It arise from the RA soon after it enters between the two heads of first dorsal interosseous to form the DPA and passes along the first metacarpal bone either palmar to the adductor pollicis or between the first dorsal interosseous muscle and adductor pollicis. At the level of the metacarpal phalangeal joint, and deep to the flexor pollicis longus tendon, it usually terminates in two palmar digital arteries namely RPDA and UPDA to the thumb [2, 5, 16]. Fig. 1

Or FPMA trifurcates into RPDA and UPDA to the thumb and FDMA [5].

Or FPMA gives RPDA and UPDA as separate branch and the terminal end of FPMA continues as RIA [Present study]. Fig. 3

Or the FPMA divides into UPDA to the thumb and RIA [Present study]. Fig. 8

Or the FPMA provides only RPDA [Present study]. Fig. 2

It arise from the RA just before it passes between the two heads of the first dorsal interosseous. In most cases, FDMA follows a fascial course overlying the first dorsal interosseous and parallel to the second metacarpal bone. Occasionally, it may follow an intramuscular course. It divides, into UDDA and RIA [6]. Fig.11 Sometimes the FDMA continues as UPDA [7, 12].

Formed by the terminal part of UA and completed by SPBRA [2, 5, 6, 9]. Figs. 2, 7, 10

Sometimes RPDA and UPDA arise separately from the typical SPA [6].

Or RPDA, UPDA and RIA arise from the common trunk called first CPDA from this arch [Present study]. Fig. 7

Or only UPDA and RIA arise from the first CPDA from this arch [Present study]. Fig. 10

The parent sources of the RPDA and UPDA to the thumb that arise from first CPDA from the SPA were classified under branches from SPA.

It arises from the RA just before it curves round the carpus and passes superficial to flexor retinaculum. In the hand it passes either superficial to or through the thenar muscles. It gives both the RPDA and UPDA to thumb and also the RIA [5, 6, Present study]. Fig. 5

Sometimes it continues as only RPDA to the thumb [5].

The classical/ typical complete SPA gives a common trunk called first CPDA to the first web space which gives three branches namely RPDA and UPDA to the thumb and RIA [Present study]. Fig. 7

Or the first CPDA divides into UPDA and RIA [5, 10, Present study]. Fig. 10

Or this common trunk gives only UPDA and RPDA to thumb [5].

To avoid confusion palmar digital arteries to the thumb arising either through first CPDA from typical SPA or directly from the typical SPA were classified under branches of SPA.

Sometimes MA gives first CPDA that trifurcates into RPDA, UPDA to the thumb and RIA [Present study]. Fig. 6

Or first CPDA from the MA gives only UPDA and RIA [5, 15, 16].

In the above two conditions the parent source of palmar digital arteries to thumb were classified under branch from MA only.

SPBRA after providing RPDA to the thumb continues as first CPDA that divides into UPDA and RIA [Present study]. Fig. 5

In this case the parent source of UPDA was classified under SPBRA only.

The terminal part of UA continues as first CPDA to the first web space and divides into UPDA to the thumb and RIA [11, Present study]. Fig. 9

Or the terminal part of UA provides first CPDA that later divides into UPDA to the thumb and RIA then it continues as RPDA [Present study]. Fig. 4

The parent source of palmar digital arteries to the thumb from the terminal part UA and through the first CPDA was classified under branch of UA only.

Note: When palmar continuity of FDMA provides UPDA to the thumb and RIA Bilge et al. [9] considered the continuity of FDMA as first CPDA. But we didn’t agree with this naming as the so called first CPDA didn’t arise from any of superficial palmar arterial system and it came from the dorsal side of the hand.