Sinus tarsi

The sinus tarsi, also known as the talocalcaneal sulcus,^[1] is a cylindrical canal in the hindfoot. It has a complex anatomy, with five ligamentous structures and a pad of adipose tissue (fat).^[2] The tarsal canal opens up into the sinus tarsi,^[3] however, the tarsal canal is a distinct structure.

Sinus tarsi
A labeled diagram of the foot bones, with the sinus tarsi labeled (upper right; next to Tarsus label)
Synonyms	Talocalcaneal sulcus
Identifiers
TA98	A02.5.11.009
TA2	1476
FMA	35138
Anatomical terminology [edit on Wikidata]

Structure

The sinus tarsi located in the hindfoot, it is contained by the calcaneus, talus, talocalcaneonavicular joint, and the bottom of the subtalar joint.^[1] There are five ligamentous structures present inside it: the intermediate, medial, and lateral roots of the inferior extensor retinaculum; the cervical ligament, and the interosseous talocalcaneal ligament. There is also a pad of adipose tissue.^[2] The tarsal canal also opens up into the sinus tarsi.^[3]

Physiology

The sinus tarsi helps stabilize the ankle, as the cervical ligament limits inversion of the (turning in) and the interosseous talocalcaneal ligament limits eversion (turning out).^[2]

Clinical significance

Prior to the discovery of sinus tarsi syndrome, the sinus tarsi was not well studied and was seen as irrelevant.^[4]

Sinus tarsi syndrome

Sinus tarsi syndrome is a clinical disorder of pain and tenderness in the sinus tarsi. This disorder can have a variety of causes; however, the most common is an inversion ankle sprain.^[5]

Surgery access

In recent years, approaching a displaced intra-articular calcaneus fracture via the sinus tarsi during surgery has been found to be more efficient in reconstructing the bone and less invasive, preserving soft tissue around the bone.^[6][7]