Anatomy Review 4

7/27/2019 Anatomy Review 4

1/23

1

ANATOMY-HEAD &NECK

20-Posterior Triangle of Neck

1. Hyoid: u-shaped bone at C3 level2. Thyroid cartilage: (C4/5) Laryngeal prominence (Adams apple)3. Arch of cricoid: only complete trachea ring4. Rings of trachea: C-shaped, membrane in posterior5. Temporal bone:

a. Mastoid process: SCM attachmentb. Styloid process: stylohyoid m. attachment, attached to hyoid b. in front of EAM

6. Occipital bone: attachment for trapeziusa. External occipital protuberance: midlineb.

Nuchal lines: two ridges7. Mandible: upper border of neck

a. Body: horizontal; Ramus: vertical portionthe two meet at the Angleb. Head: forms part of TMJ

8. Cervical vertebrae: have 7 cervical vertebrate, but 8 cervical nerves:i. C1C7 pass abovecorrespondingly numbered vertebrae

ii. C8passes belowC7 vertebraeb. Transverse foramina: transmit subclavian branches which ascend to skull base

i. Atlanto-occipital joint: flexion & extension of head on C1c. Atlanto-occipital membrane: closes space between skull & atlas; penetration

of vertebral arteries through foramen magnumd. Atlas(C1): two depressions articulate with occipital condyles & supportsskull; no vertebral body presentspace for dens

i. Atlanto-axial joint: rotationof atlas & skull together around densii. Jefferson Fracture: fracture of C1 anterior arch; from falling on head

e. Axis(C2): dens (Odontoid process) projects into atlas to allow pivotingi. Hangmans Fracture: bilateral fracture posterior arch of C2 with

anterior subluxation of C2 on C3; hyperextension/distraction injury

Omo h y o i d m .S u p e r io r b e l l y

I nfer i or belly

Ster noclei domastoi d m.

T r a p ez i u s m .


2/23

2

f. Transverse ligament: posterior to dens toprevent atlas anterior displacementg. Alar ligaments:prevent excessive rotationfrom side to sideh. Internal Craniocervical ligaments:

i. Cruciate l.: Superior & inferior longitudinal + Transverse ligamentii. Anterior longitudinal l.: prevents excessive extension

1.

Tear Drop Fracture: neck hyperextension

sudden pull ofA.L.Lig on anterior inferior vertebral bodyC2 fractureiii. Posterior longitudinal l.: prevents excessive flexion

i. Nuccal ligament: prevents skull flexion; divides back m.s into right & left sidesj. Herniated disksin cervical region: pain in neck & upper limbs

9. Facial Layers of Neck:a. Superficial layer: nerves, blood vessels, fat, Platysma m.b. Investing fascia: (deeper) splits twice to surround Trapezius and then SCMc. Pre-vertebral fascia: compartmentalizes neck muscles

i. Danger space: openspace between Alar &Pre-vertebral fasciaextending into posteriormediastinum; infection spread route to heart

ii. Anterior: splits into Alar fasciawhich crossesmidline from one transverse process to another

iii. Retropharyngeal space: closedspace betweenAlar & Visceral fascia

d. Visceral fascia: tube around trachea, esophagus, thyroide. Carotid sheath: condensation of other layers,

surrounds carotid a., internal jugular v. & vagus

10.Muscles:a. Platysma: thin m. facial expression in superficial fascia; fibers extend over clavicle &

under mandible to blend in with facial muscles; leaves midline gapi. Nerve supply: Cervical branchof Facial n.

1. Depresses mandible, draws down lower lip & angle of mouthb. Sternocleidomastoid(SCM): two heads (sternal & clavicular) join to form

flat strap muscle that attaches to mastoid process

i. Motor - Spinal Accessory n. (CNXI)1. Both m.: extend head at atlanto-occipital joint, flex cervical column2. One m.: rotates the face to the opposite side

ii. Proprioceptive - Ventral rami of C2-3iii. Torticollis(Wry Neck): shortening of SCMhead tilts towards

affected side & turns towards unaffected side; caused by:

1. Congenital: excessive stretching of SCM during labor2. Spasmodic: usually psychogenic3. Injury to spinal part of accessory nerve, brachial plexus, nerve

to platysma, or pleura & lung injuries in the root of neckc. Trapezius: acts on shoulder

i. Upper part elevates, Middle part retracts, Lower part depressesii. Also acts with serratus anterior to rotate shoulder superiorly

iii. Nerve supply: Spinal Accessory n. (CNXI)

Re

p h a rS p

D a

S p


3/23

3

d. Scalenemuscles:i. Anterior&Middle scalene: first rib to transverse processes for lateral bending

1. Brachial Plexus is sandwiched between anterior & middle s.m.ii. Posterior scalene: off second rib, inserts on lower cervical vertebrae

e. Levator scapulae: attaches to superior scapula angle; elevates scapula (w/ trapezius)f.

Splenius capitis: (bandage) extends & laterally rotates skull to same side

11.Vessels:a. External jugular vein: origin near mandible from

confluence ofposterior auricular& posteriorretromandibular v.s(superficial temporal + maxillary v.s)

runs superficial to SCM, empties into subclavian v.

i. External Jugular Vein Distension: fromelevated central venous pressure (CVP)right heart failure; tricuspid stenosis

1. Hepatojugular reflux: hepaticpressure increases EJVDb. Subclavian branches:

i. Transverse cervical a.: deep to trapeziusii. Supracapular artery a.: through scapula notch

12.Nerves:a. Dorsal primary rami: facet joint sensationb. Suboccipital n.: C1 dorsal ramus; no sensory

i. Motor to positional muscles which help inextension (nodding) & lateral skull rotation

1. Rectus capitus posterior (major & minor)2. Obliquius capitus (superior & inferior)

c. Greater occipital:C2 dorsal ramus; sensation from back of skulld. Cervical plexus(C1-C4 Ventral primary rami):

Sensation only; cutaneous branches emerge at nerve pointof the neck; loops formed between adjacent primary rami

