Dynamic Morphologic Study of the Ulnar Nerve Around the Elbow Using Ultrasonography Jeon, In-Ho; Lee, Seong-Man; Choi, Jin-Won; Kim, Poong-Tak;
Purpose: The morphological study and dynamic stability of the ulnar nerve around the elbow joint was investigated in asymptomatic normal population using ultrasonography. The purpose of this study is to provide fundamental data for ultrasonographic diagnosis of ulnar neuropathy in cubital tunnel syndrome. Materials and Methods: Fifty cases of 25 healthy male volunteers, aged between 20 to 30 years, included in this study. High resolution 7.5 MHz linear probe was used to examine the ulnar nerve in axial and longitudinal views. In a longitudinal view, the course, position and the thickness of nerve were monitored, the diameter of ulnar nerve and dynamic stability at elbow flexion and extension were measured in an axial view at four different points; 1cm proximal to medial epicondyle, behind the medial epicondyle, entrance to Osborne ligament, and 1cm distal to Osborne ligament. Results: The short diameters of ulnar nerve at elbow extension at four anatomic points were 2.66 mm, 2.97 mm, 2.64 mm, and 2.69 mm and the long diameters were 4.61 mm, 4.56 mm, 4.36 mm, and 4.37 mm, which showed no significant change at each point. However, at elbow flexion, the short diameters were changed to 2.72 mm, 2.34 mm, 2.65 mm, and 2.41 mm and the long diameters into 4.49 mm, 5.40 mm, 4.16 mm, and 4.66 mm. At elbow flexion, significant morphologic change was observed in the medial epicondyle area, and the diameter of the ulnar nerve was shortest at the entrance of Osborne ligament both at flexion and extension. In terms of dynamic stability, nine subluxations and seven dislocations were observed. Conclusion: This study shows dynamic instability and a morphological change of long and short diameters of ulnar nerve at flexion and extension in a normal person, which should be considered in the ultrasonographic diagnosis of ulnar neuropathy.
Chung MS, Baek GH, Kim SL, Park YC: Medial Epicondylectomy for the Treatment of Cubital Thnnel Syndrome-A Retrospective Comparison with Anterior Subcutaneous Transposition. J Korean Shoulder Elbow Soc, 1: 100-108 1998.
Dong WL, Kyoo SS, Jong SK, Jung SK: Decompression and Medial Epicondyloplasty in Ulnar Nerve Entrapment Syndrome at Elbow. J Korean Shoulder Elbow Soc, 3: 54-60, 2000.
Fornage BD: Peripheral nerves of the extremities: imaging with US. Radiology, 167: 179-182, 1988.
Kato H, Hirayama T, Minami A, Iwasaki N, Hirachi K: Cubital tunnel syndrome associated with medial elbow ganglia and osteoarthritis of the elbow. J Bone Joint Surg Am, 84: 1413-149, 2002.