Head and Neck: 2nd Term Flashcards
What branches of the internal carotid a. supply the scalp (2)? via what artery? Give their relation to one another.
Supraorbital (lateral), supratrochlear (medial), via ophthalmic branch of internal carotid a.
What provides sensory innervation behind the auricle (4) and where from?
Cervical plexus: Lesser occipital (C2) – scalp and neck posterior to auricle. Greater Auricular (C2-C3) –Skin over angle of mandible, over parotid gland, maxillary process, and bottom 2/3 of auricle.
Dorsal Rami C2-C3: Greater occipital n. (C2) –posterior most cranium. Third occipital n. (C3) – Area posterior to lesser occipital innervation. These aren’t from cervical plexus
What muscle of facial expression is not innervated by one of the five main branches of CN VII? What other muscle is innervated by this same nerve/branch?
Occipital belly of occipitofrontalis —> Posterior auricular branch of VII.
Auricularis posterior
What are the three parts to orbicularis oculi and what are their actions? What is the origin of the first two?
1.) Orbital part: Closes lids tightly/squinting (most superior part, so think that it has the most downward force).
ORIGIN: Medial part of medial palpebral ligament.
2.) Palpebral part (eyelid part): Closes lids gently.
ORIGIN: Lateral part of medial palpebral ligament.
3.) Lacrimal part: Dilate lacrimal sac.
#82 Lobo
What is the action of corrugator supercilii?
Draws eyebrows medially (demonstrating concern or worry), creating vertical wrinkles above nose.
- ) What is the origin of buccinator?
2. ) What is its shared action and with what muscle?
- ) Pterigomandibular raphe.
2. ) Prevents accumulation of food in the vestibule of mouth —> shared with orbicularis oris.
What is the terminal branch of the facial artery?
Angular artery at bridge of nose.
Which two nerves supply sensation to the posterior-most portion of the scalp? Describe them and their roots.
Dorsal rami of C2-C3, Not part of cervical plexus. Greater occipital (C2): Occipital scalp. 3rd occipital (C3): Lower occipital and sub-occipital regions. #12 njp, #35
Describe the pre- and post-ganglionic PSNS innervation to the parotid gland. What does PSNS stimulation do?
Pre-ganglionic: Inferior salivatory nucleus —> Lesser petrosal n. (Glossopharyngeal n., CN IX) —> Otic ganglion (PSNS ganglion) —post-ganglionic—> Auriculotemporal n. (CN V3) —> Parotid.
PSNS stimulation causes saliva production. #112 lobo
Describe four important relations of the parotid gland (two nerves, one artery, one vein).
1.) External carotid ends, giving off its two terminal branches – Superficial temporal a. and maxillary a.
2.) External carotid vein forms from the superficial temporal vein and maxillary vein.
3.) Auriculotemporal n. (V3) passes through
4.) Facial nerve (CN VII) – parotid plexus within gland; separates it into superficial and deep layers.
#111 lobo
- ) If the right spinal accessory nerve is injured, what SCM actions are compromised?
- ) What other muscle will be affected and how will it manifest?
- ) ipsilateral flexion and CONTRALATERAL ROTATION.
- ) Trapezius –ipsilateral shoulder will droop.
p. 991 Moore
What nerve innervates the skin over the parotid gland? Give its distribution.
Great auricular n. (C2-C3; from cervical plexus). Innervates skin of auricle, over angle of mandible, over mastoid process, and over parotid gland.
In which articular cavities of the TMJ do these movements occur – Gliding (protrusion and retraction), hinge (depression and elevation), rotational movements.
Protrusion/retraction: Upper cavity
Depression/elevation: Lower cavity
Rotation: Lower cavity.
Associate each type of motion at the TMJ with the muscles responsible —> Elevation (3), depression (3), protrusion (3), retrusion (2 –specify fibers), lateral movements/grinding/chewing (3 – specify laterality)
Elevation: Masseter, medial pterygoid, temporalis.
Depression: Lateral pterygoid, supra- and infrahyoids.
Protrusion: Lateral pterygoid, medial pterygoid, masseter.
Retrusion: Temporalis (post. oblique and horizontal fibers), and masseter.
Grinding/chewing/lateral mvmts: Temporal of same side, pterygoids of opposite side, and masseter.
#161 lobo, p.922
Which ligament serves as a swinging hinge for the TMJ? Where does it insert?
