Orbits, eye, ear, nose oral cavity and airway Flashcards
Orbit
7 bones
frontal bone
zygomatic bone
spheniod
ethmoid bone
lacrimal bone
palatine bone (tiny part)
maxilla bone
Lacrimal Apparatus and Gland
- Lacrinmal gland secretes lacrimal fluid (tears)
- paraysmpathetic innervation by N VII (via pterygopalatine ganglion)
- lactimal ducts convey tears to conjectival sac
- lacrimal canaliculi convey tears to lacrimal sac
- nasolacrimal duct converys tears to nasal cavity
Extra-ocular Muscles
(innervated by CN III)
- CN III:
- levetor palpebrae superioris
- interior oblique
- superior rectus
- inferior rectus
- medial rectus
Extra-occular muscles that are not innervated by CN III
- SO4
- superior oblique- CN IV (trochlear)
- LR6
- Lacteral Rectus - CN VI (abducent)
Optic Canal
(nerves and arteries)
- optic nerve (CN II)
- Opthalmic artery (branch of internal carotid artery)
Superior orbital fissure
(nerves)
- Occulomotor (CNIII)
- Trochlear (CN IV)
- abducent (CNVI)
- divisions of the opthalmic branch of trigeminal nerve (V1)
Common Tendinous Ring
(contents and importance)
- Optic nerve (II)
- Opthalimic artery
- superior branch of oculomotor nerve (III)
- nasocillary branch of opthalmic nerve (V1)
- abducent nerve (VI)
“Just make sure you know CN 2, 3, 6, and opthalmic artery –> reason this is important: retrobulbar block
- nerves are harder to hit bc they are protected by this ring”
Fibrous Layer of eyeball
- sclera- rough opaque part
- provides for muscular attachment to eye
- mostly avascular
- “white of the eye”
- Cornea
- transparent
- completely avscular
- innervated by CN V1
Vascular layerof eyeball
- Choroid - highly perfused
- ciliary body
- provides attachement for the lens and controls the thickness of the lens (focus-accomadation)
- ciliary process secrets aquesous humor which fills the posterior chamber
- Iris
- thin contractile diaphragm on the anterior surface of the lense
- sympathetic and parasymathetic control
- thin contractile diaphragm on the anterior surface of the lense
*take home: these surgeries require anesthesia providers to be present but you dont really give much sedation, just there to monitor
Inner Layer of Eyeball
- retina
- fundus: part where light enetering the eyeball is focused
- 2 parts:
- optic part- sensitive to visual light rays
- macula of hte retina with fovea centralis: most acute vision
- nonvisual parts- optic disk: CN II and vessels enter the eye; no photoreceptors, blind spot
- white spot = aka blind spot
- where the optic nerve and opthamic artery come into the eye
- white spot = aka blind spot
*take home: surgery of inner eye needs A VERY DEEP sedation, which means you will have BP issues and you need to support it (can’t have that eye ball moving)
retrobulbar block
- find the maxillary bone and inject LA behind the eye
- common tendinous ring - makes CN 2, 3, 6 harder to hit*
- will block eye movement and sensation
peribulbar block
- block is not as deep; will not inhibit the nerves as much (bc of the CTR)
- mostly for pain sensation (will have min movement)
Ear
Facial nerve and Vestibulocochlear
- facial nerve and vestibulocochlear nerve exit through the interal acoustic meatus together
- CN 8 will innervate semicircular canals and cochlear for hearing and balance
- CN 7 continues and passes through the facial cannal and exits via the stylomastoid formamen
- surgery of inner ear: you cannot use muscle relaxants!
