Cutaneous distributions of genitofemoral and ilioinguinal nerves to pubic, perineal and ventromedial thigh regions in Thais.

Objective: To determine the cutaneous distributions of genitofemoral (Gf) and ilioinguinal (Ig) nerves to pubic, perineal and ventromedial thigh regions in Thais. Methods: The present study was performed bilaterally in 98 halves of 49 embalmed cadavers. The cutaneous distributions of the Gf and/or Ig nerves to these regions were dissected, identified and recorded. Results: Based on the cutaneous distributions of Gf and/or Ig to pubic, perineal, and ventromedial thigh regions, five different types of cutaneous branching patterns of both nerves were identified. Type A (18.28% of cases) had only the branches of Gf to the mons pubis, anteroproximal part of the root of penis, the scrotal or labial and the ventromedial thigh regions but in type B (21.51% of cases) had only the branches of Ig to these regions. The most frequent type of these innervations was type C (39.78% of cases) with dominance of both nerves branching to these regions. In type D (8.60% of cases), having the branches of both nerves but with a dominance of Gf, consisted of 2 subtypes D-1 (2.15% of cases) and D-2 (6.45% of cases). In contrast to type D, type E (11.83% of cases) having the branches of both nerves but with a dominance of Ig, consisted of 2 subtypes E-1 (8.60% of cases) and E-2 (3.23% of cases). Conclusions: These findings would provide the marked anatomic variability of Gf and/or Ig nerves in pubic, perineal and ventromedial thigh regions in Thais, and may assist diagnosis, anesthetic nerve block and prevention nerve damage during surgery.

Anatomic variations of the lumbar plexus in Thais.

The aim of this study was to examine the variation of the lumbar plexus in Thais in terms of its origin, branches, and variation of each branch. Anatomical dissections were conducted in 150 halves of formalin-embalmed cadavers. All preserved cadavers were Thais, ranging the age from 35 to 85 years old, 86 males and 64 females. The lumbar plexus was markedly composed of the first to fourth lumbar ventral rami (L1-L4) in 81.33% of the plexuses (or 122 cases), but its origin varied, as it was derived from the ventral rami of the twelfth thoracic to fifth lumbar ventral rami (T12-L5) in 18.67% of the cases. Eight branches of the plexus were found, including seven typical branches and an additional branch. The seven typical branches occured in 100% of cases, and they were the iliohypogastric, ilioinguinal, genitofemoral, lateral cutaneous nerve of the thigh, femoral, obturator nerve and lumbosacral trunk. The additional branch, the accessory obturator nerve occurred in only 3.33% of the cases. In conclusion, the variation pattern of the plexuses occurred on both sides. However, the anatomic variability of the plexuses was not statistically different with regard to either side or gender. The result from this study provided additional information different with regard to either side or gender. The results from this study provided additional information and new insights into the lumbar plexus in terms of its origins, branches, and variations of each branch that might be useful in medicine, anesthesia, surgery and physical therapy.