Morphometry of spinal nerve composition and thicknesses of lumbar plexus nerves for use in clinical applications / Morfometría de la composición del nervio espinal y espesores de nervios del plexo lumbar para su uso en aplicaciones clínicas

SUMMARY: The aim of this study was to clarify the diverse spinal compositions of the branches of the lumbar plexus in terms of their prevalence rates and thicknesses. Thirty lumbar plexuses extracted from Korean adults were used in this study. The nerve fascicles were separated and traced with the aid of a surgical microscope. The thickness of each spinal nerve component was calculated based on the mean of the largest and smallest diameters using digital calipers under the surgical microscope. The most common patterns of the spinal composition of the branches of the lumbar plexus were as follows: The iliohypogastric nerve (IHN) and the ilioinguinal nerve (IIN) arose from the ventral ramus of the first lumbar nerve (L1), the genitofemoral nerve (GFN) arose from the anterior division of the ventral ramus of the second lumbar nerve (L2), and the lateral femoral cutaneous nerve (LFCN) arose from the posterior division of the ventral ramus of theL2, the femoral nerve (FN) arose from the posterior division of the ventral ramus of L2-the fourth lumbar nerve (L4), with the thickest spinal component derived from the third lumbar nerve (L3), and the obturator nerve (OBN) arose from the anterior division of the ventral ramus of L2-L4, with the thickest spinal component derived from L3. However, when L5 constituted the FN and OBN, the thickest spinal components of the FN and OBN was L4. This morphometric study has measured the thicknesses of diverse spinal components that constitute the branches of the lumbar plexus after separating the nerve fascicles. The thicknesses of the various spinal components of these branches can be compared in order to understand which make the main and minor contributions to the lower limb.

RESUMEN: El objetivo de este estudio fue evaluar las diversas composiciones espinales de los ramos del plexo lumbar en cuanto a sus tasas de prevalencia y grosor. Se utilizaron treinta plexos lumbares extraídos de individuos adultos coreanos. Se separaron y trazaron los fascículos nerviosos por medio de un microscopio quirúrgico. El grosor de cada componente del nervio espinal se calculó con base en la media de los diámetros mayor y menor utilizando calibradores digitales bajo el microscopio. Los patrones más comunes de la composición espinal de los ramos del plexo lumbar fueron los siguientes: el nervio iliohipogástrico (NIH) y el nervio ilioinguinal (NII) surgieron del ramo ventral del primer nervio lumbar (L1). El nervio genitofemoral (NGF) surgió de la división anterior del ramo ventral del segundo nervio lumbar (L2). El nervio cutáneo femoral lateral (NCFM) surgió de la división posterior del ramo ventral L2. El nervio femoral (NF) surgió de la división posterior del ramo ventral de L2. El cuarto nervio lumbar (L4), con el componente espinal más grueso derivado del tercer nervio lumbar (L3) y el nervio obturador (NOB) surgieron de la división anterior del ramo ventral de L2-L4, con el componente espinal más grueso derivado de L3. Sin embargo, cuando L5 constituía el NF y NOB, los componentes espinales más gruesos del NF y NOB eran de L4. Este estudio morfométrico analizó los espesores de diversos componentes espinales que constituyen las ramas del plexo lumbar después de separar los fascículos nerviosos. Es posible comparar los espesores de los diversos componentes espinales de estos ramos para comprender las contribuciones principales y menores al miembro inferior.

The Muscular Branch of the Radial Nerve to the Brachialis Muscle in Korean / 체질인류학회지

Most textbooks describe the brachialis muscle is innervated by the musculocutaneous and radial nerves. This study was performed to clarify the incidence and morphology of the branch of the radial nerve to the brachialis muscle. Eighty sides of 40 adult Korean cadavers were used in this study. The incidence of the radial nerve to the brachialis muscle was 75% of 80 sides and the radial nerve was innervated bilaterally in 65% (26 sides). The number of the branch arising from the radial nerve was one (65%), two (31.7%) or three (3.3%). The average distance from the lateral epicondyle to the branch arising from the radial nerve was 68.5 mm (range: 4 ~126 mm). The brachialis muscle received a branch from radial nerve, through a descending branch (58.5%), a transverse branch (26.8%) or an ascending branch (14.6%). A branch of the radial nerve was usually divided into one or two branches (79.3%) before piecing the brachialis muscle. The average distance from the lateral epicondyle to the perforating point of the branch was 52.4 mm (range: 3 ~123 mm). The branch of the radial nerve penetrated inferior and middle third of the brachialis muscle in 44.2% and 53.2% respectively.