Dorsum of foot

Dorsum pedis

  • Latin synonym: Regio dorsalis pedis; Regio superior pedis
  • Synonym: Dorsal region of foot; Superior region of foot

Definition

The dorsum of foot refers to the upper surface of the foot, where the extensor muscles are located. It is positioned distal to the ankle and covers the dorsal/extensor surface of the tarsus, metatarsus, and digits of the foot.

The dorsum of foot is characterized by the presence of long tendons belonging to the extensor muscles of the leg. These tendons cross over the ankle joint to reach the dorsum of foot. Among these tendons are the tibialis anterior, extensor hallucis longus, extensor digitorum longus, and fibularis (peroneus) tertius muscles. All of these muscles contribute to dorsiflexion of the ankle joint. The tibialis anterior, situated medially, also causes inversion of the foot, while the peroneus tertius, located on the lateral side of the foot, also contributes to eversion of the foot.

Please note that as the long extensor tendons reach the dorsum of foot, these are held in place against the underlying bones in the anterior region of the ankle by deep fascial thickenings called the extensor retinacula.

In addition to the long extensors, there is an intrinsic muscle called the extensor digitorum brevis, which lies on the dorsum of foot. It originates from the superolateral surface of the calcaneus and forms four tendons. The first tendon inserts into the base of the proximal phalanx of the big toe, while the remaining three tendons insert into the lateral sides of the extensor digitorum longus tendons for toes II, III, and IV. The muscle is responsible for extending the toes I to IV.

The dorsum of foot is also characterized by the presence of extensor hoods, which are triangular fibrous expansions of the distal tendons of the extensor digitorum longus and brevis and extensor hallucis longus muscles. These extensor hoods are located on the dorsum of the toes and attach to the distal phalanges at their apices, to the middle phalanges along their midway, and wrap around the proximal phalanges at their bases, where they connect to the deep transverse metatarsal ligaments. They provide a specialized mechanism for flexion at the metacarpophalangeal joint and extension at the interphalangeal joints. This mechanism is achieved through the pull-action of the lumbricals and interossei muscles, which insert into the bases of the extensor hoods.

Vessels and nerves from the anterior leg region also pass through the extensor retinacula to reach the dorsum of foot. These include the dorsalis pedis artery, which is a continuation of the anterior tibial artery. It descends into the first interdigital space and connects with the deep plantar arch in the sole of the foot. Additionally, the deep peroneal nerve supplies cutaneous innervation to the skin in the first interdigital space.

Superficial vessels and nerves, located within the superficial fascia, course along the dorsum of foot. For example, there is a dorsal venous arch that gives rise to the great saphenous vein on the medial side and the small saphenous vein on the lateral side. The former drains into the femoral vein, while the latter drains into the popliteal vein. Cutaneous innervation is provided by the superficial and deep peroneal nerves. The skin on the lateral side is innervated by the sural nerve, while the skin on the medial side is innervated by the saphenous nerve.

Text written by Muhammad A. Javaid, MD, PhD © 2023 IMAIOS.

  • Drake, R.L., Vogl, A.W. and Mitchell, A.W.M. (2009). ‘Chapter 6: Lower Limb’ in Gray’s anatomy for Students. (2nd ed.) Philadelphia PA 19103-2899: Elsevier, pp. 596-598, 613, 616-617.


Comparative anatomy in animals

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