Mastoid Cells


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Mastoid Cells

 

air-filled sacs of the floor and external walls of the tympanic cavity in most mammals. They are formed of tympanic bone, an angular bone homologous to the lower jaw in reptiles. Primitive mastoid cells protect the auditory ossicles and tympanic cavity. Increasing complication of the mastoid cells converts them into acoustic resonators or absorbers. Four types of eardrums are distinguished: spherical, chambered, large-cellular, and spongy-small-cellular. The functions of each type are determined by the acoustic properties of the animals’ habitat and characteristics of their orientation.

G. N. SIMKIN

References in periodicals archive ?
Mastoid cell development was assessed by preoperative computed tomography and classified into one of the four degrees following the 2015 JOS staging system: MC0 (almost no cell growth), MC1 (cellular structures only around the mastoid antrum), MC2 (well-developed cellular structures), and MC3 (cellular structures extending to the peri-labyrinthine area) (Figure 2) [2].
Five out of eight recommended a TNM style system to incorporate other parameters such as ossicular status, mucosal status, and pneumatization of the mastoid cells. Three out of eight recommended increasing the number of stages within the system to incorporate extra parameters.
(1,2,6) Occlusion of the lateral sinus as a result of a nonseptic thrombus impairs venous drainage from the mastoid cells, resulting in venous congestion, interstitial edema, and transudation of fluid into the air spaces.
Computed tomography (CT) showed a loss of aeration in the mastoid cells on the left (figure 1).