Head & Neck Flashcards
Level of C3
-Hyoid bone
Level of C6
- Cricoid cartilage
- Tracheotomy @ this LVL
- Junction between larynx & trachea
- Carotid artery can be compressed against transverse process
- inferior & middle thyroid arteries enter thyroid (common carotid)
- Site for blocks of the brachial plexus (subclavian vein ant.)
Cervical fascia
- Superficial: contains platysma (covers the sterno. muscle fascia)
- Deep:
1. investing SCM & Trapezius
2. Prevertebral: surrounds vertebrae & muscles
3. pretracheal: surrounds trachea, esophagus, & thyroid
4. carotid sheath: continuous w/ pretracheal fascia
Carotid Sheath
- Continuous w/ pretracheal fascia (3)
- Contains: 1. internal carotid, internal jugular, vagus nerve (CN10)
- 90% of strokes occur here
- 10% circle of willis @ base of brain
Posterior Triangle
- Floor: Clavicle, scalenes (anterior, medius, posterior - resp. accessory muscle) levator scapulae, splenius capitis (whiplash)
- Roof: investing fascia surrounding SCM & Trapezius (superficial, innv. by CN 11)
- Brachial plexus/subclavian artery.
- Phrenic nerve (C3,4,5)
Sternocleidomastoid (SCM)
- Enclosed by Fascia
- 2 origins & 2 Insertions
- O: Manubriumsterni & Medial 1/3 clavicle
- I: Mastoid process & lateral nucheal line (behind the ear)
- Accessory muscle for breathing (pump handle)
- Innv: Spinal accessory nerve CN 11
Anterior Triangle
- Roof: Superficial cervical fascia/Platysma
- Subdivided into: submandibular, carotid, muscular triangle
- Contains larynx, pharynx, trachea, thyroid, carotid sheath, & strap muscles
Anterior Triangle (muscular)
Boundaries: -Omohyoid (depresses hyoid bone) -SCM -Midline Contains: 4 infrahyoid (strap) muscles & thyroid/parathyroid 1. Mylohyoid 2. Sternohyoid 3. Thryrohyoid 4. Omohyoid
Anterior Triangle (submandibular)
- Boundaries: Ant. & post. bodies of digastric muscles (ant & post) - push bolus and move mandible
- Contains: submandibular gland & lymph nodes & hypoglossal nerve CN 12
Anterior Triangle (carotid)
- Boundaries: posterior belly of digastric, omohyoid, & trapezius
- Contrains: Carotid sheath & vagus nerve CN 10
Anatomy of Thyroid Gland
- Bi-lobed endocrine gland overlying cricoid cartilage
- Two lobe bridged by isthmus ant. to trachea
- Strap muscles & SCM ant.
- Carotid sheath lateral
- thyroid cartilage & trachea posterior
- Blood supply: Sup/inf thyroid artery
- Recurrent laryngeal nerve post.
Blood supply to Thyroid
- Right subclavian–>Thyrocervial–>inferior thyroid artery (ant & post)
- Right subclavian–>superior thyroid artery (ant & post)
- Brachiocephalic trunk–>Thyroid Ima artery (midline supply ant)
Venous drainage head/neck
-Right/left internal jugular vein–>Left/Right subclavian–>SVC
Contents of the Larynx
- Superior to Inferior:
- Tip of epiglottis
- Body of Hyoid bone (C3)
- Thyrohyoid membrane
- Laryngeal prominence (adam’s apple) & posterior is arytenoid cartilage
- Cricothyroid ligament/membrane
- Cricoid cartilage (C6) & lateral cricothyroid muscle
Laryngeal cartilage (Thyroid)
- 2 thin laminae joined @ midline
- Joining forms laryngeal prominence
- Attachment of infra hyoid (strap) muscle to hyoid bone (C3)
Laryngeal cartilage (Epiglottis)
- Post. aspect of thyroid cartilage inside Thyrohyoid membrane
- Attached by quadrangular membrane (false vocal cords) to arytenoid cartilage
Laryngeal cartilage (cricoid/artenoids)
- Cricoid: C6, articulates with thyroid cartilage through cricohyroid muscle
- Artenoids: Pyramid shape post aspect articulate with cricoid cartilage & attach to cricoartenoid muscles/vocal ligament
Laryngeal muscles (extrinsic)
- Suprahyoid (elevate)
- Infrahyoid (depress)
Laryngeal muscles (intrinsic)
- Open/close the airway & responsible for phonation
- Cricothyroid (external laryngeal nerve)
- Thyroarytenoid
- Posterior & lateral circoartenoid
- Transverse & oblique arytenoid
- ALL innv. by recurrent laryngeal nerve (CN 10)
Phonation
- Articulation at the synovial cricothryoid & cricoaryenoid joints alter LENGTH, TENSION & POSITION of vocal cords.