- must be able to monitor CN 7 to make sure they do not injur it
Nose
(functions)
- olfaction
- respiration
- filtration
- humidification
- reception and elemination of secretions from the nasal mucosa, paranasal sinuses, and nasolacrimal ducts
Nose
(8 bones)
- frontal
- nasal
- sphenoid
- ethmoid (makes up nasal septum)
- palatine
- inferior nasal concha
- maxillary
- vomer (makes up nasal septum)
Nasal Cavities
- lined by nasal mucosa
- superior 1/3 is the olfactory area
- inferior 2/3 is the respiratory area
- three nasal concha divide cavity into four air passages
- spheno-ethmoidal recess (allows for sense of smell), superior nasal meatus, middle nasal meatus, and inferior nasal meatus
Paranasal Sinuses
(action and name the 4 sinuses/innervations)
- air filled extension of the respiratoy part of the nasal cavity (allows protection/decreases weight of head)
- drains into nasal cavity via mulpitle openings
- frontal sinus -CN V1
- ethmoid sinus (cells) - CN V1
- sphenoidal sinuses - very thin bone seperates from several important structures (CN V1)
- maxillary sinuses - CN V2
Nasal Cavity
(vasculature and innervation)
- “highly vascularized”
- innervation:
- olfactory nerve (CN1) - smell
- Trigeminal nerve
- opthalic division (CN V1)- anterosuperior part
- maxillary division (CN V2)-(*per Nicole) - postero-inferior half to 2/3 of the nasal mucosa
Oral Cavity
- dental arches anteriorly and laterally (where teeth sit)
- palates
- occupied by the tongue
- communicates posteriorly with the oropharynx
- 2 arches
- palatoglossal arch - anterior and attaches to tongue
- palatopharyngeal arch - posterior; attaches to oral arch
Oral Cavity
(bones)
- mandible
- maxilla
- palatine bone
Oral Cavity
(teeth)
- 32 adult teeth
- numbered 1-16 right to left on maxilla
- supplied by CN V2 (superior alveolar nerve branch)
- numbered 17-32 left to right on mandible
- supplied by CN V2 (inferior alveolar nerve branch)
Palate
(generals)
- arched roof of the oral cavity proper and floor of nasal cavities
- hard palate
- soft palate
- palatine tonsils- lymphoid tissue on each side of the oropharynx between the two arches
Hard Palate
- anterior 2/3
- palatine processes of the maxillae and horizontal plates of the palatine bones
- incisive fossa and greater palatine foramen allow for vessels of maxillary artery (external cartoid) and nerves of CN V2)
Soft Palate
- movable posterior 1/3
- uvula
- continuous with wall of the pharynx and joined to tongue and pharynx by the platoglossal and palatopharyngeal arches
* if the right vagal nerve is damaged, you will see a left sided deviation of your uvula
Soft palate muscles:
Tensor Veli Palatini
- only muscle innervated by CN V3
- action:
- tenses soft palate and opens mouth of pharygotoympanic tube during swallowing and yawning
*can cause occlusion of airway if damaged*
Soft Palate Muscles
Levator veli palatini
- Action:
- elevates soft palate during swallowing and yawning
- Innervation:
- Vagus Nerve
Soft Palate Muscles
Palatoglossus
- Action:
- elevates posterior part of tongue and draws soft palate onto tongue
- Innervation:
- Vagus Nerve
Soft Palate Muscles:
Palatopharyngeus
- Action:
- tenses soft palate
- puls wall of pharynx superiorly, anteriorly, medially with swallowing
- Innervation:
- Vagus Nerve
Soft Palate Muscles:
Musculus Uvulae
- Action:
- shortens uvula and pulls it superiorly
- Innervation:
- Vagus Nerve
Sublingual/submandibular Sympathetic Innervation
- come from T1, T2, T3
- travel to the superior cervical ganglion (synapses with postsynaptic nerve); exits by the grey rami
- travel along the facial artery
“superior cervical ganglion in the facial plexus that innervates the submandibular and sublingual glands”
Parotid Gland
(sympathetic innervation)
- travels to superior cervical ganglion
- then travels up the external carotid plexus
- innervates the parotid gland
