From an anatomical study and clinical review of fractures of the lateral humeral condyle in children, the following conclusions are drawn. The mechanism of injury is a violent varus force with the elbow in extension, the condyle being avulsed. by the lateral ligament and the extensor muscles. If the fracture is incomplete, with an intact hinge of pre-osseous cartilage medially, the fragment will not be displaced. If the fracture is complete the fragment may be displaced, and open reduction with internal fixation is mandatory.

The results of open reduction more than three weeks after the fracture are no better than those of no treatment at all, and may kill the lateral condylar fragment by damaging its blood supply. The major problem of a neglected fracture is tardy ulnar nerve palsy; to avoid this, immediate anterior transposition of the nerve is recommended, operation for the fracture itself being of no benefit.

Displaced extension supracondylar fractures of the elbow 1. One hundred and ten children were treated by reduction and stabilisation by two pins inserted laterally at an angle of 30 degrees to one another.

2. The complications before and after treatment included fifteen nerve lesions in thirteen patients. The ulnar nerve was involved on one occasion only. Solitary radial nerve injuries occurred with postero-medial displacement of the distal fragment, while median nerve and brachial artery injuries were associated with postero-lateral displacement. All the lesions recovered spontaneously.

3. There were no ischaemic complications after treatment, despite the ligation of one ruptured brachial artery.

4. The average stay in hospital was four days, compared with twenty days for thirty-two other patients treated in traction because of gross oedema.

5. Of eighty patients seen six months to five years after the fracture, seventy (or 87·5 per cent) had excellent or good results, seven patients with marked varus deformities had fair results, and two patients had poor results with very stiff elbows.

Displaced flexion fractures 1. The clinical features, complications and treatment of seventeen cases are described.

2. There were no complications involving the median or radial nerves or the brachial artery, but three patients had a lesion of the ulnar nerve.

3. Nine children had closed reduction and fixation by two lateral percutaneous pins.

4. Reduction was difficult and the results poor compared with extension fractures. Closed reduction failed in one-third of the children, and the functional and cosmetic results were unsatisfactory in over half the patients reviewed.

1. Forty patients with solitary eosinophilic granuloma of bone from the Hospital for Sick Children, Toronto, have been reviewed. They had clinical and laboratory findings similar to those reported by others except for the erythrocyte sedimentation rate, which was raised in nearly half the patients tested.

2. Radiographs in all cases showed the lesion to be osteolytic. In the skull and cervical spine there was no bony reaction ; in the thoracic and lumbar spine the typical picture of Calvés disease was produced; in long bones the cortex commonly showed endosteal erosion and periosteal reaction.

3. In one patient the lesion progressed so rapidly that the body of a cervical vertebra was destroyed within ten days.

4. The differential diagnosis includes sarcoma. Biopsy is essential.

5. All the patients improved regardless of the treatment they received. Complications were due either to the site of the lesion or to its treatment.

6. Expansion of the lesion after biopsy indicates a more widespread manifestation of histiocytosis X.