thenar space

Last reviewed 01/2018

The thenar space is one of the three deep palmar spaces. It is rarely the site of hand infections. The fibrofatty space contains the first lumbrical muscle.


  • ulnarly: midpalmar septum from border of palmar aponeurosis to palmar border of third metacarpal bone
  • radially: fascia of adductor pollicis longus muscle
  • dorsally: adductor pollicis
  • volarly: flexor tendons of index finger
  • distally: margin of synovial sheath of index finger
  • proximally: distal margin of carpal tunnel

The thenar eminence demarcates the thenar space on the palmar surface.