Sphenomandibular ligament –into the lingula of the mandible.
What is the intrinsic ligament of the TMJ? What movements does it prohibit/in which direction is it strengthened? What helps it?
Lateral ligament of the TMJ (aka temporomandibular ligament –essentially a thickened capsule at the condylar process) strengthens the joint LATERALLY and, along with the POSTGLENOID TUBERCLE, prevents POSTERIOR DISLOCATION.
What is the TMJs primary passive support?
Sphenomandibular ligament.
Which muscles does the mandibular division of trigeminal (CN V3) innervate (8)?
muscles of mastication (temporalis, medial and lateral pterygoids, masseter) tensor veli palatini, tensor tympani, ant. belly digastric, mylohyoid.
What muscle of mastication is the prime mover in TMJ protrusion? Others involved?
Lateral pterygoid (1˚), masseter, medial pterygoid.
Damage to INTRAarticular disc of TMJ will impede functions of which muscle and why?
LATERAL PTERYGOID because it inserts onto the joint capsule on the coronoid process head.
What are the two potentially dangerous anastomoses with the pterygoid venous plexus?
Anteriorly: w/ Facial a. via deep facial vein.
Superiorly: w/ Cavernous sinus via Emissary veins.
p.921 Moore —> GET THIS STRAIGHT
Between which two muscles does the pterygoid venous plexus lie?
pterygoids and temporalis (p.921 Moore)
What are two important nerve relations to the middle meningeal artery in the infratemporal fossa?
- ) Auriculotemporal n. from V3 forms a loop that m.meningeal passes through (i.e. auriculotemporal n. passes both anterior and posterior to middle meningeal a).
- ) Chorda tympani (of CN VII) passes inferior to middle meningeal as well.
p. 925 Moore, plate 50 Netter, #50 lecture
What nerve(s) provide taste and sensory to the anterior 2/3 of the tongue?
Taste: Chorda tympani n. (from CN VII).
Sensory: Ligual n. (V3).
They join one another in the infratemporal fossa, between the mandible and medial pterygoid, just inferior to the mandibular foramen
What nerve(s) provide sensory and post-ganglionic PSNS innervation to the parotid gland?
Auriculotemporal n. (CN V3) provides BOTH sensory and post-ganglionic PSNS fibers to the parotid gland.
What nerve provides articular (sensory) fibers to the TMJ?
Auriculotemporal n. (CN V3) #54
What are the 5 branches of CN V3 (mandibular div.)? Mnemonic?
BAIL —> Buccal n., Auriculotemporal n., Inferior alveolar n., Lingual n.
What nerve innervates the mandibular teeth and how does it get there?
Inferior alveolar nerve – Enters infratemporal fossa through foramen ovale —> Descends between medial and lateral pterygoids, deep to 1st part of maxillary a. and enters the mandibular foramen to supply mandibular teeth on its side.
plate 50, #56, p.925
What is the relationship between inferior alveolar nerve and lingual nerve in the infratemporal fossa?
Lingual lies ANTERIOR to inferior alveolar nerve —> #57, plate 50.
Describe the two most common TMJ dislocations, i.e. cause(s) and resulting injury.
- ) Most common, a sideways blow to the chin by a clenched hand (fist) when the mouth is open dislocates the TMJ on the side that received the blow.
- ) Anterior dislocation can occur due to excessive contraction of the lateral pterygoids (during yawning or taking a large bite). This causes the heads of the mandible to dislocate anteriorly pass anterior to the articular tubercles
p. 927
To administer a mandibular nerve block, where must one inject? Which nerves will be anesthetized?
In the mandibular notch of the ramus of the mandible (extra-oral approach). It will anesthetize the buccal, auriculotemporal, inferior alveolar, and lingual nerves.
p.927
How is the dura mater of the cranium different from that of the spinal cord?
Consists of two layers in the cranium: (1) Outer periosteal layer (periosteum on inner surface of calvaria) and, (2) Inner meningeal layer –continuous with spinal dura.
Where, generally speaking do the dural venous sinuses exist?
Where the dural layers separate, i.e. between the periosteal and meningeal layers. #4
What is the cause of subdural hematomas? Where do they occur?
Due to rupture of bridging cerebral veins as they pass from the brain surface into the venous sinuses. They occur at the Arachnoid-dura interface. #5, plate 103
What do bridging veins “bridge”?
