Berihu; Debeb (2015)1212. Berihu BA, Debeb YG. Anatomical variation in bifurcation and trifurcations of sciatic nerve and its clinical implications: in selected university in Ethiopia. BMC Res Notes. 2015 Nov;8(633):633. https://doi.org/10.1186/s13104-015-1626-6
https://doi.org/10.1186/s13104-015-1626-...
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28 corpses (56 lower limbs) |
Corpse dissection |
75% of the limbs showed normal anatomy of the sciatic nerve. Of the 25% that showed variations, 11% were related to the piriformis muscle, 5% to the trifurcation of the sciatic nerve and 9% to the variation in the sural nerve origin |
Carnevalli, et al. (2017)1313. Carnevalli FU, Fagundes LE, Pelozo Junior O, Garbelotti Junior SA. [Piriformis syndrome and its topographical relationships]. In: IX Encontro Latino Americano de Iniciação Cientifica, V Encontro Latino Americano de Pós-Graduação – Universidade do Vale do Paraíva. [s.d.] [cited 2017 Sept 7]. Available from: http://www.inicepg.univap.br/cd/INIC_2005/epg/EPG2/EPG2-9.pdf
http://www.inicepg.univap.br/cd/INIC_200...
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104 gluteal regions of adult cadavers, of both sexes |
Corpse dissection |
In 87.5% the sciatic nerve emerges undivided and passes under the piriformis muscle; in 11.54% the sciatic nerve emerges divided, and the common fibular nerve traverses the piriformis muscle, and in 0.96% the sciatic nerve exists as the single trunk through the suprapiriform area. |
Gomes, et al. (2014)1414. Gomes BA, Ramos MR, Fiorelli RK, Almeida CR, Fiorelli SK. Topographic anatomical study of the sciatic nerve relationship to the posterior portal in hip arthroscopy. Rev Col Bras Cir. 2014;41(6):440-4. https://doi.org/10.1590/0100-69912014006010
https://doi.org/10.1590/0100-69912014006...
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20 corpses, 17 males and 3 females |
Corpse dissection |
17 corpses had a normal branching pattern, ie, the nerve emerged undivided and passed beneath the piriformis muscle. In 12.5%, the fibular nerve passed inside the belly of piriformis muscle. One cadaver presented with an anatomical variation type 3 in the left hip and type 1 in the right |
Jacomo, et al. (2014)1515. Jacomo AL, Martinez CA, Saleh SO, Andrade M, Akamatsu FE. Unusual relationship between the piriform muscle and sciatic, inferior gluteal and posterior femoral cutaneous nerves. Int J Morphol. 2014;32(2):432-4. https://doi.org/10.4067/S0717-95022014000200008
https://doi.org/10.4067/S0717-9502201400...
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One Caucasian corpse of 58 years of age |
Corpse dissection |
The cadaver showed high division of the sciatic nerve and the presence of an accessory piriformis muscle. The sciatic nerve was divided under the piriformis muscle, whereas the tibial nerve reflected anteriorly to pass between the accessory piriformis and the superior gemellus muscle |
Kabakci, et al. (2016)1616. Kabacki AD, Buyukmumcu M, Yilmaz MT, Cicekcisabi AE, Akin D. Anatomical structure and topographic anatomy of sciatic nerve in human fetuses. J Anat Soc India. 2016;65(suppl 1):25-38. https://doi.org/10.1016/j.jasi.2015.12.001
https://doi.org/10.1016/j.jasi.2015.12.0...
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60 fetuses (9 and 40 weeks of gestation) |
Corpse dissection |
In 82.5% of the cases, the sciatic nerve division was observed in the popliteal fossa, 15.83% above it, and in 1.67% a high division occurred. In addition, in 98.3%, the sciatic nerve was observed exiting below the piriformis muscle as a single trunk and in 1.67% higher divisions were observed |
Lewis, et al. (2016)1717. Lewis S, Jurak J, Lee C, Lewis R, Gest T. Anatomical variations of the sciatic nerve, in relation to the piriformis muscle. Translational Res Anat. 2016;5(1):15-9. https://doi.org/10.1016/j.tria.2016.11.001
https://doi.org/10.1016/j.tria.2016.11.0...
