Intraorbital anatomy of the koala (Phascolarctos cinereus)

This is the first documented study of the anatomical details of the contents of the normal koala orbit, excluding the bulbus oculi. Baseline data were established which are necessary for understanding and treating ocular disease in the koala (Phascolarctos cinereus). The anatomy of the orbital contents of the koala were examined and described from animals that presented dead or were euthanized for humane reasons. Dissections of the orbital cavity were performed under magnification. Polymethyl methacrylate (PMMA) casts of the nasolacrimal system and the vascular supply of the orbit were also made in order to study these systems. The superficial lymphatic drainage of the conjunctival tissues was studied by subcutaneous injection of Evan's Blue into the palpebral conjunctiva of a freshly deceased animal, and by Microfil casts of the efferent lymphatics. In general, the orbital contents of the koala are consistent with those of other carnivorous polyprotodont and herbivorous diprotodont marsupials.

Physiological importance of the coronary arterial blood supply to the rattlesnake heart

The reptilian heart consists of a thick inner spongy myocardium that derives its oxygen and nutrient supply directly from the blood within the ventricular cavity, which is surrounded by a thin outer compact layer supplied by coronary arteries. The functional importance of these coronary arteries remains unknown. In the present study we investigate the effects of permanent coronary artery occlusion in the South American rattlesnake (Crotalus durissus) on the ability to maintain heart rate and blood pressure at rest and during short term activity. We used colored silicone rubber (Microfil) to identify the coronary artery distribution and interarterial anastomoses. The coronary circulation was occluded and the snakes were then kept for 4 days at 30 degrees C. Microfil injections verified that virtually all coronary arteries had successfully been occluded, but also made visible an extensive coronary supply to the outer compact layer in untreated snakes. Electrocardiogram (ECG), blood pressure (P(sys)) and heart rate (f(H)) were measured at rest and during enforced activity at day 1 and 4. Four days after occlusion of the coronary circulation, the snakes could still maintain a P(sys) and f(H) of 5.2 +/- 0.2 kPa and 58.2 +/- 2.2 beats min(-1), respectively, during activity and the ECG was not affected. This was not different from sham-operated snakes. Thus, while the outer compact layer of the rattlesnake heart clearly has an extensive coronary supply, rattlesnakes sustain a high blood pressure and heart rate during activity without coronary artery blood supply.

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Mamoplastia de reducción con incisión periareolar: anatomía y clínica del pedículo central

Antecedentes y Objetivos. La mamoplastía de reducción periareolar es una técnica poco invasiva. Su característica principal es el dejar una cicatriz camuflada en el margen areolar. El objetivo del presente artículo es presentar la anatomía del pedículo central en mamoplastia de reducción con incisión periareolar, la técnica quirúrgica, una serie de pacientes operadas, y revisar la literatura al respecto. Pacientes y Método. Empleamos para el estudio anatómico 24 mamas de 12 cadáveres frescos femeninos, basándonos en la irrigación mediante ramas de la arteria mamaria interna, que irriga el complejo areolo-mamilar y su estuche cutáneo. La técnica consiste en desepitelizar un segmento cutáneo, previamente demarcado alrededor de la areola, telescopar la glándula desde su estuche cutáneo, resecar el tejido mamario deseado mediante cuñas que posteriormente se suturan, y cerrar la incisión alrededor de la areola pasando de una circunferencia mamaria mayor a una de menor diámetro. Presentamos además la experiencia del primer autor en 35 pacientes operadas con la técnica descrita. Resultados. Identificamos una rama de la quinta arteria intercostal en el 80% de las disecciones anatómicas realizadas en cadáveres inyectados con Microfil®, y una rama de la cuarta arteria intercostal en el 20% de los especímenes, que asegura la irrigación del complejo areolo-mamilar y del estuche cutáneo. En las 35 pacientes operadas con la técnica periareolar usando el pedículo central, 5 ellas (14%) presentaron complicaciones menores, sin requerir reintervenciones ni hospitalización. Los resultados fueron adecuados. Conclusiones. Consideramos que la técnica de reducción mamaria con incisión periareolar es segura y proporciona buenos resultados si se hace una adecuada selección de pacientes y la realiza un profesional calificado. Se recomienda para pacientes jóvenes, con piel elástica, distancia clavícula-pezón de hasta 25 cm, y con un peso mamario a resecar no superior a 500 gr.