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  • Author or Editor: Anjop J. Venker-van Haagen x
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SUMMARY

The innervation of the levator ani and coccygeal muscles and the external anal sphincter was studied by anatomic dissection in 6 clinically normal male dogs and by electrical stimulation in 5 clinically normal male dogs. Variations in innervation occasionally were found that were comparable to those reported in previous studies.

Electromyographic recordings were made from the levator ani and coccygeal muscles and from the anal sphincter in 40 dogs during perineal hernia repair. Spontaneous potentials of 4 types were found in 35 dogs: fibrillation potentials, positive sharp waves, complex repetitive discharges, and fasciculations.

Biopsy specimens of the cranial part of the levator ani muscle were taken in 12 dogs during perineal hernia repair. Histologic examination revealed atrophy in 7 specimens. Spontaneous potentials were recorded from all muscles with histologic evidence of atrophy. All examinations of the levator ani muscle concerned the cranial part of this muscle, because the caudal part was absent in all 40 dogs.

From combined results of electromyography and histologic examination, it was concluded that atrophy of the muscles of the pelvic diaphragm, which develops in some dogs with perineal hernia, is likely to be of neurogenic origin. Nerve damage is localized in the sacral plexus proximal to the muscular branches of the pudendal nerve or in the muscular branches separately.

Free access
in American Journal of Veterinary Research

SUMMARY

In 11 dogs, potentials recorded from the scalp and from the solitary nucleus after stimulation of the glossopharyngeal nerve were compared. The far-field potentials recorded from the scalp consisted of negativity, with peak latency of 2.10 to 3.45 milliseconds (mean, 2.93 milliseconds), followed by positivity, with peak latency of 3.20 to 5.95 milliseconds (mean, 4.86 milliseconds) and duration of 4.65 to 6.95 milliseconds (mean, 5.70 milliseconds). The near-field potentials recorded from the solitary nucleus consisted of positivity, with peak latency of 2.15 to 2.70 milliseconds (mean, 2.45 milliseconds), followed by negativity, with peak latency of 4.05 to 5.05 milliseconds (mean, 4.39 milliseconds) and duration of 4.45 to 5.80 milliseconds (mean, 5.21 milliseconds). Comparison of the far-field potentials (n = 10) with the near-field potentials (n = 5) indicated that polarity of the waves was reversed and that the first peak’s latency was slightly (approx 0.5 milliseconds) longer in the scalp-recorded far-field potentials. Neither the difference in latency of the second peak nor the difference in its duration, measured from the onset of the potentials to the return to the baseline of the activity, was significant. The results strongly suggest that the response in the solitary nucleus evoked by electrical stimulation of the glossopharyngeal nerve is the source of at least part of the scalp-recorded responses to stimulation of the same nerve. The scalp-recorded far-field potentials could, therefore, be characterized as volume conducted from the evoked response in the solitary nucleus.

Free access
in American Journal of Veterinary Research