Heterotopic ossification is often complicated in head injury patients and involves their neurologically affected joints. It can be ignored in early stage of head injury because of their altered consciousness, which ultimately produces limitation of joint motion and interferes the ability of maximum rehabilitation.

This study reports 13 cases of heterotopic ossifications found in 5 head injury patients who were admitted to the department of Rehabilitation Medicine of the Presbyterian Medical Center from june, 1984 through December, 1987 with the review of literatures. The findings are as follows;

1) Mean age was 31.4 years old, the males were more prevalent than the females.

2) Types of head injury were cerebral contusions, subdural hemorrhages, intracerebral hemorrhages, and intraventricular hemorrhages. Level of consciousness on admission was semicoma to stuporous.

3) All heterotopic ossifications were involved in affected joints and frequently involved joints were hip, elbow, knee and shoulder in order.

4) Time since head injury to detection of heterotopic ossification was from 4 to 11 months.

5) One patient who had ulnar nerve entrapment because of heterotopic ossification showed improvement after receiving anterior transposition of ulnar nerve.

6) Preventive intervention is important especially for the high risk patients having spastic paralysis, brain stem injury, severe head injury or poor neurological recovery.