open access
Evaluation of the sciatic nerve location regarding its relationship to the piriformis muscle
Affiliations- Department of Anatomy, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
open access
Abstract
Background: The localisation of sciatic nerve (SN) is essential for the achievement of several procedures performed in the gluteal region. This study proposed to investigate the location of SN regarding its relationship to the piriformis (PM) by the line joining the posterior superior iliac spine (PSIS), ischial tuberosity (IT) and greater trochanter (GT).
Materials and methods: SN-PM relationship was examined in 204 specimens from 102 embalmed cadavers (55 males, 47 females). Distances between PSIS, IT and GT were measured. Midpoints of SN at the lower edge of PM (S1) and IT-GT line (S2) were marked. Perpendicular line from S1 to PSIS-GT (S1-R) and to PSIS-IT (S1-Q), were created and measured. Distances of PSIS-R, PSIS-Q (S1) and IT-S2 were measured and calculated into percentage of PSIS-GT, PSIS-IT and IT-GT lengths, respectively.
Results: Regarding the classification of Beaton and Anson, three types of SN-PM relationship (a, b and c) were obtained. The percentage of type a, b and c was 74.02, 22.55 and 3.43, respectively. Symmetrical SN-PM relationship was found in 75.49%. The mean length of PSIS-IT, PSIS-GT and IT-GT in all types was 129.63 ± 11.89 mm, 151.34 ± 14.78 mm and 73.02 ± 10.20 mm, respectively. A statistically significant difference was found between types a and b (p = 0.013) in PSIS-IT length, whereas mean length of IT-GT and PSIS-GT showed no statistically significant difference between SN-PM types. PSIS-IT line passed SN at the lower edge of PM (S1) in 112 specimens (54.90%). In these cases, S1 and Q were the same point. A statistically significant difference was also found between types a and b (p = 0.023) in PSIS-Q (S1) length. The mean lengths of PSIS-Q (S1), PSIS-R and IT-S2 in term of percentage of PSIS-IT, PSIS-GT and IT-GT line in all types were 60.06 ± 5.90%, 54.19 ± 6.10%, and 37.87 ± 8.27%, respectively. The mean lengths of S1-R and S1-Q were 30.07 ± 8.30 mm and 6.54 ± 7.99 mm. Therefore, SN at S1 could be located at the point of 54.19 ± 6.10% of PSIS-GT length (R) with a distance of 30.07 ± 8.30 mm perpendicular to PSIS-GT line (S1-R). Since the PSIS-IT line did not pass SN at S1 in every case, it might not be suitable for localizing SN at S1. SN at S2 could be located at the point of 37.87 ± 8.27% of IT-GT line. No significant difference was found between types.
Conclusions: Sciatic nerve can be localised by PSIS-GT and IT-GT lines without statistically significant difference between types (a, b, and c) of SN-PM relationship.
Abstract
Background: The localisation of sciatic nerve (SN) is essential for the achievement of several procedures performed in the gluteal region. This study proposed to investigate the location of SN regarding its relationship to the piriformis (PM) by the line joining the posterior superior iliac spine (PSIS), ischial tuberosity (IT) and greater trochanter (GT).
Materials and methods: SN-PM relationship was examined in 204 specimens from 102 embalmed cadavers (55 males, 47 females). Distances between PSIS, IT and GT were measured. Midpoints of SN at the lower edge of PM (S1) and IT-GT line (S2) were marked. Perpendicular line from S1 to PSIS-GT (S1-R) and to PSIS-IT (S1-Q), were created and measured. Distances of PSIS-R, PSIS-Q (S1) and IT-S2 were measured and calculated into percentage of PSIS-GT, PSIS-IT and IT-GT lengths, respectively.
