Sonographic Evaluation of the Optimal Needle Insertion Site in the Biceps Femoris Short Head

The aim of the study was to identify the optimal needle placement for electromyographic examination of the biceps femoris short head muscle in relation to the biceps femoris long head tendon through sonographic evaluation.

This cross-sectional observational study involved 36 lower limbs of 18 healthy volunteers. The distances and angles indicating the relationships between the common fibular nerve and the medial or lateral border of the biceps femoris long head tendon were measured at 5 and 7 cm proximal to the tip of the fibular head (P1 and P2, respectively) using ultrasonography.

The median values of the distance between the biceps femoris long head tendon and the common fibular nerve were significantly longer in the lateral approach than in the medial approach at the P1 and P2 levels. The median values of the angles between the vertical line to the biceps femoris long head tendon and the common fibular nerve were significantly larger in the lateral approach than in the medial approach at both levels.

The common fibular nerve is located just below the medial border of the biceps femoris long head tendon at a near-vertical degree from the skin. It is strongly recommended that the needle should be inserted on the lateral side of the biceps femoris long head tendon during needle electromyographic examination of the biceps femoris short head muscle.