- Tilting forward of larynx lengthens the vocal cords producing a higher pitch
- Cricohyroid = forward
- Thyroartenoid = reverse back
Swallowing
- Involves RAISING of larynx to meet bolus coming from the pharynx & depression of the epiglottis towards the artenoid cartilage (pyramid shape/post)
- Mainly passive due to passage of bolus
Muscle actions of vocal cords
- Posterior cricoarytenoid = bring together to midline = opening
- Transverse arytenoid = midline = closing
- Thyroarytenoid = ant = closing
- Lateral cricoarytenoid = ant = closing
- Oblique arynoid = midline = closing
Piriform Fossa
-Space surrounds the epiglottis
Neck Trauma
- Zone 1 & 3 most prone to airway obstruction or bleeding
- Zone 2 are more common to injury BUT bleeding can be controlled & Cricothyroidotomy can overcome obstruction
- Zone 3 = above chin
- Zone 2 = Chin to clavicle
- Zone 1 = Manubrium
External carotid artery
- 8 main branches supplies whole head and neck
1. Superior thyroid
2. lingual
3. Facial
4. Superficial temporal
5. maxillary
6. posterior auricular
7. occipitan
8. ascending pharyngeal
7 Bones of the ocular cavity
- From posterior to anterior
1. Greater/Lesser wing of sphenoid
2. Frontal bone (roof)
3. Ethmoid bone
4. Lacrimal bone
5. Palantine bone (between ethmoid/maxilla)
6. Maxilla (most anterior/medial)
7. Zygomatic (anterior/lateral next to maxilla)
Borders of orbit
- Superior wall: Frontal bone
- Medial wall: Ethmoid bone
- Lateral wall: Zygomatic/greater wing of Sphenoid
- Inferior wall: Maxilla
- Apex: Optic canal (most medial)
3 layers of the eyeball
- Fibrous: sclera (wraps around entire circumference) & cornea (located in front)
- Vascular: Choroid (below the sclera wraps around entire circum), ciliary body (muscles that make adjustments) & iris (below the iris)
- Inner layer: Retina (cones, blind spot = optic nerve)
Anatomy of the Pupil
- opening through the Iris
- round shape is controlled by sympathetic/parasympathetic within iris = dilator & sphincter muscles (ciliary body)
- Pupil size can be affected by drugs like atropine dilates pupils.
