The Lateral cutaneous nerve is the branch of lumbar plexus , it emerges from psoas above the iliac crest. It passes obliquely across iliacus towards the anterior superior iliac spine, and enters the thigh posterior to the lateral end of the inguinal ligament^1,2.

Orgin

It is derived from the dorsal branches of the ventral rami of second and third lumbar nerves (L₂,L₃).

Course and relations

 It passes downwards and laterally across the iliac fossa in front of the iliacus muscle and lies under cover of the fascia iliaca. The nerve enters the thigh beneath the inguinal ligament through a notch between the anterior superior and anterior inferior iliac spines.

Branches and Distribution

In the iliac fossa the nerve provides branches to the parietal peritoneum; it passes behind the caecum on the right side, and behind the iliac part of descending colon on the left side. In the thigh the lateral cutaneous nerve passes downward in front of  or through the sartorius muscle, and divides into anterior and posterior branches

.

AIM OF THE STUDY

To understand the variations in the anatomy of the Lateral femoral cutaneous nerves.

OBJECTIVES

1) To identify the variations in the formation lateral femoral cutaneous nerves

2) To identify variations in the branching pattern of lateral femoral cutaneous nerves

MATERIALS AND METHODS

                       The study was carried out after due ethical clearance from the institution.

• Study design: Cross sectional study
• Sample size : 60 specimens
• Inclusion criteria: Adult human cadavers from the department of Anatomy with no evidence of surgical intervention on the abdomen and pelvic cavity.
• Exclusion criteria: Those specimens with evidence of surgical intervention on the abdomen or pelvis were excluded from the study.
• Methodology:

Dissection method:       

The lumbar plexus were dissected by the method described in Cunninghams manual of practical anatomy, 15^th edition.                                                                                                                                                                             

RESULTS

VARIATIONS IN THE LATERAL FEMORAL CUTANEOUS NERVE (Pie chart. , Bar diagram. )

• LFCN was absent in 5 (8.3%) lumbar plexus.
• Accessory LFCN was noticed in 6 (10%) lumbar plexus.
• In 2 plexus (3.3%) the nerve was split in the middle of the course in the pelvic cavity.
• In 5 plexus it was formed from L₂ (8.3%).
• In 19 out of 60 it was formed from L₃ (51.66%).
• Variations in the formation were noticed  in 24 plexus (40%).
• Variations in the branching pattern were noticed in 2 specimen (3.3%).

Pie chart.  Observations in lateral femoral cutaneous nerve

Bar diagram. 4  Differentorigin of lateral femoral cutaneous nerve

Table. 2 Observations on anatomy of  lumbar plexus in a study of 60 LFCN

Figure. 5  Differentorigin of nerves of lumbar plexus

L₁,L₂,L₃,L₄-Lumbar nerve  roots, 1-Iliohypogastric nerve, 2-Ilioinguinal nerve, 3-Genitofemoral nerve , 4-Lateral femoral cutaneous  nerve,  4a-Accessory LFCN, 5- Femoral nerve, 6- Obturator nerve. Genitofemoral nerve originate from L₂, Lateral femoral cutaneous nerve from L₃, Accessory lateral femoral cutaneous nerve from L₃-L₄.

Figure.7 Accessory lateral femoral cutaneous nerve originating from L₂-L₃

L₁,L₂,L₃,L₄-Lumbar nerve  roots,1-Iliohypogastric nerve, 2-Ilioinguinal nerve, 3-Genitofemoral nerve , 4-Lateral femoral cutaneous  nerve, Accessory lateral femoral nerve present in between 3 and 4, 5- Femoral nerve, 6- Obturator nerve.