Nasal, Palates and Lacrimal Glands
(sympathetic innervation)
- superior cervical ganglion along the internal cartiod plexus
Tongue: Extrinsic Muscles
(Names and innervations)
- Genioglossus
- Hyoglossus
- Styloglossus
- Palatoglossus (only one innervated by Vagus)
*all muscles innervated by hypoglossal (CN XII) except Palatoglossus
**if your right hypoglossal nerve is injured, will cause right side deviation on tongue
Tongue Innervation
General somatic motor
- hypoglossal nerve (CNXII)
- palatoglossus - only one innervated by Vagus (CN X)
Tongue Innervation:
General somatic sensory
- aka touch and temp
- anterior 2/3
- Lingual nerve of V3
- Posterior 1/3 tongue and anterior epiglottis
- glossopharyngeal nerve (CNXI)
- inferior epiglottis
- Internal laryngeal nerve of Vagus Nerve
Tongue Innervation:
special sensory
- taste
- anterior 2/3
- chorda tympani via facial nerve (CN VII)
- posterior 1/3 and anterior epiglottis
- glossopharyngeal nerve (CN IX)
Cervical Viscera:
Pharynx
(includes what? -generals)
- cranial base to C6- continuous with esophagus
- nasopharngyx
- oropharynx
- laryngopharynx
- vallecula
Nasopharynx
- posterior to nose (choanae), superior to soft palate
- respiratory function
- pharyngeal tonsils, adenoids when enlarged
Oropharynx
- posterior to the mouth
- soft palate -superior
- base of tongue- inferior
- palatoglossal and palatopharyngeal arches - laterally
- ends at the superior border of epiglottis
- digestive function
- palatine tonsils
Laryngopharynx
- posterior to the larynx
- extends from superior border of epiglottis
- to inferior border of cricoid cartilage (C4-C6)
superior, middle and inferior pharygeal constrictors
(innervation)
Motor via Vagus
Palatopharygngeus and salpingopharyngeus
Stylopharyneus
(innervations)
- “pharyngeal muscles”
- Pala and salpi - Vagus Nerve
- Stylopharyngeus -Glossopharyngeal (CN IX)
Sensory innervation of pharynx
- nasopharynx - V2
- Oropharynx - CN IX (glossopharyngeal)
- laryngopharynx - CN X
Larynx
- fucntions
- airway protection
- respiration
- phonation
- location
- C3-C6
- connects oropharynx with trachea
- C3-C6
Laryngeal cartilages
3 unpaired and 3 paired
- paired
- Arytenoid
- Corniculate
- Cuneform
- unpaired
- thyroid
- cricoid
- epiglottic
Thyroid Cartilage
- level of C4
- largest and most prominent
- anterior attachement for vocal cords
Epiglottic Cartilage
- covers opening to the larynx during swallowing
Cricoid Cartilage
- only complete cartilaginous ring
- singet shaped
- arch faces anteriorly (thickest part in the back)
Arytenoid Cartilages
- posterior attachement for vocal cords
Corniculate Cartilages
- attach to the apices of the arytenoid cartilages
- posterior portion of the aryepiglottic fold
Cuneiform Cartilages
- do not directly attach to any other cartilages
- in the aryepiglottic fold, not always present
- lateral to corniculates
True vocal cords
- control sound production with audible vibrations
- appear pearly white
- formed by the vocal ligaments
- attached anteriorly to the thyroid cartilage and posteriorly to the arytenoid cartilages
Glottic Opening
(rima glottidis)
- triangular aperture between the cords
- variation in the:
- tension and length of the vocal folds
- width of the rima glottidis
- intensity of expiratory effort
- produces changes in voice pitch
Intrinsic Laryngeal Muscles
- control the movements of the lyrngeal cartilages
- control the length ad tension of the vocal cords and the size of the glottic opening
- cricothyroid muscle innervated by the external branch of the superior laryngeal nerve, a branch of the vagus nerve
- all others innervated by the recurrent laryngeal nerve, a branch of the vagus nerve
Cricothyroid Muscle
- Crycothryoid = Cords tense
- stretches and tenses vocal ligament
Thyro-arytenoid
- Thyro-arytenoid =They relax
- relaxes vocal ligament
Posterior crico-arytenoid
- Posterior crico-arytenoid = Please come apart!
