First dorsal metatarsal artery

The first dorsal metatarsal artery (FDMA) is a terminal branch of the dorsalis pedis artery that courses through the first intermetatarsal space (between the first and second metatarsal bones) on the dorsum of the foot. It is the principal arterial supply to the first web space and a major contributor to the vascular supply of the great toe and second toe.

Origin and Course

The FDMA arises from the dorsalis pedis artery in approximately 90% of cases, and less commonly from the lateral tarsal artery (~9%). Its origin is located approximately 10 mm distal to the tarsometatarsal joint and about 5.5 mm plantar to the dorsal surface of the second metatarsal bone. The artery proceeds distally through the first intermetatarsal space, running close to the first metatarsal bone, and terminates by dividing into digital branches that supply the adjacent sides of the great and second toes.

Relationship to the First Dorsal Interosseous Muscle

The course of the FDMA relative to the first dorsal interosseous muscle is highly variable and has been classified into three main types:

• Superficial (supramuscular): The artery courses superficial to the muscle (~54–59% of cases)

• Intramuscular: The artery is partially or fully embedded within the muscle (~19–40%)

• Submuscular (deep): The artery courses beneath the muscle (~9–22%)

Anastomoses

The FDMA communicates with the first plantar metatarsal artery in approximately 88% of feet, forming an important anastomotic network in the first web space. The FDMA is the dominant vessel in the first web space in about 54% of cases, while the first plantar metatarsal artery is dominant in approximately 29%.

Caliber

The average diameter of the FDMA at its origin is approximately 1.0–2.0 mm, with a mean of about 1.98 mm on CT angiography and 1.0 ± 0.5 mm on ultrasound.

Clinical Significance

The FDMA is of major importance in reconstructive and microsurgery. It serves as the vascular pedicle for several commonly used tissue transfers, including the dorsalis pedis flap, toe-to-hand transfers, and the first dorsal metatarsal artery perforator flap for hallux soft-tissue reconstruction. It is also the dominant vessel supplying the first metatarsal head in the majority of specimens, making its preservation relevant during hallux valgus surgery (e.g., chevron osteotomy) to reduce the risk of osteonecrosis. Preoperative assessment of the FDMA anatomy — via ultrasound or CT angiography — is recommended before microsurgical procedures given its significant anatomical variability.