Histological evidence for a supraspinous ligament in sauropod dinosaurs

Supraspinous ossified rods have been reported in the sacra of some derived sauropod dinosaurs. Although different hypotheses have been proposed to explain the origin ofthis structure, histological evidence has never been provided to support or reject any of them. In order to establish its origin, we analyse and characterize the microstructure of thesupraspinous rod of two sauropod dinosaurs from the Upper Cretaceous of Argentina. The supraspinous ossified rod is almost entirely formed by dense Haversian bone. Remains ofprimary bone consist entirely of an avascular tissue composed of two types of fibre-like structures, which are coarse and longitudinally (parallel to the main axis of the element) oriented. These structures are differentiated on the basis of their optical properties under polarized light. Very thin fibrous strands are also observed in some regions. These small fibres are all oriented parallel to one another but perpendicular to the element main axis. Histological features of the primary bone tissue indicate that the sacral supraspinous rod corresponds to an ossified supraspinous ligament. The formation of this structure appears to have been a non-pathological metaplastic ossification, possibly induced by the continuous tensile forces applied to the element.Fil: Cerda, Ignacio Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Universidad Nacional de Río Negro; ArgentinaFil: Casal, Gabriel. Universidad Nacional de la Patagonia; ArgentinaFil: Martínez, Rubén Darío. Universidad Nacional de la Patagonia ; ArgentinaFil: Ibiricu, Lucio Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

Comparative prospective study of foreign body removal from external auditory canals of cadavers with right angle hook or cyanoacrylate glue

Objectives: Foreign bodies of the external auditory canal are a relatively common problem in emergency departments. Repeated attempts at removal with standard instrumentation can lead to significant ear injury. Recent case reports of using cyanoacrylate impregnated cotton buds suggest this is less traumatic and well tolerated by patients. No studies on this method have been performed. The objectives of this study were to identify whether there were significant differences in success rate, duration and injury caused by extracting beads from the external auditory canals of adult cadaveric ears using two different methods. This is the first study in a planned series of anatomical and clinical studies relating to foreign body extraction from the external auditory canal. Methods: In this study the success rate, time taken and injury rate were assessed for removal of impacted spherical foreign bodies in the external auditory canals of cadavers using both a blunt right angle hook and cotton buds impregnated with cyanoacrylate glue. This process was performed by a specialist registrar in otolaryngology and repeated by a specialist registrar in emergency medicine. Results: It was shown that both methods had a statistically similar success rate (two tailed binomial test p=0.5) and no injury was identified for either method. In addition the median extraction time for a right angle hook was 6 seconds and 42 seconds for cyanoacrylate. It was also noted that failed extraction was associated with a poor view of the foreign body in the external canal. This was caused by hair, a large tragus or tortuous external canal. Conclusions: The authors feel that cyanoacrylate impregnated cotton buds are as effective at removing impacted foreign bodies as a right angle hook but the process takes longer. It is believed that patients could tolerate this longer time as the cyanoacrylate method is in theory less traumatic