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ObjectiveThis study aimed to investigate petrous apex pneumatisation in children, as an understanding of petrous apex pneumatisation is useful in the diagnosis and surgical management of middle-ear disease.MethodsComputed tomography head scans from 1700 patients aged 0–16 years were assessed. Petrous apex bone and air cell volumes were calculated to determine the degree of petrous apex pneumatisation. Scans were analysed for communicating tracts between the middle ear and petrous apex.ResultsPetrous apex pneumatisation was found in 21.0 per cent of patients. Positive relationships were found between age and petrous apex pneumatisation prevalence (rs = 0.990, p < 0.001), and between age and degree of petrous apex pneumatisation (rs = 0.319, p < 0.001). Petrous apex pneumatisation prevalence did not significantly differ by sex or ethnicity. Communicating tracts were identified in 84.3 per cent of patients with petrous apex pneumatisation, most commonly anterior to the otic capsule.ConclusionIn children, the prevalence and degree of petrous apex pneumatisation increases with age, but prevalence is not affected by sex or ethnicity.

Introduction High-resolution computed tomography (HRCT) magnifies the role of preoperative imaging for detailed inner and middle ear anatomical information and enhances more efforts for better dependent correlation and measurements of round window (RW). Objectives The aim of this study was to find an appropriate way by HRCT imaging for the prediction of the visibility of the round window during cochlear implant (CI) surgery. Methods The study was conducted using hospital information from patients referring the Khuzestan Cochlear Implant Center (2017–2018). 87 patients underwent cochlear implant surgery, 56 patients with high resolution CT scans were included in the study. All patients underwent surgical treatment via posterior tympanotomy approach. Results 56 patients were examined. Patients were divided into three groups: children (0–12 years) and adolescence (18-13 years) and adults (19–59 years), of whom 45 patients (80.4%) were children, and 3 patients were adolescence (5.4%) and 8 patients (14.3%) were adults. 22 patients (39.3%) were fully visible and 13 patients (23.2%) were partially visible and 21 (37.5%) patients were difficult to visualize. In high-resolution imaging studies, mastoid 2 cases (3.6%) were poorly aerated and 8 cases (14.3%) were moderately aerated and 46 (86.1%) were well aerated. The amount of round window overhanging in 43 patients (76.8%) was 4.4 and in 12 patients (21.4%) was 3.4%. Conclusion The presence of the air cell around the facial recess may provide easier access to the facial recess. There was a significant relationship between the RW in the operation and the angle between the RW and the facial nerve and the coronal axis. There is no significant relationship between the visibility of the RW and the facial recess, Vertical height RW and facial nerve (FN), the distance between the FN and the posterior canal in the axial, the angle between the FN and inner margin of RW, and the angle between the FN and the tympanic annulus with the inner margin RW in the Axial and FRL was not found.

Patients with advanced- or terminal-stage cancer and persons receiving palliative care are at high risk for pressure ulcers (PUs). Purpose The purpose of this study was to examine the rate of PU development and levels of comfort of a dual-fit, air-cell mattress compared with an alternating, 2-layer overlay air-cell mattress in patients with advanced- or terminal-stage cancer receiving palliative care. Methods From January 2011 to December 2013, hospitalized patients with advanced- or terminal-stage cancer who were referred to a palliative care team, at least 20 years of age, able to communicate, experiencing pain, and did not have a PU were recruited to participate. Patients who consented were alternately placed on the intervention (dual-fit, air-cell) or control (2-layer air) mattress until hospital discharge or death. Demographic and clinical data, pain scores, performance status, Palliative Performance Scale scores, Braden Scale scores, tissue interface pressure, and comfort were assessed via interview using closed-end questions. If a PU developed, clinical characteristics were assessed using DESIGN-R. Descriptive statistics and the Mann-Whitney U, chi-squared, and Fisher's exact tests were used to analyze the data. Results Of the 123 eligible patients, 73 were randomized and 52 completed the study (23 intervention patients, median age 63 [range 27-80] years; and 29 control group patients, median age 61.0 [range 27-82] years). Mattresses were used a median of 17 (range 4-113) days in the intervention group and a median of 32 (range 3-270) days in the control group. The incidence of PUs did not significantly differ between the 2 groups (13% in the intervention and 17.2% in the control group). Interface pressures were significantly higher in the intervention group (27.0 mm Hg vs. 24.3 mm Hg). Comfort scores at rest were significantly better in the intervention than in the control group (sinking into bed [3 vs. 14, respectively]; slipping on bed [o vs. 16, respectively]; and feel pressure of air cell [2 vs. 14, respectively]), as were scores with movement (instability during movement [4 vs. 18, respectively] and feeling of floating of the buttocks [6 vs. 21, respectively]) (P Conclusion Dual-fit, air-cell mattresses may help prevent PUs and improve comfort at rest and during activity among patients with end-stage cancer receiving palliative care. Further research regarding mattress selection protocols for this patient population is warranted.

Background: The mastoid air cells are considered to develop better in children with congenital cholesteatoma but only a few quantitative studies have examined. Aims/objectives: The present study was undertaken in order to clarify the relationships between the development of the mastoid air cells in children with congenital cholesteatoma and clinical factors. Materials and methods: Mastoid air cell development was evaluated in 53 children with congenital cholesteatoma. The sizes of the mastoid air cells were measured on computed tomography scans of the temporal bone, and clinical factors, including age, the extent of invasion, and whether it was located close to the eustachian tube were evaluated. Results: The cross-sectional area of the mastoid air cells was significantly smaller on the affected side than on the unaffected side, especially in the older patients. The cases involving invasion into the mastoid portion also had smaller mastoid cells. Whether the cholesteatoma was located close to the eustachian tube had no effect. Conclusions and significance: The mastoid air cells on the affected side were less well developed. Our findings indicate that a high age and the presence of cholesteatoma in the mastoid region might be associated with suppressed mastoid pneumatization.

