Anatomical Structure of the Brachial Plexus in the Merlin (Falco columbarius)

Ultrasound-guided ventral approach to the brachial plexus block in barred owls (Strix varia): a cadaveric study

OBJECTIVE

To develop an ultrasound (US)-guided ventral approach to the brachial plexus (BP) and evaluate nerve anatomy and staining in barred owl cadavers.

STUDY DESIGN

Prospective, cadaveric study.

ANIMALS

Eleven adult male and female barred owl cadavers with a body mass of 0.43-0.98 kg.

METHODS

Eleven frozen cadavers were thawed for 48 hours, weighed and assigned a body condition score. Ten cadavers were placed in dorsal recumbency with wings abducted. US-guided visualization of the BP was achieved by placing a 13-6 MHz linear probe over the ventral aspect of the scapulohumeral joint, parallel to the sternum. A 22 gauge, 50 mm insulated needle was advanced in-plane in a caudal-to-cranial direction. In each owl, injection targeting one BP was performed with 0.4 mL kg-1 of a 1:1 0.5% ropivacaine and 1% methylene blue solution. Dissection was performed 15 minutes postinjection. Nerve staining was deemed successful if ≥ 1 cm of circumferential staining was achieved. The eleventh owl cadaver was injected with a 1:1 solution of 1% methylene blue and 74% ioversol contrast into both wings, and computed tomography (CT) was performed just before and 15 minutes after injection.

RESULTS

The BP was clearly identified ultrasonographically in cadavers weighing > 0.5 kg. An injectate volume of 0.4 mL kg-1 provided complete staining of the BP branches in all cadavers. CT scan revealed no contrast within the coelomic cavity.

CONCLUSIONS AND CLINICAL RELEVANCE

The US-guided BP injection using a ventral approach was easily performed in barred owl cadavers weighing > 0.5 kg. The injection of 0.4 mL kg-1 of a ropivacaine-dye solution resulted in complete staining of the BP branches in all wings, suggesting that this technique could provide analgesia for structures distal to the scapulohumeral joint. Clinical studies are necessary to confirm the safety and efficacy of this technique in barred owls and other bird species.

Pain in Birds: The Anatomical and Physiological Basis

This article reviews the current understanding of the anatomy and physiology of pain in birds, with consideration of some of its differences from mammalian pain. From transduction to transmission, modulation, projection, and perception, birds possess the neurologic components necessary to respond to painful stimuli and they likely perceive pain in a manner similar to mammals. This article also describes the current understating of opioid receptors, inflammatory mediators, and additional factors in the modulation of pain in avian species.

FORMAÇÃO E DISTRIBUIÇÃO DO PLEXO BRAQUIAL EM PAPAGAIOS VERDADEIROS (Amazona aestiva, Linnaeus, 1758)

<title>Resumo</title><p>Procedimentos anestésicos locais são realizados comumente em aves domésticas e silvestres, por ser de baixo custo e de rápida indução, desde que feitos com precisão, o que requer conhecimento anatômico específico da área a ser operada. Este trabalho objetivou estabelecer a origem e a distribuição do plexo braquial do papagaio verdadeiro (<italic>Amazona aestiva</italic>), através da dissecação da pele e da musculatura de 22 papagaios (17 machos e 5 fêmeas), provenientes do Centro de Triagem de Animais Silvestres do Distrito Federal, após óbito motivado por causas naturais, promovendo o isolamento das raízes formadoras do plexo braquial, bem como de sua ramificação. O plexo braquial foi formado através de quatro troncos, envolvendo os ramos ventrais dos segmentos medulares de C9 a C10, C10 a C11, C11 a T1 e T1 a T2, que se uniram em um curto tronco comum, ramificado em cordões dorsal e ventral. O tronco comum emitiu os delgados nervos subcoracóide e subescapular, além do ramo para o músculo escapuloumeral. O cordão dorsal deu origem aos nervos anconeal, axilar e radial, e o cordão ventral, os nervos peitoral cranial, peitoral caudal, coracobraquial e medianoulnar, cujos ramos supriram os músculos dos compartimentos extensor e flexor do membro torácico, músculos peitorais e pele sobrejacente.</p>