Neural vasculature and dural sinuses (brain, through arachnoid, meningeal dura layer, into sinuses).
What is the cause of an epidural hematoma? Where does it occur?
Middle meningeal a. rupture. Occurs at the Dura-skull interface.
What layer(s) of dura do the dural folds consist of?
Meningeal only.
- ) Where does the falx cerebri lie, what does it separate, and where does it attach?
- ) Which dural venous sinus(es) lie within it (3)?
Largest dural fold
1.) In the cerebral longitudinal fissure, separating the cerebral hemispheres into right and left. Runs from the crista galli and frontal crest (anterior midline) to the internal occipital protuberance (posterior midline). Ends by becoming continuous with the tentorium cerebelli.
2.) Contains the superior and inferior sagittal sinuses, and the straight sinus.
#9, p.867 Moore
- ) Where does the tentorium cerebelli lie, what does it separate, and where does it attach?
- ) Which dural venous sinus(es) lie within it (3)?
- 2nd largest dural fold*
1. ) A posterior structure that separates the occipital lobes (supporting them) of the cerebrum from the cerebellum (horizontally), and covers the cerebellum. Attaches rostrally to to clinoid process (just above the sella turcica) in the middle cranial fossa, and posteriorly to the temporal (petrous part), occipital, and parietal bones.
2. ) It encloses the transverse sinuses posteriorly, the superior petrosal sinuses anteriorly, and straight sinus along its attachment to the falx cerebri.
p. 870 and 867 moore
What layers of the skull/meninges do the emissary veins span?
They begin in the subdermal layer and span the galea aponeurotica, pericranium, calvaria, dura mater (periosteal layer), and enter the superior sagittal sinus. They connect the veins outside the cranium to the dural sinuses, permitting transmission of infection to these regions because emissary veins are valveless (p.373 BRS, p.870 Moore).
- ) Where does the falx cerebelli lie, what does it separate, and where does it attach?
- ) Which dural venous sinus(es) lie within it?
- ) Lies vertically between the cerebellar hemispheres (separating them), inferior to the tentorium cerebelli in the POSTERIOR cranial fossa. It attaches to the internal occipital crest.
- ) Contains the OCCIPITAL SINUS at its point of attachment.
p. 867 and 869 Moore
- ) Where does the diaphragma sella lie, what does it separate, and where does it attach?
- ) Which dural venous sinus(es) lie within it?
- Smallest dural fold*
1. ) Circular sheet of dura suspended between the clinoid processes in the middle cranial fossa. Partially covers the hypophysial fossa containing the pituitary gland surrounded by cavernous sinus on each side.
2. ) Cavernous sinuses (doesn’t seem like it, no sources mention it, even though it looks like it does)?
p. 867 Moore, #12
All dural sinuses ultimately drain into the _______ sinus, which continues inferiorly as the _______.
Sigmoid sinus, IJV.
p.869, #16
What are the contents of the cavernous sinus superior to inferior? What is a potential risk of injury to this area?
Lateral wall —> CN III (oculomotor), CN IV (trochlear) –middle wall of sinus—> Internal carotid a. lies superior to CN VI (abducens) –back to lateral wall—>CN V1 (ophthalmic), CN V2 (maxillary). *With cavernous sinus thrombosis or internal carotid thrombosis, the abducens nerve is injured, causing diplopia due to unopposed action of medial rectus (affected eye is pulled medially). #26
What are the four communications with the cavernous sinus?
1.) Pterygoid plexus via emissary veins.
2.) Facial vein via deep facial v. and superior ophthalmic v.
3.) Sphenoparietal sinus
4.) Superior petrosal sinus
#182 lobo
What are two consequences of cavernous sinus thrombosis?
1.) Severe pain in the eye and forehead (region of V1 and V2 distribution).
2.) Paralysis of CNs 3, 4, and 6.
#183 Lobo
Where does the inferior sagittal sinus drain into?
Straight sinus
Where does the superior sagittal sinus drain into?
Right transverse sinus (typically)
Where does the straight sinus drain into?
Left transverse sinus (typically)
Where does the occipital sinus drain into?
Confluence of sinuses
Where do the sphenoparietal sinuses drain into?
Cavernous sinuses
Where do the cavernous sinuses drain into?
Superior and inferior petrosal sinuses
Where does the superior petrosal sinus drain into?
Transverse sinuses
Where do the transverse sinuses drain into?
