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Anatomical Record (Hoboken, N.J. : 2007) Nov 2023The placental order Dermoptera, which includes two extant species, the Philippine and Sunda flying lemurs, Cynocephalus volans and Galeopterus variegatus, respectively,...
The placental order Dermoptera, which includes two extant species, the Philippine and Sunda flying lemurs, Cynocephalus volans and Galeopterus variegatus, respectively, is generally held to be the sister group of Primates. Yet, little has been reported on their cranial anatomy. Here, the anatomy of the ear region is described and illustrated for a juvenile and adult C. volans based on CT scans. The inclusion of a juvenile is essential as nearly all cranial sutures are fused in the adult. Soft tissues are reconstructed based on sectioned histological pre- and postnatal specimens previously reported by the author. Numerous unusual features are identified, including: a small parasphenoid beneath the basisphenoid, a tensor tympani fossa on the epitympanic wing of the squamosal, a cavum supracochleare for the geniculate ganglion of the facial nerve that is not enclosed in the petrosal bone, a secondary facial foramen between the petrosal and squamosal, a secondary posttemporal foramen leading to the primary one, a subarcuate fossa that is floored in part by a large contribution from the squamosal, a body of the incus larger than the head of the malleus, and a crus longum of the incus that lacks an osseous connection to the lenticular process. Documentation of the anatomy of the Philippine flying lemur ear region is an essential first step in morphological phylogenetic analyses where features of the basicranium are widely sampled.
Topics: Pregnancy; Animals; Female; Phylogeny; Lemur; Philippines; Placenta; Primates; Chiroptera
PubMed: 36897245
DOI: 10.1002/ar.25174 -
Anatomical Record (Hoboken, N.J. : 2007) Nov 2019Development of mouse gonial bone and initial ossification process of malleus were investigated. Before the formation of the gonial bone, the osteogenic area expressing...
Development of mouse gonial bone and initial ossification process of malleus were investigated. Before the formation of the gonial bone, the osteogenic area expressing alkaline phosphatase and Runx2 mRNA was widely recognized inferior to Meckel's cartilage. The gonial bone was first formed within the perichondrium at E16.0 via intramembranous ossification, surrounded the lower part of Meckel's cartilage, and then continued to extend anteriorly and medially until postnatal day (P) 3.0. At P0, multinucleated chondroclasts started to resorb the mineralized cartilage matrix with ruffled borders at the initial ossification site of the malleus (most posterior part of Meckel's cartilage). Almost all CD31-positive capillaries did not run through the gonial bone but entered the cartilage through the site where the gonial bone was not attached, indicating the forms of the initial ossification site of the malleus are similar to those at the secondary ossification center rather than the primary ossification center in the long bone. Then, the reducing process of the posterior part of Meckel's cartilage with extending gonial bone was investigated. Numerous tartrate-resistant acid phosphatase-positive mononuclear cells invaded the reducing Meckel's cartilage, and the continuity between the malleus and Meckel's cartilage was completely lost by P3.5. Both the cartilage matrix and the perichondrium were degraded, and they seemed to be incorporated into the periosteum of the gonial bone. The tensor tympani and tensor veli palatini muscles were attached to the ligament extending from the gonial bone. These findings indicated that the gonial bone has multiple functions and plays important roles in cranial formation. Anat Rec, 302:1916-1933, 2019. © 2019 American Association for Anatomy.
Topics: Animals; Bone Development; Cartilage; Female; Malleus; Mandible; Mice; Mice, Inbred ICR; Ossification, Heterotopic; Osteogenesis
PubMed: 31197954
DOI: 10.1002/ar.24201 -
Otology & Neurotology : Official... Jan 2021This study aimed to evaluate success rates after ossicular chain reconstruction using different materials.
OBJECTIVE
This study aimed to evaluate success rates after ossicular chain reconstruction using different materials.
STUDY DESIGN
Retrospective cohort study.
SETTING
Tertiary referral center.
PATIENTS
Four hundred forty-three participants who underwent ossiculoplasty at a tertiary medical center were included.
INTERVENTION
Ossicular chain reconstruction using five materials: autologous malleus, incus, and cortical bone, as well as Hydroxyapatite (HA) and titanium.
MAIN OUTCOME MEASURES
Hearing data were measured 1 day preoperatively and 6 months postoperatively. Successful hearing outcomes were defined by the fulfillment of more than one of the following criteria: postoperative air-bone gap of 20 dB or less, hearing air conduction (AC) gain of 15 dB or more, or postoperative AC hearing less than 30 dB.