Results: Regarding the classification of Beaton and Anson, three types of SN-PM relationship (a, b and c) were obtained. The percentage of type a, b and c was 74.02, 22.55 and 3.43, respectively. Symmetrical SN-PM relationship was found in 75.49%. The mean length of PSIS-IT, PSIS-GT and IT-GT in all types was 129.63 ± 11.89 mm, 151.34 ± 14.78 mm and 73.02 ± 10.20 mm, respectively. A statistically significant difference was found between types a and b (p = 0.013) in PSIS-IT length, whereas mean length of IT-GT and PSIS-GT showed no statistically significant difference between SN-PM types. PSIS-IT line passed SN at the lower edge of PM (S1) in 112 specimens (54.90%). In these cases, S1 and Q were the same point. A statistically significant difference was also found between types a and b (p = 0.023) in PSIS-Q (S1) length. The mean lengths of PSIS-Q (S1), PSIS-R and IT-S2 in term of percentage of PSIS-IT, PSIS-GT and IT-GT line in all types were 60.06 ± 5.90%, 54.19 ± 6.10%, and 37.87 ± 8.27%, respectively. The mean lengths of S1-R and S1-Q were 30.07 ± 8.30 mm and 6.54 ± 7.99 mm. Therefore, SN at S1 could be located at the point of 54.19 ± 6.10% of PSIS-GT length (R) with a distance of 30.07 ± 8.30 mm perpendicular to PSIS-GT line (S1-R). Since the PSIS-IT line did not pass SN at S1 in every case, it might not be suitable for localizing SN at S1. SN at S2 could be located at the point of 37.87 ± 8.27% of IT-GT line. No significant difference was found between types.
Conclusions: Sciatic nerve can be localised by PSIS-GT and IT-GT lines without statistically significant difference between types (a, b, and c) of SN-PM relationship.
Keywords
greater trochanter, ischial tuberosity, localisation, piriformis muscle, posterior superior iliac spine, sciatic nerve
About this articleTitle
Evaluation of the sciatic nerve location regarding its relationship to the piriformis muscle
Journal
Issue
Article type
Original article
Pages
681-689
Published online
2019-12-30
Page views
998
Article views/downloads
1219
DOI
Pubmed
Bibliographic record
Folia Morphol 2020;79(4):681-689.
Keywords
greater trochanter
ischial tuberosity
localisation
piriformis muscle
posterior superior iliac spine
sciatic nerve
Authors
P. Wan-ae-loh
T. Huanmanop
S. Agthong
V. Chentanez
References (34)- Anbumani TL, Thamarai Selvi A, Anthony Ammal S. Sciatic nerve and its variations: an anatomical study. Int J Anat Res. 2015; 3(2): 1121–1127.
- Bardeen KVA. statistical study of the variations in the formation and position of the lumbosacral plexus in man. Anat Anz. 1901; 19: 209–238.
- Beaton L, Anson B. The relation of the sciatic nerve and of its subdivisions to the piriformis muscle. Anat Rec. 1937; 70(1): 1–5.
- Benzon HT, Katz JA, Benzon HA, et al. Piriformis syndrome: anatomic considerations, a new injection technique, and a review of the literature. Anesthesiology. 2003; 98(6): 1442–1448.
- Boyajian-O'Neill LA, McClain RL, Coleman MK, et al. Diagnosis and management of piriformis syndrome: an osteopathic approach. J Am Osteopath Assoc. 2008; 108(11): 657–664.
- Budhiraja V, Rastogi R, Jain S, et al. Variant relation of the sciatic nerve to the piriformis muscle: a cadaveric study from North India. Revista Argentina de Anatomía Clínica. 2016; 8(1): 38–42.
- Chiba S. [Multiple positional relationships of nerves arising from the sacral plexus to the piriformis muscle in humans]. Kaibogaku Zasshi. 1992; 67(6): 691–724.
- Chung KW, Chung HM. Gross Anatomy. 7th ed. Lippincott Williams & Wilkins, a Wolters Kluwer business, Philadelphia 2012: 102–114.
- Currin SS, Mirjalili SA, Meikle G, et al. Revisiting the surface anatomy of the sciatic nerve in the gluteal region. Clin Anat. 2014; 28(1): 144–149.
- Dikici F, Kale A, Ugras AA, et al. Sciatic nerve localization relative to the position of the hip, an anatomical study. Hip Int. 2011; 21(2): 187–191.
- Geyik S, Geyik M, Yigiter R, et al. Preventing sciatic nerve injury due to intramuscular injection: ten-year single-center experience and literature review. Turk Neurosurg. 2017; 27(4): 636–640.
