Flashcards in Clinical correlations from Gross Anatomy Deck (65)
What are the layers of the scalp?
-loose connective tissue
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?
Which sinuses normally drain their blood into the confluence of sinuses?
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?
-anterior: frontal lobe
Mumps is a viral infection of which 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?
Which nerve innervates the skin of the forehead?
Which nerve innervates the skin of the lower eyelid?
Which nerve innervates the skin of the cheek?
Which nerve innervates the lower lip?
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?
-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
Identify the bones that make up the opening and the areas the opening connects: superior orbital fissure
-between greater and lesser wings of the sphenoid
-communicates with middle cranial fossa
Identify the bones that make up the opening and the areas the opening connects: inferior orbital fissure
-between greater wing of the sphenoid and maxilla
-communicates with infra temporal fossa and pterygopalatine fossa
Identify the bones that make up the opening and the areas the opening connects: supraorbital notch (foramen)
-communicates with forehead
Identify the bones that make up the opening and the areas the opening connects: infraorbital groove
-communicates with infraorbital foramen anteriorly and pterygopalatine fossa posteriorly
Identify the bones that make up the opening and the areas the opening connects: nasolacrimal canal
-in lacrimal bone
-communicates with nasal cavity
What is Sjogren's syndrome?
-systemic autoimmune disease in which immune cells attack and destroy the lacrimal and salivary glands
-affects mainly women
-symptoms: dry mouth and dry eye
-treatment: tear replacement therapy, plugging tiny openings that drain tears from medial corner of the eye
Describe the innervation of the parotid gland.
-secretion of saliva: parasymp control from CN IX glossopharyngeal
-para/pre from IX pass through foramen oval to synapse in otic ganglion (on mandibular nerve)
-para/post hitchhike with auriculotemporal nerve to parotid gland
What are the components of the chorda tympani nerve? Trace its course.
-components: parasymp, taste
-from facial nerve, joins lingual nerve as it enters the intratemporal fossa, para/pre synapses on submandibular ganglion
-para/post goes to innervate submandibular and sublingual salivary glands
-taste goes to anterior 2/3 of the tongue
What are the clinical symptoms of damage to the lingual nerve after the chord tympani joins it?
-lost of SS, taste, and salivation to anterior region of tongue
Which nerve is susceptible to damage with a jaw dislocation?
Damage to the auriculotemporal nerve due to a fracture in the neck of the mandible would result in what deficits?
-para/post to parotid gland
-SS to side of face anterior to external ear and continuing superiorly to temporal region
What are the borders of the anterior triangle of the neck?
midline of neck
inferior border of mandible
Contains within borders the submandibular triangle
What is the laryngeal prominence?
Adam's apple of the thyroid cartilage
Where would you perform an emergency tracheostomy?
In cricothyroid membrane
What are sublingual caruncles?
-small bumps just lateral to the base of the frenulum that mark opening sod the submandibular ducts
What are the 6 pericervical collar lymph nodes?
1. submental nodes
3. buccal nodes
4. parotid nodes
5. retro-auricular nodes
6. Occipital nodes
Describe the strap muscles and their positions relative to each other.
1. sternohyoid-most medial, longest muscle
2. omohyoid-lateral to sternohyoid
3. sternothryoid and thyrohyoid: looks in series with each other and deep to sternohyoid
What innervates the strap muscles?
Ansa cervicalis from C1, 2, 3
-innervation to thyrohyoid hitchhikes with CN XII, so looks like it is innervated by XII, but it is not
What is contained within the carotid sheath?
1. common carotid
2. internal jugular vein
3. vagus neves
4. ansa cervicalis embedded in the connective tissue of the sheath
Which is more lateral, the IJV or common carotid?
-needle and catheter may be inserted into IJV for diagnosis or therapeutic purposes
What is contained in the carotid sinus?
