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Age / Sex : 29 / M
Chief complaint: Wrist pain
1) What is your impression?
Two weeks later, you can see the final diagnosis with a brief discussion of this case.
(Quiz는 quiz일 뿐이오니 답안은 한개만 보내주시기 바라오며, 복수의 답안을 보내주시는 분은 정답이 포함되어 있더라도 부득이 semi-correct answer로 처리토록 하겠습니다.)
Courtesy: 김완태(Wan Tae Kim), 중앙보훈병원(Veterans Health Service Medical Center)
Diagnosis: Bifid median nerve and persistent median artery
Discussion
Answer:
Bifid median nerve and persistent median artery
Findings: Axial MR image shows two
branches of the median nerve with 2 clearly separated nerve trunks at the level
of the proximal carpal tunnel. A persisent median artery is positioned between
the 2 nerve trunks. The artery is shown beneath the transverse carpal ligament.
Diagnosis: Bifid median nerve and persistent
median artery
Discussion:
High division of the median
nerve proximal to the carpal tunnel or bifid median nerve has been described in
the surgery literature as a median nerve anomaly with an incidence of 2.8%.
Each nerve trunk was abnormally
hypoechoic compared with the alternating hypo- and hyperechoic fascicular
pattern of a normal peripheral nerve.
The median artery provides blood
supply to the forearm and the hand during embryonic development. As the radial
and ulnar arteries develop, the median artery atrophies to a small vessel
accompanying the median nerve in the forearm. Persist median artery is a vessel
variation in the carpal tunnel described in anatomic studies.
About 63% of the persist median
artery is associated with anatomic variations of the median nerve. In most
cases, the persist median artery is situated between the radial and ulnar
trunks of the median nerve.
A bifid median nerve and persist median artery is associated relatively
frequently with carpal tunnel syndrome. Knowledge of median nerve
anomalies is important before performing surgical intervention to avoid
potential nerve injury.
References:
1.
Propeck T, Quinn TJ, Jacobson JA, Paulino AF, Habra G, Darian VB. Sonography
and MR imaging of bifid median nerve with anatomic and histologic correlation. AJR Am J Roentgenol 2000;175(6):1721-5.
2.
Iannicelli E, Chianta GA, Salvini V, Almberger M, Monacelli G, Passariello R.
Evaluation of bifid median nerve with sonography and MR imaging. J Ultrasound Med 2000;19(7):481-5.
3.
Klauser AS, Halpern EJ, Faschingbauer R, Guerra F, Martinoli C, Gabl MF, et al.
Bifid median nerve in carpal tunnel syndrome: assessment with US
cross-sectional area measurement. Radiology
2011;259(3):808-15
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