INVESTIGATION ON THE INNERVATION AND EXACT SITE FOR BLOCKING OF PARAVERTEBRAL SPINAL NERVES IN BLACK BENGAL GOAT

Abstract

The present study was conducted to investigate the topographic descriptions and illustrations of the spinal nerve innervations to the flank region and the exact site of infiltration of local anaesthetics for the T13, L1 and L2 paravertebral spinal nerve block in 10 Black Bengal does from January to June 2009 in the Dept. of Anatomy and Histology, Chittagong Veterinary and Animal Sciences University, Chittagong. The animals were anaesthetized with pentobarbital sodium @ 20 mg / kg body weight IM and bled to death by giving incision on the right common carotid artery. Whole vascular system was flashed with 0.85 % physiological saline solution and then 10 % formalin was injected through the same route for well preservation. Then the animals were dissected to study the innervations of spinal nerves at flank region and also to determine the exact site of infiltration of local anaesthetic for paravertebral nerve block. The study revealed that the cranial, middle and caudal portion of the flank region is innervated by ventral branches of the last thoracic (T13), first (L1) and second (L2) lumbar spinal nerves respectively. In vertical or proximal approach, the exact site for the infiltration of local anaesthetic in T13 spinal nerve block is at 0.8 ± 0.17 cm caudally from head of the last rib, 0.7 ± 0.22 cm cranio-medially from cranial angle of L1 transverse process and 3.4 ± 0.20 cm laterally from dorsal midline; in L1 spinal nerve block is at 1.2 ± 0.40 cm medially from cranial angle of L2 transverse process and 3.5 ± 0.17 cm laterally from the dorsal midline and in L2 spinal nerve block is at 1.6 ± 0.26 cm medially from cranial angle of L3 transverse process and 3.7 ± 0.14 cm laterally from the dorsal midline. In horizontal or distal approach, the exact site for the infiltration of local anaesthetic in T13 spinal nerve block is at 0.5 ± 0.10 cm and 1.8 ± 0.63 cm cranially from the cranial and caudal angle of L1 transverse process respectively and 4.6 ± 0.30 cm laterally from dorsal midline at lateral border of L1 transverse process; in L1 spinal nerve block is at 0.4 ± 0.10 cm and 1.4 ± 0.28 cm caudally and cranially from the cranial and caudal angle of L2 transverse process respectively and 5.1 ± 0.20 cm laterally from dorsal midline at lateral border of L2 transverse process and in L2 spinal nerve block is at 2.5 ± 0.42 cm and 0.5 ± 0.10 cm caudally and cranially from the cranial and caudal angle of L3 transverse process respectively and 5.5 ± 0.28 cm laterally from dorsal midline at lateral border of L3 transverse process.