The ulnar nerve is known to be vulnerable because of its anatomical path since the beginning of the twentieth century. A traumatic origin, or one secondary to a degenerative damage, was frequently found, and in 1957 Osborne described the concept of the cubital tunnel syndrome. He showed that opening this tunnel has positive effects on the symptomatology. However, the ulnar nerve can also be compressed at the level of the wrist when it passes in the Guyon’s canal. Rehabilitation of the entrapment syndromes of the ulnar nerve without surgery only concerns the early stages of the nerve compression; more advanced stages require surgery. Its goal is to improve the tissue glidings around the nerve and the sensitivity of the damaged areas and to maintain the trophicity of the concerned muscles in advanced cases. A thermoformed resting orthosis can also be useful in this treatment. After surgery, the keys of rehabilitation will be the fight against perineural fibrosis and recovering mobility, strength, and sensitivity.