Anatomical localization of motor entry points of hamstring muscles - for neurolysis in hamstring spasticity

Objectives: To study the motor entry points of hamstring muscles of lower limb and to suggest ideal sites formotor point procedures for treatment of spasticity in the above muscles.Materials and Methods: The study was done after approval from Institutional Review Board. Sample size wasestimated using Population mean-Absolute precision method. A total of 10 adult lower limbs were chosen. Thenerve branches to hamstring muscles were dissected up to its motor entry point. Position of proximal and distalmotor entry points were marked and following variables measured: a) The length of muscle; b)Number of motorentry points; c)The distance of proximal entry point (PEP) and distal entry point (DEP) from the origin of muscle;e)The position of PEP and DEP as a fraction of length of muscle; f) Ideal site of motor entry point injection; g) Idealsite of motor point injection expressed as a percentage of muscle length.Results: The proximal and distal motor entry points of long head of Biceps Femoris were located at 35% and 51%of the total length of muscle. Most of the motor entry points of Semitendinosus were located between 43% and48% of muscle length ie, in the third-fifth of total muscle length. Semimembranosus had its motor entry pointslocated between 52% and 70% of the total muscle length ie, in the third-fifth and fourth-fifth of muscle length.Conclusion: The interventions done for relief of spasticity will have the best outcomes if planned at the abovementioned areas of the respective muscles