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Background: The aim of the study was to determine morphometric and macroanatomic features of auditory ossicles and the tympanic bulla in wolf., Materials and Methods: For this purpose, 7 skulls of adult male wolf were used in the study. Auditory ossicles was photographed on a dissection microscope after it was removed from the skull. A total of 14 morphometric measurements were taken among the different points of malleus, incus and stapes in Image J programme. Mean values of the measurements were obtained and statistically compared in terms of sides (right-left)., Results: In male wolves, the lengths of the right and left malleus were determined as mean 9.35 ± 0.14 and 9.57 ± 0.25 mm, the lengths of the incus as mean 3.01 ± 0.32 and 2.94 ± 0.16 mm, and the lengths of the stapes as mean 2.57 ± 0.12 and 2.59 ± 0.14 mm, respectively. The differences were not statistically significant when all the morphometric parameters were compared in terms of sides (p > 0.05)., Conclusions: It is considered that this study will contribute to the anatomical studies to be conducted in the Canidae family regarding auditory ossicles.

The middle ear bones of Mesozoic mammals are rarely preserved as fossils and the morphology of these ossicles in the earliest mammals remains poorly known. Here, we report the stapes and incus of the euharamiyidan Arboroharamiya from the lower Upper Jurassic (∼160 Ma) of northern China, which represent the earliest known mammalian middle ear ossicles. Both bones are miniscule in relation to those in non-mammalian cynodonts. The skull length/stapedial footplate diameter ratio is estimated as 51.74 and the stapes length as the percentage of the skull length is 4%; both numbers fall into the stapes size ranges of mammals. The stapes is "rod-like" and has a large stapedial foramen. It is unique among mammaliaforms in having a distinct posterior process that is interpreted as for insertion of the stapedius muscle and homologized to the ossified proximal (stapedial) end of the interhyal, on which the stapedius muscle attached. The incus differs from the quadrate of non-mammalian cynodonts such as morganucodontids in having small size and a slim short process. Along with lack of the postdentary trough and Meckelian groove on the medial surface of the dentary, the ossicles suggest development of the definitive mammalian middle ear (DMME) in Arboroharamiya. Among various higher-level phylogenetic hypotheses of mammals, the one we preferred places "haramiyidans" within Mammalia. Given this phylogeny, development of the DMME took place once in the allotherian clade containing euharamiyidans and multituberculates, probably independent to those of monotremes and therians. Thus, the DMME has evolved at least three times independently in mammals. Alternative hypothesis that placed "haramiyidans" outside of Mammalia would require independent acquisition of the DMME in multituberculates and euharamiyidans as well as parallel evolution of numerous derived similarities in the dentition, occlusion pattern, mandibles, cranium, and postcranium between the two groups and between "haramiyidans" and other mammals. J. Morphol. 279:441-457, 2018. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Determining the degree of ossicular fixation is a difficult task, with the final assessment often being made with manual palpation during exploratory tympanotomy. A more objective method to evaluate ossicular fixation would be valuable. In this paper we describe a new method which makes use of a magnet and coil to measure ossicular motion through the ear canal with an elevated tympanic membrane. We report measurements of the vibration response at the umbo, the tip of the incus long process and the lateral posterior crus of the stapes before and after artificially fixing the stapes footplate and anterior mallear ligament with luting cement. Results were obtained on temporal bones, but the practicality of the method allows easy clinical implementation. Velocity ratios between different measurement points along the ossicular chain may provide a quantitative indication of the degree of stapes fixation. Isolated anterior mallear ligament fixation was not distinguishable from the unfixed condition., (Copyright © 2016 Elsevier B.V. All rights reserved.)

We have performed a study on 11 human embryos regarding the development of the tympanic ossicles and their relationship with the first pharyngeal arch. After performing measurements to date the embryos and foetuses chronologically, we performed a meticulous dissection of the temporal bones. Subsequently, they were fixed in 10% formol, decalcified with 2% nitric acid, embedded in Paraplast, sectioned in 7-mm sequences and stained with Martin's trichrome technique. In the 21- and 24-mm cranium-raquis (CR) length human embryos, we have observed the head of the malleus and the body of the incus close to Meckel's cartilage, in addition to the handle of the malleus, the long limb of the incus and the stapes. Between them there was a mesenchymal band inside the primordium of the tympanic cavity. In the 27-mm CR embryo, the various components of the malleus and incus were fusing, and in the 30-mm CR embryo the union was complete. From our observations, we can conclude that the malleus and the incus are derived from the first and second pharyngeal arches.

The auditory anatomy of the Florida manatee (Trichechus manatus latirostris) was investigated using computerized tomography (CT), three-dimensional reconstructions, and traditional dissection of heads removed during necropsy. The densities (kg/m3) of the soft tissues of the head were measured directly using the displacement method and those of the soft tissues and bone were calculated from CT measurements (Hounsfield units). The manatee's fatty tissue was significantly less dense than the other soft tissues within the head (p<0.05). The squamosal bone was significantly less dense than the other bones of the head (p<0.05). Measurements of the ear bones (tympanic, periotic, malleus, incus, and stapes) collected during dissection revealed that the ossicular chain was overly massive for the mass of the tympanoperiotic complex.

