11/3 Anatomy And Cranial Nerves!!!! Flashcards
what is the menu or outline of CN modalities?
Sensory Neurons (GS,SS,VS) to CNS (MB,P,M) to Motor Neurons (SM,BM,VM)
what are the three types of sensory neurons of the cranial nerve modalities?
general sensational (GS); Special Sensation (SS); Visceral Senses (VS).
what type of innervation is CN modality of general sensation (GS)?
Pain, temp. touch, vibrations, proprioception.
what type of innervation is the CN modality of special sensation (SS)?
hear, smell, see, taste.
what type of innervation is CN modality of visceral sensation (VS)?
barrel receptors, stretch receptors etc.
where is the primary center of interneurons processing?
the Brain stem:
what are the parts of the brain stem?
the midbrain, the Pons, and the Medulla.
what are the three types of motor neurons of the cranial nerve modalities?
Somatic Motor; Brachial Motor; Visceral Motor.
what type of innervation is CN modality Somatic Motor (SM)?
Voluntary Motor innervation to skeletal muscles derived from somites.
what type of innervation is CN modality of Brachial Motor (BM)?
Voluntary motor innervation to skeletal muscles derived from the brachial arches.
what type of innervation is CN modality Visceral Motor (VM)?
Involuntary motor innervation to salivary glands, tear glands, sweat glands, parasympathetics etc.
what are cranial nerves in the end?
they are a bundle of neurons that can choose from the menu of cranial nerve modalities to provide sensory or motor innervation to the head! One Nerve can provide multiple sensory or motor modalities from the “menu”
what are other terms for GS, SS, VS modalities of cranial nerve innervation?
GS = General Somatic Afferent; SS= Special Visceral Afferent; VS= General Visceral Afferent.
what are other terms for SM, BM, and VM modalities of cranial nerve innervation?
SM= General Somatic Efferent; BM= Special Visceral Efferent; VM= General Visceral Efferent.
Describe the segmental pattern to CN and spinal nerve origins including what nerves come from what part of the brain stem:
Midbrain (CNIII, IV); Pons (CN V, VI, VII, VIII); Medulla (CN IX, X, XI, XII); Then the spinal nerves arise segmentally down the spine from C1 to S5!
what are the names of the Cranial Nerves?
CN1-Olfactory, CNII-Optic, CNIII-Oculomotor, CNIV-Trochlear CNV-Trigeminal CNVI-Abducens CNVII-Facial CNVIII-Vestibulocochlear CNIX-glossopharyngeal CNX-Vegus CNXI-Spinal Accessory Nerve CNXII-Hypoglossal
What is the Name, Origin, Foramen, Function, and clinical complaint/test for CN 1
CNI
Name: Olfactory Nerve
Origin: the ofactory epithelium in the superior part of the lateral and septal walls of the nasal cavity to the primary and association areas of the cerebral cortex
Foramen: Cribriform foramina
Function: Smell
Clinical Complaint/Test: Change in taste, no desire for food, early finding in parkinsons, test each nostril seperate for smell of something smelly!
What is the Name, Origin, Foramen, Function, and clinical complaint/test for CN 2
CNII
Name: Optic Nerve
Origin: The Optic chiasm
Foramen: The Optic Canal
Function: SS: Sight
SM: Levator palpebrae superioris m.; superior, media, ad inferior rectus mm.; inferior oblique mm.
Clinical complaint/test: Monocular blindness, and the only CN affected by M.S. (myelinated by oligodendrocytes). Snellen test; confrontation; Pupillary reflexes (II in, III out); Funduscopy.
What is the Name, Origin, Foramen, Function, and clinical complaint/test for CN 3
CNIII
Name: Oculomotor Nerve
Origin: edinger-westphal nucleus in the forebrain
Foramen: Superior orbital fissure
Function: open eye, eye movement, pupil constrict, lens focus
SM: four of the extraocular muscles (superior rectus, medial rectus, inferior rectus, and inferior oblique) and the levator palpebrae superioris muscle.
