The most complete arm of "Therizinosaurus" is represented by the specimen MPC-D 100/15 which preserves an almost complete right arm and a more fragmented left arm. The right arm covers in total length. The scapula measures long with a stocky and flattened dorsal blade, wide acromial process and a very widened ventral surface; the blade seems to be broken at the end though. Near the anterior edge of the scapular widening and near the scapulocoracoid suture, a foramen is visible; it likely functioned as a channel for blood vessels and nerves when alive. The posterior edge of the scapula is robust and the acromion is lightly built, likely fused into a cartilaginous system with its periphery in life. The coracoid measures in length, it has a broad and convex lateral surface that forms a slightly inclined concavity near of the scapulocoracoid suture. This concavity bends down towards the scapular widening. Near the scapulocoracoid suture, this edge turns very thin and possibly into cartilage along with the periphery of the coracoid in life, as the case of the scapular edge. A large foramen is also present on the coracoid. The glenoid is broad and deep, slightly pointing to the outer lateral side. It has robust, convex crest-like borders. The supraglenoid thickness is developed in a convex crest-shaped form, it is divided across the top of the scapulocoracoid suture. The attachment for the biceps muscle is prominently developed by a large tubercle with a stocky top, indicating powerful muscles in life.