Anatomical basis of pronator teres for electromyography needle placement using ultrasonography.
OBJECTIVE
To find the optimal needle insertion site for needle electromyography of the pronator teres (PT) muscle among commonly used sites.


METHODS
Fifty forearms of 25 healthy subjects were evaluated. Four expected needle insertion points were designated as follows. Point 0 was positioned at the midpoint between the medial epicondyle and medial border of biceps tendon in the elbow crease. Points 1, 2, and 3 were located 2 cm, 3.5 cm and 5 cm distal to point 0, respectively. We assumed that the thickness of PT and the distances between a vertical line from each point to the medial margin of the PT were significant parameters for finding the optimal site. Thus, we measured these parameters through ultrasonographic examination.


RESULTS
In men, the PT was thickest at point 2, and in women, at point 1. The distance between the expected needle insertion line and medial margin of PT was longest at point 1 in both men and women, and was statistically significant compared to points 2 and 3. Both men and women had neurovascular bundles located lateral to the expected needle insertion line.


CONCLUSIONS
The most appropriate and safe needle electromyographic insertional site for the PT is 2-3.5 cm distal to the mid-point between the biceps tendon and medial epicondyle in the elbow crease and the needle should be inserted upward and medial.
Department of Physical Medicine and Rehabilitation, Korea University College of Medicine, Seoul, Korea.
Myung Kyu
MK
Park
Department of Physical Medicine and Rehabilitation, Korea University College of Medicine, Seoul, Korea.
In Yae
IY
Cheong
Department of Physical Medicine and Rehabilitation, Korea University College of Medicine, Seoul, Korea.
Ki Hoon
KH
Kim
Department of Physical Medicine and Rehabilitation, Korea University College of Medicine, Seoul, Korea.
Byung Kyu
BK
Park
Department of Physical Medicine and Rehabilitation, Korea University College of Medicine, Seoul, Korea.
Dong Hwee
DH
Kim
Electromyography; Forearm; Ultrasonography