maxillary (V2) exit?

Answer 33

(All sensory)

Foramen rotundum

Question 34

Where does mandibular (V3) exit an innervate?

Answer 34

(Sensory and motor)
Exits foramen ovale
Supplies muscles of mastication

Question 35

41 year old female presents two months after elective endoscopic forehead lift. She complains of persistent eye dryness and irritation in her right eye. On physical exam, physician notices her right eyelid is held up slightly when asked to closer her eyes. When doc places cotton swab in left canthus, her left eyelid blinks fully, but her right does not. When the swab is placed in right canthus, right eye does not fully close, but left fully closes. If nerve damage is causing this patient’s presentation, what is the most likley damaged nerve?

Answer 35

Temporal branch of VII

Question 36

Describe innervation of corneal reflex

Answer 36

Afferent: nasocillary nerve (V1)
Efferent: temporal and zygomatic branches of VII
In by 5, out by 7

Question 37

18 year old presents after MVA. Other driver says that pt “pulled right out in front of me like he didn’t even see me.” On physical exam, patient is awake but anxious. Neuro exam shows temporal eye field defects. CT shows large mass. Doc diagnoses him with pituitary macroadenoma that has infiltrated cavernous sinus and is pressing upon optic chiasm, causing peripheral vision loss. As the tumor expands into cavernous sinus, what structures are at risk of being impaired?

Answer 37

Cranial nerve III, IV, VI

Internal carotid artery

Question 38

50 year old male presents with irritation of left eye for past 2 weeks. Irritation is not relieved with eye drops. On exam, his left eye is erythematous and dry. He has no history of these symptoms, has NKA, and is not taking medications. He is diagnosed with lacrimal gland dysfunction due to a decrease in parasympathetic innervation. What is this pathway?

Answer 38

Preganlgionic fibers synapse in sphenopalatine ganglion