Anatomy 2 Flashcards
What is the name of the thinnest part of the skull
Pterion (was called God’s little joke)
What runs behind the Pterion
The middle meningeal artery
What does the temporal bone contain
organs of hearing and balance (special sensory)
Facial and vestibulocochlear nerves
Where does the sternocleidomastoid attach
The mastoid process
What bones make up the anterior cranial fossa
Frontal, ethmoid and sphenoid
What bones make up the middle cranial fossa
Sphenoid and temporal (majority)
What bones make up the posterior cranial fossa
Temporal and occipital (majority)
What bone makes up part of the middle and posterior cranial fossae
Temporal
Pathology in the internal acoustic meatus (e.g. and acoustic neuroma) could cause damage to what
CNs VII and VIII
Where does CN 1 pass through
Cribiform plate of ethmoid bone
Where does CN 2 pass through
Optic canal
What nerves pass through eh superior orbital fissure
3,4,5a and 6
What nerve passes through the foramen rotunda
5b
What nerve passes through the foramen oval
5c
What passes through the intracranial opening of the carotid canal
Carotid artery
What nerves pass through the internal acoustic meatus
7 and 8
What nerves pass through he jugular foramen
9, 10, 11
What nerve passes through the hypoglossal canal
12
What passes through the foramen magnum
Spinal cord
Where is the external ear
Auricle to tympanic membrane via external acoustic meatus
Where is the middle ear
Tympanic membrane to oval window and eustachian tube
Where is the internal ear
Oval window to internal acoustic meatus
What is the main function of the external ear
Collects and conveys sound waves to tympanic membrane
What is the main function of the middle ear
Amplifies and conducts sound waves to the internal ear
What is the main function of the internal ear
Converts special sensory information:
- into fluid waves
- then APs
- conducts APs to the brain
What is the tympanic membrane more commonly known as
Ear drum
What is the majority of the external ear made up of
Elastic cartilage but the lobe is not cartilage
What is the EAM made up of
2/3rds bony and 1/3rd cartilage
What lines the EAM
Skin
What is ear wax also known as
Cerumin (produced via ceruminous glands
What is the ear lobe made up of
Fibrous and fatty tissue
What is the nerve supply to the skin of the auricle
Most comes from C2/C3
What other nerves innervate near the EAM
Maxillary and Facial
Why is the auricle lymphatic drainage important
Auricles are prone to skin cancer which can metastasise
Where does the lymph from the lateral surface of the superior half of the auricle drain
Parotid lymph nodes
Where does the lymph from the cranial surface of superior half of the auricle drain
Mastoid lymph nodes (and deep cervical)
Where does lymph from the rest of the auricle drain
Superficial cervical lymph nodes
Where does all of the lymph associated with the auricle drain eventually
Deep cervical lymph nodes, thoracic duct or right lymphatic duct and then the venous angle
What is the main difference for examining a child’s ear to an adults ear?
Child - gently pull auricle posteroinferiorly
Adult - gently pull posterosuperiorly
What is the most important structure in the ear to identify and describe its appearance
The umbo
The most depressed part of the tympanic membrane
What is the nerve supplying the external surface of the tympanic membrane
Mostly CN V3
What is the nerve supplying the internal surface of the tympanic membrane
CN IX
What does the glossopharyngeal nerve provide
Sensory innervation to: Middle ear cavity Eustachian tube Nasopharynx Oropharynx Tonsils
What are other names for the Eustachian Tube
Auditory tube or pharyngotmypanic tube
What is the function of the eustachian tube
To help equalise pressure with the atmospheric pressure
Why can tonsilitis mimic earache
They have a common sensory nerve supply (CN IX) and causes referred pain
What are the bones in the middle ear called and what is the type of joint between them?