REVIEW OF LITERATURE

LITERATURE

In 22 (36.7%) of  60 plexus, the lateral femoral  cutaneous nerve arose from the first two lumbar nerves. In one plexus (1.7%) the nerve arose from second lumbar ventral ramus and and in 6 plexus (10%), it was derived from the femoral nerve, total variation being 48.3%.³

Lateral cutaneous nerve of thigh  arose directly from the femoral nerve  in 6 plexuses (10%) in one study.³

The lateral femoral cutaneous nerve of the thigh was formed by the union of the anterior rami of the L₁ and L₂ lumbar spinal nerves.⁴

Origin of lateral femoral cutaneous nerve of thigh from the  femoral nerve was also reported in another case.⁵

In 27.6% of the 29 cadavers, the lateral femoral cutaneous nerve bifurcated into additional branches before crossing the inguinal ligament.⁶

Injuries to this nerve can cause decreased sensation and neuropathic pain around the anterolateral thigh. Meralgia paresthetica, is a pain and/or disesthesia syndrome caused by the impingement, injury or the neurinoma of the lateral femoral cutaneous nerve .⁷Anatomical variations in the course and localization of the lateral femoral cutaneous nerve may lead to have more mechanical traumas of this nerve.⁸

15 (30%) accessory lateral femoral cutaneous nerve were reported in the bilateral dissection in 26 cadavers ⁹.

There was origin of lateral cutaneous nerve of thigh from the femoral nerve inferior to the inguinal ligament in one case in a study.⁹

Inbilateral dissection in 26 cadavers 3 of the accessory lateral femoral cutaneous nerves were arising from the genitofemoral nerve, one of them was arising from the ventral ramus of L₁ and L₂, another one arising from the ventral ramus of L₂ and L₃ and the rest were arising from the ventral ramus of L₂. In one case the lateral femoral cutaneous nerve was arising from the femoral nerve.⁹

There are variations of the lateral femoral cutaneous nerve related to the anterior superior iliac spine and iliac crest that the nerve can be damaged during surgical intervention   such as applying the external fixator of the pelvis. After operations such as appendectomy, inguinal hernia repair, iliac crest bone graft harvesting and gynaecological procedures through transverse incision several clinical conditions may be encountered such as meralgia paresthetica, groin pain and testicular pain in which the the lateral femoral cutaneous nerve, ilioinguinal and the genitofemoral nerves are mostly involved.^10,11

Multiple variations of the nerves arising from the lumbar plexus on the right side of a 35 year old female cadaver were found. These were the accessory lateral femoral cutaneous nerve arising from the femoral nerve, double ilioinguinal nerves and an accessory nerve joining with the genital branch of the genitofemoral nerve. The lateral femoral cutaneous nerve which was formed by the union of the dorsal rami of L₂ and L₃ spinal nerves, was observed passing posterolateral to the psoas major muscle to course on the iliacus.¹²

It was reported that the accessory lateral cutaneous nerve of thigh originated from the femoral nerve above the inguinal ligament in 4 plexuses in one study.¹³

In another study in 6 of the 34 plexus (17.6%) variations were demonstrated in lateral femoral cutaneus nerve. In 4 lumbar plexus lateral femoral cutaneous nerve arose from the L₁ and L₂ nerve roots and in one plexus it had its origin solely from the L₂ nerve (2.9%).¹³   Another noted eight distinct patterns of nerves.¹⁴

Another study reported that in 24 of 200 cadavers the lateral femoral cutaneous nerve arose from  L₁ and L₂ and even solely from the L₂ or L₃  nerves.¹⁵

In 23% the lateral  femoral cutaneous nerve  gaverise  to two branches.¹⁶

Two unilateral accessory lateral femoral cutaneous nerve  were reported in a series of 28 cadavers. In one of these  2 cases there were 2 lateral femoral cutaneous nerves arising from a common root  which was formed by the union of the ventral rami of L₁ and L₂ ,while in the other there were 3 lateral femoral cutaneous  nerves arising from the dorsal divisions of the ventral rami of L₂ and L₃.¹⁷

Variations in lateral femoral cutaneous nerves were reported in 2 cadavers out of 28 cadavers in another study. On the right side of one cadaver, the ventral rami of the first and second lumbar spinal nerves were united and then this nerve was divided into 4 branches. From medial to lateral these branches were the obturator nerve,the femoral nerve the medially located lateral femoral cutaneous nerve. On the left side of another cadaver there were 3 lateral femoral cutaneous nerve.¹⁷