Anatomy of Iris
- Most anterior extension of the uveal tract (Iris, ciliary body, choroid)
- Made up of blood vessels, connective tissue, melanocyctes (melanin producing) make different eye colors
- Dilator/Sphincter muscles
- Anterior/posterior layer of cells- collagen, fibrils, matrix of mucopolysaccharide (long chain sugar mol. make fluid)
Anatomy of ciliary muscles
- Middle portion of the uveal tract
- 3 muscles fibers
1. longitudinal muscles
2. radial
3. Circular
Anatomy of Choroid
- posterior portion of the uveal tract & nourishes the retina (blood supply/O2)
- Supplies rods which require ALOT of blood
- Basement membrane = Bruch’s membrane (transports metabolic waste)
Anterior chambers structures
- Aqueous humor (secreted by ciliary epithelium)
- Trabecular meshwork (drains the aqueous humor)
- Canal of schlemm: meshwork allows for fluid to drain into canal and finally blood supply
Role of eyelids & Lacrimal glands
- Major role to protect cornea & eyeball from injury/irritation
- Production of of lacrimal fluid from glands stimulated by parasympathetic from Facial nerve (CN7)
- Convey fluid into conjunctival sacs (between eyeballs and lids)
- When cornea becomes dry–>eyelid blinks pushing film fluid medially over the cornea
- Debris is pushed medially in lacrimal lake (eye boogers) & drains by capillary action
- Fluid passes inferior by nasolacrimal duct to inferior meatus of nose to be swallowed
Extra ocular muscles NOT CN3
- Superior oblique (CN4) = Abducts,depresses and rotates eyeball medially (intorsion)
- Lateral rectus (CN6): ABducts eyeball
Extra ocular nerves CN 3
- Superior Rectus: elevates, ADducts, rotates eyeball medially (intorsion)
- Medial rectus: Adducts
- Inferior rectus: depresses, Adducts, rotates eyeball laterally (extorsion)
- Inferior oblique: ABducts, elevates, rotates laterally (extorsion)
Fracture to orbit
- Most common to inferior & medial walls due their thinness
- Medial wall fractures may involve ethmodial & sphenodial sinuses
- Inferior wall involve maxillary
- Fractures can have bleeding occur which causes pressure = exophathalmos (protrusion of eyeball)
“Blow out” fracture of orbit
-indirect trauma that displaces orbital walls
Normal landmarks of eye exam
- Blood vessels of surface of retina
- Optic disc (blind spot)-Blood vessels radiate from & optic nerve exits here
- The macula (lutea): middle for each retina, yellowish in color & BV absent
- Fovea: dark spot in the macula midline marker
Clinical conditions of eye exam
- Papilloedema: associated with intracranial pressure seen @ optic disc as widening.
- Bacterial endocarditis: starts from bacterial infection of lining of heart chambers that travels through the blood. Appears as mini hemorrhages in eye
Papilloedema
- Optic nerve surrounded by dura, arachnoid, & pia mater
- Increased ICP –> Obstruction to axoplasmic transport
- Swelling @ the optic disc –>optic atrophy & Blindness
CN 3 Palsy
- Appearance: Ptosis (drooping superior eyelid), pupil fully dilated, down & out
- Causes: Hypertension, Diabetes, Trauma
CN 6 Palsy
- Appearance: Eye deviated nasally/Eye can not be abducted from midline
- Causes: Diabetes, MS, ICP, Trauma
Horner’s syndrome
Appearance: Partial Ptosis, Miosis (excessive constriction of pupil), Anhydrosis (dry eye)
-Causes: Damage to sympathetic cervical trunk, Pancoast tumor (@ apex of lung) can spread
Overview of External Ear
- Auricle & Pinna: Collect sound
2. External auditory meatus: responsible for transmitting sound to tympanic membrane
Auricle (Pinna)
- Framework of elastic cartilage adherent to perichondrium
- Lobule has NO cartilage
- Attached to skull with anterior/posterior ligaments & useless auricular muscles
- Helix (superior part)
- Antihelix (middle & inferior to helix)
- Antitragus (midline ridge before meatus)
- Concha (inner/outer ear sup. to meatus)
- Targus (midline closest to nose)
External Auditory Meatus
- Curves anteriorly, inferiorly, medially
- Lateral 1/3 cartilage & medial 2/3 bony (temporal)
- Meatus guarded by Ceruminous glands = secrete ear wax (antibacterial)
Tympanic membrane
- outer ear
- Cone of light (reflex back)-midline
- Pars flaccida (most posterior)
- Pars Tensa (anterior/superior to malleus)
- Umbo (located superior to cone of light)-midline
- Malleus (long bone forms line w/umbo)
Middle ear boundaries
- between tympanic membrane (lateral wall) & Cochlea (medial wall)
- Roof & floor = Temporal bone
- Anterior = Carotid sheath (internal jugular vein & artery) & mastoid process
- Posterior = CN 7 (facial)
Middle ear ossicles
- Malleus
- Incus
- Stapes
- 1-3 = Ossicular chain (movement transmits sound to inner ear through oval window)
- 2 muscles: Stapedius & tensor tympani (protect inner ear by reducing movement of tympanic membrane = reducing movement of stapes)
- Innv. by chorda tympani of CN 7
- Communicates with pharynx through eusacian tube = meningitis
Pharyngotympanic tube
- Equalizes pressure between middle ear and outside
- Tube @ rest is closed=active process of 2 muscles tensor & levator palanti
- EX. Yawning
Otalgia (ear pain)
- From Otitis media or Otitis externa
- referred pain from dental pain, esophageal pain due to different CN innervation.
