Abstract Aims. Peroneal neuropathy, meralgia paresthetica and tarsal tunnel syndrome are the most common entrapment neuropathies of the lower extremities. Although, the effect of Body Mass Index on the entrapment neuropathies of the upper extremities, especially carpal tunnel syndrome, has been studied extensively, its effect on the entrapment neuropathies of the lower extremities, except meralgia paresthetica which is well known to be associated with obesity, is not well understood. In this study, we aimed to investigate the relations between Body Mass Index and the common entrapment neurophaties of the lower extremities. Methods. This retrospective study focused on 204 patients that were referred to our electrophysiology laboratory with a pre-diagnosis of peroneal neuropathy, meralgia paresthetica, and tarsal tunnel syndrome. Each group is separated into two subgroups consisting of patients with and without entrapment neuropathy. Age, sex, and Body Mass Index values are compared amongst the groups. In addition, all of the patients with a pre-diagnosis of entrapment neuropathy are further divided into two subgroups based on their Body Mass Index as ‘obese’ and ‘non-obese’ patients, and type and frequency of entrapment neuropathies are investigated. Results. The mean age of the patients pre-diagnosed with entrapment neuropathy was 42.61± 13.75. There were 97 men and 107 women. Of the 100 patients that were verified to have entrapment neuropathy, 39 were diagnosed with peroneal neuropathy, 39 with meralgia paresthetica and remaining 22 with tarsal tunnel syndrome. 93.8% of the ‘obese’ patients who admitted with the pre-diagnosis of meralgia paresthetica were confirmed to have this diagnosis. Body Mass Index values of the patients with verified meralgia paresthetica were significantly higher than those of the patients who were found not to have meralgia paresthetica. There were no significant differences regarding Body Mass Index values between the patients with and without peroneal neuropathy or tarsal tunnel syndrome. Conclusion. It is suggested that meralgia paresthetica is related to high Body Mass Index and obesity. Very limited number of the past studies mentioned associations between high Body Mass Index and tarsal tunnel syndrome, and weight loss and peroneal neuropathy. In this investigation, no significant association was found between obesity or emaciation and peroneal neuropathy or tarsal tunnel syndrome. In addition, the rate of meralgia paresthetica was higher in patients with advanced age, but there was no significant relationship between advancing age and peroneal neuropathy or tarsal tunnel syndrome in this study. Keywords: Lower extremity, Body Mass Index, nerve compression syndromes Ozet Amac. Alt ekstremite tuzak noropatileri arasinda en sik olanlar peroneal noropati, meralgia parestetica ve tarsal tunel sendromudur. Ust ekstremite tuzak noropatilerinde ozellikle karpal tunel sendromu ile Vucut Kitle Indeksi iliskisi konusunda pek cok calisma yapilmis olmasina ragmen alt ekstremitede obeziteyle iliskisi iyi bilinen meralgia parestetica disinda diger tuzak noropatileri ve Vucut Kitle Indeksi iliskisi belirgin bir sekilde ifade edilmemistir. Bu calismada klinik pratikte sik karsimiza cikan alt ekstremite tuzak noropatileri ile Vucut Kitle Indeksi iliskisini arastirmayi amacladik. Yontemler. Bu retrospektif calismada elektrofizyoloji laboratuvarimiza peroneal noropati, meralgia parestetica ve tarsal tunel sendromu on tanilari ile gonderilen 204 hasta incelendi. Her grup kendi icinde tuzak noropatisi olan ve olmayanlar olarak ikiye ayrildi. Yas, cins ve Vucut Kitle Indeksi degerleri gruplar arasinda karsilastirildi. Ayrica tuzak noropatisi ontanili tum hastalar Vucut Kitle Indekslerine gore 'obez' ve 'obez olmayan' seklinde 2 gruba ayrildi ve gruplarda tuzak noropati tipleri ve sikliklari arastirildi. Bulgular. Tuzak noropatisi on-tanisi ile gelen hastalarin yas ortalamalari 42,61±13,75 idi. Bunlarin 97’si erkek, 107 tanesi kadindi. Toplam 204 hastanin 100'unde tuzak noropatisi saptandi. Bunlarin 39 tanesi peroneal noropati, 39 tanesi meralgia parestetica, 22 tanesi ise tarsal tunel sendromu idi. 'Obez' grubun %93,8'inde meralgia parestetica on tanisi teyit edildi. Meralgia parestetica tanisi alan hastalarin Vucut Kitle Indeksi degerleri meralgia parestetica’si cikmayan hastalardan anlamli derecede daha yuksekti. peroneal noropati, tarsal tunel sendromu saptanan ve saptanmayan hastalar arasinda Vucut Kitle Indeksi degerleri acisindan anlamli bir fark saptanmadi. Sonuc. Meralgia parestetica, yuksek Vucut Kitle Indeksi ve obezite ile belirgin sekilde iliskilidir. Az sayida calismada tarsal tunel sendromu ile yuksek Vucut Kitle Indeksi birlikteliginden ve peroneal noropati ile kilo kaybi iliskisinden bahsedilmistir. Bizim calismamizda ise peroneal noropati ve tarsal tunel sendromunun obezite ya da zayiflikla belirgin iliskisi saptanmamistir. Ayrica calismamizda meralgia parestetica orani yasla birlikte artis gostermekteydi, ancak bu calismada ileri yas ile peroneal noropati veya tarsal tunel sendromu arasinda anlamli iliski saptanmad i. Anahtar sozcukler: Alt ekstremite, Vucut Kitle Indeksi, sinir basisi sendromlari