Ear Lecture Flashcards
What is the Auricle?
Single piece of elastic cartilage covered with skin with hair, sweat, and sebaceous glands
What is the role of the auricle?
To funnel the sound waves into the external acoustic meatus
Where does the auricle get its blood supply from?
Posterior auricular artery & Superficial temporal artery
What is the nerve supply for the auricle
Great auricular & auriculotemporal
What are the lymph nodes that drain the auricle?
Superficial parotid nodes, retroauricular nodes, deep cervical nodes, superficial cervical nodes
What is the make up of the external acoustic meatus?
Lateral 1/3 is cartilaginous and the medial 2/3 is bony
Where does the EAM get its blood supply?
Posterior auricular artery, Deep auricular of maxillary artery, Superficial auricular artery
Where vein does the EAM drain into?
External jugular vein, Maxillary vein, Pterygoid plexus
What nerves supply the EAM?
Auricular branch of auriculotemporal nerve V3, Facial nerve via tympanic plexus, Auricular branch of vagus
Where is the lypmhatic drainage for the EAM?
Mastoid tip area, Pre-auricular nodes, Upper deep cervical
What is the role of the tympanic Membrane
To seperate the external ear from the middle ear.
explain the make up of the TM?
Externally it is covered by thin fibrous membrane in internally with mucous membrane.
Where does the TM get its blood supply from?
Deep auricular artery of maxillary artery, Stylomastoid arteries of posterior auricular, Tympanic arteries of maxillary
What veins do the TM drain into?
External jugular vein, Transverse sinus, Veins of dura matter, Venous plexus of auditory tube
Where does the TM get its nerve supply from?
Auriculotemporal nerve V3, CN VII, IX, X
What are the contents of the tympanic cavity?
Auditory ossicles, two muscles, chorda tympani nerve, tympanic plexus of nerves
What are the boundaries that make up the Tympanic cavity?
Roof: Tegmental wall Floor: Jugular wall Lateral: Membranous wall Posterior: Mastoid wall Anterior: Carotid wall
What is significant about the jugular wall?
It is the point where the internal carotid artery and internal jugular vein diverge
What are the contents of the lateral wall of the tympanic cavity?
Fenestra vestibuli or oval window- base of staples fixed by annular ligament & fenestra cochlea or round window
What are the contents of the posterior wall of the tympanic cavity?
Aditus to the mastoid antrum- from epitympanic recess
pyramidal eminence and stapedius muscle
aperture for chorda tympani
What are the contents of the anterior wall of the tympanic cavity?
Tensor tympani muscle, auditory tube
Explain the make up of the auditory tube.
Anterior 2/3- cartilaginous; Posterior 1/3- bony
Where is the auditory tube the widest and what is found in relation to this opening?
Widest at pharyngeal end- opens opposite the nasal meatus with tubal tonsil near the opening
Opening into tympanic cavity is below processes cochleaformis