Early lateral femoral cutaneous nerve bifurcation have been reported.  It has also been noted that the lateral femoral cutaneous nerve was wholly absent in 13 (8.8%) of 148 patients who received surgical intervention in one study.¹⁸

In another report a variant lateral femoral cutaneous nerve where two lateral femoral cutaneous nerve branches were encountered arising from the lumbar plexus was noted. In specific, the anterior lateral femoral cutaneous nerve branch originated from the femoral nerve, where as at the level of inguinal ligament four nerve branches were present.¹⁹

A study reported the chance of nerve injury in 10% during harvesting bone graft. Injuries to this nerve can cause decreased sensation and neuropathic pain around the anterolateral thigh.²⁰

Several studies have demonstrated injury to the nerve in harvesting bone graft from iliac crest.^21,22           

DISCUSSION

In current study  lateral femoral cutaneous nerve  was absent in 5 (8.3%) lumbar plexus. And accessory lateral femoral cutaneous nerve  was noticed in 6 (10%) lumbar plexus. In 2 plexus (3.3%) the nerve was split in the middle of the course in the pelvic cavity. In 5  plexus it was formed from L₂ (8.3%), in 31 plexus it arose from L₂-L₃(51.66%). In 19 out of 60 it was formed from  L₃ (31.66%). Total variations in the formation were 24(40%) and total variation in the branching pattern were 2 (3.3%). Accessory  lateral femoral cutaneous nerve  was found in 4 plexuses

In another study it was  foundthat  rightlateral  femoral cutaneous nerve was derived from the anterior divisions of the first and second lumbar nerve roots⁵. In another study it was found that right lateral  femoral cutaneous nerve derived from the anterior divisions of the first and second lumbar nerve roots³

Lateral femoral cutaneous nerve bifurcated into additional branches before crossing the inguinal ligament.(27.6% of the 29 cadavers).⁵

Out of 34 (2.9%) specimens one lumbar plexus was found to have lateral femoral cutaneous nerve  arising from L₂.¹³

Normally lateral femoral cutaneous nerve  arises from posterior division of the L₂ and L₃ nerve roots.  Variation in the formation of lateral femoral cutaneous nerve  has been reported in previous studies in varying percentages as 17.6%,¹³ 25% ,¹⁵  48.3%.²³ Out of 148 specimens 13 (8.8%) lumbar plexuses were found to have absence of lateral femoral cutaneous nerve  in a study.¹⁸In a study  27.6% of the 29 cadavers had the lateral  femoral   cutaneous  nerve  bifurcating  into additional  branches  before crossing  the inguinal ligament⁶ and in other study 23% of the lateral  cutaneous nerve  gave  rise  to two branches.. The present study showed many variations in the formation and branching pattern of lateral femoral cutaneous nerve¹⁶.

CONCLUSION

• Lateral femoral cutaneous nerve (LFCN) absentin 5 (8.3%)
• Accessory lateral femoral cutaneous nerve  in 6 (10%)
• LFCN splits during its course in 2 (3.3%)
• LFCN arises from L₂ in 5 (8.3%)
• LFCN arises from L₂,L₃ in 31 (51.66%)
• LFCN arises from L₃ in 19 (31.66%)
• Variation in the formation in 24 (40%)
• Variation in the branching pattern in 2 (3.3%)
• 29 plexus originate from L₂,L₃. Out of 31 normal formation, 6 plexus show variation in branching. So total variations of genitofemoral nerve are 35 (58.33%)
•  

A key to carry out therapeutic and diagnostic procedures successfully on lateral cutaneous nerve depends on the knowledge of the possible variations of nerves. Such neurological variations are not only more prone to iatrogenic injuries but they interfere in the correct interpretation of clinical conditions as well. A proper understanding of the anatomy of this nerve is elementary for improving the results of operative treatment.

SUMMARY

The knowledge of variations and their branching pattern is important for the clinicians in investigating the level of injury and to plan appropriate treatment. The present study was conducted to know the variations of the origin  and  branching pattern of  lateral femoral cutaneous nerve. As, many variations were seen, If these are unrecognized, there is a risk of iatrogenic injury to the involved structures leading to unfavourable surgical outcomes.

