Noninvasive characterization of the healthy human manubrium using diffuse optical spectroscopies.

The abnormal, uncontrolled production of blood cells in the bone marrow causes hematological malignancies which are common and tend to have a poor prognosis. These types of cancers may alter the hemodynamics of bone marrow. Therefore, noninvasive methods that measure the hemodynamics in the bone marrow have a potential impact on the earlier diagnosis, more accurate prognosis, and in treatment monitoring. In adults, the manubrium is one of the few sites of bone marrow that is rich in hematopoietic tissue and is also relatively superficial and accessible. To this end we have combined time resolved spectroscopy and diffuse correlation spectroscopy to evaluate the feasibility of the noninvasive measurement of the hemodynamics properties of the healthy manubrium in 32 subjects. The distribution of the optical properties (absorption and scattering) and physiological properties (hemoglobin concentration, oxygen saturation and blood flow index) of this tissue are presented as the first step toward investigating its pathology.

Small tympanic membrane perforations in the inferior quadrants do not impact the manubrium vibration in guinea pigs.

BACKGROUND: It has been believed that location of the perforation has a significant impact on hearing loss. However, recent studies have demonstrated that the perforation sites had no impact on hearing loss. We measured the velocity and pattern of the manubrium vibration in guinea pigs with intact and perforated eardrum using a laser Doppler vibrometer in order to determine the effects of different location perforations on the middle ear transfer functions. METHODS: Two bullas from 2 guinea pigs were used to determine stability of the umbo velocities, and 12 bullas from six guinea pigs to determine the effects of different location perforations on sound transmission. The manubrium velocity was measured at three points on the manubrium in the frequencies of 0.5-8 kHz before and after a perforation was made. The sites of perforations were in anterior-inferior (AI) quadrants of left ears and posterior-inferior (PI) quadrants of right ears. RESULTS: The manubrium vibration velocity losses were noticed in the perforated ears only below 1.5 kHz. The maximum velocity loss was about 7 dB at 500 Hz with the PI perforation. No significant difference in the velocity loss was found between AI and PI perforations. The average ratio of short process velocity to the umbo velocity was approximately 0.5 at all frequencies. No significant differences were found before and after perforation at all frequencies (p>0.05) except 7 kHz (p = 0.004) for both AI and PI perforations. CONCLUSIONS: The manubrium vibration velocity losses from eardrum perforation were frequency-dependent and the largest losses occur at low frequencies. Manubrium velocity losses caused by small acute inferior perforations in guinea pigs have no significant impact on middle ear sound transmission at any frequency tested. The manubrium vibration axis may be perpendicular to the manubrium below 8 kHz in guinea pigs.

Biomechanical impact response of the human chin and manubrium.

Chin-to-chest impact commonly occurs in frontal crash simulations with restrained anthropomorphic test devices (ATDs) in non-airbag situations. This study investigated the biofidelity of this contact by evaluating the impact response of both the chin and manubrium of adult post-mortem human subjects (PMHSs). The adult PMHS data were scaled to a 10-year-old (YO) human size and then compared with the Hybrid III 10YO child (HIII-10C) ATD response with the same test configurations. For both the chin and manubrium, the responses of the scaled PMHS had different characteristics than the HIII-10C ATD responses. Elevated energy impact tests to the PMHS mandible provided a mean injury tolerance value for chin impact force. Chin contact forces in the HIII-10C ATD were calculated in previously conducted HYGE sled crash simulation tests, and these contact forces were strongly correlated with the Head Injury Criterion (HIC(36 ms)). The mean injurious force from the PMHS tests corresponded to a HIC(36 ms) value that would predict an elevated injury risk if it is assumed that fractures of the chin and skull are similarly correlated with HIC(36 ms). Given the rarity of same occupant-induced chin injury in booster-seated occupants in real crash data and the disparity in chin and manubrium stiffnesses between scaled PMHS and HIII-10C ATD, the data from this study can be made use of to improve biofidelity of chin-to-manubrium contact in ATDs.

A sum of simple and complex motions on the eardrum and manubrium in gerbil.