1. Nerve point of the neck: half way upposterior edge of SCMlocation of

Cervical plexus block

ii. Lesser occipital(C2,3): skin right behindear & auricle; travels anterior Trapezius

iii. Great auricular(C2,3): skin from mastoid process to lower ear &mandible angle; runs travels external jugular vein

iv. Transverse cervical(C2,3): anterior triangle skinv. Supraclavicular(C3,4): above clavicle; 3 trunks: medial, intermediate, lateral

1. Phrenic nerve shares spinal segments with cutaneousinnervation of Supraclavicular - - referred painto shoulderfrom diaphragm irritation

vi. **C1 has no area of sensation on outside of head/neck


4/23

4

21-Anterior Triangle of Neck

1. Anterior Triangle:a. Submandibular triangle: below mandibleb. Submental triangle: between two anterior bellies of digastric

i. Small veins give rise to Anterior Jugular v. (superficial to muscular t.)ii. Submental lymph nodes: enlarged with infected tongue tip, lower lip, chin

c. Carotid triangle: bounded by posterior belly of digastric & SCM; location ofi. IJV: lateral to Common Carotid; Vagus n.(between & posterior to both)

d. Muscular triangle: bounded by superior belly omohyoid, extending to SCM;location of infrahyoid m., trachea, thyroid, & larynx

2. Muscles:a. Suprahyoidm.s: raises oral cavity floori. Digastric: two bellies connect to hyoid {sling}; elevates hyoid bone

1. Posterior belly: attaches to deep surface of mastoida. Cervical n.branch of Facial n.

2. Anterior belly:N. to Mylohoid (br. Inferior alveolar n. (V3))ii. Mylohyoid: deep to digastric anterior belly; extends towards midline to

attach to raphae;shortens& pulls towards hyoid bone,pushing tongue to

roof of mouth;N. to Mylohoidiii. Stylohyoid: styloid process (temporal b.), splits in two, to hyoid b.

a. Cervical n.branch of Facial n.iv. Geniohyoid: attaches near mandible bend; pulls hyoid bone forward

a. Branch of C1(which piggybacks along hypoglossal n.)b. Infrahyoid(strap) muscles: anterior to larynx, trachea, thyroid; raise larynx& depresses hyoid during speech & swallowing

i. Sternohyoid: attached to side of thyroid cartilagecan depress itii. Omohyoid(superior belly): depress hyoid bone

iii. Sternothyroid: depresses hyoid bone towards myoidiv. Thyrohyoid: from side of thyroid cartilage to undersurface of hyoid

a. Branch of C1(which piggybacks along hypoglossal n.)

EJV

IJV

Anterior J.V.

Dig as tr ic A n ter ior belly

S t e r no t h y ro i


5/23

5

Muscle Innervation Action

SUPRAHYOID MUSCLES

MylohyoidN. To mylohyoid (br. of inferior alveolar n.

CN V3)Elevates hyoid, depresses mandible

Geniohyoid C1 via Hypoglossal nPulls hyoid superiorly

Stylohyoid Cervical br. Facial n.Elevates & retracts hyoid

Digastric anterior belly N. To mylohyoid Depresses mandible

Digastric posterior belly Cervical br. Cn VII Elevates hyoid

INFRAHYOID MUSCLES

Sternohyoid Ansa cervicalis Depresses hyoid

Sternothyroid Ansa cervicalis Depresses thyroid cartilage

Omohyoid Ansa cervicalis Depresses, retracts hyoid

Thyrohyoid* *C1 via Hypoglossal Depresses hyoid, elevates thyroid cartilage

3. Brachiocephalica.Common carotid: C4/5 bifurcationa. Carotid artery Stenosis:i. TIA:brief periods of inadequate perfusion in portion of middle cerebral a.temporary & focal lossof neurological function (hand, vision sx.)

ii. Stroke/Infarction: sudden insufficiency of arterial supplydue to emboli or thrombi macroscopic brain necrosis

b. INTERNAL CAROTID: (posterior) no branches in neck; entersthrough carotid foramen to supply brain

i. Arterial Circle of Willis: base of brain around pituitarygland & optic chiasm

ii. Opthalmic a.: supply eyeball & muscles and forehead1.

Supraorbital: anastamose w/ superficial temporal a.iii. Carotid sinus: dilated part of internal carotid

c. EXTERNAL CAROTID: (anterior) supply neck(SALFOPSMax)

i. Superior thyroid: down to supply upper thyroid gland1. Superior laryngeal:

ii. Ascending pharyngeal:iii. Lingual: floor of oral cavity, tongueiv. Facial: deep to mandible, supplies skin & muscles of facial expression

1. Submental:v. Occipital: deep to SCM & post. belly digastric

vi.

Posterior auricular:vii. Superficial temporal(terminal br.): scalp & skin above earviii. Maxillary(terminal br.): infratemporal fossa & deep head (nasal cavity,

palate, floor of orbit); courses transversely medial to mandible condyle neck


6/23

6

4. Veins:a. Internal jugular: drains brain & neck; valve before joining

subclavian to prevent blood from flowing back into brainb. At the root of the neck, joins Subclavian vein

5. Lymph:a. Deep Cervical Lymph

Nodes: drain deep parts of

head

b. Superficial CervicalLymph Nodes: drains scalp;

lie along fascia of posterior

triangle & EJV; join lymph

nodes along IJV to emptyinto Thoracic duct

c. Jugulo-digastric node:behind mandible angle;enlarged in Tonsilitis &

Pharynx infectionsd. Supraclavicular (Sentinal)

node: enlarged with tumors, cancer, infections of thorax/abdomene. Virchows node: left side enlarged in abdominal (stomach fundus) cancer

6. Nerves:a. Ansa cervicalis: motor innervation infrahyoid m.s

i. Descendens hypoglossi (C1): superior rootii. Descendens cervicalis(C2, 3): inferior root

b. C1(thyrohyoid & geniohyoid): piggybacks along hypoglossal n.c. Sympathetic trunk: cervical portion: Superior cervical

ganglion: postganglionic sympathetic cell bodies that

piggyback blood vessels (carotid artery & branches)

7. TracheoStomy: permanent or semi-permanent trachea openinga. Placed in lower trachea, between tracheal ringsb. Indications: foreign body, vocal cord paralysis, upper airway tumors or traumac. Need to be careful not to puncture brachiocephalic a. or left brachio. v.

