The main causes of hallux valgus in hemiplegia include hypertonia, parenchymal brain injury or prolonged bed rest affecting ligaments, and the patient then loses control of the foot muscles. 1. Hypertonia: hemiplegic patients are prone to hypertonia, which leads to weakening of the antagonist muscles of the foot, especially the tibialis anterior muscles, and thus the lower limb adductor muscle tone is out of balance, resulting in the performance of pronation of the foot. 2. Cerebral parenchymal injury: hemiplegic patients often have cerebral parenchymal injury, which leads to the inability of the higher center of the brain to regulate the tensor reflexes of the foot muscles, and the imbalance of the inner and outer limb muscle tone. At this time, the medial side of the lower limb is the dominant side, then the foot inversion manifests. 3. Long-term bed rest and ligament loss of vitality: As hemiplegic patients lie in bed for a long period of time, joint ligaments will lose their elasticity, prompting changes in the structure of the tibia and the heel bone and the emergence of inversion of the foot. There are many factors that can lead to hallux valgus in hemiplegic patients, so patients with hemiplegia should consult a doctor as soon as possible to find out the cause of the condition.