Trauma: Regeneration & Regrowth of Nerves After Severe Trauma
Animation: Image diagnosis of eight-year-old boy with partial reinnervation of right leg muscles.
The animation depicts the right-leg muscles of an eight-year-old boy with partial reinnervation eight months after being struck by a motor vehicle. Initially he had flaccid paralysis of the sciatic innervated muscles but by five months began to develop flexion at the knee which was 4/5 strength at the time of the imaging exam.
(A1) - Sagittal image of right thigh showing the femur fracture (fx), damaged sciatic nerve (sc) and patella (pat) for orientation.
(A2) - The sciatic nerve was fully transected by the initial injury and its healed stump is seen with marked nerve injury hyperintensity. Several new growth nerves are seen emerging from the stump to reinnervate the long head of the biceps femoris. (TSN) - truncated sciatic nerve. (NGN) - new growth nerve reinnervating biceps.
(B1) - The semitendinosus and semimembranosus demonstrate muscle denervation hyperintensity (*).
(B2) - The short head of the biceps femoris (**) also continues to demonstrate hyperintensity of denervation.
(C) - Axial image three inches below the level of the sciatic stump (ps(C)) demonstrating the hyperintense semimembranosus and semitendinosus (*) and short head of the biceps femoris (**). There is normal muscle image appearance in the long head of the biceps femoris (***). The femur (fe) is labeled for orientation and the placement of the sagittal image slices for B1 and B2 are also marked ps(B1) and ps(B2).