10/3/2013

10/3/2013

Answers:

Longitudinal fracture of the temporal bone result in CHL via all of the following mechanisms except:
A) Hemotympanium
B) Disruption of otic capsule
C) Perforation of TM
D) Ossicular Chain Disruption
E) Longitudinal fractures cause CHL by all of the above

Transverse fractures of the temporal bone produce CHL by disrupting the otic capsule. Hemotympanum, TM perf and ossicular chain disruption are caused by longitudinal temporal bone fractures and cause CHL.

Name four surgical procedures used to treat various forms of CHL.

-Tympanoplasty = closure of TM if perforated.
-Ossiculoplasty = repair of ossicles if ossicular discontinuity present.
-Stapedectomy = remove and replace stapes with prosthesis for stiffening/fixation of stapes footplate to oval window in otosclerosis.
-Mastoidectomy = Allows approach for removal/exteriorization of cholesteatoma and repair of damaged structures.

MC Questions:
A common starting point for cholesteatoma is...
A) Shrapnell membrane 
B) Pars Tensa 
C) EAC 
D) Eustachian tube 
E) None of the above

Free Response Question:
Describe the "tragal pointer"

Quick Facts:
Middle Ear Cavity
-From 1st branchial pouch, connected to nasopharynx via eustachian tube.
-post to middle ear is mastoid air cells which connect with the attic through aditus ad antrum.
-Lined w/ ciliated mucosal epithelium
-Can be divided into 5 sections:
-mesotympanum
-hypotympanum
-protympanum
-retrotympanic (includes sinus tympani and facial recess)
-attic
-Blood supply is from internal (caroticotympanic) and external (ant. tympanic artery/deep auricular (from imax), sup petrosal, sup tympanic (middle meningeal) and stylomastoid arteries (from occipital) carotids