Cross-Sectional Area Reference Values of Nerves in the Upper and Lower Extremities using Ultrasonography in the Indian Population

Abstract

Background and purpose: Cross-sectional area (CSA) is the most important parameter to study peripheral nerves by high-resolution ultrasonography. The aim was to acquire normative data of CSA of the main upper and lower limb nerves in the Indian population.

Methods: CSA of nerves was determined in 100 healthy volunteers at 11 predetermined sites: median and ulnar at the wrist, mid-forearm, elbow; radial (spiral groove); tibial (popliteal fossa, medial malleolus); common peroneal (CPN, fibular head) and sural (lateral malleolus).

Results: The mean age of participants was 40.7 ± 13.0 years (range: 18-79). Fifty were < 40 years of age. The mean height, weight and BMI were 161.5 ± 8.3 centimeters (range: 145-179), 58.6 ± 10.1 kilograms (range: 32-90) and 22.4 ± 3.2 kilogram/square meter (range: 14.03-30.44), respectively. The median and ulnar nerve measurements were non-uniform throughout its course, and the CSA was largest at the elbow and ulnar groove, respectively. With advancing age, there was a significant difference for median and ulnar nerves at the wrist (median P = 0.002, ulnar P = 0.009) and tibial nerve (popliteal fossa, P = 0.045, medial malleolus, P = 0.005), CPN (P = 0.047). Men had greater CSA of upper limb nerves and tibial nerves at popliteal fossa (P < 0.05) as compared to women. A positive correlation was noted with weight.

Conclusion: It is apt for every defined population to have its own set of normative data of CSA as it varies with ethnicity, age, and the built of individuals. We provide a valuable set of CSA data for nerves in the Indian population, which can be used for comparison while investigating peripheral nerve disorders.

Keywords: Cross-sectional area; India; normative data; peripheral nerve; ultrasound.

Figure 1

USG cross section images of median and Ulnar nerves: Median nerve at wrist (a), at mid forearm between the flexor digitorum superficialis and flexor digitorumprofundus (b) and at the elbow medial to the brachial artery (c), Ulnar nerve at the wrist beside the ulnar artery (d), at the mid forearm beside the ulnar artery (e) and at the elbow between the olecranon and medial epicondyle (f).

Figure 2

USG cross section images of radial and lower limb nerves: Radial nerve at the spiral groove (a), Tibial nerve at the popliteal fossa, just above the popliteal vein (b) and posterior to the medial malleolus in relation to the posterior artery and vein (c), Common peroneal nerve lateral to the fibular head (d) and Sural nerve at the lateral aspect of the distal leg, lateral to the lesser saphenous vein (e)