J Vet Sci.  2009 Mar;10(1):77-80. 10.4142/jvs.2009.10.1.77.

Ultrasonographic examination of the carpal canal in dogs

• Turan E
• Ozsunar Y
• Yildirim I

• KMID: 1089350
• DOI: http://doi.org/10.4142/jvs.2009.10.1.77

Abstract

The aim of this study was to determine the course of the median nerve and its adjacent structures in the carpal canals of 8 healthy dogs by using high-frequency transducers. Before performing ultrasonography, the transverse and posteroanterior diameters as well as the perimeter of the carpus were measured at just proximal to the side of the carpal pad. The anatomical structures were then determined at two levels of the carpal canal, which were named the proximal and distal levels, on the transverse sonograms. The cross-sectional areas, perimeters and the transverse and posteroanterior diameters of the median nerve were measured at these levels. Although all the measurements were larger at the proximal level, significant differences between the proximal and distal levels were determined for the cross-sectional area, the perimeter and the transverse diameter of the median nerve. On the transverse sonogram, the deep digital flexor tendon was seen in almost the center of the carpal canal like a comma shape and also it had a small concavity on the caudal side. The superficial digital flexor tendon was seen as an ovoid shape on the transverse sonograms and it was located nearly at the posterior side of the carpal canal. Both tendons were seen as intermediate-grade echogenic structures. The median artery was located inside of the concavity of the deep digital flexor tendon. Also, the median nerve was seen at the posteromedial side of the median artery. As a result of this study, the cross-sectional areas of the median nerve ranged between 1.01-2.68 mm2 at the proximal level and between 0.93-1.91 mm2 at the distal level.

Keyword

carpal canal; dog; median nerve; ultrasonography

MeSH Terms

Animals
Dogs/*anatomy & histology
Forelimb/*innervation
Ultrasonography/*veterinary

Figure

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  Fig. 1 Schematic presentation of the probe placement for the proximal (PCCL) and distal (DCCL) carpal canal levels in the left forelimb.

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  Fig. 2 Transverse ultrasonographic scans of the carpal canal at the proximal (P) and the distal (D) levels of the carpal canal. Color Doppler imaging is helpful to easily localize the median nerve. Note that the size of the median nerve is larger at the proximal part of the carpal canal as compared to the distal part. The transverse diameter (A) and the posteroanterior diameter (B) of the median nerve, the median nerve (MN), the median artery (MA), the deep digital flexor (DDFT) tendons and the superficial digital flexor tendons (SDFT).

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