Development of Ultrasound-Guided Technique for 4 Points Blockade of Manus in Dromedary Camel: A Cadaveric Investigation

Abstract

The purposes of this study were to describe the most applicable approach of manus blockade in camel using ultrasound-guided techniques. The study was performed on 40 forelimbs of 20 apparently healthy mature freshly slaughtered camels. Limbs were randomly allocated into 3 phases of the study. Phase-I (n=8 limbs): dissection of both dorsal and palmar aspects to identify the topographical anatomy of the target nerves. Phase-II (n=8 limbs): dissection after US guided needle insertion to confirm the needle insertion position. Phase-III (n=24 limbs): US-guided methylene blue injection using one of three volumes (3, 5, or 7 mL) to establish the ideal injection volume. Our results revealed that the dorsal aspect of manus received its innervation from dorsal common digital nerves II and III (DCDN-II & III) and dorsal common digital nerve IV (DCDN-IV). The palmar aspect of manus was received its innervation from the palmar common digital nerve IV (PCDN-IV) and the median nerve. Under Ultrasonographic guidance, the most applicable approach for blocking the DCDN-II & III is at the dorsomedial aspect at about 8-10 c.m below the carpometacarpal joint (CMJ) and 2 cm medial to CDET. Blocking of the DCDN-IV is performed at the dorsolateral aspect at about 8-10 c.m below the CMJ and 2 cm lateral to CDET. Blocking the PCDN IV was performed at the lateral and palmar aspect at about 10-12 c.m below the accessory carpal bone (ACB) and 5 cm palmar to the imaginary line bisect the forelimb longitudinally from lateral to medial. Blocking the median nerve was performed at the proximal third of medial and palmar aspect of metacarpal bone at about 10-12 c.m below the ACB and about 5 cm palmar to the same imaginary line. In conclusion, four point blockade of the manus region in dromedary cadavers can be achieved by US-guided injection of the DCDN-II, III, DCDN-IV, PCDN-IV, and the median nerve.