The tarsal tunnel is a passage found along the inner

leg A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element ca ...

underneath the

medial malleolus A malleolus is the bony prominence on each side of the human ankle. Each leg is supported by two bones, the tibia on the inner side (medial) of the leg and the fibula on the outer side (lateral) of the leg. The medial malleolus is the promine ...

of the

ankle The ankle, or the talocrural region, or the jumping bone (informal) is the area where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular join ...

Structure

The roof of the tarsal tunnel is formed by the flexor retinaculum of the foot. The floor of the tarsal tunnel is formed by the

and the

calcaneus In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock. S ...

The

tibial nerve The tibial nerve is a branch of the sciatic nerve. The tibial nerve passes through the popliteal fossa to pass below the arch of soleus. Structure Popliteal fossa The tibial nerve is the larger terminal branch of the sciatic nerve with root val ...

posterior tibial artery The posterior tibial artery of the lower limb is an artery that carries blood to the posterior compartment of the leg and plantar surface of the foot. It branches from the popliteal artery via the tibial-fibular trunk. Structure The posterior ...

posterior tibial vein The posterior tibial veins are veins of the leg in humans. They drain the posterior compartment of the leg and the plantar surface of the foot to the popliteal vein. Structure The posterior tibial veins receive blood from the medial and latera ...

, and flexor tendons travel in a bundle along this pathway through the tarsal tunnel, in the following order from anteromedial to posterolateral: * Tibialis posterior tendon. * Flexor digitorum longus tendon. *

Posterior tibial artery The posterior tibial artery of the lower limb is an artery that carries blood to the posterior compartment of the leg and plantar surface of the foot. It branches from the popliteal artery via the tibial-fibular trunk. Structure The posterior ...

. *

Posterior tibial vein The posterior tibial veins are veins of the leg in humans. They drain the posterior compartment of the leg and the plantar surface of the foot to the popliteal vein. Structure The posterior tibial veins receive blood from the medial and latera ...

. *

Tibial nerve The tibial nerve is a branch of the sciatic nerve. The tibial nerve passes through the popliteal fossa to pass below the arch of soleus. Structure Popliteal fossa The tibial nerve is the larger terminal branch of the sciatic nerve with root val ...

. * Flexor hallucis longus tendon. In the tunnel, the tibial nerve splits into three different paths. The

medial calcaneal branches of the tibial nerve The medial calcaneal branches of the tibial nerve (internal calcaneal branches) perforate the laciniate ligament, and supply the skin of the heel and medial side of the sole of the foot. Structure The medial calcaneal nerve originates either fr ...

continues to the heel, while the

medial plantar nerve The medial plantar nerve (internal plantar nerve) is the larger of the two terminal divisions of the tibial nerve (medial and lateral plantar nerve), which accompanies the medial plantar artery. From its origin under the laciniate ligament it p ...

and the

lateral plantar nerve The lateral plantar nerve (external plantar nerve) is a branch of the tibial nerve, in turn a branch of the sciatic nerve and supplies the skin of the fifth toe and lateral half of the fourth, as well as most of the deep muscles, its distribution ...

continue on to the bottom of the

foot The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made ...

Clinical significance

Tarsal tunnel syndrome

Tarsal tunnel syndrome is the most commonly reported nerve entrapment of the ankle. It is analogous to

carpal tunnel syndrome Carpal tunnel syndrome (CTS) is the collection of symptoms and signs associated with median neuropathy at the carpal tunnel. Most CTS is related to idiopathic compression of the median nerve as it travels through the wrist at the carpal tunn ...

in the

wrist In human anatomy, the wrist is variously defined as (1) the Carpal bones, carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known ...

. It is caused by compression of the

underneath the flexor retinaculum of the foot. People with tarsal tunnel syndrome have pain in the plantar aspect of the foot mostly at night. Weight bearing increases pain and weakness is found on intrinsic foot muscles with positive Tinel sign at the tunnel. There is no tenderness present on the plantar foot, though this is typically the primary site of complaint.

Additional images

File:Sobo 1909 316.png, The mucous sheaths of the tendons around the ankle. Medial aspect. The flexor retinaculum is labelled as laciniate lig. File:Slide2BER.JPG, Dissection image. Around the medial malleolus seeing from below. File:Tarsal tunnel by Majid Doroudi.webm, Dissection video (41 s)

References

External links

Description at curtin.edu.au
* http://www.ithaca.edu/faculty/lahr/LE2000/ankle%20pics/5Asupmed.jpg {{Muscles of lower limb Lower limb anatomy