The auditory ossicles
Synovial joint
What are the names of the middle ear bones
Incus (anvil)
Malleus (Mallet)
Stapes (stirrup)
What causes the jumbo to be depressed
The malleus pulling on it
What lies posterior to the tympanic membrane
Tympanic cavity proper (middle cavity proper)
What is the aditus
A doorway into the mastoid bone from the epitympanic recess
What is mastoiditis due to
Spread of infection from the middle ear cavity
What forms the promontory on the medial wall
The cochlea of the internal ear. Bony parts can push into the wall and make a bump
Where is the tympanic cavity found
In the petrous temporal bone
What can cause other bumps in the medial wall of the middle ear
Semicircular canals
What does the facial nerve run through
The internal acoustic meatus (runs back and down the posterior wall of the middle ear)
Eventually, where does the facial nerve pass into
The stylomastoid foramen
What are the 4 aspects of the facial nerve
Special sensory
sensory
motor
parasympathetic
What is meant by the cranial nerve course
Where it comes from , how it runs, how it gets to where its goingg
Where does the facial nerve connect to the CNS
Ponstomedullary centre
Brainstem at junction between pons and medulla
Describe the intracranial part of the course of the facial nerve
Directly into the internal acoustic meatus in the posterior cranial fossa
Describe the facial nerve’s base of skull course
Through the petrous temporal bone
What is the chorda tympani
A brand of CN VII
What does the chorda tympani do
Supplies the taste buds of the anterior 2/3rds of the tongue
Parasympathetic supply to the submandibular and sublingual salivary glands (salivation)
All of the special sensory nerves.
What is the smallest skeletal muscle in the body
The stapedius
What is the function of the stapedius
It reduces the stapes movement to protect the internal ear from excessive noise
What supplies the stapedius
CN VII
What branch does the facial nerve give off just before the stylomastoid foramen
Chorda tympani
What does the chords tympani connect to
The lingual nerve branch of CNV3
What do the parasympathetic axons of CN VII supply
The submandibular salivary gland
name the 4 main muscles of facial expression
Frontalis
Oribuclaris oculi
Elevators of lips
Orbicularis oris
What do we get a patient to do in order to test the nerves supplying the muscles of facial expression
Frown
Close eyes tightly
smile
puff out cheeks
What gives the appearance of sunken cheeks and is a clinical sign of malnutrition
Buccal fat pad
Where do the muscles of facial expression originate and insert
Originate on bone and insert into superficial fascia
What nerve supplies the muscles of facial expression
Motor function of CN VII
What is the name of the area found around the lips that must be very carefully sutured by a specialist if there is a laceration
Vermillion border
What is Bell’s palsy
A condition that can cause temporary weakness or paralysis of of the muscles in one side of the face
Where does the internal ear run to and from
The oval window to the internal acoustic meatus
Where is the internal ear located
Th petrous part of the temporal bone
What is the function of the internal ear
To convert special sensory information
What are the two parts of CN VIII
Cochlear nerve and vestibular nerve
What does the cochlear nerve control
Hearing
What does the vestibular nerve control
Balance
Describe the density of the otic capsule bone to the surrounding temporal bone
It is denser in the otic capsule
What does the otic capsule contain
Bony labyrinth - fluid (perilymph) filled
What is suspended within perilymph of the bony labyrinth
Membranous labyrinth
Communicating sacs and ducts
contains endolymph fluid
What is perilymph similar to
Extracellular fluid
What are the 2 windows of the labyrinth
Oval and round windows
What fluid is found on the outermost part of the semicircular canal
Periplymph
What fluid is found floating inside the perilymph
Endolymph
How many turns does the cupula make
2.5
What are the names of the 3 semicircular canals
Anterior, lateral and posterior
What is the cochlear duct a bit like
A long balloon-like structure
What is the cochlear duct filled with
Endolymph
What are the semicircular ducts a bit like
Inter-linked balloon-like structures
What are the semicircular ducts filled with
Endolymph
Cochlear ducts connect to which nerve
Cochlear nerve
Semicircular ducts connect to which nerve
vestibular nerve
Give an overview of how sound is transmitted within the ear
- Sound waves make the tympanic membrane vibrate
- Vibrations are transmitted through ossicles
- Base of stapes (foot) vibrates in the oval window
- Vibration of stapes creates pressure waves in perilymph
- Hair cells in the cochlea are moved, neurotransmitter is released and Action Potentials are stimulated and conveyed to the brain by the cochlear nerve
- Pressure waves descend and become vibrations again
- Pressure waves are dampened at the round window
What is the function of the round window in sound transmission
It dampens down the pressure waves and dissipates the sound waves into the oval window
Where do CN VII and CN VIII connect with the brainstem
At the junction between the pons and the medulla oblongata
Name 4 symptoms associated with pathology of CN VII
Ispilateral loss of facial expression
Ipsilateral loss of taste
Dry mouth (reduced ipsilateral salivation)
Reduced general sensation in the auricle (immediately posterior to the tragus)
What are some symptoms associated with pathology of CN VIII
Ipsilateral los of hearing (cochlear nerve)
Ispilateral loss of balance (vestibular nerve)