{"references": ["1. Yoo SD, Kim HS, Yun DH, et al. Monome- licamyotrophy (Hirayama disease) with upper motor neuron signs: a case report. Ann Rehabi Med. 2015;39(1):122\u2013127. 2. Hirayama K, Toyokura Y, Tsubaki T. Juvenile muscular atrophy of unilateral upper extremity: a new clinical entity. Jap J Psych Neuro. 1959;61 :2190\u20132197. 3. Tashiro K, Kikuchi S, Y. Itoyama et al., \"Nationwide survey of juvenile muscular atrophy of distal upper extremity (Hirayama disease) in Japan. Amyo Lat Scleros. 2006;7(1):38\u201345. 4. Hirayama K, Tomonaga M, Kitano K, Yamada T, Kojima S, Arai K. Focal cervical poliopathy causing juvenile muscular atrophy of distal upper extremity: a pathological study. J Neuro, Neurosur Psych. 1987;50(3):285\u2013290. 5. Kikuchi S, Tashiro K, Kitagawa M, Iwasaki Y, Abe H. A mechanism of juvenile muscular atrophy localized in the hand and forearm (Hirayama's disease)\u2014flexion myelopathy with tight dural canal in flexion. Clin Neuro. 1987;27(4):412-9."]}

Hirayama disease, also known as monomelicamyotrophy (MMA), is a rare cervical myelopathy that manifests itself as a self-limited, asymmetrical, slowly progressive atrophic weakness of the forearms and hands predominantly in young males. The forward displacement of the posterior dura of the lower cervical dural canal during neck flexion has been postulated to lead to lower cervical cord atrophy with asymmetric flattening. We report a case of Hirayama disease in a 18- year-old male presenting with gradually progressive asymmetrical weakness and wasting of right hand and forearms.