Anatomical studies on the spinal cord of the greater cane rat (Thryonomys swinderianus, Temminck) II: histomorphology and spinal tracings

The field of neuroanatomy and the knowledge of spinal cord, in particular, requires an accurate base on which data can be mapped. Lately, researchers have taken into consideration studies on Greater cane rat (GCR) because of its large body size and African origin. This study was designed to elucidate the histomorphologic features of the GCR spinal cord. A total of 10 adult GCR (five males and five females) raised in captivity were used for this study. Twenty-seven spinal segments (Cervical-8, Thoracic-13, Lumbar-5 and Sacral-1) were identified. Each segment was transected, processed histologically into Nissl-stained sections and observed features of the spinal cord were described. The GCR spinal segments possess the typical Hshaped inner gray matter core surrounded by an outer white matter. Variations in the shape of the central canals were observed across the spinal segments. A total of sixty-four features were delineated: twelve observed in the white matter, forty-nine in the gray matter and the remaining three were attached to the spinal cord. Laminar organisations, tracts, nuclei and motor neuron groups of the spinal cord identified were also traced and possible functions adduced in this rodent. No sexual dimorphism was observed in this study. This work has provided valuable and qualitative baseline information for understanding the laminar characteristics relevant to pathophysiologic conditions of the spinal cord. It has also contributed to the knowledge of neuroanatomy of this rodent and will be valuable for spinal cord research especially in this species.Keywords: Spinal cord, Greater cane rat, Histology, Laminar organisation, Spinal tracing