BIBLIOGRAPHY

1. Standring S. Gray’s anatomy. The anatomical basis of clinical practice. London. Churchill and Livingstone. 2008;40: 1078-1079.
2. Romanes GJ. Cunninghams manual of practical anatomy. Oxford. New York.1986; 15(2):183-184.
3. Quain J. Quain’s Elements of Anatomy. Longmans. Green and co.1896; 10(3):315, 317, 319.
4. Erbil KM, Oderoğlu S, Başar R. Unusual branching in lumbar plexus: Case report. Okajimas Folia Anat Jpn. 1999;76:55–59.
5. Astik RB, Dave UH. Anatomical variation in formation and branching pattern of femoral nerve in iliac fossa. People’s Journal of Scientific Research, 2011; 4(2): 14-19.
6. Grothaus MC, Holt M, Mekhail AO, Ebraheim NA, Yeasting RA. Lateral femoral cutaneous nerve: An anatomic study. Clin Orthop. 2005;437:164–168
7. Williams PH, Trzil KP. Management of meralgia paresthetica. J. Neurosurg. 1991; 74: 76–80.
8. Aszmann OC, Dellon ES, Dellon AL. Anatomical course of the lateral femoral cutaneous nerve and its susceptibility to compression and injury. Plast. Reconstr. Surg. 1997; 100: 600–604.
9. Dias Filho LC, Valenc MM¸ Guimaraes Filho FAV, Medeiros RC, Silva RAM, Morais MGV, Valente FP, França SML. Lateral femoral cutaneous neuralgia: an anatomical insight. Clin. Anat. 2003; 16: 309–316.
10. Ducic I, Dellon AL. Testicular pain after inguinal hernia repair: an approach to resection of the genital branch of genitofemoral nevre. J. Am. Coll. Surg. 2004; 198: 181–184.
11. Siu TL, Chandran KN. Neurolysis for meralgia paresthetica: an operative series of 45 cases. Surg. Neurol. 2005; 63: 19–23.
12. Uzmansel D, Aktekin M, Kara A.Multiple variations of the nerves arising from the lumbar plexus. Neuroanatomy.2006; 5 (1): 37–39.
13. Anloague PA, Huijbregts P. Anatomical Variations of the Lumbar Plexus: A Descriptive Anatomy Study with Proposed Clinical Implications. The Journal of Manual& Manipulative Therapy. 2009; 17(4): 107-114.
14. Webber RH. Some variations in the lumbar plexus of nerves in man. Acta Anat. 1961;44:336–345.
15. De Ridder VA, De Lange S, Popta J. Anatomical variations of the lateral femoral cutaneous nerve and the consequences for surgery. J Orthop Trauma. 1999;13:207–211.
16. Rosenberger RJ, Loeweneck H, Meyer G. The cutaneous nerves encountered during laparoscopic repair of inguinal hernia: New anatomical findings for the surgeon. 2000;14:731–735.
17. Erbil KM, Sargon FM, Sen F. Examination of the variations of the lateral femoral cutaneous nerves: Report of two cases. Anat Sci Inc. 2002;77:247–249.
18. Carai A, Fenu G, Sechi E, Crotti FM, Montella A. Anatomical variability of the lateral femoral cutaneous nerve: Findings from a surgical series. Clin Anat. 2009;22:365–370.
19. Natsis K , Paraskevas G,  TzikaM ,Papathananasiou E. Variable Origin and Ramification Pattern of the Lateral Femoral Cutaneous Nerve: A case Report and Neurosurgical Considerations. Turkish Neurosurgery. 2013;23(6): 840-843.
20. Murata Y, Takahashi K, Yamagata M, Sameda H, Moriya H. Injury to the lateral femoral cutaneous nerve during harvest of iliac bone graft, with reference to the size of the graft. Journal of Bone  Joint Surg Br.2002; 84(6):798-801.
21. MirovsdyT,Neuwirth M. Injuries to the lateral femoral cutaneous nerve during spine surgery.Spine.2000;25: 1266-9.
22. Kurz LT, Grafin SR, Booth RE. Harvesting autogenous iliac bone grafts.Spine. 1989;14: 1324-31.