This study was designed to reveal, in detail, the features of the auditory ossicles of the New Zealand rabbit, one of the most frequently used animals in scientific researches. Heads of 10 dead adult New Zealand rabbits of both sexes weighing 2.5 +/- 0.2 kg were used in the study. The auditory ossicles were gently removed from their situs and observed. The auditory ossicles were three small bones: the malleus, the incus and the stapes. The lenticular bone seemed to be the lenticular process, as is in human beings. In general, macroanatomic features of the bones were similar to those reported in the literature. Findings in this study, however, differed greatly, especially in detail. There were statistically significant differences in the morphometric data of the features of the auditory ossicles between the right- and left-hand sides. Data from the right-hand side were significantly higher.

Background: The human middle ear presents some anatomical detail which can not be explained exclusively by sound transmission (joints, muscles). These details can be interpreted as an adaptation to environmental atmospheric pressure loads. In order to further investigate the influence of these non-acoustic loads on the geometry of the middle ear structures, the ossicles of animals from different environments were examined., Methods: In the first half of our century, the zoologist C. F. Werner collected the ossicles of 175 species, mostly mammals and birds. This collection was now cataloged and analysed with light and x-ray microscopy., Results and Discussion: The diversity in size and design of the ossicles seems to be influenced not only by the acoustic environment of the animal--the ossicles of mammals living in the desert are relatively large, reflecting the better sensitivity of their middle ear for the far traveling low frequencies--but especially the bony structure of the ossicles can be related to the static loads of the environment of the animal. Ossicles of aquatic mammals are more solid and denser than in terrestrial forms. The bony structure aligns to the static load. This structural principle forms the basis of the skeleton and muscles and can also be found in the human stapes: the asymmetry of the stapedial arch can be explained as adaptation of the bony structure to the pull of the stapedius muscle., Conclusions: The anatomical structure of the ossicles of human and animal origin is not only influenced by its function as sound transmitter, but it is also shaped by nonacoustic forces and static loads of the environment.

The dimensions of the space between the handle of the malleus and the plane of the head of the stapes have been investigated in 31 preserved temporal bones and 20 patients with defects of the incus. The width (A) and depth (B) were measured directly and other dimensions were then calculated. In the preserved temporal bones A varied between 0.5 and 3 mm (mean 2.0 mm), while for the patients the range was 1.5-3.8 mm (mean 2.2 mm). The dimension B varied between 1 and 2.5 mm (mean 1.7 mm) in the temporal bones and between 0 and 2 mm in the patients (mean 0.9 mm). This difference is statistically significant (P less than 0.0001). The angle at which a graft placed directly between the stapes head and malleus handle would lie relative to the long axis of the stapes varied between 14 degrees and 71 degrees in the temporal bones (mean 49 degrees) and between 0 degrees and 79 degrees in the patients (mean 63 degrees). This difference is also statistically significant (P less than 0.001). These differences may be due to chronic Eustachian tube dysfunction or to a tendency of the malleus to become displaced medially when it is not supported by the incus/stapes complex. These findings have significant implications for the mechanical properties of different methods of ossiculoplasty, and the relative position of the malleus and stapes should be taken into account when choosing the technique to be used in an individual case.

The dimensions and the mass of the auditive ossicles was determined bilaterally in 100 human fetuses, of each sex aged from 21 to 40 weeks and 20 individual adults aged 18 to 40 years. It was found that the development of auditive ossicles in human is not completed during fetal life. The analyzed parameters of malleus (a, b, c, d1, d2, e) in the over fetal life period increased adequately by 14.02%, 11.22%, 16.70%, 12.80%, 12.01%, 21.98%, incus by (a, b, c1, c2, d, e) - 7.61%, 11.48%, 11.40%, 23.59%, 12.14%, 14.94%, stapes by (a, b, c, d, e, f) - 6.28%, 7.66%, 8.40%, 4.54%, 4.54%, 4.16%. In the over fetal life period increase of weight of malleus by 22.05%, incus by 26.49%, stapes by 11.57% was also observed. Described parameters of ossicles system are very important with respect to classification to the operations improving hearing in the system convecting of vibration of the tympanic membrane in children.

The evolution of the middle ear is central to the discussion of how the first tetrapods adapted to life on land as well as their phylogeny. Here I report the discovery of the stapes of Acanthostega gunnari, from the Upper Devonian of east Greenland. This is the earliest tetrapod stapes so far described, and it throws new light on both these aspects of early tetrapod biology. It has been assumed that the common inheritance of all early tetrapods was a light, rod-like stapes associated with a temporal notch in the otic region that was thought to have supported a tympanum, or eardrum. The stapes would have conducted vibrations from the tympanum to the otic capsule. By contrast, the stapes of Acanthostega was stout with a broad distal ramus associated with the temporal notch. I suggest that the temporal notch of Acanthostega and other early tetrapods supported a spiracular opening rather than a tympanum, and that the stapes controlled palatal and spiracular movements in ventilation.

