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Variant anatomy of sciatic nerve in a black Kenyan population
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Abstract
One hundred and sixty-four sciatic nerves from 82 cadavers of black Kenyans were exposed by dissection at the Department of Human Anatomy, University of Nairobi, Kenya. The level of bifurcation, relationship to piriformis, and topographic relations between the branches were studied. The results were analysed by SPSS version 16.0 and are presented by macrographs.
In 33 (20.1%) cases division occurred in the pelvis, while in 131 (79.9%) it occurred outside the pelvis. A single trunk sciatic nerve exited below the piriformis muscle in 131 (79.9%) cases. In cases of pelvic division, the tibial nerve was always infrapiriformic, while the common peroneal nerve passed below piriformis in 16 (9.8%) cases, pierced the piriformis in 13 (7.9%), and passed above it in 4 (2.4%). For those in which division was extrapelvic, 110 (67.1%) were in the popliteal fossa, 17 (10.4%) in the middle third of the thigh, and 4 (2.4%) in the gluteal region. Where the division was pelvic, in 19 (11.6%) cases they continued separately, in 8 (4.9%) the two nerves reunited, and in 6 (3.7%) they were connected by a communicating nerve.
The sciatic nerve in the Kenyan population varies from the classical description in over 30% of cases, with many high divisions, low incidence of piriformic course of common peroneal nerve, reunion, and unusual connection between common peroneal and tibial nerves. These variations may complicate surgery and interpretation of sciatic neuropathy. Preoperative nerve imaging and extra operative diligence in the gluteal region and the back of the thigh are recommended. (Folia Morphol 2011; 70, 3: 175–179)
Abstract
One hundred and sixty-four sciatic nerves from 82 cadavers of black Kenyans were exposed by dissection at the Department of Human Anatomy, University of Nairobi, Kenya. The level of bifurcation, relationship to piriformis, and topographic relations between the branches were studied. The results were analysed by SPSS version 16.0 and are presented by macrographs.
In 33 (20.1%) cases division occurred in the pelvis, while in 131 (79.9%) it occurred outside the pelvis. A single trunk sciatic nerve exited below the piriformis muscle in 131 (79.9%) cases. In cases of pelvic division, the tibial nerve was always infrapiriformic, while the common peroneal nerve passed below piriformis in 16 (9.8%) cases, pierced the piriformis in 13 (7.9%), and passed above it in 4 (2.4%). For those in which division was extrapelvic, 110 (67.1%) were in the popliteal fossa, 17 (10.4%) in the middle third of the thigh, and 4 (2.4%) in the gluteal region. Where the division was pelvic, in 19 (11.6%) cases they continued separately, in 8 (4.9%) the two nerves reunited, and in 6 (3.7%) they were connected by a communicating nerve.
The sciatic nerve in the Kenyan population varies from the classical description in over 30% of cases, with many high divisions, low incidence of piriformic course of common peroneal nerve, reunion, and unusual connection between common peroneal and tibial nerves. These variations may complicate surgery and interpretation of sciatic neuropathy. Preoperative nerve imaging and extra operative diligence in the gluteal region and the back of the thigh are recommended. (Folia Morphol 2011; 70, 3: 175–179)
Keywords
sciatic nerve; variations; piriformis syndrome; sciatica


Title
Variant anatomy of sciatic nerve in a black Kenyan population
Journal
Issue
Article type
Original article
Pages
175-179
Published online
2011-08-24
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783
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1614
Bibliographic record
Folia Morphol 2011;70(3):175-179.
Keywords
sciatic nerve
variations
piriformis syndrome
sciatica
Authors
J.A. Ogeng’o
H. El-Busaidy
P.M. Mwika
M.M. Khanbhai
J. Munguti