Abstract
1. Haemorrhage into the fascial compartment which contains the iliacus muscle and the femoral nerve is a common complication of haemophilia.
2. The iliacus haematoma syndrome is described and illustrated from the authors' study of thirty episodes occurring in twenty-four patients.
3. The anatomy of the iliopsoas fascia is described and the mechanism of femoral nerve compression explained.
4. Differential diagnosis, prognosis and treatment are discussed and the necropsy findings in one patient are presented.
5. An instance of iliacus haematoma occurring as a complication of anticoagulant therapy is recorded.