One hundred upper extremities from fresh human cadavers aged 20 to 80 years were injected with coloured latex or Indian ink and gelatin. Under the dissecting microscope two main and one occasional source of vascularization of the digital sheath were identified. Originating from the digitopalmar arches, from the proper palmar digital arteries and occasionally from the arcus palmaris superficialis, a complex arterial system supplies the various parts of the digital sheath. The best vascularized area is the floor of the sheath, while the pulleys and the palmar surface of the sheath are less well vascularized. These data may be of interest to those involved in reconstruction of the tendons of the digital flexor muscles.