Baroreceptors: sense changes in blood pressure (viscerosensory)
-innervated by CN IX
-there is also a carotid body that has chemoreceptors innervated by viscerosensory axons from CN IX to detect changes in oxygen levels
What nerves can be damaged in a thyroidectomy?
-recurrent laryngeal nerves that course adjacent to the inferior thyroid arteries
-external branches of the superior laryngeal nerves parallel to the superior thyroid arteries
-damage to these nerves can cause paralysis of vocal muscles
What does the external branch of the superior laryngeal nerve innervate?
Cricothyroid muscles (SM)
What does the internal branch of the superior laryngeal nerve innervate?
viscerosensory (cough reflex), taste, parasymp to the larynx and epiglottis
-pierces thyrohyoid membrane to enter larynx
What is the difference between a cricothyrotomy vs tracheostomy?
-Cricothyrotomy: emergency procedure as last resort in life threatening situations such as airway obstruction. Performed at cricothyroid membrane because it is below the level of vocal cords, narrowest part of airway, where food is often stuck
-Tracheostomy: surgical opening in trachea with goal of inserting a tube to maintain patent airway
What are the borders of the submandibular triangle?
Anterior and posterior bellies of digastric muscle, and inferior margin of mandible.
What supplies the innervation to the anterior belly of the digastric muscle?
Mylohyoid nerve from V3
What are the fascia layers that are encountered in an emergency cricothyrotomy? Which organ lies anterior to the trachea and may be inadvertently damaged during an emergency tracheotomy? Which part of this organ lies in the midline?
1. superficial investing fascia
2. deep investing fascia
3. pre-tracheal fascia
Anterior organ: thyroid gland
midline: thryoid isthmus and pyramidal lobe
Which arteries and veins would need to be ligated before removing the thyroid gland? what is the origin of these arteries?
-right and left superior thyroid arteries and veins. Arteries arise from external carotid.
-right and left inferior thyroid arteries and veins, from thyrocervical trunk off the subclavian artery (these arteries may be spared)
Which three branches of the external carotid artery and internal carotid anastomose in the scalp?
1. Occipital artery
2. superficial temporal artery
3. supraorbital (from internal carotid)
What is Zenker's Diverticulum?
-Weakness in the pharynx where inferior pharyngeal constrictor meets cricopharyngeus muscle
-under high pharyngeal pressure, a mucosal diverticulum can form there
-causes: spasm of cricopharyngeus and uncoordinated swallowing
touching mucosa on back of throat with anything other than food or liquid elicits which reflex? due to which nerve?
gag reflex, via VS from glossopharyngeal CNIX
Stimulation of the mucosa of the vestibule of the larynx by any solid substance will elicit which reflex? via nerve?
-internal branch of the superior laryngeal (CNX)
What is the sensory limb of the cough reflex if elicited in the infraglottic region?
-recurrent laryngeal nerve (CNX)
What nerve conveys pain sensations to the epiglottic valleculae? to the piriform recess?
-epiglottic valleculae: CN IX
-piriform recess: recurrent laryngeal CN X
What are the nerve components of the recurrent laryngeal nerves and what do they innervate? Which artery crosses each recurrent nerve as the nerves ascend in the groove between the esophagus and trachea?
-SM to intrinsic muscles of the larynx
-VS pain and reflex to infraglottic mucosa
-para/post to mucuous glands in infraglottic mucosa
-They cross the inferior thyroid artery
Which sinuses are typically involved in a blowout fracture of the orbit? Which extraocular muscle is commonly entrapped by a blowout fracture into the maxillary sinus?
Ethmoid medially and maxillary inferiorly
How can a tumor or chronic infection of the sphenoid sinus lead to a loss of lacrimation and dry nasal mucousa?
Nerve of pterygoid canal courses within floor of sphenoid sinus. Bone is thin, the tumor/infection can affect there nerve, which carries para to lacrimal gland and to nasopalatine nerve to nasal mucosa.