{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,1]],"date-time":"2026-08-01T09:52:18Z","timestamp":1785577938997,"version":"3.56.0"},"reference-count":20,"publisher":"American Veterinary Medical Association (AVMA)","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["ajvr"],"published-print":{"date-parts":[[2012,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n<jats:p><jats:bold>Objective<\/jats:bold>\u2014To evaluate the osseous structures of the external acoustic meatus, tympanic cavity, and tympanic bulla of llamas (<jats:italic>Lama glama<\/jats:italic>) by use of computed tomography (CT) and establish measurement values for use in detection of abnormalities associated with the external or middle ear in llamas.<\/jats:p>\n<jats:p><jats:bold>Animals<\/jats:bold>\u201410 adult llama heads without any evidence of ear disease.<\/jats:p>\n<jats:p><jats:bold>Procedures<\/jats:bold>\u2014Heads of 10 healthy llamas euthanized by use of a captive bolt striking the dorsal aspect of the skull were collected. Transverse images of the heads were acquired with 1-mm slice thickness, and images were reconstructed in sagittal and dorsal planes. Measurements of the bony structures of the external and middle ear of each head were obtained.<\/jats:p>\n<jats:p><jats:bold>Results<\/jats:bold>\u2014The osseous external acoustic meatus curved ventrally as it tracked medially. Its narrowest portion was located at the level of the tympanic annulus. The tympanic bulla conformation differed widely from the bubble-shaped tympanic bulla in dogs and cats. The bulla was divided by the stylohyoid fossa into a larger caudolateral and a smaller caudomedial process; its interior had a honeycombed structure with pneumatized cells similar to the honeycombed appearance of the human mastoid process.<\/jats:p>\n<jats:p><jats:bold>Conclusions and Clinical Relevance<\/jats:bold>\u2014Results provided new information regarding the shape and dimensions of the osseous external and middle ear structures in adult llamas without ear disease. Specific landmarks for location of the external acoustic meatus, tympanic cavity, and tympanic bulla in relation to each other were identified. Knowledge of the CT appearance of normal structures will help clinicians to identify changes attributable to middle ear otitis, external ear canal stenosis, or congenital malformations of the ear in this species.<\/jats:p>","DOI":"10.2460\/ajvr.73.1.42","type":"journal-article","created":{"date-parts":[[2011,12,28]],"date-time":"2011-12-28T19:37:15Z","timestamp":1325101035000},"page":"42-52","source":"Crossref","is-referenced-by-count":12,"title":["Computed tomographic features of the osseous structures of the external acoustic meatus, tympanic cavity, and tympanic bulla of llamas (Lama glama)"],"prefix":"10.2460","volume":"73","author":[{"given":"Ismael","family":"Concha-Albornoz","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Susanne M.","family":"Stieger-Vanegas","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christopher K.","family":"Cebra","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1272","reference":[{"key":"ref1","series-title":"Aust Vet J","doi-asserted-by":"publisher","first-page":"301","DOI":"10.1111\/j.1751-0813.1999.tb10267.x","article-title":"Total ear canal ablation and lateral bulla osteotomy in an alpaca","volume":"77","author":"Marriott","year":"1999"},{"key":"ref2","series-title":"Organ of special sense","first-page":"438","author":"Fowler","year":"1998"},{"key":"ref3","series-title":"Clin Anat","doi-asserted-by":"publisher","first-page":"503","DOI":"10.1002\/ca.20218","article-title":"Morphometric study of the external and middle ear anatomy in sheep: a possible model for ear experiments","volume":"19","author":"Seibel","year":"2006"},{"key":"ref4","series-title":"Anat Histol Embryol","doi-asserted-by":"publisher","first-page":"52","DOI":"10.1111\/j.1439-0264.2004.00572.x","article-title":"Anatomy of the cranioencephalic structures of the camel (Camelus dromedarius L.) by imaging techniques: a magnetic resonance imaging study","volume":"34","author":"Arencibia","year":"2005"},{"key":"ref5","series-title":"J Small Anim Pract","doi-asserted-by":"publisher","first-page":"233","DOI":"10.1111\/j.1748-5827.2006.00241.x","article-title":"External auditory canal atresia of probable congenital origin in a dog","volume":"48","author":"Schmidt","year":"2007"},{"key":"ref6","series-title":"Vet Radiol Ultrasound","doi-asserted-by":"publisher","first-page":"545","DOI":"10.1111\/j.1740-8261.2008.00428.x","article-title":"Virtual CT otoscopy of the middle ear and ossicles in dogs","volume":"49","author":"Eom","year":"2008"},{"key":"ref7","series-title":"Vet Radiol Ultrasound","doi-asserted-by":"publisher","first-page":"557","DOI":"10.1111\/j.1740-8261.2008.00421.x","article-title":"Computed tomographic imaging of the normal immature California sea lion head (Zalophus californianus)","volume":"49","author":"Dennison","year":"2008"},{"key":"ref8","series-title":"Vestn Rentgenol Radiol","first-page":"4","article-title":"Computed tomography of the temporal bones in children with developmental anomalies of the external and middle ear [in Russian]","volume":"5","author":"Kurilenkov","year":"2001"},{"key":"ref9","series-title":"Vestn Otorinolaringol","first-page":"7","article-title":"Potential of temporal bone CT in the study of external acoustic meatus in health and pathology [in Russian]","volume":"3","author":"Zelikovich","year":"2007"},{"key":"ref10","series-title":"Neurol Med Chir (Tokyo)","doi-asserted-by":"publisher","first-page":"335","DOI":"10.2176\/nmc.47.335","article-title":"Assessment of the anatomical relationship between the arcuate eminence and superior semicircular canal by computed tomography","volume":"47","author":"Seo","year":"2007"},{"key":"ref11","series-title":"J Am Vet Med Assoc","first-page":"1095","article-title":"Morphometric evaluation of growth in llamas (Lama glama) from birth to maturity","volume":"200","author":"Smith","year":"1992"},{"key":"ref12","series-title":"Osteologia","first-page":"10","author":"Schaller","year":"1992"},{"key":"ref13","series-title":"Texbook of veterinary anatomy","first-page":"346","author":"Dyce","year":"2002"},{"key":"ref14","series-title":"The ear","first-page":"244","author":"Ellenport","year":"1975"},{"key":"ref15","series-title":"Veterinary anatomy of domestic mammals. 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