On the coupling between the incus and the stapes in the cat. (1/15)
The connection between the long process and the lenticular process of the incus is extremely fine, so much so that some authors have treated the lenticular process as a separate bone. We review descriptions of the lenticular process that have appeared in the literature, and present some new histological observations. We discuss the dimensions and composition of the lenticular process and of the incudostapedial joint, and present estimates of the material properties for the bone, cartilage, and ligament of which they are composed. We present a preliminary finite-element model which includes the lenticular plate, the bony pedicle connecting the lenticular plate to the long process, the head of the stapes, and the incudostapedial joint. The model has a much simplified geometry. We present simulation results for ranges of values for the material properties. We then present simulation results for this model when it is incorporated into an overall model of the middle ear of the cat. For the geometries and material properties used here, the bony pedicle is found to contribute significant flexibility to the coupling between the incus and the stapes. (+info)Joint formation in the middle ear: lessons from the mouse and guinea pig. (2/15)
The malleus, incus and stapes form an ossicle chain in the mammalian middle ear. These ossicles are articulated by joints that link the chain together. In humans and mice, fusion of the ossicles leads to hearing loss. However, in the adult guinea pig the malleus and incus are normally found as a single complex. In this report, we investigate how the malleus and incus form during mouse and guinea pig development. The murine malleus and incus develop from a single condensation that splits to form the two ossicles. Even before a morphological split, we show that the ossicles have distinct genetic identities and joint markers are expressed. In the guinea pig embryo, joint formation is initiated but no cavitation is observed, resulting in a single complex divided by a thin suture. The malleal-incudo complex in the guinea pig is, therefore, not caused by a defect in joint initiation. (+info)Single-shot, turbo spin-echo, diffusion-weighted imaging versus spin-echo-planar, diffusion-weighted imaging in the detection of acquired middle ear cholesteatoma. (3/15)
Diagnosis of acquired middle ear cholesteatoma on MR imaging is mostly done on late postgadolinium T1-weighted MR images and/or echo-planar (EPI) diffusion-weighted (DWI) MR images. We describe the appearance of a case of a complicated attical middle ear cholesteatoma on single-shot (SS) turbo spin-echo (TSE) DWI compared with EPI-DWI. This case suggests a higher reliability of SS TSE-DWI in the diagnosis of acquired middle ear cholesteatoma. (+info)Soft tissue morphometry of the malleus-incus complex from micro-CT imaging. (4/15)
(+info)How reproducibly can human ear ossicles be measured? A study of inter-observer error. (5/15)
(+info)The lenticular process of the incus. (6/15)
(+info)Effects of middle-ear disorders on power reflectance measured in cadaveric ear canals. (7/15)
(+info)Vibrations in the human middle ear. (8/15)
BACKGROUND: Middle ear surgery techniques can improve hearing destroyed by disease, but results of treatment are difficult to predict. Therefore, researchers use a Laser Doppler Vibrometer to measure vibrations of human middle ear ossicles. MATERIAL/METHODS: Measurements of ossicular chain vibrations are performed on fresh human temporal bone specimens using Laser Doppler Vibrometer. Vibrations of stapes are recorded in 3 cases: 1) for intact ossicular chain, 2) when incus long process is removed, and 3) after long process reconstruction with bone cement. A typical analysis of transfer function is completed by other methods applied in dynamics. RESULTS: Measurements and analysis of stapes vibrations in case of intact and damaged ossicular chain show regular and irregular behavior which can be recognize with the help of phase portraits, recurrence plots, correlation dimension, and Hurst and Lyapunov exponents. The long process reconstruction with bone cement gives good results in improving hearing. CONCLUSIONS: Recurrence plots, and Lyapunov and Hurst exponents used in the study complete information obtained from transfer function and can be employed to enrich the classical approach to ossicular chain vibrations.(+info)