Midterm anatomy Flashcards
Cartilage frame, helps funnel and localize sound, amplifies sound as it enters EAC
Pinna
Concavities of Pinna
Concha-Tragus
Triangular fossa
Scaphoid fossa
Convexities of Pinna
Helix
Antihelix
Length of external auditory canal
2.5 cm
What part of external auditory canal is cartilage?
Lateral 1/3
What part of external auditory canal is bony?
Medial 2/3
Skin of external auditory canal
Cartilaginous portion- hair follicles, sebaceous glands, and ceruminous glands
Bony- thinner with no other structures
Neural innervation of external auditory canal
Trigeminal nerve
Greater auriculnar nerve
Auricular branch of Vegus
Facial nerve & chordo tympani
Tympanic membrane characteristics
Approx 9mm diameter, approx 140 degrees, attached to canal wall & malleus
Layers of pars Tensa
Lateral epidermal- continuous with EAC skin
Medial mucosal
Intermedial fibrous
Ossicular chain bones
Malleus
Incus
Stapes
Parts of malleus
Manubrium-attaches to TM at umbo due to encircling by pars propria
Head & neck
Lateral process-adheres to pars propria of TM
Anterior process
Parts of incus
Body- articulates with head of malleus
Short process- anchors to posterior ligament
Long process- parallels manubrium
Lenticular process- articulates with stapes
Parts of stapes
Head- attaches to incus
Footplate- attaches to oval window by the annular ligament
2 crura- support the footplate to head
Middle ear tegmen
Serves as roof & floor to middle cranial fossa