6/3/2023 0 Comments Superior quadranto![]() ![]() This quadrant is where it is easiest to see TM movement when a patient performs a Valsalva maneuver. Sometimes the chordi tempani nerve can also be seen in this quadrant. The posterior superior quadrant also contains the incus bone and the stapes bone. This is the “looser” portion of the membrane that forms the “roof.” This is the area where middle ear pressure in the form of bulging is first evident, for example in acute otitis media. This quadrant contains most of the pars flaccida portion of the tympanic membrane. Now that the quadrants have been identified, the significance of each quadrant can be discussed. We now have all four quadrants of the TM identified. This new line separates superior from inferior. At the umbo a line is drawn perpendicular to the previous line separating anterior from posterior. The next step in identifying the quadrants is to locate the umbo of the malleus. Since we now know that this is the left ear, this line separates anterior (front) from posterior (back). Identifying the quadrants proceeds by drawing a line through the malleus. In this example, the malleus is pointing up and to the left, so this must be the left ear. The malleus is also a prominent landmark associated with the TM that helps to distinguish left vs right ear. The malleus is the first ossicle (bone) in the three bone chain that transfers motion of the tympanic membrane to the inner ear. The first step in identifying the quadrants of the tympanic membrane (TM) is locating the malleus bone. The shadow of the eustachian tube orifice is commonly seen in the anterior superior quadrant. For example, infections often first present as bulging in the pars flaccida which is contained mostly in the posterior superior quadrant. Understanding the quadrants of the tympanic membrane (TM, ear drum) is useful to know where to look for certain features.
0 Comments
Leave a Reply. |