Studies on the morphology of cercariae obtained from freshwater snails at Erawan Waterfall, Erawan National Park, Thailand.

The morphology of cercariae of freshwater snails from Erawan Waterfall, Erawan National Park, Kanchanaburi Province was studied between December 2002 and August 2003. The snail samples were collected by handpicking using a counts per unit of time sampling method. The cercariae, larva stage of a trematode, were investigated using the shedding method where they were categorized into three groups and six species. The first group, Pleurolophocercous cercariae, consists of Haplorchis pumillo (C1) and Stictodora tridactyla (C3). The second group, Furcocercous cercariae, consisted of Mesostephanus appendicalatus (C2), Transversotrema laruei (C6) and Cardicola alseae(C4). The third group, Xiphidio cercariae, has only one species which is Loxogenoides bicolor (C5). Out of 1163 snails, only 62 were found to be infected by cercariae, equivalent to a 5.33% infection rate. The infections grouped by species of the cercariae are as follows: C, 22 (1.9%), C, 29 (2.5%), C2 1 (0.1%), C6 1 (0.1%), C4 6 (0.5%) and C5 3 (0.3%). The freshwater snail samples consist of four species. From a total of 1163 samples, there are 687 Melanoides jugicostis, 91 Tarebia granifera, 296 Thiara scabra and 89 Melanoides tuberculata. Infections were found in 45 (6.5%), 6 (6.6%), 1 (0.3%) and 10 (11.2%), respectively.

Precise localization of motor branching and motor points: a cadeveric study.

In order to facilitate precise localization of motor nerves and motor points, and to increase effectiveness and minimize complications of neurolytic blocks. Locations of motor branching points and motor points of 31 cadavers were measured as relative to medial femoral condyle and mid posterior calf line. Needle insertion points 1.5 centimeters and 0.5 centimeters proximal to the level of medial femoral condyle yielded the best chance (66.25%-76.19%) of finding motor branches to medial gastrocnemius muscles and lateral gastrocnemius respectively. The points with greatest chance of success (67.69%-86.41%) for soleus, tibialis posterior and flexor hallucis longus motor branches blocks were found to be at 2.5, 6, and 11 centimeters distal to the level of medial femoral condyle respectively. However; even if these points are used as guidelline when performing motor branch block prodedure, the risk of sensory nerve fiber injury are still as high as 20.98% upto 50.0%. To avoid such complication, the authors have proposed a set of landmarks that would make it possible to access all of the motor branches of any single calf muscle with only three or less needle insertions, and still maintaining about 1% risk of sensory fiber injury.