RESULTS
Preoperative median AC values (95% confidence interval) among participants with malleus, incus, cortical bone, HA, and titanium transplants or prostheses were 50 (39.6-54.6) dB, 51.3 (48.1-51.8) dB, 50 (45.2-52.2) dB, 56.3 (50.9-57.6) dB, and 54.3 (48.5-56.0) dB, respectively (p = 0.092). The success rates in malleus, incus, cortical bone, HA, and titanium were 53.3%, 60.3%, 51.7%, 61.6%, and 69.7%, respectively. Titanium had the highest success rate among the five materials, but the differences between the materials were not statistically significant (p = 0.283). Titanium had highest success rate among the participants with erosive stapes suprastructure or obstructed Eustachian tubes (p = 0.042 for erosive stapes suprastructure and p = 0.010 for obstructed Eustachian tubes).
CONCLUSION
Our study demonstrated that titanium prostheses would be a good alternative for ossiculoplasty in cases wherein autologous material is unavailable, especially in association with unfavorable conditions, such as with the presence of cholesteatoma, erosive stapes suprastructure, edematous middle ear mucosa, and obstructed Eustachian tube.
Topics: Humans; Ossicular Prosthesis; Ossicular Replacement; Otitis Media; Retrospective Studies; Treatment Outcome; Tympanoplasty
PubMed: 33201076
DOI: 10.1097/MAO.0000000000002847 -
Indian Journal of Otolaryngology and... Dec 2023The temporal bone is a complex anatomical space that houses the middle ear and its ossicles, as well as the inner ear, which includes the vestibule, cochlea, and the...
The temporal bone is a complex anatomical space that houses the middle ear and its ossicles, as well as the inner ear, which includes the vestibule, cochlea, and the semicircular canals. Henle's spine, also known as the suprameatal spine/spina suprameatica/ is found to guide the lateral wall of the mastoid antrum [J Res Med Dent Sci 8(7):420-422, Stat-Pearls Publishing, Treasure Island. Available from: https://www.ncbi.nlm.nih.gov/books/NBK559153/]. It is found that the Henle's spine is present in 85% of the human skulls and when present, it could be used as a reliable anatomical landmark for isolating various foramina during skull base surgeries [J Laryngol Otol 119:856-861], and to assess the location of handle of malleus and subsequently the mastoid antrum, in many cases. We present here 3 cases in which tympanoplasty was planned, and the position of spine of Henle was found to be anterosuperior and so was the handle of malleus. Antrostomy was done by following the spine of Henle in all cases to establish patency and maintain ventilation in the post-operative ear. These 3 cases had a much more anteriorly placed spine. Such cases need to be reported so that it creates a paradigm shift in the way that mastoid surgeries are being done. Any variation in the positioning of the spine of henle points to variability in the position of the mastoid antrum. This is extremely important while drilling the mastoid in the correct position and also to prevent drilling over the sigmoid sinus or the dura. To conclude, an anteriorly placed spine of Henle corresponds to anteriorly placed mastoid antrum.
PubMed: 37974806
DOI: 10.1007/s12070-023-04017-4 -
Auris, Nasus, Larynx Aug 2021Fibrous dysplasia is an unusual pathologic condition caused by abnormal bone metabolism. Temporal bone involvement is often seen, but it is uncommon to find fibrous...
Fibrous dysplasia is an unusual pathologic condition caused by abnormal bone metabolism. Temporal bone involvement is often seen, but it is uncommon to find fibrous dysplasia limited to the middle ear, especially originating in and confined to a single ossicle. Here we report a case of osteofibrous dysplasia limited exclusively to an ossicle (malleus) causing gradual conductive hearing loss, which recovered after eventual complete removal of the dysplastic area. The lesion showed firm attachment to adjacent structures and initial removal was not possible. This report provides information to help other otologic surgeons facing similar conditions.
Topics: Bone Diseases, Developmental; Female; Fibrous Dysplasia, Monostotic; Hearing Loss, Conductive; Hearing Loss, Unilateral; Humans; Magnetic Resonance Imaging; Malleus; Tinnitus; Tomography, X-Ray Computed; Young Adult
PubMed: 32473859
DOI: 10.1016/j.anl.2020.05.005 -
Hearing Research Jul 2021The incudo-malleal joint (IMJ) in the human middle ear is a true diarthrodial joint and it has been known that the flexibility of this joint does not contribute to...
