Head Clinical Supplement Flashcards
What is involved in an anterior fossa fracture?
Involves the cribriform plate or frontal bone
Cribiform plate: epistaxis, leakage of CSF (rhinorrhea), anosmia
Frontal bone: exophthalmos
What is involved in a middle fossa fracture?
Temporal bone – may damage CN VII and VIII; leakage of CSF from the external meatus
Involving cavernous sinus – CN III, IV, VI
What is involved in a posterior fossa?
Involvement of the jugular foramen may affect CN IX, X and XI
What is a battle sign involving posterior fossa?
Bruising over the mastoid process that occurs ~2 days after a fracture in the posterior cranial fossa
What is most commonly involved in a facial fracture?
Nasal, zygomatic arch, maxilla, orbital fractures, mandible, temporal bone, mastoid process
What is a blowout fracture of the orbit?
Result in bleeding into maxillary sinus; may entrap inferior rectus (restricted upward gaze) or inferior oblique muscle and/or lacerate the infraorbital n. (sensory loss on lower eyelid & maxilla)
What will a medial orbital fracture impact?
Impact the ethmoid»_space; sphenoid sinus; can entrap the
medial rectus muscle (restricted lateral gaze)
What does the neck of mandible fracture endanger?
Facial and auriculotemporal ns.
What does the superior ramus endanger?
Inferior alveolar and lingual ns.
What are the signs/symptoms of temporal bone fracture?
Battle sign, facial paralysis, sensorineuronal hearing loss (disruption of ossicular chain), dizziness, leakage of CSF from the external auditory meatus, hemorrhage (epidural or subarachnoid)
What will a mastoid process fracture endanger?
Facial nerve as it exits stylomastoid foramen
What is Eagle Syndrome?
- results from elongation of the styloid process or calcification of the stylohyoid ligament
- can compress cranial nerves V, VII, IX and X
- can compress the carotid artery, resulting in:
▪ visual difficulties, syncope, carotid dissection
▪ pain (eye, referred) due to irritation of the sympathetic plexus
What is the arterial support of anterior cranial fossa?
Anterior meningeal artery from anterior + posterior ethmoidal arteries
What is the arterial support of middle cranial fossa?
Middle meningeal artery + accessory meningeal artery from maxillary artery
What is the arterial support of posterior cranial fossa?
Posterior meningeal artery from ascending pharyngeal artery, branches from the vertebral, occipital and ascending pharyngeal arteries
What is the innervation of the anterior fossa?
CN V1 (from anterior + posterior ethmoidal nerves)
What is the innervation of the middle fossa?
CN V2 and CN V3
What is the innervation of the posterior fossa?
C1-3 + CN X (meningeal irritation here can cause NAUSEA)
What is the innervation of the falx cerebri?
CN V1
What is the innervation of the tentorium cerebelli?
CN V1
Where can the facial artery be palpated?
As it crosses the inferior border of the mandible, anterior to the masseter
Where can the superficial temporal artery be palpated?
Where it crosses the zygomatic arch, anterior to the ear
Why do scalp lacerations bleed profusely?
The dense connective tissue tends to hold cut vessels open
(they would otherwise collapse) and there are abundant anastomoses between the arteries supplying the scalp, especially the superficial temporal artery (across the midline) and branches from the occipital artery
Deep scalp lacerations tend to…
Gape - the epicranial aponeurosis (when cut, especially in the coronal plane) tends to retract and hold wounds open
Infections within the deep, loose connective tissue can spread
Into the cranial cavity via emissary veins -> causes meningitis
What is the Danger Triangle? Why is it named so?
a. a triangular area extending from the corners of the mouth to bridge of the nose
b. the veins draining the skin in this region (facial and ophthalamic v.) have connections to the cavernous
sinus
c. skin infections in this region can spread through venous channels:
- intracranially to the cavernous sinus (see #43)
- to the infratemporal fossa and the pterygoid venous plexus
What does the parotid duct pierce?
Buccinator muscle, enters oral cavity opposite the 2nd maxillary molars -> can be blocked by crystallized secretions
What CN transverses this gland and is in danger during a parotidectomy?