8. Cricothyrotomy: Emergency surgical airwayincision of cricothyroid membranea. Safer alternative - avoid vocal cords, thyroid gland & associated vessels


7/23

7

22-Intro to Skull

1. BONES OF THE SKULL:a. Frontal: unpaired bone making skeleton of forehead & superior orbit margin

i. Supraorbital foramen: transmits Supraorbital n. (V1) for sensationb. Coronal suture: between frontal & parietalc. Parietal: top to back of skull

i. Sagittal suture: down the paired parietal bonesd. Lambdoid suture: between parietal & occipitale. Occipital: lower back of skullf. Squamous suture: between parietal & temporalg. Temporal: lateral sides

i. External acoustic meatus: from the auricle to the tympanic membraneii. Temporal Fossa: located above the zygomatic arch.

1. Superior, Inferior temporal lines: Temporalis m.originatesbetween the two lines & attaches to mandible for jaw clenching

iii. Zygomatic process/ridge: sutures with zygomatic boneiv. Infratemporal fossa: irregular space inferior to zygomatic arch

1. Contains: muscles of mastication, maxillary a. branches,pterygoid venous plexus, CN V3branches

v. Petrous part: pyramidal wedge between the sphenoid and occipital1. Internal acoustic meatus: where facial n. enters skull

h. Zygomatic: cheek-bone, part of zygomatic archi. Sphenoid:

i. Superior orbital fissure: slit between Greater &Lesser wings;passage for nerves from middle c fossa to orbit

ii. Body: depression for pituitary glandiii. Lateral & Medial pterygoid plates: Pterygoid m.s attachments

j. Nasal: nose ridgek. Lacrimal: orbit medial wall; most fragile facial bonel. Maxilla: upper jaw & medial inferior orbit margin

i. Alveoli: sockets for upper teethii. Infraorbital foramen: transmits Infraorbital n. (V2)

iii. Pterygopalatine fossa:between maxilla & lateral pterygoid plate1. Pterygopalatine ganglion: suspended from Maxillary n

a. PNS root:i. Preganglionic via G. Petrosal (Facial n.)

ii. Postganglionic supplies lacrimal, nasal, &palatine glands

b. SNS root: sympathetic efferent (postganglionic) fibersfrom the superior cervical ganglion

2. Passages that connect with other parts of the skull:a. Foramen rotundummiddle cranial fossa

b. Vidian canalForamen lacerumc. Splenopalatine foramennasal cavityd. Inferior orbital fissureorbite. Pterygomaxillary fissueinfratemporal fossaf. Greater palatine canaloral cavity


8/23

8

m. Mandible:i. Mandibular foramen: entrance for Inferior alveolar n.

ii. Mental foramen: Mental n. (Inferior alveolar V3br.)n. Pterion: suture point of frontal, GWS, parietal, temporal; Middle meningeal a.

branches lie deep to pterion and run in dura layers

i.

Area thin & susceptible to fractures

Epidural Hematomao. Basilar Skull Fracture: (skull base) swelling of soft tissuei. Battle sign: bruising & redness behind ear from vessel hemorrhage

p. Paranasal sinuses: air-filled spaces developed from excavation of bone byair-filled sacs (pneumatic diverticula) from the nasal cavity

i. Maxillary sinuses: surround nasal cavity1. Opening is high in the sinus wall, so head must be tipped to

opposite side to drainfluid can accumulate causing infection

ii. Frontal sinuses: above eyesiii. Ethmoidal sinuses: between the eyesiv. Sphenoidal sinuses: behind the ethmoids

1.

Anterior approach through nasal cavity to sella turcica, usedwhen operating on pituitary gland

v. Sinusitis: infection, often precipitated by earlier upper resp. infection1. Often accompanied by headaches, pain, pressure in head, and

referred painto upper teeth because sinuses are supplied bysensory fibers from Trigeminal n. (V2Superior alveolar n.)

2. INFANT SKULL GROWTH: sutures allow skull expansion brain developsa. Metopic suture: down frontal bone

i. Metopid ridge: metopic suture fuses earlyskull & forehead deformitiesb. Anterior fontanelle: between frontal & parietalc. Posterior fontanelle: between parietal & occipitald. Mastoid fontanelle: between occipital & temporale. Sphenoid fontanelle: between GWS & parietalf. Craniosynostosis: one or more fibrous sutures in infant skull prematurely

fuses; may be inherited, associated with other problems of facial development

i. Prominent forehead, swellingon one side of headii. Increased pressure on brain; developmental delays

iii. Surgery used to separate the fused sutures and to reshape the skull


9/23

9

3. MENINGES:a. Epidural space: between dura & skull

i. Epidural Hematoma: arterialorigin (torn br. middle meningeal a.);lens-shaped blood accumulation between; pterion swelling, headache

b. Dura mater:i.

