To prospectively evaluate the signal intensity (SI), course, and
diameter of elbow nerves and to identify anatomic variants that are
potentially associated with nerve compression syndromes on magnetic
resonance (MR) images of asymptomatic elbows.
MATERIALS AND METHODS
This study was approved by the institutional review board. Informed
consent was obtained from each volunteer. Sixty subjects with
asymptomatic elbows (age range, 22.4-51.7 years; median age, 32.8
years) underwent MR imaging. Increased SI compared with surrounding
muscles on fluid-sensitive MR images, anatomic course, anatomic
nerve and muscle variants potentially associated with nerve
compression syndromes, and qualitative changes in nerve diameters
were evaluated. Quantitative data on the shortest and longest nerve
diameters were obtained.
Increased SI on fluid-sensitive MR images was seen in the ulnar
nerve in 60% (36 of 60) of subjects but was never observed in the
median and radial nerves. An atypical intermuscular course of the
median nerve between the brachialis and pronator muscles was
detected in 17% (10 of 60) of subjects. Ulnar nerve subluxation at
the level of the cubital tunnel was seen in 2% (one of 60) of
subjects; an anconeus epitrochlearis muscle, in 23% (14 of 60); and
a hypertrophic leash of Henry, in 15% (nine of 60). Median nerve
dimensions were 2.4 x 4.0 mm (range, 1.0-4.0 x 3.0-7.0 mm) for the
ulnar nerve, 1.0 x 1.9 mm (range, 0.8-2.0 x 0.9-5.0 mm) for the
radial nerve, and 3.0 x 5.4 mm (range, 1.0-5.0 x 3.0-9.0 mm) for the
Increased SI of the ulnar nerve on fluid-sensitive images (60%), an
atypical intermuscular course of the median nerve (17%), and an
anconeus epitrochlearis muscle (23%) are common MR findings in
Husarik D B, Saupe N, Pfirrmann C W A, Jost B, Hodler J, Zanetti M.
Elbow nerves: MR findings in 60 asymptomatic subjects--normal
anatomy, variants, and pitfalls. Radiology 2009; 252:148-56.