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51 corpses (102 lower limbs) |
Corpse dissection |
89% presented normal anatomy of the sciatic nerve and its path. Two distinct variations were identified: in 8.8%, the common fibular branch was observed passing through the piriformis and in 2.9% the common fibular branch passed over the piriformis |
Natsis, et al. (2014)44. Natsis K, Totlis T, Konstantinidis GA, Paraskevas G, Piagkou M, Koebke J. Anatomical variations between the sciatic nerve and the piriformis muscle: a contribution to surgical anatomy in piriformis syndrome. Surg Radiol Anat. 2014 Apr;36(3):273-80. https://doi.org/10.1007/s00276-013-1180-7
https://doi.org/10.1007/s00276-013-1180-...
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147 Caucasian corpses (294 lower limbs) |
Corpse dissection |
A typical anatomical pattern was found in 93.6%. In 4.1%, the common fibular nerve and the tibial nerve passed below a double piriformis. In 0.3%, both nerves penetrated the piriformis. In 0.3% both nerves passed above the piriformis and 1.4% presented anatomical variations not classified |
Pokorný, et al (2006)1818. Pokorný D, Jahoda D, Veigl D, Pinskerová V, Sosna A. Topographic variations of the relationship of the sciatic nerve and the piriformis muscle and its relevance to palsy after total hip arthroplasty. Surg Radiol Anat. 2006 Mar;28(1):88-91. https://doi.org/10.1007/s00276-005-0056-x
https://doi.org/10.1007/s00276-005-0056-...
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91 corpses |
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In 73.1% of the cases, the sciatic nerve followed its normal pattern. In 14.3% it was divided into its terminal branches above the piriformis. One branch going through the muscle, the other under it |
Polesello, et al. (2013)1919. Polesello GC, Queiroz MC, Linhares JP, Amaral DT, Ono NK. Anatomical variation of piriformis muscle as a cause of deep gluteal pain: diagnosis using MR neurography and treatment. Rev Bras Ortop. 2013;48(1):114-7. https://doi.org/10.1016/j.rbo.2012.12.001.
https://doi.org/10.1016/j.rbo.2012.12.00...
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One female patient, 42 years old |
Magnetic resonance imaging |
An accessory muscle belly of the left piriformis was observed, and the common fibular branch passed between its fibers and the standard piriformis muscle |
Sulak, et al. (2014)2020. Sulak O, Sakalli B, Ozguner G, Kastamoni Y. Anatomical relation between sciatic nerve and piriformis muscle and its bifurcation level during fetal period in human. Surg Radiol Anat. 2014 Apr;36(3):265-72. https://doi.org/10.1007/s00276-013-1179-0
https://doi.org/10.1007/s00276-013-1179-...
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20 sciatic nerves in human fetuses |
Corpse dissection |
In 98% of cases, on both sides, the sciatic nerve passed below the piriformis muscle (normal pattern). And in the other 2% variant formations occurred, which could be related to piriformis syndrome |
Ugrenovic, et al. (2005)2121. Ugrenović S, Jovanović I, Krstić V, Stojanović V, Vasović L, Antić S, et al. [The level of the sciatic nerve division and its relations to the piriform muscle]. Vojnosanit Pregl. 2005 Jan;62(1):45-9. https://doi.org/10.2298/VSP0501045U
https://doi.org/10.2298/VSP0501045U...
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100 human fetuses in various gestational periods and for both sexes |
Corpse dissection |
In 72.5% of the cases the normal anatomical pattern was verified (bilaterally 66%). In 27.5%, there was a high division of this nerve in the gluteal region. In addition, 96% of the nerve left the pelvis through the infrapiriform foramen, while in 4% variations of the sciatic nerve in relation to the piriformis muscle were detected |
Varenika, et al. (2017)2222. Varenika V, Lutz AM, Beaulieu CF, Bucknor MD. Detection and prevalence of variant sciatic nerve anatomy in relation to the piriformis muscle on MRI. Skeletal Radiol. 2017 Jun;46(6):751-7. https://doi.org/10.1007/s00256-017-2597-6
https://doi.org/10.1007/s00256-017-2597-...
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755 exams |
Magnetic resonance imaging |
The normal anatomy patterns were found in 87% of cases. The other 13% showed one of the divisions of the sciatic nerve passing through the piriformis, and the other division passing below |