Tentorium cerebelli: infolding of dura that separates occipital fromcerebellum;brainstem can be pushed & cut by TC in Epidural Hematomaii. Two layers:Periosteal layer(skull contact)&Meningeal layer(deeper)

iii. Between the two layers is1. Middle meningeal a.(& v.): runs in infratemporal fossa

a. Br. of Maxillary a. (term. br. External Carotid a.)b. Small branch enters skull throughforamen spinosum

2. Also supplying blood to duraMeningeal br.s of Occipital&Ascending Pharyngeal a.s

3. Superior sagittal sinus: drainage of cerebral v.s; located atsuperior edge of Falx cerebri

iv. Falx cerebri: midline projection of durabetween cerebral hemispheres

1. Inferior sagittal sinus: runs atinferior edge of Falx cerebri;

a. Joins Great Cerebral v. toform Straight Sagittal sinus

b. Joins Superior sagittalsinus to form Transverse

sinusflow toSigmoid sinus& through Jugular foramen

v. Cavernous sinus: at sphenoid body; receives v. blood from orbit & face1. CN II, IV, VI, V1(V2) pass through2. Cav.Sinus infection(from face)double vision, headache,eye pain3. ICAAneurysmcan also affect CN VI (supplies lateral rectus m.)

affecting lateral eye movementdouble vision (diplopia)

a. Unable to supply the retina (since central a. of the retina is abranch of the ophthalmic a. & thus ICA)blindness


10/23

10

4. Cavernous carotid AV fistula: enlarged cavernous sinus &dilated superior ophthalmic v.orbital pain, chemosis,

exophthalmos; tx with embolizationvi. Pterygoid plexus: below orbit in infratemporal fossaMaxillary v.

c. Cerebral veins: between dura & arachnoid; to superior sagittal sinus & IJVd.

Subdural space: between dura & arachnoid; potential spacei. Subdural Hemorrhage(SDH): venousorigin; head trauma where

brain moves within skull; forms crescent shape

e. Arachnoid mater:i. Arachnoid granulations(villi): small arachnoid protrusions through

dura into v. sinuses - CSF exits sub-arachnoid to enter blood stream

ii. Hydrocephalus: CSF resorption blockage1. Sx of increased intracranial pressure: headaches, vomiting,

nausea, papilledema (optic disc swelling), sleepiness, comaf. Subarachnoid space: true space with CSFcirculation & cerebral a.s

i. Basilar Tip Aneurysm: associated with subarachnoid hemorrhageii.

Subarachnoid Hemorrhage: arterialorigin (ruptured intracranialaneurysm); also associated with trauma; blood mixes with CSF and

can diffuse widelyirregularin space, may cause a lot of pain

g. Pia mater: thin fibrous tissue impermeable to fluid, surrounding brain & spinal cord23-Face and Parotid

1. LeFort Fractures:a. Type I: horizontal maxillaryfracture, separating teeth from upper face

i. Fracture line passes through alveolar ridge, lateral nose, & inferiorwall of maxillary sinus

b. Type II: pyramidal fracture; teethat pyramid base, nasofrontalsuture at apexi. Fracture arch passes through posterior alveolar ridge, lateral maxillary

sinus walls, inferior orbital rim, & nasal bonesc. Type III: craniofacialdisjunction

i. Fracture line passes through nasofrontal suture, maxilla-frontal suture,orbital wall, & zygomatic arch

2. FACE:a. Aging of facial skin: Tensor lines (Langers lines) corresponding to direction

of collagen & elastin fibers; loss of elastic fibers causes permanent wrinkles

b. Botox: blocks release of ACh which triggers contractions that create wrinkles3. Sensory & Motor Facial innervation comes from different cranial nerves due to

organizing principlehead structures are derived from Five Primitive PharyngealArches: each contains cartilaginous & muscular component, aortic arch, and a nerve

a. Arch I: CN V (Maxillary & Mandibular n.s)b. Arch II: CN VII (Facial n.)c. Arch III: CN IX (Glossopharyngeal n.)d. Arch IV/VI: CN X (Superior laryngeal br. & Recurrent laryngeal br. of Vagus) e. *Arch V develops and quickly regresses


11/23

11

4. THE CRANIAL CAVITY: is divided into 3 fossa

5. Facial Expression muscles: covered by superficial but not deepfascia; br.s Facial n.a. Occipitofrontalis: raises eyebrowsb. Orbicularis oculi: acts as sphincter to close eyec.

Zygomaticus major: smiled. Buccinator: cheek

i. Motor: Buccaln. (br. Facialn. - CNVII)ii. Sensation: Long buccaln. (V3)

e. Levator labii superioris: elevate upper lipf. Orbicularis oris: lip pursingg. Depressor anguli inferioris: frownh. Platysma: frown

Superior

Orbital Fissure

P i tui tary

In t ern al Acoust ic M eat us

F o r a me n O v a l e

J u g u la r F o r a me n


12/23

12

i. Bells Palsy: weakness or paralysis of facial expression m.{ one side} due toFacial n. trauma; 85% have complete recovering in a year

i. Pain behind or in front of ear on affected sideii. Sounds seem louder on same side (affects N. to Stapedius m.)

iii. Loss of taste anterior tongueiv. Drooling mouth corner on affected side (paralysis of buccinators m.)v. Difficult closing eye (paralysis of orbicularis oculi m.)vi. Changes in amount of tears or saliva

6. Muscles of Mastication: attach to mandible; Mandibular n. (only V3division with motor)a. Temporalis: closes/clenches jaw; fan-shaped m., attaches to coronoid processb. Masseter: closesjaw (pulls mandible up); from zygomatic arch to mandible anglec. Medial Pterygoid: elevatesmandible, pulls jaw to opposite side (grinding);

originates on medial surface of lateral pterygoid& tuberosity of maxilla

d. Lateral Pterygoid: mandible protrusion(pulls forward); two heads7. Tempero-mandibular joint: synovial joint between mandiblular condyle & mandibular fossa

j.

