eISSN 1308-4038 International Journal of Anatomical Variations (2013) 6: 120–123 Case Report

Variant presentations of “Foramen of Huschke” in seven adult human crania

Published online July 24th, 2013 © http://www.ijav.org Phalguni SRIMANI [1] Abstract Pranab MUKHERJEE [1] So far the development of tympanic plate is concerned; gaps or ‘foramen of Huschke’ may affect its [2] surface, which bear not only anatomical significance but also clinical correlation with etiogenesis Enakshi GHOSH of different diseases. Such records though available in literature in different ethnicity and groups, Hironmoy ROY [3] but till date not available in Bengali population of India. A meticulous observation in preserved adult human crania in the Museum of Anatomy Department at the Medical College of Kolkata, Department of Anatomy, RG Kar Medical College, Kolkata seven crania showed variant presentations, detailed in the report. [1], Department of Anatomy, Burdwan Medical College, © Int J Anat Var (IJAV). 2013; 6: 120–123. Burdwan [2], Department of Anatomy, North Bengal Medical College, Darjeeling [3], INDIA.

Prof. Pranab Mukherjee Department of Anatomy RG Kar Medical College Kolkata, INDIA. +91 943 4568024 [email protected]

Received March 6th, 2013; accepted April 21st, 2013 Key words [foramen of Huschke] [tympanic plate]

Introduction of Huschke. Shapes of such foramina were confirmed by naked Professor Emil Huschke (1797-1858), a German anatomist first eye examination with the help of divider, pointers, ruled scale described the probability of deficiency in the development and flat cardboard. of tympanic plate of , which was named as Amongst the 53 skull studied, seven of them found to have the “Foramen of Huschke” or foramen tympanicum, which usually deficiencies of tympanic plates in form of foramen of Huschke to get apposed in adulthood [1, 2]. with variant presentations as below: It, if persistent in adult life, may result in complications like Case 1: In a cranium, on the left side a single large oval foramen herniation of temporomandibular joint (TMJ), formation having transverse diameter of 0.2 cm and longitudinal of salivary otorrhea, spread of infection or tumor from diameter of 0.3 cm encroaching to the free margin of tympanic external auditory to the and vice plate was present. Whereas, the right side tympanic plate versa. There may be other otologic complications also due to showed no variations (Figure 1). inadvertent passage of arthroscope into the external auditory In another cranium, on the left side pinhead-sized canal during TMJ arthroscopy [2–6]. Case 2: three foramina were present at different levels at tympanic Previous studies have explored its prevalence in different plate, whereas on the fellow side a single round foramen of populations with variations of different developmental diameter of 0.2 cm was noted centrally (Figure 2). deficiencies of tympanic plate of temporal bone, but till date no such data gets available amongst Bengali population from Case 3: A single triangular foramen having base of 0.1 cm and India, till searched for. two sides of 0.2 cm each was noted in tympanic plate on left side and in the right side a pinhead-sized foramen was found Case Report (Figure 3). With prior permission from the principal of the institutes and Case 4: A single oval shaped foramen having transverse Head of the Department, the dry adult human crania (with diameter of 0.2 cm and longitudinal diameter of 0.1 cm was intact tympanic plates) were collected from the Museum noted on left tympanic plate and a single rounded foramen of of Anatomy Department. Tympanic plates were observed 0.1 cm in diameter present was noted on fellow side (Figure meticulously to rule out any deficiency in the form of foramen 4). Foramen of Huschke 121 having base of 0.1 cm and two sides of 0.2 cm each; and lower right one was rounded having diameter of 0.1 cm. Whereas on the right side a large rounded foramen was present at the center having diameter of 0.2 cm and two small pinhead sized foramina were present on the tympanic plate (Figure 7). Discussion Variations of ‘foramen of Huschke’ has been evident that such a deficiency may exist in single or pleural; it may be pin-head sized to a large gap; and it may central to in margin of the tympanic plate. Three of them have unilateral defect and that is on the left side.

Figure 1. Picture shows a single large oval foramen on the left side (red arrow), having transverse diameter of 0.2 cm and longitudinal diameter of 0.3 cm encroaching to the free margin of tympanic plate.

Figure 3. Picture showing here a single triangular foramen on the left side (red arrow) having base of 0.1 cm and two sides of 0.2 cm each; and a pinhead-sized foramen on the right side (white arrow).