Sigmoid sinus
Where does the inferior petrosal sinus drain into?
Sigmoid sinus
Where do the sigmoid sinuses drain into?
IJV
- ) What do the emissary veins connect?
2. ) Describe their valve status and directionality of blood flow.
1.) Connect dural venous sinuses with veins outside the cranium.
2.) Valve-less with BI-directional flow; though usually direct blood AWAY from the brain.
#28
Which two vessels converge to form the straight sinus?
Inferior sagittal sinus + Great cerebral vein (of Galen).
Lobo said in review
Which vessel connects the posterior auricular v. (or occipital v.) with the sigmoid sinus?
Mastoid emissary vein #33
Which vessel connects the sigmoid sinus with the suboccipital venous plexus?
Posterior condyloid emissary vein #33
The middle meningeal veins drain into what?
Pterygoid venous plexus #35
What is the main blood supply to the dura mater?
Middle meningeal a.
What provides sensory innervation to the infratentorial dura mater?
Upper cervical spinal nerves (C2, C3) #38, #175 lobo
- ) What provides innervation to dura of the tentorium cerebelli and posterior falx cerebri (all of the posterior cranial fossa)?
- ) Anterior falx cerebri (anterior cranial fossa)?
- ) Tentorial n. (CN V1)
- ) Anterior meningeal branches of CN V1.
p. 872, #175 lobo
What supplies innervation to dura of the middle cranial fossa (perhaps including the diaphragm sella)?
Meningeal branches of ethmoidal nerves (V1), and mandibular nerves (V3).
p.872, #175 lobo
The straight sinus is formed at the union of which two dural folds?
Falx cerebri and tentorium cerebelli. #187 Lobo
Describe the vascularity of pia and arachnoid mater
Pia: Highly vascular CT.
Arachnoid: Thin, nonvascular membrane –Loosely attached to dura mater. Separated from pia mater by subarachnoid space.
Describe the epidural space
aka Dura-cranial interface: Not a natural space (between cranium and external periosteal layer of dura), because the dura at this level is attached to the bones. It becomes an extra-/epidural space only pathologically –e.g. When blood from the middle meningeal a. pushes the periosteum away from the cranium.
p.872 Moore
Describe the subarachnoid space
Real space between arachnoid and pia mater –Contains CSF from the ventricular system –Cushions brain. #42
What are intracranial subarachnoid cisterns?
Certain areas (usually near the base of the brain) where the arachnoid and pia mater are widely separated by subarachnoid cisterns containing CSF and arachnoid trabeculae. p.880 Moore
What is the main site of CSF absorption into the venous system?
Arachnoid granulations that protrude up into the superior sagittal sinus and its lateral lacunae.
p.881
Where is CSF produced and by what?
Produced by choroid epithelial cells (modified ependymal cells) of the CHOROID PLEXUSES in the:
- ) ROOFS of the 3rd, and 4th ventricles.
- ) FLOORS of the bodies and inferior horns of the lateral ventricles.
p. 881
A change in the quantity of intracranial blood can occur ONLY through …….
displacement or replacement of CSF.
p.881 Moore
- ) The cerebral hemispheres occupy which cranial fossae?
2. ) What is the space between the two hemispheres called, what occupies this space, and what joins the two hemispheres?
1.) Anterior and middle
2.) Longitudinal cerebral fissure occupied by falx cerebri, and joined by corpus callosum at the base of the longitudinal fissure.
#55
Which part of the brain surrounds the THIRD ventricle between its right and left halves?
Diencephalon (its right and left halves surround the 3rd ventricle).
p.879
Which part of the brain contains the cerebral aqueduct (of Sylvius)?
Midbrain (mesencephalon)
p.879
Who part(s) of the brain contain the 4th ventricle, and which parts of it?
Pons contains a cavity contributing to the superior part of the 4th ventricle.
The medulla contains the inferior portion of the 4th ventricle.
Which cerebral artery is most commonly blocked during a stroke?
Middle cerebral a. #81
What vessel is the most common cause of a subarachnoid hemorrhage/aneurysm? Second most common?
Most common: Posterior communicating a. —> From basilar a. —> From vertebral aa.
2nd most common: Anterior communicating a.
MAKE SURE OF THIS!
The c.carotid and carotid sheath lies immediately deep to what muscular landmark?
Immediately deep to the junction of the clavicular and sternal heads of SCM immediately above the sternoclavicular joint.