La microlitiasis alveolar pulmonar es una enfermedad rara cuya principal característica es la acumulación de sales de calcio dentro del alvéolo pulmonar, esto debido a la presencia de una mutación genética autosómica recesiva. Esta entidad se encuentra dentro del grupo de enfermedades pulmonares difusas y el diagnóstico principal es un reto para los profesionales de la salud. No existe un tratamiento hasta la fecha; se ha planteado el uso de bisfosfonatos, los esteroides y lavado bronco alveolar sin llegar a resultados concluyentes. Se prefiere llevar a cabo el trasplante pulmonar, para mejores resultados, antes de que se haya establecido el desarrollo de la insuficiencia ventricular derecha. El diagnóstico definitivo es histopatológico. De acuerdo con la literatura nacional publicada, a nuestro alcance, en Perú se ha reportado esta enfermedad tan solo con sospecha radiológica, sin publicar el diagnóstico histopatológico definitivo. Presentamos un caso diagnosticado en el Departamento de Cirugía de Tórax y Cardiovascular del Hospital Nacional Hipólito Unanue de Lima., Pulmonary alveolar microlithiasis a rare disease whose main characteristic accumulation of calcium salts within the air cell, this due to the presence of a genetic mutation autosomal recessive. This entity is within the group of diffuse lung diseases and primary diagnosis is a challenge for health professionals. There is no treatment to date, has raised the use of bisphosphonate, steroids and bronchoalveolar lavage without reaching conclusive results. It is preferred to perform the transplant before the development of right ventricular failure for best results. The definitive diagnosis is histopathological. In Peru it has been poorly described this disease as the only report found no definitive histopathological diagnosis. We report a case diagnosed in the Department of Thoracic and Cardiovascular Surgery Hipolito Unanue National Hospital in Lima, Peru.

Acute otitis media is a localized infection. Advanced cases demonstrate local spread and abscess formation in the mastoid, temporomandibular joint, and zygomatic root if anatomy allows. We present a case of acute otitis media complicated by an abscess of a pneumatized zygomatic root extending into the temporomandibular joint treated by incision and drainage.

Posterior tympanotomy is the avenue to the facial recess of the middle ear from mastoid antrum. The entry into the facial recess in many cases is heralded by a distinct air cell before approaching the facial-chordal plane. The current study was undertaken to determine the prevalence of this 'Herald Cell' in an adult cadaveric population. It was a human cadaveric temporal bone dissection study. The bones were dissected to carry out cortical mastoidectomy and posterior tympanotomy using standard otologic drills under microscopic visualization (Leica M320 F12). Appropriate snapshots were taken to document the presence or absence of Herald cell. A total of 51 temporal bones were dissected (26 right, 25 left sided). The Herald cell was found to be present in 22 bones (43.1%). Herald cell, when present, is a convenient and reliable landmark to carry out a safe posterior tympanotomy.

Osteoma of EAC is a rare tumour. Cholesteatoma of EAC associated with osteoma is consequence of osteoma of EAC. Its incidence is rare and very few cases have been reported in the literature. Its association with exuberant granulation tissue in the mastoid air cell system without extension of Cholesteatoma into middle ear cleft is even rare. This association has been reported for the first time as evident from review of literature.

The aim of this study was to compare mastoid air cell volumes in patients with or without a pneumatized articular tubercle (PAT) on cone-beam computed tomography (CBCT) images.The CBCT images of 224 patients were retrospectively analyzed for the presence of PAT. The Digital Imaging and Communications in Medicine data of 30 patients with PAT and 30 individuals without PAT were transferred to 3D Doctor Software. Mastoid air cell volumes were measured using semi-automatic segmentation on axial sections. Data were analyzed using SPSS version 20.0.The patients with PAT and those without PAT had a mean mastoid volume of 6.31±2.86 cmThe detection of PAT on routine dental radiographic examinations might be a potential prognostic factor that could be used to detect extensive pneumatization in the temporal bone. Clinicians should be aware that there may be widespread pneumatization of mastoid air cells in patients in whom PAT is detected. Advanced imaging should be performed in these cases, and possible complications due to surgical interventions should be considered.

Background: Mastoid development, tympanic sinus depth, and residual disease after surgery for congenital cholesteatoma are probably related, but these relationships have not been examined in detail...

This study aimed to investigate the prevalence of tympanic plate (TP) pneumatisation as well as the various potential patterns. A retrospective study involving the archived Cone-Beam Computed Tomography (CBCT) files of 70 patients was performed to investigate anatomical variations of TP pneumatisation. Forty-eight TPs were found to be non-pneumatised, while 92 were found to contain at least peritubal air cells. Twenty patients (28.5%) did not present any variety of TP pneumatisation, while 36 patients (51.4%) exhibited a symmetrical pattern of pneumatisation. Aside from those patients who lacked TP pneumatisation, the peritubal pneumatisation pattern was found to be the most common. Further, bilateral symmetry was found to occur in more than half of all cases. CBCT is a powerful diagnostic tool, although appropriate knowledge of the anatomical possibilities remains mandatory for adequate surgical planning.

Background Learning surgical anatomy of the petrous pyramid can be a challenge, especially in the beginning of the training process. Providing an easier, holistic approach can be of help to everyone with interest in learning and teaching skull base anatomy. We present the complex organization of petrous pyramid anatomy using a new compartmental approach that is simple to understand and remember. Methods The surfaces of the petrous pyramid of two temporal bones were examined; and the contents of the petrous pyramid of 8 temporal bones were exposed through progressive drilling of the superior surface. Results The petrous pyramid is made up of a bony container, and its contents were grouped into 4 compartments (mucosal, cutaneous, neural, and vascular). Two reference lines were identified (mucosal and external-internal auditory canal lines) intersecting at the level of the middle ear. The localization of contents relative to these reference lines was then described, and 2 methods of segmentation (the X method and the V method) were then proposed. This description was then used to describe middle ear relationships, facial nerve anatomy, and air cell distribution. Conclusions This new compartmental approach allows a comprehensive understanding of the distribution of petrous pyramid contents. Dividing it into anatomic compartments, and then navigating this mental map along specific reference points, lines, spaces, and segments, could create a useful tool to teach or learn its complex tridimensional anatomy.

The skull base attachment of the second lamella and suprabullar pneumatization are likely to be consistent landmarks if they are systematically classified. This study aimed to classify the pneumatization pattern according to the second lamella skull base attachment. A total of 202 computed tomography sides of 101 patients who underwent endoscopic sinus surgery were studied. Suprabullar pneumatization was defined as air cells present above the ethmoid bulla between the second and third lamellae. Its pattern was classified according to the air cell number and location as in the frontal cell classification. Type 0 suprabullar pneumatization was defined as no air cells between the ethmoid bulla and skull base; type 1, as a single suprabullar cell; and type 2, as multiple suprabullar cells above the ethmoid bulla. In type 3 pneumatization, the second lamella extended into the frontal sinus forming a frontal bullar cell. Type 2 was the most prevalent (40.1 %), followed by types 1, 3, and 0 (24.3, 23.3, and 12.4 %, respectively). The distance between the second lamella and anterior ethmoid artery was 8.93, 8.30, 8.50, and 11.25 mm in types 0, 1, 2, and 3 pneumatization, respectively. No patients had intraoperative injuries in the anterior ethmoid artery or lateral lamella. The second lamella skull base attachment and suprabullar pneumatization pattern could be systematically classified and be a consistent landmark to identify the frontal sinus opening.

