Clinical correlations from Gross Anatomy Flashcards
What are the layers of the scalp?
- skin
- connective tissue
- aponeurotic layer
- loose connective tissue
- periosteal layer
Why do scalp wounds bleed profusely? What is the separation plan typically when parts of the scalp are torn away in an accident? Which layer of scalp do infections spread easily through?
- scalp arteries that are lacerated and held open by the dense connective tissue layer through which they course and there are rich anastomoses
- separation plan is usually the loose connective tissue
- infections spread through the loose connective tissue layer because this layer allows movement of the scalp relative to the skull
What causes epidural hematomas?
- torn middle meningeal arteries
- since it’s an arterial bleed, blood accumulates quickly
- associated with skull fractures
What causes subdural hematomas?
- cerebral veins that are torn
- caused by sudden displacement of the brain inside the skull
- blood accumulates slowly since flow is under low pressure
What causes subarachnoid hematomas?
- cerebral arteries that are ruptured
- e.g. berry aneurysm that leads to hemorrhagic stroke
What is a uncal herniation?
- the uncus of the temporal lobe is forced medially over the free edge of the tentorium cerebella and presses against the brainstem
- due to increased intracranial pressure
- can squeeze CN III and affect parasympathetics to the eye
What is a cavernous sinus thrombosis?
- infections that reach cavernous sinus can lead to formation of a clot due to trabecular that slow blood flow thru the sinus
- central vein of the retina drains into the superior ophthalmic vein, which drains into the cavernous sinus. A thrombosis can slow drainage of blood from the retina and cause blindness
Which cranial nerves are located within the wall of the cavernous sinus?
-CN 3, 4, V1, VI
Which nerve is located within the cavernous sinus adjacent to the lateral side of the internal carotid artery?
Abducent nerve
Which sinuses normally drain their blood into the confluence of sinuses?
- superior saggittal
- straight sinus
- occipital sinus
- transverse sinus
Which portion of the brain is associated with the tentorial notch? Which is associated with the posterior cranial fossa? with the middle cranial fossa? with the anterior cranial fossa?
- brainstem
- posterior: cerebellum
- middle: temporal
- anterior: frontal lobe
Mumps is a viral infection of which gland?
- parotid gland
- mumps causes swollen cheeks due to inflammation and edema
Trace the course of the facial artery. Where does the vein lie?
- the facial artery courses obliquely across the anterior aspect of the face from the body of the mandible to the medial angle of the eye
- passes posterior to the angle of the mouth
- facial vein is posterior to the artery
What muscles do the buccal branch of the facial nerve innervate?
-buccinator muscle and obicularis oris
Which nerve innervates the skin on the bridge of the nose?
-V1 Opthalmic
Which nerve innervates the skin of the forehead?
-V1 opthalmic
Which nerve innervates the skin of the lower eyelid?
V2 maxillary
Which nerve innervates the skin of the cheek?
V2 maxillary
Which nerve innervates the lower lip?
V3 mandibular
Where is the best place to compress the facial artery to reduce bleeding?
-as it crosses the body of the mandible just anterior to the masseter muscle
Where is the best location to reduce bleeding from a scalp wound to the side of the head?
- bleeding from superficial temporal artery
- compress it where it crosses the zygomatic arch immediately anterior to the external auditory meatus
- also more superiorly where it crosses on the cranial vault
Which arteries anastomose with the superficial temporal artery?
-supraorbital and occipital arteries
Where does the parotid duct terminate in the oral cavity?
-opposite the upper second molar
What are the bones that make up the walls of the orbit?
- orbital roof: frontal and lesser wing of the sphenoid
- orbital floor: maxilla
- medial wall: ethmoid and lacrimal
- lateral wall: zygomatic and greater wing of the sphenoid
What nerves does the corneal reflex test?
- afferent: V1
- efferent: facial nerve that innervates the orbicular is oculi
Identify the bones that make up the opening and the areas the opening connects: optic canal.
- in lesser wing of sphenoid
- communicates with middle cranial fossa