Localization of obturator and pectineal motoneurons in the dog

The motoneuron columns of the obturator and pectineal nerves were localized within the lumbar spinal cords of dogs by observing retrograde chromatolysis following resection of the respective nerves. The obturator column was located in segments L4 through L6 while the pectineal column was located in segments L4 and L5. The dorsal‐to‐ventral and medial‐to‐lateral boundaries were determined for each column and the pectineal column was located within the boundaries determined for the obturator column in segments L4 and L5. Antidromic stimulation of the pectineal nerve localized the origin of motor fibers from lumbar spinal nerves L4 and L5. The results provide an anatomical basis for studies of motoneurons innervating the pectineus muscles of dogs affected with a developmental myopathy of this muscle.