Location of motor branches of tibialis posterior muscle and its relation in treatment of spastic equinovarus foot: a cadaveric study

BACKGROUND AND OBJECTIVES: Nerve block or neurolysis is an important approach in the treatment of spastic equinovarus foot. To illustrate the accurate location of the nerve branch to the tibialis posterior muscle (TP) in clinical practice, 21 adult cadavers were dissected and 14 complete both lower limb specimens were obtained. A total of 28 lower limbs were included. METHODS: We measured the length of the motor branch nerve (LM) of the tibialis posterior muscle, the length of the fibula (LF), the vertical distance (D1) from the midpoint of LM to the fibula tip as well as the horizontal distance (D2) from the midpoint of LM to the inner edge of the fibula. RESULTS: The LM was higher (35.74 ± 7.28 mm) in male than in female (30.40 ± 6.88 mm) specimens but there was no significant correlation between LM and gender (p > 0.05). Additionally, among male specimens, the LM on the right side was longer than that on the left (p ≤ 0.05) while among female specimens, the D1 on the left side was longer than that on the right (p ≤ 0.05). The LF in male specimen was significantly longer than that in female (p ≤ 0.05). The midpoint of the nerve to the motor branch of the tibialis posterior muscle was about 50 mm distal to the fibular head and 10 mm at the inner edge of the fibula. CONCLUSION: Using this coordinate, the midpoint of the nerve branch to the TP could be accurately located.