Investigation of anatomical landmarks for paravertebral anaesthesia in West African Dwarf goats (Capra hircus)

Abstract

West African dwarf goats play important roles in providing meat, milk and generate income in farmers. Information on the techniques and morphometric dimensions on performing paravertebral regional anaesthesia in our local breeds of goats is scanty. The proximal and distal paravertebral nerve block postulated by Farquharson and Magda are used in caprine and ovine species by extrapolation. This study was carried out to quantitatively determine the anatomical site of the spinal nerves (T₁₃, L₁. L₂, L₃ and L₄) for the standardized administration of paravertebral regional anaesthesia in West African dwarf goats. Ten adult WAD goats of either sex weighing 10-15kg were used for the study. The animals were euthanized then used for dissection to expose the spinal nerves and subsequently morphometry was carried out. The result of this study showed that the spinal nerve emerges from the intervertebral foramina and bifurcates into dorsal and ventral branches with the dorsal nerve branch passing cranially to the body of the succeeding lumbar transverse process in a caudolateral manner. While the ventral branches of the lumbar nerves each run obliquely, just below the intertransverse ligament, across the space between the transverse processes. The means of (T₁₃, L₁, L₂ , L₃ and L₄ ) were considered for the right and left sides of the WAD goats. The mean depth was 3.00±0.38cm while the mean length of nerve was 2.65±0.47cm. This study established reference anatomical landmarks of the spinal nerves 2-3cm away from the spine dorsolateral for proximal approach and 1-1.5cm for the distance of needle placement medially from the tip of the transverse process dorsal and ventral.

Keywords: Land marks, Morphometry, Paravertebral anaesthesia, Spinal nerve, WAD goat