Articular eminence: prevents displacement of jaw forwardk. Upper compartment: sliding movement, disc moves with mandible; can lockl. Lower compartment: hinge motionm. Branches of Auriculotemporal n.: sensation from TMJn. TMJ disorders: aching pain in/around ear & face, recurrent headache, jaw

tenderness, clicking/grating, joint lockingdifficult to open & close mouth

8. PAROTID GLAND: largest salivary glandall salivary g.s under autonomic controla. Parotid duct: from gland, across masseter, pierces buccinators & opens in

cheek mucosa along 2nd

maxillary (upper) molar tooth - delivers saliva to oral cavity

b. Structures within the Parotid Gland: External carotid a.; Retromandibular v.s.i. Auricotemporal n. branches (V

3); Terminal motor branches of VII

1. Parotid tumorscan compress Facial n. branchespain anterior to leftear, accentuated when chewing, food collects in space between cheek &

teeth, and dribbling out mouth corner; left lower eyelid & mouth droop c. Glossopharyngeal(CNIX) br.: parasympathetic innervation & secretomotor

2. Herpes Zoster(Shingles): chicken pox (varicella) infects trigeminal ganglion; once activated, travels alongafferent axons to skin where forms painful rash; often has a typical dermatomal presentation

3. Trigeminal Neuralgia: intense facial pain lasting few seconds to several min/hours; enlarged blood vessel(superior cerebellar a.)is compressing/ throbbing against microvasculature of trigeminal n. near connection with pons

4. Facial vein:i.

Danger triangle of Face: infections on face may pass retrogradely into skullvia facial v.Opthalmic veinsCavernous sinusDural sinusesbrain

a. External carotid artery:i. Facial artery: deep to mandible, through submandibular gland

a. Superior& Inferior labial: upper & lower lipsb. Lateralnasal:c. Angular: medial/lower eye

ii. Superficial temporal artery:a. Transversefacial artery:


13/23

13

24-Cranial Nerves

CNs originate from the nuclei within the brainstem (except CN I & IIforebrain extensions)

a. Travel within subarachnoid space, in CSF, pierce dura to exit cranial cavityi. Except CN I & II - considered tracts(extension of brain covered by meninges)

b. MOTOR ONLY (may be all somatic motor or both somatic & visceral motor)= III, IV, VI, XI, XIIc. SENSORY ONLY (special sensory) = I, II, VIIId. MIXED (may be somatic & visceral motor and somatic & special sensory)= V, VII, IX, Xe. PARASYMPATHETICS(visceral motor to glands & smooth/cardiac m.)= I I I , VII , IX, X

1. CN IOlfactory: special sensory onlya. Nerves pass through foramen in ethmoid bone (cribiform plate), through

olfactory tract and synapse with neurons (mitral cells) in olfactory bulb

2. CN IIOptic: special sensory onlya. Optic nerve (tractcovered by meninges), pass through Optic Canalswithin

sphenoid lesser wing (along with Opthalmic a. & periarterial plexus ofpostganglionic sympathetic n.s), crosses at chiasm, back to occipital pole

b. Retinal ganglion cells in back of the retina collectively form the optic nervei. Glaucoma: death of retinal ganglion cells

3. CN IIIOculomotor: all motor (somatic & visceral)a. Travels throughsuperior orbital fissure(between lesser & greater wings) &

tendonous ring (muscles attached), divides into superior & inferior divisions

b. Edinger-Westphal nucleus(accessory Oculomotor nucleus)Pregang. PSsynapse in Ciliary ganglion(orbit)Short ciliary post-ganglionic nerves:

i. Constrictor pupillae m.: constricts iris (pupillary light reflex)1. Loss/slowness of reflexmay indicate brainstem damageand/or bleedingthat compresses CN III against petrous ridge

ii. Ciliaris m.: rounds up lens for near vision (accommodation)iii. Absenceof adequate PS stimulationpupil dilation, difficulty near focusing

c. Innervates extraocular muscles: Superior, Medial, & Inferior rectus; Inferioroblique; Levator palpebrae superioris

i. *Two are not innervated by CNIII (LR6SO4)1. Lateral rectus: CN VI; Superior oblique: CN IV


14/23

14

4. CV IVTrochlear: Superior oblique m. (medial side of eye)a. Travels throughsuperior orbital fissure

5. CN VTrigeminal: sensory to face & head outside(& including) dura mater

a.

Trigeminal ganglion: sensory; nosynapses; sits near ICS & Vidian nerve(middle cranial fossa)

b. Opthalmic division(V1):superior orbitalfissure; all somatic sensory

i. Frontal: cornea, skin of: uppereyelid, nose bridge, forehead

1. Supraorbital:supraorbitalforamen onto forehead

2. Supratrochlear: medially; sensation to forehead between eyebrowsii. Nasociliary: sensory

1. Infratrochlear: sensation angle of eye, lateral to nose bridge2. Long&Short ciliaries: sensation from cornea

a. Long = sensory + sympatheticb. Short = sensory + sympathetic + parasympatheticc. Corneal(Blink) Reflex: eye is closed by orbicularis

oculi m.(supplied by Facial n. CN VII)

i. Afferent limb: CN V1(long & short ciliary = sensory)ii. Efferent limb: CN VII(blink)

iii. Lacrimal: lacrimal gland, upper eyelid skinc. Maxillary division(V2): in pterygopalatine fossa; passes throughforamen rotundum

i. Zygomatic: lateral noseii. Infraorbital: infraorbital foramen; upper lip, lower eyelid

iii. Posterior superior alveolar: upper teeth & maxillary sinusiv. Pterygopalatine ganglion: PSN ganglion hanging off maxillary n.

stimulates lacrimation (tears & nasal cavity muscosa)

d. Mandibular division(V3):foramen ovale; contains motor & sensoryi. Sensory:

1. Long Buccal: cheek2. Lingual:sensory anterior 2/3 tongue, mouth floor

a. Submandidibular ganglion: PNS ganglion suspendedfrom Lingual n; receives fibers from Chorda Tympani n

3. Auriculotemporal: sensation from TMJii. Motor: Mandibular: muscles (& accessory m.) of mastication

iii. Motor& Sensory:1. Inferior alveolar:mandibular foramen; right mandible, lower teeth

a. N. to Mylohoid: mylohyoid & anterior belly digastrici. Pushes tongue to roof; Raises oral cavity floor

b. Mental: mental foramen(mandible) Sensory: chin, lower lip


15/23

15

6. CN VIAbducent: Lateral rectus m. (abducts {laterally moves} pupil)a. ICA Aneurysmcan affect CN VI & lateral eye movementeye medial deviation

7. CN VIIFacial: motor (somatic & visceral) and sensory (special & general)i. Internal acoustic meatus: entrance to facial canal

b.Motor:i. Cervical branchexits via Stylomastoid foramenmuscles of

facial expression+ stylohyoid,posterior belly digastric, stapedius

1. Depresses mandible, draws down lower lip & angle of mouth2. Raises oral cavity

ii. Buccal branch: muscles of facial expressionc. Sensory: Geniculate ganglion(petrous part temporal b.)

i. Skin around EA.meatusii. Proprioceptive to skeletal muscles

d. Superior salivatory nucleus: preganglionic parasymp. fibers of Greater Pet.ne. Parasympathetic& Sensory branches:

i.

