“…Various underlying disorders were associated with LUH such as Frey's syndrome, cerebral infarction, Buerger disease, Holmes-Adiesyndrome, intra-thoracic malignancies, Riley-Day syndrome, LUH secondary to an eccrine nevus and type 1 Neurofibromatosis [6]. As reported by some authors it can be secondary to trauma [2,7,8,9] or idiopathic [10,6,11]. anterior to the transverse process of C7, superior to the neck of the first rib, and just below the subclavian artery.…”