VM: PARASYMPATHETIC innervate the ciliary body (lens accommodation) and sphincter pupillae muscle (pupil constriction)
Clinical Complaints/ Test: Mydriasis (dilated pupil), ptosis (droopy eyelid), eyeball down and out, loss of pupillary reflex on the side of the lesion and loss of the accommodation reflex. Use Pupillary response, confrontation
What is the Name, Origin, Foramen, Function, and clinical complaint/test for CN 4
Name: Trochlear Nerve
Origin: from the posterior aspect of the brainstem at the level of the pons
Foramen: Superior Orbital fissure
Function: Innervates the Superior Oblique muscle
Clinical complaint/test
What is the Name, Origin, Foramen, Function, and clinical complaint/test for CN 5
Name: Trigeminal Nerve
CN V-1: opthalmic Division
CN V-2 Maxillary Division
CN V-3: Mandibular Division
Origin: the lateral surface of the Pons
Foramen:
V-1: Superior Orbital Fissure
V-2: Foramen rotundum
V-3: Foramen Ovale
Function: Principal General Sensory supply to the head
V-1: GS to the orbit, cornea and skin of the bridge of the nose, scalp and forehead
V-2: GS to the maxillary face (between the lateral corners of the eye and the cornes of the mouth)
V-3: GS to the lower part of the face and teeth, anterior of tounge, and BM to the muscle of mastication
Clinical compaints/tests: Loss of sensory to any of the three fields of the face; V-1: corneal reflex V-2: upper teeth and skin; V-3: toungue, lower teeth and weekness in chewing. Do the swipe the skin test to check! and the corneal reflex.
What is the Name, Origin, Foramen, Function, and clinical complaint/test for CN 6
Name: Abducens
Origin: Pons
Foramen: superior orbital fissure
Function:
SM: lateral rectus muscle
GS: external acoustic meatus and auricle
SS: anterior two thirds of toungue
Clinical complaints/Tests: CN VI palsy or the inability to move the eye laterally, resulting in diplopia on lateral gaze. do the “H” test!
What is the Name, Origin, Foramen, Function, and clinical complaint/test for CN 7
Name: Facial nerve:
Origin: from the pons and lateral to the Abducens Nerve.
Foramen: Internal acoustic Meatus
Function: Motor innervation to the muscles of facial expression, lacrimal gland, and submandibular and sublingual salivary glands, taste, and anterior two thrids of the tongue.
BM: 2nd branchial arch muscles: facial expression, stapedius, posterior digastricus,a nd stylohoid
VM: glands of the head except parotid gland (CN IX)
SS: taste from anterior 2/3 of the tongue
GS: transmit general sensation from a portion of the external acoustic meatus and auricle.
PARASYMPATHETIC! Saliavation, Lacrimation, Nasa/palatal glands.
Clinical: Bell’s palsy on one side of the face or paralysis on lower 1/3 of one side due to stroke. Test with the smile and raise eyebrow test!
What is the Name, Origin, Foramen, Function, and clinical complaint/test for CN 8
Name: Vestibulocochlear Nerve
Origin: from the Pons and just barely lateral to the Facial nerve.
Foramen: Internal Acoustic meatus
Function: Hearing and equilibrium
SS: hearing/equilibrium
Clinical: Hearing loss on one side, and tinnitus and vertigo; test with the finger rub test w/eyes closed.
What is the Name, Origin, Foramen, Function, and clinical complaint/test for CN 9
Name: Glossopharyngeal nerve
Origin: from the lateral aspect of Medulla and just lateral and caudal the vestibulocochlear nerve.
Foramen: Jugular foramen
Function: motor innervation to the stylopharyngeus muscle and parotid glands and sensory innervation from the carotid body and sinus, posterior one-third of toungue and the auditory tube.
PARASYMPATHETIC! Parotid gland.
it does: BM, VM, GS, SS, VS !
clinical: Palate symmetry, swallow, and gag reflex, vasovagal reflex.
What is the Name, Origin, Foramen, Function, and clinical complaint/test for CN 10
Name: Vegus nerve
Origin: from the lateral aspect of the Medulla
Foramne: Jugular foramen
Function: innervates muscles of the larnx, pharynx, palate in addition to the gut tube, heart and lungs.