Chorda tympani: travels through tympanic cavity (middle ear)1. Secretomotor: PS submandibular & sublingual glands2. Preganglionic synapse in Submandibular ganglion3. Sensory: taste anterior 2/3 tongue

a. Travels along Lingual n.; exits through petrotympanic fissureii. Greater petrosal: parasympathetic to lacrimal & mucosal glands

{nasal cavity, soft palate}

1. Preganglionic synapse in pterygopalatine ganglioniii. GPN at Geniculate ganglionmeets up with sympathetic fibers from

the Deep Petrosal n. to form the Vidian n.travels to

pterygopalatine fossa where parasympathetic fibers synapsefibers

travels along V1& V2to reach Lacrimal gland1. Vidian: mixedpregang. parasymp.;postgang. sympathetic

f. N. to stapedius: origin in tympanic canal


16/23

16

L oos e motor

p a rt s o f V I I (Bells

P a l s y) , s e c r e ti o n

o f l o w e r s a l i va r y

g l a n ds , t a s t e o n

a n t e r io r 2 / 3

Chord a tymp ani n. l o o s e s p e c ia ls e n s e o n t o n g u e & s e c r et i o n o f

lower two s alivary g land s

G r e a t er P e t r o sa l n . loos e

s e c r e ti o n o f p a l a t i n e , n a s a l ,

& lacrimal g land s (DRYEYE )


17/23

17

8. CN VIIIVestibulocochlear: special sensory; enter in ternal acoustic meatuswith CN VIIa. Vestibular systembalanceb. Cochleahearing

9. CN IXGlossopharyngeal: motor (somatic & visceral) & sensory (general & special)i.

Exits cranial cavity atjugular foramen(beginning of IJV)a. Motor: stylopharyngeus m. onlyb. Sensory(general): pharynx, carotid body, carotid sinus (n. to Carotid sinus)c. Sensory(general&special): posterior 1/3 tongue (taste & sensoryGag reflex)d. Parasympathetic: to parotid glands for secretion

i. Preganglionic fibers in Inferior salivatory nucleustravel with CN XIii. Tympanic n. of Jacobson:joins with sympathetic (from

superior cervical ganglion) to form

iii. Lesser petrosal n. (IX & VII) emerges from middle eariv. Synapse at Otic ganglion(infratemporal fossa)v. Postganglionic fibers follow Auriculotemporal(V3) to parotid

10.CN XVagus: motor (somatic & visceral) & sensory (general & special)a. Motor: pharyngeal constrictors, laryngeal & palatal muscles

i. Superior laryngeal n.: motor (crichothyroid) & sensory (vocal cords)1. Important for cough reflex

b. Motor + Sensory: Recurrent laryngeal nerve: between trachea & esophagus;motor to esophagus, larynx muscles; sensory to trachea

i. Damaged during Thyroid Removal(proximity to a.)hoarse voicec. Parasympathetic: GI tract, heart, lungs {thorax}

11.CN XISpinal Accessory: somatic motori. Trunks enterforamen magnumand then out throughjugular foramen

a. Spinal Parti. Motor: SCM (extend head, flex column, rotate face to opposite side)

& trapezius (rotate shoulder superiorly)f. Cranial Partjoins Vagus n.

i. Motor: larynx & pharynx muscles1. Salpingopharyngeal m.: elevates pharynx

b. Torticollis(Wry Neck): shortening of SCMhead tilts towards affected side& turns towards unaffected side

12.CN XII - Hypoglossal: somatic motor only to tonguea. Innervates muscles: genioglossus, hyoglossus, styloglossus

1. Mandible fracture: damage to left CN XIIaffectsgenioglossustongue deviates to left when protruded (pushes

tongue to affected side due to action of m. on unaffected side)2. Still have sensation in cheek (V3Long Buccal n.) & lower teeth

a. Seen between the olives & pyramids; exits through hypoglossal canalb. C1 fibers join hypoglossal and then become part of ansa cervicalis superior root


18/23

18

25-Orbit

1. Orbital surfacesa. Medial: Lacrimal bone {very thin}

i. Medial Blow-out fracture: fracture through ethmoid b. showing orbitalemphysema & herniation of fat into ethmoid air cells, caused by sneezing

b. Floor: Maxillary & Zygomatic {& lateral wall} bonesi. Inferior Blow-out fracture: fracture of orbit floor; orbit contents into

maxillary sinus; affects inferior rectus m.unable to elevate eye; double vision

2. FORAMINA: most structures enter orbit from middle cranial fossaa. Optic canal: in base of sphenoid lesser wing

i. Contains optic n. & ophthalmic a.b. Superior orbital fissure: between

sphenoid greater & lesser wings

i. Contains CN III, IV, V1, VI, &ophthalmic v.

c. Inferior orbital fissure: slit below sup. orb.fissure; between sphenoid & maxillary

i. Contains Infraforbital & Zygomatic n., a.ii. Connects pterygopalatine fossa &

infratemporal fossa with orbitd. Orbit serves as a passageway for nerves &

vessels to face, scalp, nasal cavity

i. Supraorbital notch: frontal b.1. Contains Supraorbital n.

ii. I nfr aorbital foramen: maxilla b.1.