Inner ear
- Main function to receive sound & maintain balance
- Bony Labyrinth surrounding a membrane which is suspended in perilymph FILLED with endolymph
Inner ear (labyrinths)
- Bony Labyrinths (3 parts)
1. Cochlea: Hearing
2. Vestibule: Communicates w/middle ear
3. 3 semilunar canals: balance - Membranous Labyrinths w/in bony-
1. Cochlea duct: hearing
2. Saccule & Utricle: w/in vestibule
3. (3) semilunar valve ducts: balance
Cochlea
- Bony tube of 2.5 turns that spiral around bony pillar MODIOLUS
- Sep. into 2 perilymph chambers by thin plate of bone = spiral lamina
- Endolymph filled cochlea duct (membranous labyrinth) = another chamber
- Base opens to vestibule
- Innv. Cochlear nerve (CN 8)
Cochlea and sound
- Vibration of stapes (middle ear)
- Oval window
- Scala vestibuli
- Helicotrema
- Scala tympani
- Round window
Hair cells & hearing
- Vibration through perilymph causes movement membrane of spiral
- Movement of tectorial membrane bends sterocilia on hair cells = sensory of cochlear nerve CN 8
- Outer hair cells (connected to sterocilia) respond w/change in length alters basilar membrane = cochlear amplifier
Conductive hearing loss
- Defined as no transmission of sound into the inner ear
- Wax (cerumen) build up
- Tumor
- Otosclerosis (stiffness)
Sensorineural hearing loss
- Damage to cochlea & CN 8
- Old age
- Medications
- Immune disorders
- Noise exposure
Balance & Inner ear
- Comprised of the vestibular system
1. 3 semilunar canals
2. Utricle (larger)
3. Saccule - Each SCC: 1 ampulla - Crista sense kinetic/dynamic movement
- Utricle/Saccule contain a Macula=static head positions
Balance Problems
- Vertigo: Spinning sensation NOT dizziness = inner ear or central (BS/cerebellum) - viral infection
- Vestibular Nystagmus: Uncontrollable oscillations of eye = Peripheral lesion =horizontal/rotary form does NOT change direction & Central lesion= all directions and may change directions
External features of Nose
- Root (bridge)
- Apex (tip of nose)
- Ala (rim around the nostril)
- Nasal bone = root
- Lateral cartilage (inferior to root)
- alar cartilage - ala
Nasal cavity proper
- Vestibule (entrance)
- Inferior, middle, superior turbinate
- Cribriform plate of erythnoid bone (roof) = CN 1
- Choana (exit)
Boundaries of Nasal cavity
- Roof: ethmoid bone & sphenoid bone
- Floor: Maxilla & palantine bone
- Medial: Septal cartilage, Vomer bone (inferior) & ethmoid bone (superior)
- Lateral: 3 nasal conche/turbinates = form meatuses
Nasal passageways
- Originate from turbinates split into 4 passageways
1. Sphenoethmodial reces: Above superior conche = drains spehnoid sinus
2. Superior meatus: drains post. ethmoid
3. Middle meatus: Drains maxillary, middle ethmodial & frontal (major drainage)
4. Inferior meatus: drains naso-lacrimal duct
Paranasal Sinuses
- Named after the bone associated with
- Act to lighten skull & increase resonance in voice
- Maybe sites of infection
- Frontal sinus (sup to orbits)
- Ethmodial sinus (Bridge of nose)
- Maxillary sinus (sides of nose)
- Sphneodial sinus (post. to ethmodial)
Paranasal Sinuses (Frontal/Maxillary)
