Mesotendons of the flexor pollicis longus muscle.

A study of 100 upper extremities from fresh human cadavers injected with colored latex or india ink and gelatin revealed the vascularization of the flexor pollicis longus muscle (FPL) tendon. This tendon was found to be vascularized from four different sources with anastomoses between them. Very rich anastomoses were observed between the terminal segments of the arterial branches which form the intratendineal network of the tendon itself.