Based on comparisons of ear canal and scala vestibuli pressures the gerbil middle ear transmits sound with a gain of approximately 25 dB that is almost flat from 2 to 40 kHz, and with a delay-like phase corresponding to a 25-30 micros delay. How the middle ear is able to transmit sound with such high temporal and amplitude fidelity is not known, and is particularly mysterious given the complex motion the ossicles and tympanic membrane (TM) are known to undergo. To explore this question, we looked at the velocities of the manubrium and along a line on the TM. The TM motion was complex, and could be approximated as the combination of a wave-like motion and an in-and-out piston-like motion. The manubrium underwent bending at some stimulus frequencies and therefore its motion was not like a rigid body. It had a complex motion with frequency fine structure that seemed likely to be derived from resonances on the drum-like TM.

[Contribution to the development of the union between the manubrium of the malleus and the tympanic membrane in human fetus]. / Contribución al desarrollo de la unión del mango del martillo y la membrana del tímpano en fetos humanos.

The development of the union between the manubrium of the malleus and the tympanic membrane was studied in human embryo. For that purpose 25 temporal bones of human foetus, aged from 36 days (14 mm) to 29 weeks (270 mm) were analyzed. Samples were fixed in a 10% formaldehyde solution, decalcified with 2% nitric acid, embedded in Paraplast, cut in sections of 7 microns thick and stained with Martin's trichrome method. During the development a pseudojoint between the malleus and the tympanic membrane several stages were seen. In the first stage, the manubrium was adhered to membrane mesenchyme of primitive tympanum, in the second one this mesenchyme was loose and there appeared capillars in it, in the third one there were collagen fibers in a radial disposition, and in the forth stage, the hollow in the meatal plug gave independence to the tympanic membrane for the external acoustic meatus. The distal portion of the manubrium, included in tympanic membrane, has remained with a cartilaginous structure during end of the time it has been studied by us. The collagen fibers at the level of the umbo surround the manubrium, while the rest of it remains in its anterior edge.

Contribución al desarrollo de la unión del mango del martillo y la membrana del tímpano en fetos humanos / Contribution to the development of the union between the manubrium of the malleus and the tympanic membrane in human fetus

Se ha estudiado el desarrollo de la unión entre el mango del martillo y la membrana del tímpano en embriones y fetos humanos.Para ello se han utilizado 25 huesos temporales de fetos humanos, cuyas edades cronológicas van desde los 36 días (14 mm) hasta las 29 semanas (270 mm). Las muestras fueron fijadas en formol al 10 por ciento, descalcificadas con ácido nítrico al 2 por ciento, incluidas en parafina, cortadas en serie a 7 µm, y teñidas con el método Tricrómico de Martins. Se han identificado varias etapas en el desarrollo de la pseudoarticulación entre el martillo y la membrana del tímpano. En la primera el mango se adhiere íntimamente al mesénquima de la membrana del tímpano primitiva, en la segunda dicho mesénquima se hace laxo y en él aparecen capilares, en la tercera aparecen fibras de colágeno de disposición radial, y en la cuarta el ahuecamiento del tapón meatal da independencia a la membrana del tímpano del conducto auditivo externo. La porción distal del mango, incluida en la membrana del tímpano, ha permanecido con una estructura cartilaginosa durante todo el tiempo estudiado. Las fibras de colágeno a nivel del umbo rodean al extremo terminal del mango mientras que en el resto de él lo hacen solamente en su arista anterior (AU)

The development of the union between the manubrium of the malleus and the tympanic membrane was studied in human embryo. For that purpose 25 temporal bones of human foetus, aged from 36 days (14 mm) to 29 weeks (270 mm) were analyzed. Samples were fixed in a 10% formaldehyde solution, decalcified with 2% nitric acid, embedded in Paraplast, cut in sections of 7 microns thick and stained with Martin's trichrome method. During the development a pseudojoint between the malleus and the tympanic membrane several stages were seen. In the first stage, the manubrium was adhered to membrane mesenchyme of primitive tympanum, in the second one this mesenchyme was loose and there appeared capillars in it, in the third one there were collagen fibers in a radial disposition, and in the forth stage, the hollow in the meatal plug gave independence to the tympanic membrane for the external acoustic meatus. The distal portion of the manubrium, included in tympanic membrane, has remained with a cartilaginous structure during end of the time it has been studied by us. The collagen fibers at the level of the umbo surround the manubrium, while the rest of it remains in its anterior edge (AU)

Low-frequency coupling between eardrum and manubrium in a finite-element model.

