lumbar
adjective /ˈlʌmbə(r)/
  /ˈlʌmbər/
[only before noun] (medical)- relating to the lower part of the back
- pain in the lumbar region
 
Oxford Collocations DictionaryLumbar is used with these nouns:- region
 - spine
 
Word Originmid 17th cent.: from medieval Latin lumbaris, from Latin lumbus ‘loin’.