- abducts vocal cords
Lateral crico-arytenoid
- Lateral crico-arytenoid = Let’s close the airway
- adducts vocal folds
Transverse and Oblique arytenoids
- adducts vocal folds
vocalis
- relaxes vocal ligament
(vocalis is relaxing on vacation)
Larynx Innervation:
Specific branches off the Vagus Nerve
- Superior laryngeal nerve
- internal larygneal nerve
- motor - none
- sensory- posterior epiglottis to vocal cords/thryoepiglottic joint/cricothyroid joint
- external larngeal nerve
- motor- cricothyroid muscle
- sensory- none
- internal larygneal nerve
- recurrent laryngeal nerve
- motor- all other intrinsic laryngeal muscles
- sensory- below vocal cords and trachea
Larynx innervation (motor and sensory)
Trigeminal (CN V)
- Opthalmic
- sensory- nares/anterior septum
- maxillary
- sensory - turbinates/posterior nasal septum/nasopharynx
- mandibular
- motor - muscle sof mastication
- sensory - anteror 2/3 tongue
Larynx Innervation (motor and sensory)
Glossopharyngeal (IX)
- motor
- stylopharyneus muscle
- sensory
- soft palate
- oropharynx
- posterior 1/3 tongue
- tonsils
- vallecula
- topside (anterior) epiglottis
- afferent limb of gag reflex
Larynx Innervation (motor and sensory)
Vagus Nerve
- Superior Laryngeal Nerve
- external:
- motor - criothyroid muscle
- internal:
- sensory - underside (posterior/inferior) epiglottis to VC/thyroepiglottic joint/cricothryoid joint
- external:
- Reccurent Laryngeal Nerve
- motor
- thyroiaretenoid, vocalis, arytenoids (transverse and oblique), lateral cricoarytenoid, posterior cricoarytenoid
- sensory
- below the vocal cords to the trachea
- motor
Nerve injury to the
external branch of the superior laryngeal nerve
- controls the circothyroid muscle
- responsible for tensing the vocal cords
- injury (during a thyroidectomy) leads to hoarsenesss
- one sided, or bilteral injury to this nerve is tolerated
- injured muscle will just “flutter” and pt will sound hoarse
Nerve injury to the
recurrent laryngeal nerve
(acute bilateral injury)
- controls all other intrinsic muscles, besides crycothyroids (think posterior crico-arytenoids!)
- acute bilateral injury
- bilateral paralysis of VC abductors (prosterior crico-arytenoids) = unopposed tensing by cricothyroid muscles
- causes stridor and respiratory distress
- AIRWAY EMERGECNY!!
- causes stridor and respiratory distress
- bilateral paralysis of VC abductors (prosterior crico-arytenoids) = unopposed tensing by cricothyroid muscles
- acute bilateral injury
Nerve injury to the
recurrent laryngeal nerve
(unilateral injury)
- paralysis of ipsilateral vocal cord abductors
- not an airway emergency
- chronic unilateral injury
- generally tolerated well
Superior and Inferior Laryngeal Arteries are branches of what?
- the superior and inferior thryoid arteries
Superior Thryoid Artery
- first branch of external carotid artery
- accompanied by external branch of the superior largyneal nerve
- gives rise to:
-
superior laryngeal artery
- accompanies internal branch of the superior largyneal nerve
-
superior laryngeal artery
Inferior Thyroid Artery
- branch of the tyrocervical trunk
- gives rise to:
- inferior layrngeal artery
- which accompanies recurrent laryngeal nerve
Trachea
- extends from inferior end of larynx into the thorax
- teminates at the sternal angle (T4) where it bifurcates (carina) into left and right main bronchi
- 2.5cm in diameter
- 10-20 cm length
- 16-20 U shaped cartilages
- posterior side lacks cartilage
- posterior gap is spanned by the involuntary trachealis muscle
- innervated by the Recurrent Laryngeal Nerve of the Vagus Nerve
Lehane-Cormack Laryngeal Views
