We have conclusions after the study of muscular system about small intestine channel of hand taiyang muscle. Judging from many studies of interrelation between Meridian muscle and muscle, it is considered that Meridian muscle theory has some similarities with modern anatomical muscular system. It is considered that Small intestine channel of hand taiyang muscle contains Flexor digitorum profundus muscle, Extensor digiti minimi muscle, Abductor digiti minimi muscle, Extensor carpi ulnaris muscle, Flexor carpi ulnaris muscle, Triceps brachii muscle, Infraspinatus muscle, Levator scapulae muscle, Sternocleidomastoid muscle, Masseter muscle, Temporalis muscle. The symptoms of small intestine channel of hand taiyang muscle is similar to referred pain of modern Myofascial Pain Syndrome, and the medical treatment of "I Tong Wi Su(以痛爲輸)" is also similar to that of Myofascial Pain Syndrome. Small intestine channel of hand taiyang muscle is one of the three yang channels of hand muscle, and it has unity in extension of upper limb and trunk in the movement. And it is thought that weakness of small intestine channel of hand taiyang muscle is related with muscular system causing Round Shoulder and Head Forward Position.