Highlights • The authors successfully treated the antrochoanal polyp with turbinoethmoidal osteoma by endoscopic sinus surgery. • The mucosal continuity between the antrochoanal polyp and the osteoma was identified., Introduction Antrochoanal polyps (ACPs) have several unique features that distinguish them from other nasal polyps. Despite many investigations, the pathogenesis of ACP has not yet been elucidated. Sinonasal osteoma is the most common type of tumor of the sinonasal tract and can be caused by trauma, infection and developmental anomaly. Presentation of case We report the case of a 35-year-old man with left nasal obstruction for more than 20 years. Examination revealed ACP concomitant with an osteoma that arose from the middle turbinate and ethmoid sinus. The osteoma had an air cell in its anterosuperior area and was in a position of being pulled downward. The intranasal part of the ACP covered the posterior area of the osteoma. Discussion Considering the radiological and surgical findings, the intranasal part of the ACP seems to have affected the turbinoethmoidal osteoma during its growth. Conclusion The authors describe a very rare condition in which an ACP was connected with a turbinoethmoidal osteoma.

Introduction: The environment of middle ear cavity gets regulated mostly by pneumatized mastoid air cell system (MACS). Many theories exist that details the process of pneumatization of this MACS. The nasal septal deviation (NSD) has been shown to be instrumental in influencing pneumatization of paranasal sinuses to varied degrees. The effect of NSD on the pneumatization of MACS remains questionable due to limited literature available. And so this study was done to find the relation between the side of NSD and extent of Pneumatization of MACS on that side by computerized tomographs of Paranasal sinus region. Subjects and Methods: 120 CT images of paranasal region from archives of radiology department were studied for NSD. The NSD was classified according to the nasal septal angle. The extent of pneumatization of mastoid region was studied and classified. The relation between severe NSD and extent of mastoid pneumatization was noted. Results: NSD was found to be right sided in 90% cases studied and 20, 45, 55 were seen belonging to group I, II and III NSD respectively. The mean NSA was found to be 13.5o. Mastoid region was observed to be hypo pneumatized in the side of NSD in 42 cases of group III NSD. Conclusion: The findings of the study puts forth the need for assessment of NSD and planning possible correction of NSD prior to middle ear and mastoid surgeries for successful results.

RESULTS: Mastoid air cell volume, as well as maxillary sinus volume, of the deviated side was smaller than that of the contralateral side, but these were not statistically significant. There was no correlation between NSA and volumes of mastoid air cell and the maxillary sinus. There also was no correlation between NSD/NC ratio and mastoid air cell and maxillary sinus volumes. Significant linear and growth regression was found between age and volume of the mastoid air cell and maxillary sinus but not between age and NSA and NSD/NC ratio. CONCLUSION: Mastoid air cell volume and maxillary sinus volume of the deviated side tended to be smaller than those of the contralateral side, which suggests that NSD can influence both aerations. However, because the degree of NSD did not correlate with the volumes of the mastoid air cell and maxillary sinus in this study, we should consider that further possible factors may be involved in both aerations.

SUMMARY – The aim of the study was to analyze zygomatic air cell defect (ZACD) incidence using magnetic resonance imaging (MRI) and validity of panoramic radiograph as a comparative method of ZACD diagnostics. The connection between ZACD incidence, age, left/right temporomandibular joint (TMJ) and comorbidity with diagnosis of TMJ disorder was analyzed. Panoramic radiographs and MRIs of 140 TMJs of 70 consecutive patients with previously confirmed TMJ diagnosis were compared in the study. A grading system (4-point scale from ‘0’ for absence to ‘3’ for most extended pneumatization) was used to determine low signal on MRIs as pneumatization of temporal bone. ZACD was diagnosed in 22 joints of 15 patients (incidence, 20.4%), with seven patients having bilateral appearance. In the joints of nine patients, ZACD was identified as extensive according to the grading scale. The validity of ZACD findings on panoramic radiographs compared with MRI findings yielded 0.45 sensitivity and 0.98 specificity. There was no relation (p>0.05) between comorbidity of ZACD and TMJ disorder, either by age or side of the body. More prevalent ZACD in our MRI analysis than in other researches based on panoramic radiographs could be explained by the expected superimposed osseous structures in the area of articular eminence.

Congenital cholesteatomas of mastoid origin are extremely rare. We reported one in 2007 and experienced an additional case. A male presented with a 5-month history of right-sided ear dis- charge. Computed tomography of the temporal bone showed a soft tissue density occupying the mastoid tip. At surgery, the cholesteatoma sac was completely isolated from the mastoid antrum and lateral air cell in the mastoid tip area. We now doubt the rarity of this entity. With a brief literature review, we consider how the cholesteatoma localizes to the tip of the mastoid bone. Korean J Audiol 2014;18(2):85-88

Background Zygomatic air cell defect (ZACD) is a normal radiographic occurrence and the clinical importance has been sparsely evaluated.

Dental panoramic radiograph serves as a radiograph to visualize the maxillae, the mandible and the surrounding structures fairly well. This radiograph depicts the normal anatomy as well as its variations. One among the many anatomical landmarks and their variations noted on this radiograph is the zygomatic air cell defect (ZACD). zygomatic air cell defect is the extension of mastoid air cells into the articular eminence and the zygomatic process of temporal bone, not crossing anteriorly, the zygomatico-temporal suture. This variant of normal anatomy was recognized as early as 1934 but recognition of the same on a dental panoramic radiograph was not until 1985 by Tyndall and Matteson. Following its recognition, a few case reports and systematic studies have been conducted. In spite of its recognition early in the century, not many anatomists, radiologists are aware of this entity and its importance.

Objectives To evaluate the effect of the degree of the mastoid pneumatization on the success rate of cartilage type 1 tympanoplasty. Study design A retrospective clinical chart review. Methods In total, 90 patients (44 females and 46 males; average age, 38.40 ± 11.12 years; age range: 21-65 years) who underwent cartilage type 1 tympanoplasty were included. Demographics and anatomical outcomes were recorded. The patients were divided into 2 groups in terms of anatomical success. In group A, all patients had intact grafts without perforation, retraction, or lateralization, and a dry ear, at 6 months postoperatively. In group B, reperforation of the tympanic membrane was evident 6 months postoperatively. The mastoid air cell volumes of each groups were compared. Results The mean mastoid pneumatization in groups A and B was 5.32 ± 1.96 and 5.06 ± 2.12 cm, respectively. The mastoid pneumatization of diseased ears did not differ between the groups (P > 0.05). The mastoid pneumatization of diseased ears did not differ between males and females (P > 0.05). The mastoid pneumatization of normal ears did not differ between the groups (P > 0.05). The mastoid pneumatization of normal ears did not differ between males and females (P > 0.05). Conclusions The degree of mastoid pneumatization did not affect the success rate of cartilage type 1 tympanoplasty. Further studies with larger numbers of patients are needed to evaluate the relationship between the degree of the mastoid pneumatization and anatomical outcomes after placement of various graft types.

