Tibialis Posterior

Johnson KA, Strom DE. Tibialis posterior tendon dysfunction. Clin Orthop Relat Res 1989 239 196-206. 

In a 24-month, randomized, single-blind trial of botuhnum A in 10 children with Charcot-Marie-Tooth disease type lA aged 3-14 years the treated leg received intramuscular injections at 6-month intervals in the tibialis posterior and peroneus longus and the control leg received no injections [62 ]. The intramuscular injections proved safe and were weU tolerated but did not affect the progression of pes cavus. 

The posterior tibial artery is the direct continuation of the popliteal artery down to the distal margin of the popliteus muscle. During its course, this artery is accompanied by the tibial nerve and two or more posterior tibial veins. This posterior neurovascular bundle passes deep to the tendinous arch of the soleus and, after giving off the peroneal artery, courses superficial to the tibialis posterior muscle to reach the tarsal tunnel (Fig. 15.12a,b). The posterior tibial artery is a useful landmark to separate the deep from the superficial group of calf... 

At the medial ankle, the tibial nerve, a continuation of the medial trunk of the sciatic nerve, passes deep to the flexor retinaculum in the space between the medial malleolus and the medial wall of the calcaneus (Fig. 16.10a). The retinaculum consists of a thin fascia and forms the roof of the tarsal tunnel (Fig. 16.10). In addition to the nerve, the tarsal tunnel encloses the tibialis posterior, flexor digitorum longus and flexor hallucis longus tendons, the posterior tibial artery and two veins (Fig. 16.10a,b). Posteroinferior to the medial malleolus, the tibial nerve divides into the medial and lateral plantar nerves and the calcaneal nerve, which is responsible for the sensitive supply of the heel (Fig. 16.11). The plantar nerves supply the intrinsic foot muscles, except for the extensor digitorum brevis, which is innervated by the deep peroneal nerve. The posterior tibial artery accompanies the nerve deep to the flexor retinaculum and, inferior to the medial malleolus, it divides into medial and lateral plantar arteries (Fig. 16.11). 

Fig. 16.26. Normal tibialis posterior tendon. Short-axis 12-5 MHz US image demonstrates the tibialis posterior tendon (tp) that typically exhibits an oval shape and lies in a shallow bony groove (arrowheads) on the posterolateral aspect of the medial malleolus (MM). Compare the size of the tibialis posterior tendon with that of the flexor digitorum longus (fdl). The cross-section of the tibialis posterior is approximately twice than that of the flexor digitorum longus. The photograph at the upper left of...

Fig. 16.30 a,b. Normal tarsal tunnel, a Transverse 12-5 MHz US image obtained posterior to the medial malleolus (MM) demonstrates the tibial nerve (arrow) located close to the posterior tibial artery (a) and veins (v) and posterior to the tibialis posterior (tp) and flexor digitorum longus (fdl) tendons. All these structures lies in the tarsal tunnel and are covered by the flexor retinaculum (arrowheads), b Oblique transverse 12-5 MHz US scan at the medial heel shows the medial and lateral plantar nerves (arrows) as a result of division of the main trunk of the tibial nerve. The photographs at the upper left of the figures indicate probe positioning... 

The tibialis posterior tendon is the most commonly injured tendon on the medial side of the ankle. Its rupture is typically encountered in middle-aged obese women or as a result of systemic disease, such as rheumatoid arthritis or seronegative spondyloarthropathy (Johnson 1983). Acute fractures of the ankle may also be responsible for some cases of rupture of this tendon. In most cases, tibialis posterior tendon tears occur around the medial malleolus, but they may also be encountered at the navicular insertion. Rupture of the is frequently overlooked clinically because it often develop with no history of trauma. Initially, the patient complains of pain and swelling around the affected tendon. Then, as the severity of the lesion gradually progresses toward rupture elongation, gradual collapse... 

Based on the US findings, tibialis posterior tendon tears have been classified into three types of increasing severity of involvement (Rosenberg et al. 1998). The type 1 tear corresponds to a thickened tendon with longitudinal splits and degeneration (Fig. 16.57) ... 

Fig. 16.57 a-c. Partial-thickness (type I) tear of the tibialis posterior tendon, a Long and b short-axis 12-5 MHz US images at the level of medial malleolus (MM) with c CT-tenographic correlation demonstrate a swollen tibialis posterior tendon (arrows) with a longitudinal hypoechoic cleft (arrowheads) in its substance consistent with a partial tear... 

US has also proved an effective means of identifying tendon changes related to serous and hypertrophic tenosynovitis (Fig. 16.60) (Miller et al. 1996 Chen and Liang 1997 Premkumar et al. 2002). These changes occur commonly in patients affected by systemic arthritis. Instability of the tibialis posterior tendon, including subluxation and dislocation in... 

Two types of accessory bones can be found at the level of the distal insertion of the posterior tibialis tendon the accessory navicular type I and II (Lawson 1994). The accessory navicular bone (type I), also known as the os tibiale externum, can be enclosed within the tibialis posterior tendon. This sesamoid ranges from 2 to 6 mm in size and is located just proximal to the posteromedial aspect of the navicular bone. In general, it is asymptomatic and should not be confused with tendon calcification or avulsion fracture at US examination (Patel et al. 2002). The accessory navicular bone (type II) is an accessory ossification center of the navicular bone. It is larger than the type I form, ranging from 9 to 12 mm in size, has a triangular shape and articulates with the posterior and... 

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