- Güvençer M, Akyer P, Iyem C, et al. Anatomic considerations and the relationship between the piriformis muscle and the sciatic nerve. Surg Radiol Anat. 2008; 30(6): 467–474.
- Haładaj R, Pingot M, Polguj M, et al. Anthropometric Study of the Piriformis Muscle and Sciatic Nerve: A Morphological Analysis in a Polish Population. Med Sci Monit. 2015; 21: 3760–3768.
- Hopayian K, Song F, Riera R, et al. The clinical features of the piriformis syndrome: a systematic review. Eur Spine J. 2010; 19(12): 2095–2109.
- Kanawati AJ. Variations of the sciatic nerve anatomy and blood supply in the gluteal region: a review of the literature. ANZ J Surg. 2014; 84(11): 816–819.
- Lee CS, Tsai TL. The relation of the sciatic nerve to the piriformis muscle. Taiwan Yi Xue Hui ZaZhi. 1974; 73(2): 75–80.
- Longnecker DE, Newman MF, Brown DL. Anesthesiology. 2nd ed. McGrew-Hill, New York 2012: 843–844.
- Ming-Tzu P. The relation of the sciatic nerve to the piriformis muscle in the Chinese. Am J Physical Anthropol. 1941; 28(4): 375–380.
- Misra BD. The relations of the sciatic nerve to the piriformis in Indian cadavers. J Anat Soc India. 1954; 3: 28–33.
- Moore KL, Dalley AF, Agur Anne MR. Clinically Oriented Anatomy. 7th ed. Lippincott Williams & Wilkins, a Wolters Kluwer business, Philadelphia 2014: 532–569.
- Natsis K, Totlis T, Konstantinidis GA, et al. Anatomical variations between the sciatic nerve and the piriformis muscle: a contribution to surgical anatomy in piriformis syndrome. Surg Radiol Anat. 2014; 36(3): 273–280.
- Navarro R, Schmalzried T, Amstutz H, et al. Surgical approach and nerve palsy in total hip arthroplasty. J Arthrop. 1995; 10(1): 1–5.
- Nizankowski C, Slociak J, Szybejko J. [Variations in the anatomy of the sciatic nerve in man]. Folia Morphol. 1972; 31(4): 507–513.
- Parsons FG, Keith A. Sixth annual report of the committee of collective investigation of the anatomical society of Great Britain and Ireland, 1895–1896. J Anat Physiol. 1896; 31(Pt 1): 31–41.
- Pećina M. Contribution to the etiological explanation of the piriformis syndrome. Cells Tissues Organs. Actaanat (Basel). 1979; 105(2): 181–187.
- Pokorný D, Sosna A, Veigl P, et al. [Anatomic variability of the relation of pelvitrochanteric muscles and sciatic nerve.]. Acta Chir Orthop Traumatol Cech. 1998; 65(6): 336–339.
- Pokorný D, Jahoda D, Veigl D, et al. 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; 28(1): 88–91.
- Purnindhu D. Relation of Sciatic Nerve to Piriformis muscle in Thais. SirirajHosp Gaz. 1983; 35: 379–382.
- Robertson WJ, Kelly BT. The safe zone for hip arthroscopy: a cadaveric assessment of central, peripheral, and lateral compartment portal placement. Arthroscopy. 2008; 24(9): 1019–1026.
- Selkirk GD, Mclaughlin AC, Mirjalili SA. Revisiting the surface anatomy of the sciatic nerve in the gluteal region in children using computed tomography. Clin Anat. 2016; 29(2): 211–216.
- Smoll NR. Variations of the piriformis and sciatic nerve with clinical consequence: a review. Clin Anat. 2010; 23(1): 8–17.
- Tomaszewski KA, Graves MJ, Henry BM, et al. Surgical anatomy of the sciatic nerve: A meta-analysis. J Orthop Res. 2016; 34(10): 1820–1827.
- Ugrenović S, Jovanović I, Krstić V, et al. [The level of the sciatic nerve division and its relations to the piriform muscle]. Vojnosanit Pregl. 2005; 62(1): 45–49.
- Vicente E, Viotto M, Barbosa C, et al. Study on anatomical relationships and variations between the sciatic nerve and piriformis muscle. Revista Brasileira de Fisioterapia. 2007; 11(3): 227–232.