Contains Infraorbital n. (V2) & a.

iii. Zygomatico-Facial foramen:1. Contains zygomatico-facial n. from V2Important for

transmitting autonomic innervation to lacrimal gland

iv. Anterior & Posterior Ethmoidal foramina: between ethmoid &frontal bones; connect orbit & nasal cavities

1. Contains Ant & Post Ethmoidal n., a., & v. (V1& Opthalmic a.)v. Nasolacrimal ductopening: in maxillary, lacrimal bones & inf. nasal concha

3. EYELIDS: protect & keep eyes moista. Glands of Zeis: unilobar sebaceous glands on margin of eyelid; produce oily

substance through excretory ducts into middle of eyelash hair folliclei. Hordeolum(externalstye): glans infected when eyelashes not kept cleanb. Tarsal Plates: fibrous connective tissue eyelid skeleton, deep to orbital septum

i. Meibomian glands: sebaceous gland at eyelid rims deep to tarsal plate1. Meibum: oily substance that prevents evaporation of eyes tear

film & tear spillage; also makes closed lids airtight

2. Dysfunctional meibomian glandsdry eyes3. Obstruction by thick secretionsChalazion(internalstye)

Supra

notch/

Infraor

foram

Zygomatico-

Facial foramen

AnteriorPosterio

Ethmoid

foramin

OpeniNasola

Du

Frontal

Ethmoid

La

cr

im

al

Sphenoid

MaxillaryZygomatic

Nasal

RIGHTORBIT


19/23

19

c. Conjunctive: membrane inside lid; fuses to sclera, reflected to cornea of eyei. Conjunctivitis: conjunctive inflammationviral, bacterial, allergic

d. Blepharitis: inflammation of eyelids (bacterial staphylococcal)stypese. Lacrimal gland: located above & lateral to eye

i. Lacrimal caruncle: small pink nodule at inner corner (medial angle) ofthe eyes; made of skin covering sebaceous & sweat glandsii. Parasympathetic{pregang.} fibers from CN VII(Greater petrosal n.)join {postgang.}sympathetic fibers of deep petrosal n. to form Vidian n.

4. EYE:a. Fibrous layer: sclera, cornea; Vascular layer: iris, ciliary body, choroidb. Retina: light-sensitive cells where light is focused; Retinal a.(br. Opthalmic a.)c. Tenons capsule: fascial sheath surrounding back of eye; separates from periorbital fat

i. ThickeningsMedial& Lateralcheck ligaments:prevent excessive rotationii. Periorbital fascia: lines orbit & reflects over extraocular m.s

d. Graves Disease Exophthalmos: upper eyelid retraction, swelling, redness,conjunctivitis, proptosis (bulging eyes) {hyperthyroidism}i. AutoAbs target eye muscle fibroblasts - differentiate into fat cells

5. Extraoccular Extrinsic muscles: voluntary muscles which move eyeballa. Levator palpebrae superioris: elevates upper eyelid; attaches to tarsal plate (CNIII)b. Recti = straight, named for attachment sides; also attach to Tendinous Ring

(of Zinn): ring of CT surrounding optic canal & superior orbital fissure

1. Passing through ring is CN II, III, V12. Passing above ring is CN IV

ii. RectusSuperioris: elevates& medially rotatesiii. Medial rectus: medial deviationiv. Lateral rectus: lateral deviation of eye (CN VI) (LR

6SO

4)

1. Strabismus: eyes not properly aligned; disorder of brain incoordinating eyes or 1 or more of muscles power or direction

a. Medial deviation left eye = weak lateral rectus m.v. Inferior rectus: depresses& medially rotates

c. Superior oblique: by itself, moves eye down & out(depresses & intorts)i. Acts through pulley (trochlea) (CN IV)

ii. To clinically test Trochlear n. (CN IV), have pt look I N then DOWNd. Inferior oblique: pulls eye up & out; attaches to orbit floore. Pure elevation= superior rectus + inferior oblique togetherf. Pure depression= inferior rectus + superior oblique together


20/23

20

6. Autonomic innervation of eye - Oculomotor nerve(CN III):a. Pupillary Light reflex:

i. Dark - Dilation = sympathetic activation of dilator m.1. Superior cervical ganglion: pregang symp fibers T1-22. Postgang fibers travel with ICA to enter orbit via ophthalmic a.

& travel with Nasociliary nii. Light - Constriction = PSCN III activation sphincter m.1. Edinger-Westphal nucleus:preganglionic PS fibers2. Ciliary ganglion: postganglionic PS fiberstravel to

constrictor pupillary & ciliary muscles via Short Ciliary nervesb. Accommodation: lens rounding for near vision by tightening ciliary m. = PSCN IIIc. Horners Syndrome: interruption of sympathetic inn. to head

i. Miosis (constricted pupil)ii. Ptosis (drooping eyelid) due to weakness of smooth (Muellers) m. in

levator palpabrae superioris

iii. Anhydrosis (lack of sweating on face)iv.

Vasodilationdilated blood vessels in face

7. Vessels:a. Ophthalmic artery: first branch off internal

carotid; accompanies optic n. through optic canal

i. Supraorbital & Supratrochlear a.: foreheadii. Central a. of the retina: pierces the 3

meninges layers & travels with the optic

n. to supply inner cells of retina

1. No anastomosisblindness canoccur quickly with emboli

iii. Ciliary a.s: sclera & deeper retina in choroidiv. Lacrimal a.:v. Anterior & Posterior Ethmoidal a.s.:

Sympathetic fibers

Parasympathetic fibers Z on ular fiber r e l a x at i o n ( PS)

l e n s r o u n d i n g (accommodation)


21/23

21

8. VISION:a. Papilledema: swollenoptic nerves, blurriness of optic disc; can be caused by

i. Increased intracranial pressure (prevents back-flow from r. veins)ii. Venous drainage obstruction from compressive lesions (tumors,

vascular disorders, optic nerve ischemia/infarction)

b.