This study describes the changes in mastoid air cell system (MACS) geometry with age in ears with a history of otitis media (OM), without (GR-I) or with (GR-II) middle ear fluid on the CT scan.Thirty-seven (74 MACSs) CT scans were selected to approximate 4 MACSs/year between 1 and 18 years. For each MACS, the volume, surface area and surface area/volume ratio were reconstructed using standard procedures. Correlation analysis was used to define the left-right relatedness for the geometric parameters, and regression analysis was used to determine the effect of age on those parameters for each group.Twenty scans were from female and 17 from males. Fluid was observed in 12 left, 4 right and 10 bilateral MACSs. The MACS volume and surface area of GR-I increased with age, were significantly greater than those for age-matched MACSs in GR-II, but show large variability. Those measures in GR-II were independent of age and a large percentage of these MACS volumes was5 ml. The surface-area/volume ratio for MACSs in both groups was independent of age and group assignment. The left-right correlations for the three geometric parameters of the MACS were significant for all MACS in the two groups, and for bilateral MACS concordant for group assignment. The left-right correlations for surface area and volume were not significant for bilateral MACSs discordant for group assignment.These results suggest that: the growth of MACS volume and surface area is genetically programmed but that this is disrupted by long-lasting OM; the effect of OM on MACS growth may depend on the duration and timing of the disease, and the MACS surface area/volume ratio does not explain the effect of MACS volume on the rate of gas exchange between middle ear and blood.

AimTo determine the prevalence, radiographic appearance and characteristics of patients with zygomatic air cell defect (ZACD).Materials and MethodsRoutine panoramic radiographs of 400 patients who were visited the dental outpatient of our institute were examined retrospectively.ResultsOut of 400 study subjects, ZACD was found in 11, giving an overall prevalence of 2.75%. Out of 11 ZACD subjects, six were males and five were females. The mean age of subjects with ZACD was 33.9 (±15) years and a range of 18 to 65 years. The bilateral involvement of ZACD was seen in only one subject.ConclusionThe overall prevalence of ZACD is relatively low in present study population. Knowledge of ZACD may be helpful in interpreting panoramic radiographs, in planning surgical treatment of the temporomandibular joint and in understanding the spread of pathological processes into the joint.How to cite this articleGadda R, Patil NA, Salvi R. Zygomatic Air Cell Defect: Prevalence and Characteristics in Dental Outpatient Population. J Contemp Dent 2012;2(3):69-72.

Introduction.Osteoma of the temporal bone is a very uncommon benign tumor of bone. Osteomas may occur in the external auditory canals but are reported to be very rare in the mastoid bone.Case Report.A 36-year-old male presented to our department with a hard swelling behind the right ear diagnosed as osteoma. Complete excision was done through a postauricular approach. Histopathology confirmed the diagnosis of osteoma.Conclusion.Osteomas, although rare, should be considered when dealing with any hard mastoid swelling. Complete removal can be ensured by drilling till the normal cortical bone is reached to avoid recurrence. A cortical mastoidectomy should be done if the mastoid air cell system is involved.

Objective To clarify the position, occurrence rate, and configuration of the suprapyramidal fossa (SF) through surgical observation and 3-dimensional reconstruction. Methods SF of 300 ears with chronic otitis media were observed during surgery. The air cell and its abutting structures, including the facial nerve (FN), were reconstructed using high-resolution computed tomography (HRCT) data. Results In 68.3% (n = 205) of patients, the SF was observed in surgery. It is situated at the posterior wall of the facial recess of the retrotympanum. This air cell, usually the only one present on the surface of the pyramidal segment of the FN canal (FNC), is usually the largest if small air cells are found nearby. Its delineated location is as follows: pyramidal eminence and the pyramidal segment of the FNC medially, the deeper external acoustic meatus laterally, the aditus ad antrum superiorly, the posterior part of the tympanic annulus, and the chordal ridge anterior-inferiorly. Its configuration varies between rounded (11.7%, n = 35), curved-rod (52.7%, n = 158), and irregular (4%, n = 12). Additionally, the sensitivity and specificity of HRCT in detecting the SF were 79.0% and 88.4%, respectively. Conclusion Occurrence and configuration of the SF is not a rule; however, the positive positional relationship between the SF and the second genu of the FNC is a rule, if the SF is detected. Considering this, the SF may be an important anatomic landmark to identify the FN during otosurgery. However, HRCT has a limited diagnostic value when the SF is atypical.

Objective The aim of this study was to investigate the developmental relationship between adenoid tissue volume and mastoid air cell volume, using a 3D reconstruction technique. Study design Cross-sectional retrospective study. Subjects and methods Multislice computed tomography (MSCT) images were obtained using three-dimensional (3D) reconstruction and volume-rendering techniques (VRT). The subjects were 63 boys and 37 girls, 3–16 years of age. The volumes of bilateral mastoid air cells and adenoids marked in axial–coronal–sagittal planes were calculated. The patients were grouped into three categories according to adenoid tissue volume, total mastoid volume (TMV), and age. Results No significant difference was noted between the right mastoid volume (RMV) and the left mastoid volume (LMV) or between age and sex ( p = 0.368; p = 0.549; p = 0.454). The incremental increase in adenoid tissue volume did not correlate with TMV ( r = −0.161, r = −0.279, r = 0.015). The incremental increase in TMV did not correlate with the volume of adenoid tissue ( r = 0.024, r = 0.148, r = 0.017). Conclusions No significant correlation was obtained between the incremental increase in adenoid tissue volume and TMV or the incremental increase in TMV and adenoid tissue volume. There does not seem to be a developmental relationship between adenoid tissue volume and TMV.

