Anatomic Landmarks to Locate the Median Nerve for Safe Wrist Block or Carpal Tunnel Steroid Injection

Ron Brooks, MD; Amanda Kistler, MD; Saeed Chowdhry, MD; Andrew Swiergosz, BS; Katharina Perlin, BS; Morton L. Kasdan, MD; Bradon J. Wilhelmi, MD


ePlasty. 2019;19(e19) 

In This Article

Study Design

An anatomic cadaveric study was designed where 7 cadaveric upper extremities were utilized to obtain specific dimensions of the MN as well as its anatomic relationship to other relevant carpal tunnel and non–carpal tunnel components. Loupe magnification (2.5×) was used for the dissection. A longitudinal incision was made from the ulnar aspect of the middle finger, the third web space, to the mid forearm, and relevant anatomic landmarks were identified (Figure 1). Measurements were taken at the radial tip of the interstyloid line and performed with a Vernier side caliper. All measurements were obtained at the level of the radial tip of the interstyloid line. Each of the aforementioned distances were recorded in millimeters and used to calculate mean distances and the standard deviation. These data were extrapolated and relative calculations are demonstrated in Table 1. The prefix of "u" was assigned to indicate measurement or calculation from the ulnar aspect of the anatomic structure. These data were then used to characterize the size of the MN and its anatomic location relative to previously named structures in order to characterize a location for needle placement that would avoid iatrogenic injury to the MN.

Figure 1.

Anatomic dissection with demonstration of the median nerve and palmaris longus near midline.