Glaucoma: death of retinal cells; risk factor is increased intraocular pressurei. Intraocular pressure is a function of aqueous humor production by thecili ary body(c. processes in anterior chamber) and its drainage

through the trabecular network (canal of Schlemm: venous plexus)

c. Macular Degeneration: (age-related) results in loss of vision in maculabecause of damage to the retina

i. DRY AMD: more common; vision loss gradual1. Retinal pigment epithelium is disrupted by cellular debris (drusen)

ii. WET AMD: vision loss is rapid & severe1. Choroidal blood vessels form underneath the retina & leak

blood/fluiddetach retina & blur central vision

26-Oral Cavity/Pharynx

1. ORAL CAVITY:a. Vestibule:anteriormost portion - space between cheek/lips and teethb. Oral cavity proper: the space within the area bounded by the teethc. Pillars of the fauces: anterior pillar: separate the oral cavity from the pharynxd. Floor of the mouth: oral cavity that is located beneath the tongue

i. On each side: slight fold (sublingual papilla) which ducts of submandibular opene. Mylohyoidm.: elevates hyoid bone & floor of mouth to aid in swallowing

i. Nerve to Mylohyoid(V3)

L o o s e p e r i ph e r a l( t e m p or a l ) f i e l d o f

visio n

L o o s e v i s io n f r o mright eye

Lo o se left field o fv i s i o n ( L e f t n a s a l f i e l d

& R i g h t t e mp o r a l )

BLINDNESS

Pi tui tary T umor


22/23

22

2. Structures of NASOPHARYNX: directly behind nasal cavitiesa. Torus tubarius: protrusion on nasopharynx lateral wall marking the

pharyngeal end of the cartilaginous part of the eustachian tube

b. Opening for auditory tube: on lateral wall of nasal part of pharynxc.

Pharyngeal recess: location of Pharyngeal Tonsil; wide, slitlike lateralextension in nasopharynx wall, cranial & dorsal to pharyngeal orifice of AT

i. Adenoids: inflamed pharyngeal tonsils can compress eustachian tubeand block ear secretionslead to Otitis media: middle ear infections

d. Salpingopharyngeal fold& m.:elevates pharynx, opens auditory tube during swallowingi. Cranial part of the accessory nerve

3. Muscles of the SOFT PALATE*:a. Levator palati: pulls soft palate up and backb. Tensor veli palatine*: elevates and tenses soft palate

i. Prevents regurgitation of food & fluids from oral to nasal cavityii.

Paralysis(CN V3damage) results in uvula deviation to opposite side(CN right side damagedeviation to left side)

c. Musculus uvulae: moves the uvula upwards and laterallyd. *All muscles supplied by CNs X & XI (motor br.s of pharyngeal plexus),

except tensor veli palatini, which is supplied by CN V

4. Structures of OROPHARYNX: between soft palate & epiglottis,behind oral cavitya. Posterior pillar(palatopharyngeus fold and muscle):b. Tonsillar bed (Palatine tonsils): located between palatoglossus &

palatopharyngeus m.s., contains sensory branches of CN IX

5. Structures of LARYNGOPHARYNX: low pharynx between epiglottis & esophagusa. Piriform recess(fossa): tear shaped pocket in laryngopharynx mucosa

through which food travels so as to avoid larynx and enter esophagus

6. Muscles of the PHARYNX*: connects nasal cavity, oral cavity & laryngeal area to trachea & esophagusa. Longitudinal muscles: elevate pharynx during swallowing

i. Palatopharyngeus& Salpingopharyngeus:ii. Stylopharyngeus*: between superior & middle constrictors

iii. Gag reflex: touching posterior 1/3 tonguepharyngeal m. activatedcausing pharynx to constrict & elevate

1. Sensory (afferent): CN IX2. Motor (efferent): CN X (along with CN IX for stylopharyngeus)

b. Circular muscles: horizontal constrictors insert on base of the skulli. Superior constrictor: from pterygomandibular raphe to pharyngeal tubercle

ii. Middle constrictor: from hyoid boneiii. Inferior constrictor: from thyroid & cartilages; continues as esophagus

c. *Muscles supplied by CN X, except stylopharyngeus supplied by CN IX


23/23

23

7. TONGUE:a. Surface landmarks:

i. Foramen cecum: depression on tongue dorsum posterior end midline grooveii. Sulcus terminalis: v-shaped near back, splits it into oral & pharyngeal parts

iii. Lingual tonsil: lymphatic tissue in tongue root in oropharynx floorb.

Extrinsic muscles*:i. Genioglossus: pulls tongue forward, sticking tongue out

1. Mandible fracture: damage to left CN XIIaffectsgenioglossustongue deviates to left when protruded (pushes

tongue to affected side due to action of m. on unaffected side)a. Still have sensation in cheek (V3Long Buccal n.) & lower teeth

ii. Hyoglossus: draws tongue down (flattens)iii. Palatoglossus*: elevates tongue floor; shuts oral cavity from oropharynxiv. Styloglossus: draws tongue up and back to aid swallowing food

c. Sensory innervation:i. Lingual nerve: general

sensation from anterior 2/3

ii. Chorda tympani: taste fromanterior 2/3

iii. Glossopharyngeal nerve:general sensation & taste from

posterior 1/3

iv. Vagus: taste from vallecular(where tongue reflects onto epiglottis)

d. *All extrinsic (& intrinsic) m. supplied byCN XII, except palatoglossus by CN X

i. Paralysis of XII on one sidecauses tongue to deviate to ipsilateral side

8. Lymphatic drainage:a. Tip of tongue: to Submentalnodesb. Lateral aspect of anterior 2/3 thirds: to

Submandibularnodes of same side

c. Posterolateral aspect: to SuperiorDeepCervicalnodes of same side

d. Midline tongue: to InferiorDeepCervicalnodes of same side

i. Deep cervical lymph nodes liearound the ICV

e. Central portion of tongue: to DeepCervicalnodes of BOTH sides

Anatomy Review 4

Documents

Transcript of Anatomy Review 4