Udgivelsesdato: 2010 HYPOTHESIS:: Middle ear pressure (MEP) is actively regulated by both the Eustachian tube and the mastoid air cell system. BACKGROUND:: MEP is a highly significant factor involved in many clinical conditions related to otitis media. Basic knowledge on its overall regulation remains insufficient, but the Eustachian tube and mastoid gas exchange are important factors. The main focus has been aimed at the tube; however, evidence points to the mastoid as equally important. More detailed methods are demanded to study their complementary functions. METHODS:: A catheter was inserted into the mastoid of 12 human volunteers (patients for parotidectomy). This enabled monitoring MEP directly, and experiments were performed with volume displacements of +/-50, 100, and 200 mul resulting in a range of overpressure and underpressure. The following counter-regulation was recorded over 10 minutes. RESULTS:: In some cases, MEP counter-regulation presented as Eustachian tube openings with steep and fast pressure changes toward 0 Pa, whereas in others, gradual and slow pressure changes presented related to the mastoid; these changes sometimes crossed 0 Pa into opposite pressures. In many cases, combinations of these distinct mechanisms were found. CONCLUSION:: The human mastoid as well as the Eustachian tube was capable of active counter-regulation of the MEP in short-term experimental pressure changes in healthy ears. Thus, these 2 systems seemed to function in a complementary way, where the mastoid was related to continuous regulation of smaller pressures, whereas the tube was related to intermittent regulation of higher pressures.

The middle ear (ME) surface area/volume ratio (SA/V) is greater than that of the tympanum. The rate of ME pressure decrease is proportional to the ME SA/V. The mastoid air-cell system (MACS) will not function as an ME gas reserve unless the blood perfusion/surface area is much greater for the tympanum than the MACS and decreases as MACS volume increases.To measure the MACS and tympanum surface areas and volumes and ascertain whether the MACS could function as an ME gas reserve.Twenty adult subjects with a wide range of MACS volumes underwent CT of their MEs. The left and right surface areas and volumes of the tympanum and MACS were reconstructed and entered into a simple perfusion-limited model of transmucosal gas exchange. In this model the MACS would be a gas reserve if ME SA/V was less than the tympanum SA/V or equivalently, if their ratio was less than a critical value of 1.Both MACS and tympanum SA were linearly related to their volumes. MACS SA/V and the ME SA/V were significantly greater than those for the tympanum. Inputting the measured values into the model yielded a critical value of 1.4, which was significantly greater than 1.

This review suggests a reference to the postnatal growth of mastoid air cells and bone. Information was retrieved from studies having large consecutive age groups, in order to reveal a development pattern. Data regarding origin, gender, and antibiotic treatment was investigated as well. Most measurements were obtained by planimetry. Assessment of the various data sources suggested the antrum to be well developed at birth (1-1.5 cm2), the mastoid cells to be about 3.5-4 cm2 at 1 year, followed by a linear growth till the age of 6 (1-1.2 cm2/year), having a slower increment up to adult size at puberty (approximately 12 cm2). The mastoid bone expansion is about 0.6-0.9 cm/year in length and width and 0.4 cm/year in depth in the first year, followed by half that rate until the age of 6-7. At puberty there was a slower sprout reaching adult size. Different ethnic groups share similar mastoid aeration and bone growth patterns. There were no differences between mastoid aeration measured at the pre-antibiotic era and after its widespread use. In conclusion, there are three distinguishable phases of mastoid pneumatization from birth till reaching final size. Bone and air cell compartments share a similar growth pattern; bone expansion lags behind aeration. Antibiotic treatment for otitis may have no impact upon mastoid aeration.

The supraorbital ethmoid air cell (SOEC) is one anatomic variation of the frontal outflow region that is particularly susceptible to intraoperative complications or postoperative failure from functional endoscopic sinus surgery (FESS). The SOEC lies posterior lateral to the frontal sinus and may easily be confused with the frontal sinus intraoperatively. The anterior ethmoid artery lies posterior to both the SOEC and the frontal sinus. Detailed preoperative and intraoperative examination of imaging and image-guided navigation assists in reducing the risks of both intraoperative complications and long-term failure from misidentification or lack of identification of the SOEC.

Background The interfrontal septal cell, which often takes the shape of a wishbone on axial CT scan, was first described by Van Alyea more than 50 years ago; however, its potential role in disease of the frontal sinus was only recently recognized. The purpose of this study was to correlate the incidence and dimensions of this “frontal wishbone” (FWB) with the presence of frontal sinus disease. Methods The dimensions, drainage pathways, and disease state of the FWB were measured in 150 consecutive sinus CT scans performed at a tertiary care referral center. Statistical analysis was performed to correlate the FWB configuration to the presence of frontal sinus disease. Results A FWB was present in 77.3% of patients. The wishbone drained through a discrete ostium into either the left (54.8%), the right (45.2%), or the bilateral (0.8%) frontal sinuses. In those scans with mucosal thickening or opacification of the frontal sinus (36%), concurrent FWB disease was found in 82%. Patients with a large (>1 cm) FWB in the anterior–posterior dimension were more likely to have a diseased frontal sinus (p = 0.02). Conclusion The term FWB is used to describe an air cell within the interfrontal septum, which may play a role in the pathogenesis of frontal sinus disease.

The mastoid apophysis originates from a recent phylogenetic formation, associated with the standing attitude and it is currently considered as an evolution of the bone super-structures. The aim of the present study was to measure the diameters of the mastoid and the temporal bone in the Greek adult population. A total of 298 temporal bones from 149 cadavers (74 male, 75 female) were examined. The distances between six landmarks were measured by means of a pachymeter on both vertical and transverse axes of the mastoids and the temporal bone. The estimated mean values for each dimension were as follows: vertical diameter, 2.37 ± 0.42 cm; transverse diameter, 2.33 ± 0.51 cm; anterior margin, 2.12 ± 0.67 cm; posterior margin, 1.96 ± 0.55 cm; oblong diameter, 10.30 ± 0.60 cm; while the mean distance between the mastoid apex and mandibular fossa calva was 3.67 ± 0.35 cm. Gender differences were detected for the vertical (P < 0.001), the transverse diameter of the mastoid (P < 0.001), the anterior (P < 0.001) and the posterior margin of the mastoid (P < 0.001). In both genders, the vertical diameter of the mastoid was positively correlated with the transverse diameter, as well as with its anterior and posterior margins. In the present study, direct measurements of the mastoid and temporal bone in a Mediterranean population are reported. This description may facilitate a more accurate surgical approach to the temporal bone structures.

