Bloqueos de extremidad inferior / Lower extremity blocks

Lower limb blocks are described with emphasis on distribution according to sensitive distribution and its sonoanatomy.

Se describen los bloqueos de la extremidad inferior haciendo énfasis en la distribución de acuerdo a distribución sensitiva y a su sonoanatomia.

Variaciones del Nervio Isquiático en Relación al Músculo Piriforme / Variations of the Sciatic Nerve in Relation to the Piriformis Muscle

El nervio isquiático nace del plexo sacro y sale de la pelvis a través del foramen isquiático mayor por debajo del musculo piriforme como un tronco común. En ocasiones, este nervio puede emerger dividido en sus dos componentes: el nervio fibular común y nervio tibial, encontrándose, variaciones que podrían dar origen a una condición de compresión nerviosa. En este trabajo se exponen dos variaciones del nervio isquiático en un mismo individuo, donde en la primera el nervio fibular común atraviesa el músculo piriforme y luego desciende junto al nervio tibial y la segunda, donde el nervio fibular común se forma a partir de un ramo superior que perfora el músculo piriforme y el otro inferior que pasa debajo de él, para unirse luego en el margen inferior de éste músculo y formar el nervio fibular común, que desciende junto al nervio tibial. Las variaciones del nervio isquiático en relación al músculo piriforme podrían explicar el síndrome del músculo piriforme.

The sciatic nerve arises from the sacral plexus and exits the pelvis through the greater sciatic foramen below the piriformis muscle as a common trunk. Sometimes this nerve can emerge divided into two components: the common fibular nerve and tibial nerve, finding variations that could give rise to a condition of nerve compression. In this paper we describe two variations of the sciatic nerve in the same individual, where in the first common fibular nerve passes through the piriformis and then descends along the tibial nerve and the second, where the common fibular nerve is formed from a higher branch that pierce to piriform muscle and a lower branch passing under him, then join at the inferior margin of this muscle and form the common fibular nerve, which descends with the tibial nerve. Variations of the sciatic nerve in relation to the piriformis muscle could explain the piriformis syndrome.

Origin and distribution of the femoral nerve in fetuses of zebu-crossed bovines

In this study the femoral nerve origin and distribution was assessed through the dissection of 30 fetuses of zebu-crossed bovines, 20 males and 10 females. These animals samples fixation in 10% formaldehyde aqueous medium occurred either by subcutaneous, intra-muscle, and intra-cavity injections in different sites, or by immersion of the mentioned pieces in vessels containing the same medium. The femoral nerve originated from the forth (L4), fifth (L5), and sixth (L6) spinal lumbar ventral branches in 14 animals (46.7%), from L4 and L5 in 13 samples (43.3%), and L5 and L6 in three cases (10%). In the course of its way, on both antimeres the mentioned nerve was branched to the greater psoas (100%), iliac (100%), pectinal (56.7%), femoral quadriceps (100%), muscles, and gave off saphena nerve, which gave branches for the pectinal (43.3%) and sartorius (100%) muscles and continued distally along the saphena artery to spread on the medial face of the knee and leg medial articulation skin. Statistically, there was no significant difference between the muscle branch frequencies given by the femoral nerve to the right and left antimeres. The obtained results related to the femoral nerve origin and distribution in fetuses of zebu-crossed bovines generally presented common characteristics with the ruminant corresponding data found in the literature, and this information is important as the basis for clinical or surgical approaches involving the studied structures.