VS: larynx, trachea, esophagus, thoracic and abdominal viscera, and aortic arch stretch, chemoreceptors of aortic and carotid bodies.
GS: pinna, laryngopharynx, external acoustic meatus
BM: palatoglossus, laryngeal, and pharyngeal, palatal.
VM: PARASYMPATHETIC! Thoracis/Abd Viscera parasympathetics down to the mid gut!
Clinic: Hoarsness, dificulty swallowing, pallate drops, gag reflex. test with open mouth inspection of hte palate when say ahhhh…
What is the Name, Origin, Foramen, Function, and clinical complaint/test for CN 11
Name: Spinal Accessory Nerve
Origin: from the Medulla
Foramen: Jugular foramen
Function: BM: innervates the trapezius and sterno-cleidomastoid muscles
Clinical: Weakness in turning the head and shoulder drop: test with shoulder shrug or head turn with resistence.
What is the Name, Origin, Foramen, Function, and clinical complaint/test for CN 12
Name: Hypoglossal nerve
Origin: from the Medulla from the groove between the pyrimid and the olive.
foramen: Hypoglossal canal
Function: SM: innervates the toungue muscles (intrinsic and extrinsic muscles)
Clinical: tounge deviation towards the lesion; test by having them press tounge into cheek against resistence.
what is intramemberous bone formation?
Bones that form from dense irregular connective tissue
what is non-communicating (obstructive) hydrocephalus?
Block of the CSF flow that blocks the flow to the arachnoid space.
What is Communicating (non-obstructive) hydrocephalus?
Block of the CSF flow that doesn’t block the flow to the the arachnoid space.
FLAT PiG (hormones of the pituitary)
An acronyme for the pituitary!
From the Anterior:
FSH (follicle stimulating hormone)
LH (lutinizing hormone)
AcH (Adrenal corticotropic hormone)
TH (Thyroid Stimulating Hormone)
PgH (prolactin growth hormone)
From the Posterior:
Anti-dieretic
Oxytocin
Brain vascular supply
ICA, Vertebral – small arteries that go into the brain itself, arterioles, capilaries (blood, brain behavior). Then – Venules, small veins, Dural venous sinuses (periosteal layer and manejial layer),
what are the three hemorrhages that can occur in teh head?
epidural hemorrhage, subdural hemorrhage, subarachnoid hemorrhage.
What are the two types of strokes that can occur?
hemorrhagic; clot
what is the pterion?
the smallest or thinnest part of the skull at the temple
why do we get a discoid shape hemmorage when we have a epideral hematoma?
because the periosteal dura mater will peal away from the skull until it reaches a suture in the skull!
what do the bridging (cerebral) vein bridge?
the cerebrum and dural venous sinus (accross the arachnoid space)
What is the source of a epideral hematoma
skull fracture or other trauma that will burst the artery in teh epidural space
HOW can we get a subdural hemorrhage?
have the bridging veins burst due to tension on the bridging veins. (bad for infants and elderly or alcoholics)
how do we get a hemorrhage that is crescent shape (same shape as the skull concavity)
have a subdural hemorrhage and pooling of the blood in the space between the e MORE!
why does the brain hate a hemorrhagic stroke
pressure, lacking nutrients
what is a hemorrhagic stroke compared to ischemic stroke?
Hemorrhagic stroke is a burst vessel and bleeding into the brain. Ischemic is a stroke that occurs because of a block in the vessels.
What are the two components of the Autonomic nervous system of the head?
Parasympathetics: (CN’s III,VII, IX, and X)
Sympathetics (T1 Spinal Cord level)
What is the spinal cord level that all head sympathetics come from?
The T1!
Describe the course of sympathetic nerves into the head!
From the T1 spinal cord lateral horn-
Ventral root-
Trunk-
ventral ramus-
white matter communicon-
sympathetic chain-
up to the Superior Cervical gangleon-
Synapse in the SCG-
Out the gray matter comunicon-
Onto the ICA like christmas lights!
what is the most clinically relavent action of the sympathetic nervous system in the head?