The mastoid air cell system (MACS) with its large complex of interconnected air cells reflects an enhanced surface area (SA) relative to its volume (V), which may indicate that the MACS is adapted to gas exchange and has a potential role in middle ear pressure regulation. These geometric parameters of the MACS have been studied by high resolution clinical CT scanning. However, the resolution of these scans is limited to a voxel size of around 0.6 mm in all dimensions, and so, the geometrical parameters are also limited. Small air cells may appear below the resolution and cannot be detected. Such air cells may contribute to a much higher SA, and thus, also the SA/V ratio. More accurate parameters are important for analysis of the function of the MACS including physiological modeling. Our aim was to determine the SA, V, and SA/V ratio in the MACS in human temporal bones at highest resolution by using micro-CT-scanning. Further, the influence of the resolution on these parameters was investigated by downsampling the data. Eight normally aerated temporal bones were scanned at the highest possible resolution (30-60 μm). The SA was determined using a triangular mesh fitted onto the segmented MACS. The V was determined by summing all the voxels containing air. Downsampling of the original data was applied four times by a factor of 2. The mean SA was 194 cm(2), the mean V was 9 cm(3), and the mean SA/V amounted to 22 cm(-1) (22 cm(2)/cm(3)). Decreasing the resolution resulted in a non-linear decrement of SA and SA/V, whereas V was mainly independent of the resolution. The current study found significantly higher SA and SA/V compared with previous studies using clinical CT scanning at lower resolutions. These findings indicate a role of the MACS different from that of the tympanum, though they are limited to only a smaller sample of temporal bones without knowledge about the disease history of the subjects. The current data on mastoid geometry seems important for a more accurate modeling of the middle ear physiology and future studies may include morphological investigations of the air cells with possible implications for their postnatal development.

Objectives We investigated the factors that may possibly cause primary acquired cholesteatoma. Setting University-affiliated hospital. Subjects and methods In 20 adult patients with unilateral cholesteatoma, the sizes of the osseous eustachian tubes (ETs) and the extent of peritubal and mastoid cell development in healthy and diseased ears were examined using high-resolution cone-beam computed tomography. The height and width of the ET were measured at the tympanic orifice, the isthmus, and the midpoint, as was the length of its axis. We also assessed the extent of development of peritubal and mastoid cells. Results There were no significant differences in the size of the osseous ET between the healthy and cholesteatoma sides, but significant correlations were found in height and width between the sides at the tympanic orifice and at the isthmus. In 80% of ears with cholesteatoma, the development of both peritubal and mastoid cells was poor and, in 5% more, one or the other was poor. Mastoid and peritubal cell development was good in 60% of healthy ears and poor in 20%. In the remaining 20%, only peritubal cell development was poor. Conclusion There were no significant differences in the size of the osseous ET between the healthy and diseased sides of patients with unilateral cholesteatoma. Our results indicate that inhibition of air cell development in not only the mastoid region but also the peritubal region may contribute to cholesteatoma development.

Although many different type of alternating pressure air mattresses (APAMs) are used for the prevention and treatment of pressure ulcers, few high quality randomised controlled trials are available on which to base purchasing decisions. Faced with this situation, physiological measurements are increasingly being used as a surrogate. Laboratory evaluation techniques have centred largely on interface pressure (IP) measurement, typically analysing discrete maximum and minimum levels, or average pressure. However, since pressure relief is time varying, a time-based analysis technique may be more suitable for performance assessment. Measurements of IP, mattress air cell pressure (AP), skin tissue perfusion using laser Doppler fluxmetry (LDF), transcutaneous oxygen (tcPO2) and carbon dioxide (tcPCO2) were taken simultaneously on the sacrum, heels, trochanters and buttock over at least two alternating cycles. Duration of IP below three thresholds (30, 20, and 10 mmHg) as well as the area under the tcPO2, tcPCO2 and LDF curves were calculated automatically. Ten healthy volunteers were recruited to evaluate the pressure-relieving characteristics of two different designs of APAMs. Results indicated significant differences between the products. During the deflation phase of the cycle contact pressures on the heel were significantly lower (p0.0001) on the device whose inflation pressure was significantly higher, although there was no significant difference in deflation pressure. Therefore, it is important to note that low APs do not necessarily produce lower IPs under the heel, contrary to the intuitive classical notion. These techniques could assist in the selection of alternating or dynamic surfaces of any description confirmed by further clinical validation.

Aims: The purpose of these experiments was to determine whether the heart and lungs of young chicks harboured bacteria. Methods and Results: Samples of the heart and lungs were aseptically removed from chicks on scheduled sampling days. Experiment 1 showed that of the 360 birds evaluated during the late embryonic and early post-hatching periods, only 10·8% harboured bacteria in the heart, lungs, and heart and lungs simultaneously. Experiment 2 suggested that bacteria in these organs were transient. Twenty-three bacterial species were found in the hearts whereas 30 were found in the lungs. Experiment 3 showed that only 1·4% of embryos harboured bacteria in the yolk, albumen, heart and lungs whereas 12·9% of the embryos had bacteria in the air cell. Conclusions: During the post-hatching period, there was a higher incidence of bacterial isolation in the heart and lungs, whilst during the embryonic development period, there was a lower incidence of bacterial isolation from these two organs. Results suggested that the heart and lungs do not have a residual bacterial flora; rather, opportunistic bacteria occasionally pass through these tissues. Significance and Impact of the Study: These experiments proved that bacteria could be isolated in the heart and lungs of healthy chicks reared from E17 to 3 weeks of age.

For individuals with a spinal cord injury (SCI) who depend on a wheelchair for mobility, sitting-acquired pressure ulcers (PUs) are a common and life-endangering complication. In the short time following an SCI, pathoanatomical and patho- physiological changes that affect the weight-bearing tissues of the buttocks may increase the risk for PUs, exposing this already-at-risk population to the additional potential risk caused by soft tissue scarring. In this work, we evaluated the biomechanical efficacies of an air-cell-based (ACB) cushion for individuals with SCI who have previously experienced PUs that healed but left scars in their soft tissues. We used 11 finite element model variants of the buttocks describing various scar shapes and severities to study the effects of the scars on soft tissue stresses during sitting on an ACB cushion and the result- ing theoretical risk for the reoccurrence of PUs. Interestingly, the ACB cushion induced, in general, lower peak stress values in the soft tissues of the buttocks when scarring was present with respect to the stress levels in the (nonscarred) reference case. Our simulations therefore suggest that the ACB cushion is generally better at protecting patients with a history of severe PUs manifested by large, possibly deep tissue scarring in their buttocks.