The incudo-malleal joint (IMJ) in the human middle ear is a true diarthrodial joint and it has been known that the flexibility of this joint does not contribute to better middle-ear sound transmission. Previous studies have proposed that a gliding motion between the malleus and the incus at this joint prevents the transmission of large displacements of the malleus to the incus and stapes and thus contributes to the protection of the inner ear as an immediate response against large static pressure changes. However, dynamic behavior of this joint under static pressure changes has not been fully revealed. In this study, effects of the flexibility of the IMJ on middle-ear sound transmission under static pressure difference between the middle-ear cavity and the environment were investigated. Experiments were performed in human cadaveric temporal bones with static pressures in the range of +/- 2 kPa being applied to the ear canal (relative to middle-ear cavity). Vibrational motions of the umbo and the stapes footplate center in response to acoustic stimulation (0.2-8 kHz) were measured using a 3D-Laser Doppler vibrometer for (1) the natural IMJ and (2) the IMJ with experimentally-reduced flexibility. With the natural condition of the IMJ, vibrations of the umbo and the stapes footplate center under static pressure loads were attenuated at low frequencies below the middle-ear resonance frequency as observed in previous studies. After the flexibility of the IMJ was reduced, additional attenuations of vibrational motion were observed for the umbo under positive static pressures in the ear canal (EC) and the stapes footplate center under both positive and negative static EC pressures. The additional attenuation of vibration reached 4~7 dB for the umbo under positive static EC pressures and the stapes footplate center under negative EC pressures, and 7~11 dB for the stapes footplate center under positive EC pressures. The results of this study indicate an adaptive mechanism of the flexible IMJ in the human middle ear to changes of static EC pressure by reducing the attenuation of the middle-ear sound transmission. Such results are expected to be used for diagnosis of the IMJ stiffening and to be applied to design of middle-ear prostheses.
Topics: Ear, Middle; Humans; Incus; Malleus; Pressure; Sound; Stapes; Temporal Bone; Vibration
PubMed: 34038827
DOI: 10.1016/j.heares.2021.108272 -
Anatomia, Histologia, Embryologia Jan 2021The present paper deals with a detailed description of the auditory ossicles in Capra hircus. The paper focuses on the morphological and morphometrical description of...
The present paper deals with a detailed description of the auditory ossicles in Capra hircus. The paper focuses on the morphological and morphometrical description of the ossicular assembly, formed by malleus, incus and stapes. The malleus (overall length, as average- 8.16 mm) comprises the head of malleus (Caput mallei), a slightly strictured part-neck (Collum mallei) with 3 distinctive processes (lateral, rostral and muscular) (Processus lateralis, Processus rostralis and Processus muscularis) and a handle (Manubrium mallei). The head of malleus has an oval aspect with an obtuse articular surface on its medial surface (Facies articularis). The neck is evident with three bony processes described-the anterior, almost triangular, the muscular one quite reduced and the lateral one which is the most developed one. The manubrium is the longest sector-4.4 mm and appears as a slightly curved piece. The incus presents a body of 1.3 mm and two processes-the short and long crus (Crus breve and Crus longum). The overall shape of the ossicle resembles a biradicular molar. The lenticular process is a continuation of the distal part of the long crus. The stapes-the smallest in size of the three ossicles (2.7 mm), has a head (Caput stapedis), an anterior (Crus rostrale) and a caudal (Crus caudale) arm and a footplate (Basis stapedis). The two processes are slightly different in size and morphology, delimiting the intercrural space that shows the presence of a bony spicule. The footplate (1.6 mm area) is ellipsoidal, with an anterior narrower extremity.
Topics: Animals; Ear Ossicles; Goats
PubMed: 32946143
DOI: 10.1111/ahe.12617 -
Biology Apr 2021The aim of this study is to investigate the underlying mechanisms of the venoarteriolar reflex (VAR) in type 2 diabetes mellitus (T2DM), with and without peripheral...
