The Rearfoot: The Foundations of Stability
The hindfoot, which includes the heel and instep, plays a crucial role in the overall stability of the body. This region is subjected to many mechanical forces, particularly when walking on flat or uneven terrain. The stability of the hindfoot relies on a complex combination of the strength of the bony framework and the flexibility of the ligaments and tendons.
Anterior region of the instep
The instep is located at the junction between the foot and the leg. It is stabilized by ligamentous structures such as the retinacula, which prevent the tendons from protruding. The skin in this region is mobile but fragile, making it vulnerable to injury from excessive pressure or friction, often caused by poorly fitting shoes. Deep to the instep, the anterior region houses the tendons of the extensor muscles that pass beneath the retinacula and are essential for the dorsiflexion movement of the foot.
Key features of note in this area include the anterior tibial tendon, which is particularly prominent during foot adduction movements, and the fibular vessels and nerves that pass through the region. These structures play a crucial role in the motor and sensory function of the anterior part of the foot.
Posterior region of the instep
The posterior region of the instep is dominated by the calcaneal tendon, also known as the Achilles tendon. This tendon is the strongest in the human body and is essential for walking and running. It transmits the forces generated by the calf muscles (gastrocnemius and soleus) to the foot, thus enabling propulsion of the body. Around the tendon, structures such as the retrocalcaneal bursa and subcutaneous adipose tissue provide protection and facilitate the movements of the tendon during plantar flexion.
Medial retromalleolar groove: calcaneal canal
The medial retromalleolar groove is a key area where the posterior tibialis tendon, as well as the tendons of the flexor digitorum longus and hallucis longus muscles, pass toward the sole of the foot. This osteofibrous canal, formed by the medial malleolus and flexor retinaculum, also contains the posterior tibial vessels and nerves. The complex topographic relationships in this area are essential to understand to avoid nerve compression syndromes, such as tarsal tunnel syndrome.
Lateral retromalleolar gutter
The lateral retromalleolar groove houses the tendons of the fibular muscles (peroneus longus and peroneus brevis), which play a crucial role in the lateral stabilization of the foot. These tendons, enclosed in an osteofibrous sheath, allow eversion of the foot and are protected by specific retinacular ligaments. The topographic relationships with the sural vessels and nerves, which innervate the skin of the lateral region of the foot, are essential for understanding the pathologies associated with this region.
The midfoot and forefoot: Dynamic and adaptive structures
The midfoot and forefoot are the regions where the flexibility and adaptability of the foot are most pronounced. These areas are crucial for shock absorption and propulsion of the body during walking and running.
Dorsal side of the foot
The dorsal surface of the foot, although relatively thin, houses essential vascular and nervous structures. The skin is thin, particularly on the medial border, and houses superficial veins that are often visible through the dermis. These veins play an important role in thermoregulation and venous return, particularly during prolonged walking.
On this side, the tendons of the extensor muscles of the toes are particularly visible and allow the dorsiflexion movements of the toes. These tendons are held in place by the retinacula, which also provide protection for the underlying vessels and nerves.
Topographical reports of the plantar sole
The plantar sole, or plantar surface of the foot, is a complex and robust region, adapted to withstand the intense pressures exerted during walking. The plantar fascia, a thick band of connective tissue, plays a central role in maintaining the arch of the foot, which is essential for the dissipation of forces during walking. This structure is often subject to pathologies such as plantar fasciitis, a painful inflammation that can limit the patient's mobility.
The topographic relationships of the plantar sole also include the intrinsic muscles of the foot, which contribute to the stability and dynamics of the plantar arch. These muscles are innervated by the medial and lateral plantar nerves, which divide from the posterior tibial nerve. The plantar arteries, arising from the posterior tibial artery, provide vascularization to this region, which is essential for the health of the plantar tissues.
Topographical and functional relationships of the foot
Understanding the topographical relationships, that is, the relationships between the different bone, muscle, nerve and vascular structures, is essential for understanding the pathological mechanisms of the foot and for developing effective therapeutic strategies.
Vascular and nervous relationships
The main arteries of the foot, such as the anterior tibial artery, the dorsalis pedis artery, and the plantar arteries, are located deep, protected by tendon and bone structures. These vessels are responsible for perfusion of the tissues of the foot, and their obstruction can lead to serious pathologies, such as critical ischemia of the lower limb.
The nerves of the foot, including the deep fibular nerve, the posterior tibial nerve and their branches, provide sensation and movement to the foot. These nerves pass through narrow canals and are therefore susceptible to compression, leading to syndromes such as Morton's neuropathy or tarsal tunnel syndrome. Accurate knowledge of these anatomical relationships is crucial for diagnosing and treating these conditions.
Tendon reports
The tendons of the long flexor muscles, such as the flexor digitorum longus tendon and the flexor hallucis longus tendon, play a key role in flexing the toes and maintaining balance during walking. These tendons are surrounded by tendon sheaths that facilitate their gliding and reduce friction. Tendon pathologies, such as tendinitis, can result from repetitive microtraumas or anatomical malformations that alter these topographic relationships.
The importance of anatomical knowledge in podiatry
Mastering the topographical anatomy of the foot is essential for any podiatrist. The complexity of the structures of the foot, their interrelationship and their role in the mobility and stability of the human body require a thorough understanding for effective management of pathologies. By mastering these concepts, the podiatrist is better equipped to diagnose, treat and prevent foot conditions, thus ensuring optimal care for his patients.