The mechanical coupling between the eardrum and the manubrium was studied by means of a finite-element model of the cat eardrum. Previous calculations of the effect of varying the eardrum curvature were extended, demonstrating the critical role of curvature in the behavior of the eardrum. A new procedure was developed for directly studying the coupling of forces from different points on the eardrum to the manubrium, and the distribution of load-coupling values over the eardrum surface was calculated. A geometrically simplified eardrum with a circular outline was also studied. It was found that certain regions of the eardrum are more effective in driving the manubrium than can be explained on the basis of their distance from the axis of rotation. This enhanced coupling depends on the curvature of the eardrum but, unlike the mechanism hypothesized by Helmholtz, requires neither tension nor anisotropy.

Modelling the malleus vibration as a rigid body motion with one rotational and one translational degree of freedom.

Vibration of a set of points distributed along the manubrium of cat was measured with a heterodyne interferometer in response to sinusoidal acoustic signals. The observed motion did not fit pure rotation of the malleus around a fixed axis coinciding with the anterior mallar and posterior incudal ligament as is classically assumed. As a first approximation a model of motion consisting of a rotational and a translational component was used. At low frequencies the rotation is mostly predominant, but the situation may be entirely reversed at mid and high frequencies. The presence of a translation besides rotation was also found at some frequencies in the motion of the human malleus.

Malleus vibration mode changes with frequency.

The mode of vibration of the cat manubrium is investigated by measuring its vibration in response to sound stimulus at four locations between the umbo and the processus lateralis with a heterodyne interferometer. The determination of mode requires high precision in measurement because amplitude differences between the points are small (about 20% at low audio-frequencies). Changes in the frequency response with time have been reported in an earlier paper. The nature and magnitude of this time change is analysed in detail: over a period of 1 h the average change in amplitude is about 5% and in phase 5 degrees. The malleus vibration at some frequencies is purely translational, it is rotational at others and mixed at most frequencies. When the motion is rotational the position of the axis of rotation shifts with frequency, the shifts are so large that the axis can lie near the umbo so that amplitudes at the processus lateralis are larger than at the umbo. The classical concept of the malleus rotating around a fixed axis running from the anterior mallar to the posterior incudal ligament fits our measurements only at low frequencies.

Human tympanic membrane deformation under static pressure.

The effect of static pressures in the range of plus and minus 1.6 kPa on the shape of tympanic membrane is measured using a non-contacting optical technique on a fresh human temporal bone. Full field data of the deformation are presented as well as cross-sections along two major directions. Strong asymmetry between medial and lateral movements is demonstrated. The displacement of the umbo is compared to other work. The rotation angle of the manubrium in function of pressure is calculated and also compared to other work. It is demonstrated that the rotation angels can not account for the measured movement of the umbo, which leads to the conclusion that for static high pressure levels the classical hypothesis of rotation around a fixed axis has to be abandoned. The comparison with data of TM displacement under dynamic stimuli is discussed.

Heterodyne interferometer measurements of the frequency response of the manubrium tip in cat.

A heterodyne interferometer proved to be a very accurate tool to measure amplitude and phase of the malleus response during acoustical stimulation. It was shown that to obtain equal accuracy in the acoustical pressure measurements, pressure response must be remeasured at short time intervals. At frequencies above 4 kHz various gross resonances are apparent on the frequency response curves. The resonances are, depending on the animal, more or less pronounced. As a result of the improved accuracy changes of the malleus vibration response with time could clearly be discriminated. These changes can be related to shifts in frequency of the position of these resonances. Comparison of experimental frequency response and lumped parameter model predictions from literature shows that these resonances are not present in the model responses.