The aim of this study is to investigate the underlying mechanisms of the venoarteriolar reflex (VAR) in type 2 diabetes mellitus (T2DM), with and without peripheral neuropathy. Laser Doppler flowmetry (LDF) recordings were performed on the medial malleus and dorsal foot skin, before and during leg dependency in healthy controls, in persons with obesity, in those with T2DM, in those with T2DM and subclinical neuropathy, and in those with T2DM and confirmed neuropathy. LDF recordings were analyzed with the wavelet transform to evaluate the mechanisms controlling the flowmotion (i.e., endothelial nitric oxide-independent and -dependent, neurogenic, myogenic, respiratory and cardiac mechanisms). Skin blood perfusion decreased throughout leg dependency at both sites. The decrease was blunted in persons with confirmed neuropathy compared to those with T2DM alone and the controls. During leg dependency, total spectral power increased in all groups compared to rest. The relative contribution of the endothelial bands increased and of the myogenic band decreased, without differences between groups. Neurogenic contribution decreased in controls, in persons with obesity and in those with T2DM, whereas it increased in subclinical- and confirmed neuropathy. In conclusion, this study provides evidence that confirmed diabetic neuropathy alters the VAR through the neurogenic response to leg dependency.
PubMed: 33920825
DOI: 10.3390/biology10040333 -
Hearing Research Mar 2023The three-bone flexible ossicular chain in mammals may allow independent alterations of middle-ear (ME) sound transmission via its two attached muscles, for both... (Review)
Review
The three-bone flexible ossicular chain in mammals may allow independent alterations of middle-ear (ME) sound transmission via its two attached muscles, for both acoustic and non-acoustic stimuli. The tensor tympani (TT) muscle, which has its insertion on the malleus neck, is thought to increase tension of the tympanic membrane (TM). The stapedius (St) muscle, which has its insertion on the stapes posterior crus, is known to stiffen the stapes annular ligament. We produced ME changes in human cadaveric temporal bones by statically pulling on the TT and St muscles. The 3D static TM shape and sound-induced umbo motions from 20 Hz to 10 kHz were measured with optical coherence tomography (OCT); stapes motion was measured using laser-Doppler vibrometry (LDV). TT pulls made the TM shape more conical and moved the umbo medially, while St pulls moved the umbo laterally. In response to sound below about 1 kHz, stapes-velocity magnitudes generally decreased by about 10 dB due to TT pulls and 5 dB due to St pulls. In the 250 to 500 Hz region, the group delay calculated from stapes-velocity phase showed a decrease in transmission delay of about 150 µs by TT pulls and 60 µs by St pulls. Our interpretation of these results is that ME-muscle activity may provide a way of mechanically changing interaural time- and level-difference cues. These effects could help the brain align head-centered auditory and ocular-centered visual representations of the environment.
Topics: Animals; Humans; Tympanic Membrane; Ear, Middle; Stapes; Sound; Tensor Tympani; Temporal Bone; Vibration; Mammals
PubMed: 36821982
DOI: 10.1016/j.heares.2023.108721 -
Journal of Healthcare Engineering 2020Multispectral imaging has recently shown good performance in determining information about physiology, morphology, and composition of tissue. In the endoscopy field,...
Multispectral imaging has recently shown good performance in determining information about physiology, morphology, and composition of tissue. In the endoscopy field, many researches have shown the ability to apply multispectral or narrow-band images in surveying vascular structure based on the interaction of light wavelength with tissue composition. However, there has been no mention to assess the contrast between other components in the middle ear such as the tympanic membrane, malleus, and the surrounding area. Using CT, OCT, or ODT can clearly describe the tympanic membrane structure; nevertheless, these approaches are expensive, more complex, and time-consuming and are not suitable for most common middle ear diagnoses. Here, we show the potential of using the multispectral imaging technique to enhance the contrast of the tympanic membrane compared to the surrounding tissue. The optical absorption and scattering of biological tissues constituents are not the same at different wavelengths. In this pilot study, multiwavelength images of the tympanic membrane were captured by using the otoscope with LED light source at three distinct spectral regions: 450 nm, 530 nm, and 630 nm. Subsequently, analyses of the intensity images as well as the histogram of these images point out that the 630 nm illumination image features an evident contrast in the intensity of the tympanic membrane and malleus compared to the surrounding area. Analysis of such images could facilitate the boundary determination and segmentation of the tympanic membrane (TM) with high precision.
Topics: Ear, Middle; Endoscopes; Endoscopy; Equipment Design; Female; Hemoglobins; Humans; Male; Malleus; Optical Fibers; Otoscopy; Pilot Projects; Reproducibility of Results; Software; Tomography, X-Ray Computed; Tympanic Membrane; User-Computer Interface; Young Adult
PubMed: 33014321
DOI: 10.1155/2020/6219845