CN VII
What is the parasympathetic innervation of parotid?
By CN IX (otic ganglion) with postganglionic axons “hitchhiking” along the auriculotemporal nerve
What is the sympathetic innervation of parotid?
Superior cervical ganglion (T1-T4) via branches from external carotid nerve
What is the sensory innervation of the parotid capsule?
CN V (refers pain to ear/TMJ)
What is Frey’s syndrome?
Gustatory sweating -> may occur following surgical removal of the parotid gland or trauma (injury to auriculotemporal nerve); injured/cut parasympathetic axons grow out to innervate sweat glands on the face; seeing/smelling food = sweating on the face
What joint is the temporomandibular joint?
Combination plane/hinge joint with fibrocartilaginous disc (meniscus)
What muscles depress the mouth?
Anterior digastric, mylohyoid, inferior head of lateral pterygoid
What muscles elevate the mouth?
Masseter, temporalis, medial pterygoid, lateral pterygoid
Dislocation of mandible
Most often occur anteriorly (during depression) – the head of the mandible slides anteriorly over the articular tubercle; mandible remains depressed and cannot be elevated/closed
What is the sensory innervation of mandible?
Auriculotemporal nerve
What is the sign/symptom of mandible dislocation?
Jaw/ear pain»_space; headache > neck shoulder pain (worsened with chewing), locking of jaw, ear clicking or popping (displacement of disc)
What is the patient presentation of mandibular dislocation?
Restricted jaw opening (spasm of masseter, medial pterygoid), clicking/popping, tenderness, crepitus, lateral deviation of mandible
What does normal mean for extraocular muscles?
EOMI = extraocular muscles are intact
What does abduction test?
Lateral rectus (CN VI)
What does adduction test?
Medial rectus (CN III)
Adduction + depression tests…
Superior oblique (CN IV)
Adduction + elevation tests…
Inferior oblique (CN III)
Abduction + depression tests…
Inferior rectus (CN III)
Abduction + elevation tests…
Superior rectus (CN III)
From primary gaze, elevation tests…
Superior rectus and inferior oblique
From primary gaze, depression tests…
Inferior rectus and superior oblique
What is the accommodation? What is it controlled by?
a. changes that occur for near vision; all controlled by CN III:
- bilateral contraction of the medial rectus (GSE)
- constriction of the pupil (GVE)
- contraction of ciliary muscle (GVE) and subsequent thickening of the lens (= more refractive power)
What does PERRLA stand for?
Pupils are equal, round and reactive to light and accommodation
What is anisocoria?
Left-right asymmetry in the size of the pupils
What do 10-20% of patients have?
Benign anisocoria
What occurs in a CN III injury?
- severe ptosis (levator palpebrae), mydriasis (dilated pupil = unopposed action of dilator pupillae)
and diplopia (unopposed action of LR and SO = eye “down and out”) - more pupil asymmetry in LIGHT
What occurs in Horner’s Syndrome?
Sympathetic injury
- mild ptosis (paralysis of superior tarsal muscle), miosis in affected eye (constricted pupil =
unopposed action of constrictor pupillae)
- more pupil asymmetry in DARK
What is Argyll-Robertson pupil?
associated with neurosyphilis (“prostitutes pupil”), “light-near dissociation” = pupils respond to accommodation but not light (accommodate, but don’t react)
What is Marcus Gunn pupil?
in swinging flash light test, when light is moved from normal eye to affected eye, the affected eye appears to dilate
Pupillary reflex
IN -> retina, CN II
OUT -> CN III
Corneal reflex
IN -> CN V
OUT -> CN VII
Tearing reflex
IN -> CN V
OUT -> CN VII
Jaw-jerk reflex
IN -> CN V
OUT -> CN V
Blink to Startle reflex
IN -> retina , CN II
OUT -> CN VII
What is required for normal function of larynx?
Valsava maneuver
What is epiglottitis?
Inflammation of the epiglottis, can result in difficulty breathing and swallowing; in severe cases can completely obstruct the airway