Disease relevance of Malleus

• The audiologic test results in the fixed malleus cases reviewed for this study often presented a misleading picture, sometimes mimicking stapedial otosclerosis with a characteristic Carhart's notch and sometimes indistinguishable from sensorineural presbycusis [1].

High impact information on Malleus

• Contrary to expectations, murine Bapx1 does not affect the articulation of the malleus and incus [2].
• Msx genes, thus, appear to act in a cell autonomous manner, possibly by regulating Bmp4 expression, in the formation of the malleus [3].
• A functional redundancy of Msx1 and Msx2 in the development of the middle ear is suggested by the stronger hypomorphism in the malleus of Msx1(-/-)/Msx2(-/-) embryos, including the absence of the malleal manubrium and the malleal processus brevis [3].
• These defects included loss of the tympanic ring and malformation of the malleus, phenotypes which were reminiscent of the teratogenic effects of retinoic acid (RA) [4].
• Fracture of the malleus or incus is detected with axial or coronal images; reformatted images may also be useful [5].

Anatomical context of Malleus

• In the case of a missing incus and stapes superstructure, an incus/stapes prosthesis of dense hydroxyapatite, as assembly between footplate and handle of the malleus, was used [6].
• Formalin preserved homograft tympanic membranes with attached malleus offer significant advantages over standard tympanoplasty techniques in these specific indications [7].
• [J. Acoust. Soc. Am. 82, 1646-1654 (1987)] of malleus umbo and anterior crus of stapes displacement in 14 human temporal bones shows a mean -7.3-dB/oct slope above 1.0 kHz for stapes displacement in response to a 80-dB SPL input at the eardrum [8].

Associations of Malleus with chemical compounds

• In the case of a missing incus, an assembly prosthesis of dense hydroxyapatite is placed on top of the stapes head and the handle of the malleus, in a pocket between drum membrane and the neck of the malleus [6].
• Thin sections were cut parallel with, and perpendicular to, the handle of the malleus, stained with haematoxylin-eosin, toluidine blue or Giemsa stain and examined under a light microscope [9].
• One hour after injection, BrdU-labeled cells were found in the handle of the malleus (HM) region and in the annular region of the pars tensa of the TM [10].
• CONCLUSION: The functional results of the L-shaped Fisch titanium total prosthesis implanted in ears with the stapes but no malleus handle are best at 2 kHz and better than those of comparable columellar titanium prostheses over the remaining tested frequencies [11].

Gene context of Malleus

• Since normal drilling procedures would result in a sensorineural hearing loss, the argon laser was chosen to remove a bony spur connecting the malleus to the posterior canal wall [12].
• Reconstruction of hearing when malleus is absent: TORP vs. homograft TMMI [13].
• Histologic changes in the anterior mallear ligament and the head of the malleus in otosclerosis [14].
• When the malleus handle was present (n = 126), the PTA-ABG was 11.6+/-6.2 dB, compared with 16.9+/-10.1 dB when it was absent (n = 74), which was statistically significant (p < 0.05) [15].
• The normal Ca/P ratio for malleus is 2.10, and 2.19 for incus [16].

Analytical, diagnostic and therapeutic context of Malleus

• This study presents the details of clinical phase I, in which an electromagnetic driver was coupled with a target magnet temporarily affixed onto the lateral surface of the malleus of six hearing aid users with sensorineural losses [17].
• Stapedectomy for otosclerosis with malleus fixation [18].

References