Karine de Mattos

Origens e ramificações do plexo braquial no cachorro-do-mato Cerdocyon thous (Linnaeus, 1766)

This study aimed to describe the origin and branching of nerves from twenty brachial plexuses of crab-eating foxes (Cerdocyon thous). Ten animals of the species, obtained post mortem from being run over on highways, were used for the study, in accordance with the authorization from IBAMA / SISBIO No. 33667-1. Once collected, the cadavers were fixed in 50% formaldehyde and kept for at least 14 days in a solution of 10% formaldehyde before dissections. After removal of skin, incisions in breast muscles and reflection of thoracic limbs allowed access to axillary space and the nerves could have trajects dissected individually to each muscle insertion. To improve visualization of the cervical and thoracic ventral roots that originated every single nerve, muscles that covered the intervertebral foramina, transverse processes and vertebral bodies were removed ventrally and the spinal cord exposed. Schematic drawings and photographic records documented the origin and branching of nerves. The twenty plexuses were resulted from connections between the ventral branches of the last three cervical spinal nerves (C6, C7 and C8) and first thoracic (T1). These branches derived the nerves suprascapular, subscapular, axillary, musculocutaneous, radial, median and ulnar to the intrinsic muscles and brachiocephalic, thoracodorsal, lateral thoracic, long thoracic, cranial and caudal pectoral nerves to the extrinsic muscles of the thoracic limb. It was found that the ventral rami of C7 were the main contributors in the formation of nerves (61.5%), followed by C8 (55.4%), T1 (41.2%) and C6 (30.8%). The t-test comparison between means at a significance level of 5% showed no differences in the origin of plexus when compared antimeres and sexes. Of the total of 260 dissected nerves, 68.8% originated by the combination of two or three roots, while only 31.2% were formed by a single root. The combination between C8 and T1 was the most frequent origin of nerves to the plexus (23.8%) in this species. Comparing the origin, branching and innervation area of the brachial plexus in C. thous with other domestic and wild species, there was a greater similarity with the domestic dog. These results may give the anatomical basis to diagnosis of neuromuscular disorders, anesthetic blocks techniques and comparative morphofunctional analyzes involving this species.

Brachial Plexus in the Pampas Fox (Lycalopex gymnocercus): a Descriptive and Comparative Analysis: BRACHIAL PLEXUS OF THE PAMPAS FOX

Twenty thoracic limbs of ten Lycalopex gymnocercus were dissected to describe origin and distribution of the nerves forming brachial plexuses. The brachial plexus resulted from the connections between the ventral branches of the last three cervical nerves (C6, C7, and C8) and first thoracic nerve (T1). These branches connected the suprascapular, subscapular, axillary, musculocutaneous, radial, median and ulnar nerves to the intrinsic musculature and connected the brachiocephalic, thoracodorsal, lateral thoracic, long thoracic, cranial pectoral and caudal pectoral nerves to the extrinsic musculature. The C7 ventral branches contribute most to the formation of the nerves (62.7%), followed by C8 (58.8%), T1 (40.0%) and C6 (24.6%). Of the 260 nerves dissected, 69.2% resulted from a combination of two or three branches, while only 30.8% originated from a single branch. The origin and innervation area of the pampas fox brachial plexus, in comparison with other domestic and wild species, were most similar to the domestic dog and wild canids from the neotropics. The results of this study can serve as a base for comparative morphofunctional analysis involving this species and development of nerve block techniques. Anat Rec, 300:537–548, 2017.

Morfologia da laringe em Cerdocyon thous (Linnaeus, 1766)

Cerdocyon thous (crab-eating fox) is the most common wild canid in South American territory. The aim of this paper was to describe macroscopic, microscopic and comparative morphology of the larynx of this species. Analyses of larynges of sixteen specimens (four males and twelve females) revealed the topography, conformation, morphometrics, intrinsic muscles and histological characteristics. The larynx was positioned ventral to the axis and comprised one cricoid and one thyroid cartilage (hyaline), one epiglottis (elastic) and a pair of arytenoids (mixed). A pair of sesamoid cartilages was identified between the corniculate processes and the cricoid lamina. Morphometry revealed that thyroid cartilage was the largest. There were no conclusive signs of sexual dimorphism in the larynx of this species. Squamous stratified epithelium predominated and underwent transition to ciliated pseudo-stratified at the level of caudal thyroid and rostral cricoid portions. By comparison, larynx of C. thous showed similarity with the domestic dog, although the shape of cartilages has shown some variation.

Osteología del Miembro Torácico de la Corzuela Parda Mazama gouazoubira (G. Fischer, 1814) (Cetartiodactyla: Cervidae)

RESUMEN: El objetivo del estudio fue describir las características anatómicas y establecer hipótesis morfo-funcionales del esqueleto del miembro torácico de Mazama gouazoubira . Para ello, se utilizaron los miembros torácicos de cuatro adultos jóvenes. Los huesos se prepararon mediante ebullición y fueron blanqueados en una solución de peróxido de hidrógeno para obtener descripcion s comparativas, mediciones osteométricas y radiografías digitales. En comparación con los rumiantes domésticos, la escápula resul tó ser ancha y plana, con el acromion pequeño, el proceso coracoides muy pequeño y sin tuberosidad de la espina. El húmero se observó alargado con la diáfisis redondeada en una sección transversal y con proyecciones no articulares lisas. La ulna se unió al radi o hasta la epífisis distal y juntos formaron un espacio interóseo proximal alargado y estrecho, sin surco vascular. El esqueleto de la man o pr sentó los metacarpianos III y IV bien desarrollados y fusionados, mientras que los metacarpianos II y V resultaron rudimentarios con disp sición telemetacarpiana, filogenéticamente típico de cérvidos del Nuevo Mundo. Se encontraron cuatro dedos con tres falanges en cad uno, de los cuales, dos corresponden a los principales (III y IV) que llegan al suelo y dos son rudimentarios (II y V). Las rad iografías nos permitieron visualizar los patrones de tensiones trabeculares normales y la osteometría permitió establecer relaciones con fines comparativos. Se reconocieron las adaptaciones esqueléticas del miembro torácico para favorecer la locomoción cursorial saltato ria.

Brachial Plexus in the Pampas Fox (Lycalopex gymnocercus): a Descriptive and Comparative Analysis

Twenty thoracic limbs of ten Lycalopex gymnocercus were dissected to describe origin and distribution of the nerves forming brachial plexuses. The brachial plexus resulted from the connections between the ventral branches of the last three cervical nerves (C6, C7, and C8) and first thoracic nerve (T1). These branches connected the suprascapular, subscapular, axillary, musculocutaneous, radial, median and ulnar nerves to the intrinsic musculature and connected the brachiocephalic, thoracodorsal, lateral thoracic, long thoracic, cranial pectoral and caudal pectoral nerves to the extrinsic musculature. The C7 ventral branches contribute most to the formation of the nerves (62.7%), followed by C8 (58.8%), T1 (40.0%) and C6 (24.6%). Of the 260 nerves dissected, 69.2% resulted from a combination of two or three branches, while only 30.8% originated from a single branch. The origin and innervation area of the pampas fox brachial plexus, in comparison with other domestic and wild species, were most similar to the domestic dog and wild canids from the neotropics. The results of this study can serve as a base for comparative morphofunctional analysis involving this species and development of nerve block techniques. Anat Rec, 300:537–548, 2017.