title: Exostoses and cavernous venous formation in the external auditory canal of the hooded seal as a functional physiological organ.
abstract: Exostoses of the external auditory canal (EAC) develop after protracted mechanical, chemical or thermal irritation in particular. This is a common disorder among aquatic sportsmen and has been considered unique to Man. We dissected and photodocumented the EACs of 5 newborn and 3 adult Hooded Seals (Cystophora cristata). Serial sections of the EACs were prepared for light microscopic evaluation after staining with haematoxylin-eosin or toluidine blue. All EACs exhibited a firm, broad-based. mountain peak-shaped exostosis on the floor of the meatus, lateral to the eardrum. In addition, the meatal skin of the bony EAC harboured large venous sinuses. The exostosis and venous sinuses of the seal EAC participate in the protection of the sensitive hearing apparatus, particularly the pars tensa portion of the drum, during divine.
authors.affiliation: Department of Otolaryngology, Faculty of Medicine, University of Tromsø, Norway. larseric@fagmed.uit.no
authors.forename: L E
authors.initials: LE
authors.lastname: Stenfors
authors.forename: J
authors.initials: J
authors.lastname: Sade
authors.forename: S
authors.initials: S
authors.lastname: Hellström
authors.forename: M
authors.initials: M
authors.lastname: Anniko
authors.forename: L
authors.initials: L
authors.lastname: Folkow
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D004424:Ear Canal / Q000098:blood supply / Q000473:pathology; D004428:Ear Neoplasms / Q000098:blood supply / Q000473:pathology / Q000662:veterinary*; D005260:Female; D008297:Male; D015831:Osteochondroma / Q000098:blood supply / Q000662:veterinary*; D046048:Seals, Earless; D012727:Sex Characteristics