- Frontal: opens into middle meatus & anterior to cranial cavity
- Maxillary: Largest sinus, Root of molar teeth project into it, opens into middle meatus, Most prone to infection due to drainage against gravity. “muslim prayer position”
Paranasal Sinuses (Ethmoid/Sphenoid)
- Ethmoid: Thin wall between orbit & nasal, Opens to superior & middle meatus
- Sphenoid: Most posterior, drains into Spheno-ethmodial recess above superior concha (transphenoidial procedure for pituitary tumor)
Anterior view of Skull
- Frontal bone (Forehead)
- Nasal bone
- Lacrimal bone (lacrimal duct)
- Zygomatic bone (cheek bone)
- Maxilla (Maxillary sinus/teeth)
- Mandible (jaw bone)
- Temporal bone (temple)
Lateral view of Skull
- Parietal bone (post. to frontal)
- Coronal suture (bond between frontal/parietal)
- Sphenoid bone (ant. to temporal)
- Lacrimal bone (lacrimal duct)
- Maxilla (frontal=sup. & alveolar=inf.)
- zygomatic (cheek bone)
- Occipital (post. base of skull) - external occipital protuberance
- Temporal (1.Ant.squamos,2. zygomatic,3.external acoustic 4. mastoid process)
Posterior view of Skull
- Saggital suture (bonds both halves of parietal & superior to occipital)
- Lambdoid suture ( inferior to parietal & bonds both occipital to parietal)
Superior view of Skull
- Bregma (fontanel found on coronal suture and Saggital)
- Saggital suture (bonds both parietal bone)
- Coronal suture (bonds frontal & both parietal)
Anterior cranial Fossa
Boundaries-
- Anterior: Frontal bone
- Floor: Ethmoid bone
- Posterior: Lesser wings of sphenoid bone
- Contents: Frontal lobe
- Fracture to floor of may involve cribriform plate = CSF leakage = CSF rhinorehea
Middle cranial Fossa
- Boundaries:
1. Anterior: Greater wings of sphenoid bone
2. Floor: Temporal bone
3. Posterior: Occipital bone
4. Contents: Temporal lobe - Fracture to floor = CSF otorrhea = possible meningitis
Posterior cranial Fossa
Boundaries-
- Anterior: Temporal bone
- Floor: Occipital bone
- Contents: Cerebellum & Brainstem
Foramina @ Base of skull
- Cribriform plate: CN1 olfactory
- Optic canal: CN2 Optic
- Superior orbital fissure: CN 3, 4, 5(1), 6
- Foramen rotundum: CN 5(2)
- Foramen Ovale: CN 5(3) Mandibular
- Internal auditory meatus: CN 7, 8
- Jugular Foramen: CN 9, 10, 11
- Hypoglossal Canal: CN 12
Layers of the scalp
- Skin
- Connective tissue (avascular)
- Aponeurosis: Posterior =Occipitalis, Middle = epicranial, Anterior = Frontalis
- Loose areolar tissue
- Pericranium=periosteum loosely connected to bone
Skull Fractures
- Linear fractures: most frequent type can split bone causing miscommunication of bone
- Depressed fracture: common to thin parts of the skull depressing bone inward causing ICP
- Comminuted fracture: bone is broken is several places
- Basilar Fracture @ base of skull (occipital = CSF leakage)
- Le Fort fracture - ant. drawer test with maxillary skull
- Pterion fracture: @ temple weakest part of skull Anterior branch of middle meningeal artery = epidural haematoma
The meninges
- Skull
- Outer periosteal layer of dura mater
- Dura mater
- Inner meningeal layer of dura mater
- Arachnoid mater
- Subarachnoid space
- Pia mater (tight to brain)