MRI research of ulnar nerve of cubital tunnel

Abstract

Objective To investigate the site,MR signal types and morphological characteristics of ulnar nerve in cubital tunnel for healthy adults,in order to improve the awareness of ulnar nerve. Methods Unilateral elbow of forty healthy volunteers were scanned with MR,the sequences were as follows: T1-weighted-spin-echo,T2-weighted-spin-echo-fat-suppression,PD-weighted-spin-echo-fatsuppression,among 40,13 were supine,27 were prone.The site and MR signal types and morphological characteristics of ulnar nerve were observed,the long diameter and short diameter of the ulnar nerve on different axials were respectively measured. Results On axial,ulnar nerve was posterior to the medial condyle of the humerus at proximal elbow,lied between the flexor carpi ulnaris and the flexor digitorum profunds and superficialis muscles distally.The shape of the ulnar nerve was roundness or elliptic,the signal of 40 volunteers' (100%) ulnar nerve was isointensity on T 1-weighted,the signal of 17 volunteers' (42.5%) ulnar nerve was isointense on T 2-weighted or PD-weighted,the MRI signal of 23 volunteers' (57.5%) ulnar nerve was slight hyperintense on T2-weighted or PDweighted,especially on the axial of medial condyle of humerus.The variation range of long diameter and short diameter of the ulnar nerve respectively were 1.4—3.8 mm,1.0—3.0 mm. Conclusion The certain location,MR signal types and morphological characteristics of normal ulnar nerve play an important role in the diagnosis of cubital tunnel syndrome. Key words: Magnetic resonance imaging; Ulnar nerve; Cubital tunnel syndrome