Lecture 16: Anatomy and Histology of the Ear Flashcards
What composes the external ear?
Auricle to Tympanic Membrane
What composes the middle ear?
Tympanic Membrane to Oval Window
What composes the inner ear?
Oval Window to Internal Acoustic Meatus
What type of cartilage is the external ear mostly made up of?
Elastic Cartilage
What supplies the external ear?
Posterior Auricular Artery (from ECA)
Superficial Temporal Artery (from ECA)
What provides sensory innervation to the external ear?
- Facial Nerve
- Cervical Plexus: Lesser Occipital and Greater Auricular Nerves
- Auriculotemporal Nerve (V3)
- Vagus/Glossopharyngeal Nerve
What innervates the superior part/roof of the external acoustic meatus?
Facial Nerve
What innervates the posterior part of the external acoustic meatus?
Greater Auricular Nerve (Cervical Plexus)
What innervates the anterior part of the external acoustic meatus?
Auriculotemporal Nerve (V3)
What innervates the inferior part/floor of the external acoustic meatus?
Vagus: Arnold Nerve
-plays a role in the cough reflex
What glands make ear wax?
Ceruminous Glands
What is the composition of the external acoustic meatus?
Outer ⅔: Soft CT and Cartilage (similar to external ear)
-where you can see ceruminous and sebaceous glands + hair follicles
Inner ⅓: Just skin and bone
Where is the cone of light?
Anterior, inferior quadrant of Tympanic Membrane
What makes up the roof of the middle ear?
Tegmental Wall (from Temporal Bone) -Separates ear from brain/middle cranial fossa
What makes up the floor of the middle ear?
Jugular Wall
-Separates ear from bulb of Internal Jugular Vein
What makes up the lateral wall of the middle ear?
Membranous Wall (going to external ear)
What makes up the medial wall of the middle ear?
What is found at this wall?
Labyrinthine Wall (Oval and Round Windows)
- Lateral Semicircular Canal
- Facial Canal and Nerve
- Promontory of Labyrinthine Wall
What makes up the posterior wall of the middle ear?
Mastoid Wall
-Separates tympanic cavity from mastoid air cells and facial canal
What can be found at the anterior wall of the middle ear?
Pharyngotympanic Tube
Tensor Tympanic Muscle
-Separates Tympanic Cavity from Internal Carotid Artery
What does the pharyngotympanic tube connect?
Middle ear to nasopharynx
What does the pharyngotympanic tube do?
Equalize pressure
What two muscles expand the pharyngotympanic tube?
Levator Veli Palatini Muscle
Tensor Veli Palatini Muscle
What type of epithelium is found on the pharyngotympanic tube?
Pseudo-stratified Epithelium