Anatomy of the Tarsal Canal and Sinus in Relation to the Subtalar Joint Capsule

Background: Anatomical knowledge of the tarsal canal and sinus is still unclear owing to the complexity of the ligamentous structures within them, particularly the relationship with the capsules of the subtalar joints. The aim of this study was to examine the anatomical relationship between the fibrous tissues of the tarsal canal and sinus and the articular capsules of the subtalar joint. Methods: We conducted a descriptive anatomical study of 21 embalmed cadaveric ankles. For a macroscopic overview of the subtalar joint, we removed the talus in 18 ankles and separated the fibrous tissues from the surrounding connective tissues to analyze the layered relationship between the inferior extensor retinaculum (IER) and the subtalar joint capsule. Additionally, we histologically analyzed the tarsal canal and the medial and lateral sides of the tarsal sinus using Masson’s trichrome staining in 3 ankles. Results: The medial and intermediate roots of the IER and interosseous talocalcaneal ligament (ITCL) were located in the same layer and were connected to each other, between the capsules of the posterior talocalcaneal and talocalcaneonavicular joints. The intermediate root of the IER and the cervical ligament (CL) had adjacent attachments on the tarsal sinus, and synovial tissues originating from the joint capsules filled the remaining area in the tarsal canal and sinus. Conclusion: We determined that the tarsal canal and sinus tarsi contained 3 layered structures: the anterior capsule of the posterior talocalcaneal joint, including the anterior capsule ligament; the layer of ITCL and IER; and the posterior capsule of the talocalcaneonavicular joint, including the CL. Clinical Relevance: The results of this study may help with the understanding of the pathomechanism of subtalar instability and sinus tarsi syndrome, resulting in better treatment.

Giant Cells Osseous Tumor in the Tarsal Canal after Lateral Ankle Sprain

Ankle sprain can cause injuries to the anatomic structures surrounding the tibiotarsal joint. A possible extra-articular pathology is to be hypothesized and diagnosed as early as possible. The subtalar joint, for anatomical and functional reasons, is one of the most damaged joints following an ankle sprain. In spite of this, its involvement is often underestimated. The clinical case presented in the present article is referred to a giant cells osseous tumor in the tarsal canal that was diagnosed 2 months after an inversion ankle sprain.

Neurilemoma of the Posterior Tibial Nerve and Tarsal Tunnel Syndrome

Tarsal tunnel syndrome is defined as a compressive neuropathy of the posterior tibial nerve in the tarsal canal. A neurilemoma is an uncommon, benign, encapsulated neoplasm derived from Schwann cells. We present a case of tarsal tunnel syndrome caused by this rare space-occupying lesion. (J Am Podiatr Med Assoc 97(2): 148–150, 2007)

Intrachondral Microvasculature in the Human Fetal Talus

The intrachondral microvasculature of the growing talus of human was studied in 16 fetuses aged from 15 to 44 weeks of gestation, using interrupted serial sections and vascular injection of ink. The cartilage model of the talus was shown to be well vascularized throughout by cartilage canals. The cartilage canal contained blood vessels and connective tissue, with vessels originating from the perichondrial vessels. They were covered by a thick connective tissue wall that was continuous with the perichondrium. The functions of the cartilage canals were mainly to nourish the large masses of cartilage and to supply osteogenic tissue, which initiates the primary ossification center. As in the adult, the fetal talus was supplied with four to five main branches originating from the sinus tarsi and the tarsal canal; there were no anastomoses between the vessels of the adjacent cartilage canals and between the branches within the cartilage canal. This type of microvasculature is vulnerable to injury and, if impaired, may cause serious complications.

The Arterial Anatomy of the Talus

The extraosseous and intraosseous vascularity of the talus was studied in 26 fresh cadaver limbs. The specimens were injected with latex or Batson's compound, debrided by a nondissection technique, and cleared by a modified Spalteholz method. The extraosseous vascularity was through the branches of the three major regional arteries which entered the five nonarticulating surfaces of the bone. The major blood supply to the body was provided by the artery of the tarsal canal. The deltoid and sinus tarsi vessels provided significant minor sources of vascularity. The superior neck and posterior tubercle vessels supplied small areas of the body, but did have anastomoses with the other arteries in some specimens. These vascular patterns correlated well with the reported incidence of avascular necrosis of the body of the talus following injury.