The authors studied variations of the position of stapes in the fossula of ovale window on 300 preparations of temporal bones, under operating microscope. They noted three possible positions of the stapes: most commonly downwards to the promontorium (76%), much less frequently (15%) towards the bottom of the fossula, and rarely upwards to the facial canal (9%). Knowledge of these anatomic variations is of great importance in surgical procedures performed in this region.

In an attempt to improve results in ossicular reconstruction, a newly introduced material, PlastiPore, has been evaluated over a short term. The techniques employed are described in detail and the use of a lateral covering material such as tragal cartilage is advocated as a means of preventing extension of this foreign material. The results in over 100 ears are better than those obtained with previous methods.

Adult and fetal human stapes were removed by means of the stereoscopic microscope in order to compare the size of the lamina or crista that joins the crura of the stapes and rests in the lateral aspect of the basis. 65 out of 110 specimens showed cristae of different sizes, whereas the remaining 35% did not possess this structure. The cristae were classified into large, medium-sized and rudimentary. Several incomplete or irregular structures were also found. The cristae or laminae divide the lateral aspect of the base into two fossae: a small upper one and a large lower one, although several variations were found. An edge of the pillar groove was usually continuous with the cristae; however, compact pillars were found at the point where they reach the base, where the cristae orginates. Asymmetrical cristae and changes in the general shape of the stapes were found in several specimens. Two ossicles showed crista with orifices due to resorption or to the passage of vessels.

The amount and distribution of the post-natal bone deposition in the auditory ossicles and in the left tibia of dogs of varying ages were studied by means of alizarin labelling. The relative amount of fluorescent new-formed bone was expressed as a percentage ratio NB/(NB+PB) of new bone (NB) on the pre-existing bone (PB). The result was that the post-natal bone deposition (1) was larger in the tibia than in the incus, malleus and stapes; (2) significantly decreased with age both in the ossicles and in the tibia; (3) in the stapes it stopped at 3 months, while it was present in the tibia, incus and malleus even at 12 months. In the ossicles the post-natal bone deposition takes place both on the periosteal surfaces of the ossicles and on the internal surfaces of the haversian systems. The first process produces an appositional growth that stops in all three ossicles within the 1st month of post-natal life, the second one produces an internal growth that continues until the age of three months in the stapes, while in the incus and malleus it occurs in small amounts, even in the 12th month of life. In the ossicles all the new-formed bone tissue, periosteal and osteonic, is built up by primary bone (addition bone). In the tibia from 50 days of age the primary bone is gradually replaced by secondary haversian systems as a consequence of remodelling processes.

During exploratory tympanotomy for conductive deafness, the surgeon is occasionally perplexed to find no apparent cause for the air-bone gap. This unexplained deafness has been called "inner ear conductive hearing less" because of the apparent absence of pathology in the middle ear. The incudostapedial joint was studied in 68 vertically sectioned temporal bones and the anatomy is presented. Varying amounts of laxity is observed in the normal joint capsule at the time of surgery. A theory is suggested in which an elongated capsule allows incus motion without energy transmission to the stapes. It is proposed that hypermobility of the incudostapedial joint may exist and explain conductive hearing loss of undetermined etiology.

In a series of 100 cases, morphological variations of human ossicula tympani were studied. These have seldom been considered either in classic or recent descriptions. Among them, the malleus and stapes are the most variable ones. A geometric model is proposed to systematically study any variation from the typical ossicles. These morphological variations of ossicles could be related to age, sex, race, and could bring out peculiarities in acoustic transmission.

High-resolution Computed Tomography (HRCT) of the temporal bone has now become a routine test for the diagnosis of various temporal bone lesions. Correct assessment of such minute structures as ossicles, especially stapes, is important in the pre-operative HRCT evaluation. On the other hand, analysis for the reliability of HRCT findings has not been done, including the superstructure of the stapes. A retrospectively study was done in order to assess the availability of HRCT findings in axial overlapping scans in 226 ears, with respect to the superstructures of stapes. The study was concerned with the analysis of HRCTs of 148 normal ears, 71 ears of chronic otitis media and 7 ears of ossicular abnormalities. HRCT findings were compared to those of surgeries in pathological cases. The present study revealed that the superstructures of stapes are noted in 70% when the stapes surrounded by air. The major limitations in the proper analysis of stapes by HRCT are partial volume averaging and effects of soft tissue silhouetting, this is especially so when the stapes is surrounded by soft tissue density.

A study of mastoid bones showed a central position of stapes only at 67%. At 21% a deviation exist to the side of promontorium and at 12% a position directly at the promontorium. Secondly is to remark the position of the posterior crus incudis lateral on the footplate to the side of promontorium. The cause is to see the movement of the labyrinth in connection with the upright posture.