säri

Sääri is the lower leg, the part of the leg between the knee and the ankle. In humans it contains two long bones, the tibia (shinbone) and the fibula, connected by the interosseous membrane. The leg is enveloped by the crural fascia and is divided into three muscular compartments: anterior, lateral, and posterior (with superficial and deep portions). The arrangement allows distinct muscle groups, nerves, and blood vessels to run along the leg.

The anterior compartment contains muscles responsible for dorsiflexion of the foot and extension of the toes, such as the tibialis anterior, extensor digitorum longus, and extensor hallucis longus. The lateral compartment contains the fibularis (peroneus) longus and brevis, which evert and assist in plantarflexion. The posterior compartment is split into superficial muscles—the gastrocnemius and soleus, constituting the calf’s triceps surae—and deep muscles such as the tibialis posterior, flexor digitorum longus, and flexor hallucis longus, which mainly control plantarflexion and toe movements.

Nerve supply and blood flow correspond to the compartments. The anterior and lateral compartments are supplied mainly by branches of the common fibular nerve and by the anterior tibial artery, while the posterior compartment is supplied by the tibial nerve and posterior tibial/muscular arteries, with contributions from the peroneal arteries.

Functionally, the sääri bear body weight, absorb shock, and enable locomotion, balance, and changes in direction. Clinically relevant conditions include shin splints (medial tibial stress syndrome), tibial stress fractures, and compartment syndrome, all of which relate to the structure and use of the lower leg.