Figure 2. Picture shows a cranium, having pinhead-sized three foramina (white arrows) on the left side present at different levels at tympanic plate, whereas on the fellow side a single round foramen (red arrow)of diameter of 0.2 cm was noted centrally in the tympanic plate.

Case 5: A single rounded foramen found to be present having diameter of 0.2 cm was noted only on left side with intact tympanic plate on right side (Figure 5). Case 6: A single oval foramen having transverse diameter of 0.2 cm and longitudinal diameter of 0.1 cm was present close to the on the left side only with no deficiency in right side (Figure 6). Case 7: In one skull three foramina found on left side tympanic Figure 4. Figure showing a single oval shaped foramen (red arrow) plate placed at different levels. The upper foramen was having transverse diameter of 0.2 cm and longitudinal diameter of oval having transverse diameter of 0.2 cm and longitudinal 0.1 cm was noted on the left tympanic plate, and a single rounded foramen (white arrow) of 0.1 cm in diameter is present on the right diameter of 0.1 cm; lower right one was triangular in shape side. 122 Srimani et al.

Figure 7. Photograph shows three left sided foramina (red arrows) in different gaps, and three adjacent gaps (white arrows) on the right side. Figure 5. Figure shows a single rounded foramen (red arrow) having diameter of 0.2 cm only on the left side. Toyama et al. in 2009 reported persistent foramen tympanicum as a rare congenital cause of TMJ herniation into external auditory canal with coronal tomographic imaging from Sao Paulo, Brazil. Most patients as mentioned by them were female, of average age of 55 years with unilateral presentation. They also reported that masticatory movements could further widen the bony defect. Recognition of the bony defect being crucial to prevent iatrogenic complications mainly related to surgical and TMJ procedures like arthroscopy as stated by them [7]. Mao and Nah in 2004 identified different mechanical factors like, mastication, deglutition, respiration and hereditary factors to be responsible for influencing the ossification of tympanic plate resulting in persistence of foramen of Huschke [8]. A persistent foramen of Huschke may mimic the branchial cleft anomaly in its presentation. It may result in complication such as TMJ herniation and salivary fistula as reported by Sharma and Dawkins in 1987 [9] and Haschimoto et al. in 2011 [10]. They noted the difference in presence of such bony deficiency between males (12%) and females (20%) with Figure 6. Figure shows a single oval foramen (red arrow) having statistically significant female preponderance (p<0.001). An transverse diameter of 0.2 cm and longitudinal diameter of 0.1 cm unusual case of spontaneous salivary otorrhea of right side close to the petrotympanic fissure on the left side. was reported by Rushton and Pemberton in 2005, in which advanced imaging CT and T1-T2 weighted MRI of external auditory meatus was used to identify developmental defect in Ontogenetically it has been described that at birth the bony the anterior wall of bony external auditory meatus [11]. Such meatus exists as an incomplete ring (tympanic ring) and bony Radiologic evaluations of deficiencies were further studied external auditory canal is formed by lateral extension of that also in later period [12]. The foramen of Huschke was reported incomplete ring. During the first year of life, the anterior and as the source of fistula, which may mimic branchial cleft [13]. posterior processes of the tympanic plate grow towards each Measurement of foramen tympanicum by anatomical cone other to fuse and finally enclose a substantial opening, and beam CT study has been reported very recently by Tozoglu forms the tympanic plate. The defect in encroachment of et al. from [14]. They found foramen tympanicum in 37 of 207 ossifying plate results in occasional persistence of foramen as patients (17.9%), unilateral in 24 patients (11.6%) and bilateral ‘foramen of Huschke’. [1–6]. in 13 patients (6.3%). Mean axial (transverse) diameter was 5 Foramen of Huschke 123 mm and mean sagittal (longitudinal) diameter was 2 mm. In Its prevalence was recorded earlier in different groups. Such archeological excavation at the region of Mediterranean sea, an endeavor to record its variation in Bengali population is foramen of Huschke was present among 11.7% Jews, 10.7% probably untouched as searched for. Such a data is expected Nabataeans and 4.2% of other local populations as reported to be helpful to not only to the arena of Anatomy, but also for by Yossi in 2011 [15]. ENT surgeons, dentists as well as radiologists. Thus, from literature it could be made evident that persistent foramen of Huschke, may herald clinical problems in adult life.

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