Eyeball-
Dilator Pupillae Muscles: Dialate the pupil!
Superior Tarsal Muscle: Smooth muscle that keep the eyelid open!!!
what is the syndrome where you knock out all of the sympathethics to the head
Horner’s Syndrome
What are the symptoms of a Horner’s Syndrome?
Ptosis: Eyelid is droopy!
Anhydrosis: The face is flush and dry (sweat glands innervation)
Miosis: Different sized pupils!
“PAM has HORNS”
What are the bones of the Skull?
what bones covers the front of the skull
The Frontal Bone
what bone means “wall” and forms a wall around the sides of the brain?
Parietal bone
What bone lies under the hair that would gray first and is therefore the “time” bone?
temporal bone
What is the bone that is at the “temples”
The sphenoid bone that goes from one side of the skull to the other, that forms the back of the orbit and is a key stone bone that alot of other bones attach to.
What is the bone that you lay on your pillow?
the Occipital bone.
what are the fibrous joints that knit the bones of the head together?
The Sutures!
Knits the frontal the the pariatel bones together along the top of the head.
The coronal suture.
the suture that articulates the parietal and temporal bones
The Squamosal suture.
The suture that articulates the occipital bone to a paratial and temporal bones. makes a “triangle”
Lambdoid suture.
The tiny suture that connects the coronal and squamosal sutures.
The Pterion suture
why is the tiny little pterion suture clinically important?
Middle maningial artery courses right here where the bone is thinnest!
what are the layers of the protective seat-belt of the skull?
the Dura mater, the Arachnoid mater and the Pia mater
How is the dura mater of the head different than the dura matter of the spine?
the head has two layers that are fused together:
Dura mater:
Periosteal layer: hugs the skull
Meningeal layer: divides and goes towards the brain paranchima
what is between the Periosteal layer and the meningeal layer?
this layer isn’t always seperated but when it is, it forms Dural Venous Sinuses!
what is and How is a dura venous sinus different than a vien in the rest of the body?
It is a space between the periosteal and meningeal layers of the the cranial meninges that is full of venous blood.
It does not have a tunica media (smooth muscle layer)
It does not have valves!
the viens that travel in the diploid bone, and provide drainage to the skin of the skull!
Diploic viens!
what are the Emissary viens of the head?
they are veins that transverse the skull and connect the skin to the dural venous sinuses!
could be a source of infection into the brain!
Veins that drain the parachama of the bain from the capillaries of the brain tissue to the dura venous sinuses!
Cerebral Veins
What are the divisions of the Dura mater?
the Falx cerebri
Tentorium
Falx Cerebelli
Seperate the left and right cerebral hemisphere in a vertical plane
The Falx Cerebri
Seperates the cerebeli from the cerebellum in a horizontal plane.
The Tentorium cerebelli
Seperates both the cerebelli hemispheres
The Falx Cerebelli
Courses along the top of the Falx Cerebri from the anterior to the posterior ( a dura venous sinus)
the Superior sagittal sinus
Courses along the bottom of the falx cerebri from the fron to the back (dura venous sinus)
Inferior sagittal sinus
From the intersection of the superior and inferior sagital sinus and runs along the back of the tentorum cerebeli (dura venous sinus)
The thransverse sinus
Dura venous sinous that rises from the transverse sinus and curves down towards the IJV
The Sigmoid sinus
Dura venous sinus, paired and flanks the side of the sphenoid body
The Cavernous sinus
Important clinical considerations of the cavernous sinus
communicates with the facial vein and with the pterygoid plexus of veins (spread of infection!!!)
ICA courses through it ( in wraps around the front and comes out the top!!)
CN’s going to orbit course through it. ( CN 6 goes through the middle and in the wall of the CS from the top to the bottom are CNs: 3,4,V-1,V-2)
And it also has the pituitary gland righ in the middle at the top!
what is the blood supply to the Meninges?
the anterior, middle (most clinically rellavent), and postier meningeal artery from the maxillary arter, through the foramen spinosum, on the internal surface of the pterion!