To test the hypothesis that shoe sole composition can affect the level of bone strain and strain rates that contribute to the development of stress fractures, in vivo tibial strain measurements were made during treadmill walking while wearing four shoes which differed only in their sole composition. Soles of 65 Shore A polyurethane with an embedded heel air cell had significantly lower compression and shear strains and shear strain rates than soles of 65, 75 and a composite of 40/65 Shore A polyurethane with no embedded air cells. A sole composed of 65 Shore A polyurethane with an embedded air cell can potentially be protective against stress fracture in a walking shoe.

This study was carried out to establish which type of cholesteatoma is controllable by conservative treatment from the viewpoint of mastoid ventilation. We examined the area of the air cell system and airspace (aeration) in the mastoid cavity by computed tomography and eustachian tube (ET) function by inflation-deflation test in 20 ears (20 patients) with severe attic retraction for over 12 months (retraction pocket group), 16 ears (16 patients) with cholesteatoma which could be controlled only by conservative treatment for over 12 months (nonsurgical group) and 43 ears (43 patients) which required surgery within a year in spite of similar conservative treatment (surgical group). The size of the mastoid air cell system in the retraction pocket group, nonsurgical group and surgical group was 2.9 ± 1.3, 1.9 ± 0.7 and 1.5 ± 0.9 cm2 on average, respectively, with no significant difference between both cholesteatoma groups (nonsurgical and surgical group). While aeration was observed in the mastoid in 17 of 20 ears (85.%) in the retraction pocket group and in 12 of 16 ears (75.0%) in the nonsurgical group, aeration was present only in 9 of 43 ears (26.5%) in the surgical group, being significantly less in the surgical group than in the nonsurgical group and the retraction pocket group. In all ears in the retraction pocket and nonsurgical groups, and 19 of 30 ears in the surgical group, ET function was poor, there being no significant difference among the three groups. The present clinical observations suggest that progressiveness of cholesteatoma could be related to the ventilatory conditions in the mastoid rather than ET function, and that conservative treatment may be effective when ears with cholesteatoma have aeration in the mastoid.

Aims: To determine the prevalence, patterns of occurrence and variations of zygomatic air cell defects (ZACDs) using panoramic radiographs. Methods and Materials: Dental panoramic radiographs of 600 outpatients were examined to evaluate the variations and characteristics of ZACDs. Results: ZACDs were identified in 15 subjects out of 600, giving an overall prevalence of 2.5%. Seven ZACDs were seen in males and eight in females. Among the 15 ZACDs, nine were unilateral and six were bilateral. Conclusion: The overall prevalence of ZACD is relatively low in south Indian population and careful radiographic evaluation is needed to detect these entities.

BACKGROUND AND PURPOSE: Air cells are often seen within the frontal intersinus septum. These cells have traditionally been thought to arise from displaced ethmoid cells from the frontal recess. This study explores the possibility that such cells may actually be diverticula from the frontal sinuses themselves and not of a direct ethmoid origin. MATERIALS AND METHODS: A prospective study of 200 consecutive CT scans in the coronal and axial planes was performed on patients without a history of recent trauma. The images were interpreted independently by a radiologist and an otolaryngologist. The CT studies were evaluated for the presence of a central intersinus septal air cell. If such a cell was identified, it was further classified as either being completely isolated from both frontal sinuses by a bony rim or as a communicating diverticulum from one of the frontal sinuses. If a central cell was present, it was also assessed for how much of the height of the intersinus septum it involved (lower one-half or full height). RESULTS: There was a complete concordance of the results between the 2 observers. An intersinus septal air cell was seen in 61 (30.5%) of the 200 cases, and 85.3% of these cells were clearly seen to communicate anteromedially with either one of the frontal sinuses or both frontal sinuses (3 cases). In 9 (4.5%) of the 200 cases, the central cell had no demonstrable connection to either frontal sinus. Of the 61 cases with a central cell, 55 (90.16%) of the cells occupied the full height of the septum, and 6 (9.84%) only involved the lower half of the septum. CONCLUSION: Contrary to the present convention that frontal intersinus septal cells originate as displaced ethmoid cells from the frontal recess, we found that most such cells are actually diverticula from the frontal sinuses themselves.

A methyl methacrylate casting technique was used to make detailed casts of the intracerebral venous system of four human cadaver specimens. Seven of the eight petrous apices studied were diploeic (n = 5), or pneumatic (n = 2) and had venules coursing in the anterior petrous apex. These venules form conduits connecting the cavernous to the inferior petrosal sinus or the jugular bulb and have not been previously described. In addition to the air cell system of the petrous apex, these venules may represent pathways for the spread of infection and the development of petrous apicitis, Gradenigo's syndrome, and the rare otogenic cavernous sinus thrombophlebitis. Their presence also may help explain the location of cholesterol granulomas, which afflict this area of the skull base.

The mastoid air cell system has been recognized as an important contributor to the pathophysiology of middle ear inflammatory diseases. Various methods of temporal bone imaging have been designed to investigate the correlation between middle ear disease and mastoid pneumatization. In this study, the mastoid air cell system was reconstructed three-dimensionally from sagittal tomographic images of the temporal bone on X-ray films, using a personal computer to evaluate the mastoid pneumatization in a total of 29 patients with chronic otitis media, adhesive otitis media, adhesive-type cholesteatoma, attic cholesteatoma and cholesterol granuloma, and in five normal subjects as controls. Reconstructed three-dimensional images of the mastoid air cell system and its volume were analyzed. The reconstructed images were helpful in recognizing the three-dimensional solid appearance of the mastoid air cell system. The volume of the reconstructed mastoid air cell system was significantly reduced compared with that in the controls in each of the patient groups. Mastoid pneumatization in the patients with adhesive-type cholesteatoma was significantly suppressed compared with that in the adhesive otitis media patients. Interestingly, the adhesive otitis media group showed cell development at the tip of mastoid process, whereas the group of adhesive-type cholesteatoma did not, suggesting a difference in the pathophysiology in the two diseases. We found that three-dimensional reconstruction of the temporal bone using sagittal tomographic images was useful in evaluating the state of mastoid air cell system development in individual cases and in investigating the pathophysiology in middle ear disease.

