"The palmar radial bursa (plural: palmar bursae) is one of the bursae in the palmar surface of the hand. It is the smaller bursa, surrounds and communicates with the flexor pollicis longus tendon sheath at the metacarpophalangeal joint and usually extends around 1-2 cm proximal to the proximal edge of the transverse carpal ligament. It may communicate with the palmar ulna bursa in a variable proportion of patients proximal to the transverse carpal ligament through the space of Parona 1."