Protude into the superior sagital sinus to allow the CSF to flow from the subarachnoid space into the dura venous sinuses.
The arachnoid granulations.
space where the CSF flows, where arteries and viens are housed!
The subarachnoid space
Dives down the sulci and along the brain
the pia matter
the area of the brain that is along the top!!
the cerebrum
The hollow cavity in each cerebrum filled with CSF
Lateral ventricles
The ventricle between the dianchephelon that communicates with the lateral ventricles
the third ventricle
communicates with the 3rd ventricle and dives down through the midbrain, filled with CSF
The cerebral aqueduct
The part of the brain that is caudel to the midbrain!
Pons (CN V, VI, VII, VIII)
The brain caudel to the pons
the medulla oblengauta (CN IX, X, Xi, XII)
The califlower looking bulb in the bottom back of the brain
The Cerebellum
The parts of the brain from the top to the bottom
Cerebrum
Midbrain
Pons
Cerebellum
Medulla Oblengata
Communicates with the cerebral aquiduct above and in the subarachnoid space with the apperatures
The 4th ventricle
Describe the flow of CSF
The Choroid Plexus makes it from the blood supply
goes to the lateral ventricles
to the third ventricle
to the cerebral aquiduct
to the fourth ventricle
to the aperatures
to the sub arachnoid space
to the arachnoid granulations/Sub arachnoid villi
into a dura venous sinus
back to the IJV!
The connecting tissue between the right and left sides of the brain
Corpus callosum
Inside the later, third, and fourth ventricles to provide CSF
The choriod plexus
Openings to the subarachnoid space from the fourht ventricle
Apertures
2 Lateral
1 Median
The blood supply to the brain!!!!!!! (overview!!)
Blood supply through the skull to the front of the brain
The internal carotid artery (ICA)
The source of blood through the skull to the back of the brain
The vertebral artery
the anastimosis of the ICA and the Vertebral artery at the bottom of the brain
The cerebral arterial circel of willis
The only place in the body where an artery resides in a vein (and it doubles back and does it agian…)
The ICA coursing the carotid canal and through the Cavernous sinus
Blood supply that courses right over the corpus collosum between the two hemispheres
The Anterior cerrebral artery.
blood supply that Course between the frontal and temproal lobes of the brain
The middle cerrebral artery
blood supply that Courses in the transverse foramena of the cervical vetebra, through the foraman magnum to the back of the brain
the vetebral artery.
the arteries that supply the cerebellum
The
PICA
AICA
SCA
CN III seperates this artery from the SCA
The posterior cerebella arteries
Supply the base of the cerebellum
The anterior and posterior cerebella arteries.
Overview of the blood flow of the brain:
CNs that innervate almost all of te structures of the head and neck, the skin, mucous membranes, muscles and glands (and some targets in the trunk!)
CN V,VII,IX and X
CNs that innervate only structures in the orbit
CN III, IV, VI
CN that innervates only the tongue muslces
CN XII
Thr cranial nerves that carry parasympathetic neurons
CN III, VII, IX, and X
The top of the brain stem and what CNs come from here?
The Midbrain (CN II, III, IV)
summary of function CN 1
Transmits the sense of smell
summary of function CN 2
Transmits visual information to the brain
summary of function CN 3
Innervates eye muscles
summary of function CN IV
Innervates the superior oblique muscle
summary of function CN V
Recieves sinsation from the face and innervates the muscles of mastication
summary of function CN VI
Innervates the lateral rectus
summary of function CN VII
Provides motor innervation to the muscles of facial expression
summary of function CN VIII
Senses sound, gravity and rotation
summary of function CN IX
Motor: Phayrngeal Musculature
Sensory: posterior part of the toungue, tonsil, pharynx
summary of function CN X
Motor: heart, lungs, bronchi, GIT
Sensory: heart, lungs, bronchi, trachea GIT, external ear.
summary of function CN XI
controls sternocleidomastoid and trapezius muscles
summary of function CN XII
Provides motor innervation t the muscles of the tongue