To determine the association of agger nasi air cell disease with frontal rhinosinusitis, assessed by computed tomography (CT), in patients who require revision functional endoscopic sinus surgery (FESS).We prospectively collected data on patients undergoing revision FESS at a tertiary care medical center over an 18-month period. Sinus CT scans were graded as per Lund-Mackay. Frontal sinus findings on CT scan were correlated with the presence or absence of disease in agger nasi air cells.Eighty patients underwent revision FESS in an 18-month period. A total of 160 sides were evaluated by sinus CT scan with agger nasi being present in all but 11 sides (93%). One patient did not have a pneumatized frontal sinus on 1 side and so 148 sides were available for study. Frontal sinus disease was present in 119 and absent in 29 sides. The average CT grade of patients with frontal rhinosinusitis was 8.4 while it was only 3.0 in patients without frontal rhinosinusitis (P = 0.000). Agger nasi air cell disease was present in only 3 of 29 (10%) sides in patients without frontal rhinosinusitis and was present in all 119 (100%) sides of patients with frontal rhinosinusitis (P = 0.0000).Agger nasi air cells are a common anatomic feature, present in 93% of our patients. Agger nasi air cell disease correlates strongly with frontal sinus disease as assessed by sinus CT scan in patients undergoing revision FESS. In addition, frontal sinus disease correlates with the severity of overall sinus disease as determined by sinus CT scan.

The mastoid air cell system has traditionally been considered to have a passive role in gas exchange and pressure regulation of the middle ear possibly with some acoustic function. However, more evidence has focused on the mucosa of the mastoid, which may play a more active role in regulation of middle ear pressure. In this study we have applied micro-CT scanning on a series of three human temporal bones. This approach greatly enhances the resolution (40-60 mu m), so that we have discovered anatomical details, which has not been reported earlier. Thus, qualitative analysis using volume rendering has demonstrated notable micro-channels connecting the surface of the compact bone directly to the mastoid air cells as well as forming a network of connections between the air cells. Quantitative analysis on 2D slices was employed to determine the average diameter of these micro-channels (158 mu m; range = 40-440 mu m) as well as their density at a localized area (average = 75 cm(-2); range = 64-97 cm(-2)). These channels are hypothesized to contain a separate vascular supply for the mastoid mucosa. However, future studies of the histological structure of the micro-channels are warranted to confirm the hypothesis. Studies on the mastoid mucosa and its blood supply may improve our knowledge of its physiological properties, which may have important implications for our understanding of the pressure regulation of the middle ear. This article is part of a Special Issue entitled "MEMRO 2012". (C) 2013 Elsevier B.V. All rights reserved.

BackgroundEndoscopic sinus surgery is a common and generally safe ENT procedure. Orbital injury is a rare but devastating complication. The distance between the uncinate process and the lamina papyracea is the safety margin to avoid entering the orbital cavity and has not been measured previously.MethodsThe authors reviewed 330 consecutive coronal CT scans of the paranasal sinuses to measure this distance and identify variation.ResultsThe distance can be as narrow as 0.1 mm and varies between sides. An air cell lateral to the uncinate is not uncommon; it increases the distance considerably p

Objectives To evaluate the volumetric relationship between the mastoid air cell (MAC) and paranasal sinus (PNS) in the pediatric population using three-dimensional reconstruction and the analysis technique of CT. Study design Retrospective cross-sectional study was conducted at a university-based, secondary referral hospital. Methods PNS CT imaging data of 62 children (40 boys and 22 girls; mean age = 13.4 ± 4.0 years) was reconstructed to the three-dimensional model with the surface-rendering algorithm (lower threshold of −1024 HU and upper threshold of −318 HU), and subsequently measuring the volume of the three PNSs (frontal, maxillary and sphenoid) and MAC. Hierarchical linear regression analysis was used to control the effect of age. Results Controlling the effect of age, no significant linear regression relationship was found between the volume of MAC and PNSs. It was observed that PNSs and MAC showed a significant linear relationship with age. The regression slopes of PNSs were larger than that of MAC, especially the growth of maxillary and sphenoid sinuses was faster and larger than that of the frontal sinus and MAC. As the coefficient of determination was extremely small, the aging process itself could not effectively explain the volume variation of PNSs and MAC. Conclusion No interaction was observed in the pneumatization of the three PNSs (frontal, maxillary, and sphenoid) and MAC. It was found that the growths of PNSs and MAC are influenced by age. Further, maxillary and sphenoid sinuses tend to grow faster and become larger than the frontal sinus and mastoid air cell system. Thus, it is verified that environmental factors could be involved in the postnatal pneumatization process of the PNSs and MAC, which might influence MAC to a greater extent than the PNSs.

1. Heterophils (H) and lymphocytes (L) were measured in embryos that had pipped into the air cell and through the shell, and in chicks from 0‐d‐old to 8 d of age. 2. Numbers of lymphocytes in the perinatal stages were very low with H:L ratios greater than 5.0. 3. Posthatching H:L ratios decreased in a quadratic manner from 1.76 at hatch to 0.39 on day 8.

In the mastoid air cell system, air has been thought to be supplied only through the eustachian tube and tympanic cavity to the cells, and to be absorbed continuously in one direction through the lining mucosa of the mastoid air cells. In the ear with a blocked air supply route to the mastoid air cell system, gas in the blocked mastoid air cells has been thought to be absorbed and to be replaced by exudate. Recently, several observations have supported the existence of gas exchange not only through the eustachian tube but through the lining mucosa in the mastoid. To clarify gas exchange in mastoid air cells, tympanic cavities of the infant piglet, the tympanic bullae of which is similar to the human mastoid air cell system, were filled with jellied adhesive, an alpha-cyanoacrylate monomer, to block the aeration route to the air cells, and tympanic bullae were examined histopathologically. Group 1: Injection of adhesive into the tympanic cavity 1 month after birth following glycerin injection at 1 week after birth. Group 2: Injection of adhesive 1 month after birth without any prior injection into the tympanic cavity. Group 3: Injection of adhesive 3 months after birth without prior injection. In group 1, remarkable inflammation was subsequently observed in the tympanic bullae, development of the air cell system was markedly inhibited and very few air cells remained intact. In groups 2 and 3, however, inflammatory reactions were relatively mild normal air cells remained on the periphery and development of the air cell system was not interrupted.(ABSTRACT TRUNCATED AT 250 WORDS)

Introduction:The geometry of the adult human mastoid air cell system has not previously been described over a large range of mastoid air cell volumes.Methods:Twenty subjects with a wide range of mastoid air cell pneumatised areas, as determined by X-ray, underwent computed tomography scanning of the middle ear. Mastoid air cell surface areas and volumes were then reconstructed from serial imaging sections, using Image J software.Results:Mastoid air cell volumes varied from 0.7 to 21.4 ml, and were linearly related to the pneumatised area. Right and left mastoid air cell volumes and surface areas were highly correlated. The mastoid air cell surface area was a linear function of volume.Conclusion:The relationship between mastoid air cell surface area and volume is similar over a wide range of volumes. Given that the rate of gas exchange across the mastoid air cell mucosa is related to the mastoid air cell surface area, that rate will thus also be a direct linear function of the mastoid air cell volume.