1. The clinical features, diagnosis and treatment of osteomalacia are discussed in relation to thirty-seven recently recognised cases. It is suggested that this disease is not uncommon in elderly women, among whom it is liable to be confused with senile osteoporosis. Osteomalacia may be distinguished by, firstly, the history, in which persistent skeletal pain of long duration and muscular weakness are typical of osteomalacia, but not of osteoporosis in which transient episodes of pain usually associated with a fracture are more characteristic. There is a high incidence of previous gastric surgery in the osteomalacia patients. Secondly, the physical examination shows skeletal tenderness in osteomalacia but this is not a particular feature of osteoporosis. A shuffling "penguin gait" suggests osteomalacia. Thirdly, the biochemistry shows a low plasma calcium and phosphate, and raised alkaline phosphatase levels commonly in osteomalacia but these are usually normal in osteoporosis. Reduced twenty-four-hour urinary calcium is characteristic of osteomalacia but not of osteoporosis. Fourthly, radiology will show diminished bone density which is common to both diseases, but if the changes are more marked in the peripheral bones than in the axial skeleton osteomalacia is suggested; the opposite is typical of osteoporosis. Skeletal deformity without fracture suggests osteomalacia, as do stress fractures and greenstick fractures in the elderly. Looser's zones are diagnostic of osteomalacia in which they are the most important radiological feature. Finally, histology will show the presence of excess osteoid tissue in undecalcified sections of bone in osteomalacia. This may be the earliest and most sensitive index of the disease and biopsy is indicated in all doubtful cases.

2. The etiology is discussed and it is suggested that a dietary deficiency of vitamin D, limited exposure to sunlight and mild degrees of malabsorption may all be important either alone or in combination. No satisfactory explanation is offered for the predominant female incidence.

3. A practical method of treatment is given and the dangers of uncontrolled administration of vitamin D indicated.

4. Treatment of osteomalacia is rapidly and consistently successful, and well justifies a thorough screening of all elderly patients presenting with weakness, skeletal pain, pathological fractures or with diminished radiographic density of bone.

1. The rate of non-union of 100 intertrochanteric osteotomies of the McMurray type, with internal fixation, is reported. One in five was not united one year after operation. The criteria of union are discussed.

2. The patient's disability in twelve ununited osteotomies has been assessed, and related to the mobility of the osteotomy.

3. The factors which prejudice union have been analysed. The principal cause of non-union appeared to be the varus angulation strain on a varus osteotomy displaced medially more than half the diameter of the bone. Obliquity inwards and upwards of the osteotomy was a contributory factor. The types of internal fixation used, the use of external splintage and the period of protected weight bearing with crutches did not appear to be related to the rate of union.

4. It is concluded that marked inward displacement of the osteotomy, combined with either obliquity of the osteotomy or a varus position, prejudices union; that the use of this technique is unfounded in principle and not supported empirically; and that displacement should be eschewed to avoid this complication of intertrochanteric osteotomy in the treatment of osteoarthritis of the hip.

We conclude that conservative excision of the nail bed gives satisfactory results–89 per cent in this series. Recurrence is common but rarely causes symptoms. No patient had symptoms without recurrence. We think that recurrence is related to technique and to infection. Syme's terminal amputation is recommended for troublesome recurrence because repetition of Zadik's operation proved unsatisfactory.

1. Ten patients with neurological evidence of damage to the intrathecal sacral nerve roots of the cauda equina by verified lumbar disc prolapse are described.

2. The nature of the bladder paralysis has been investigated by cystometry and the findings contrasted with published opinions.

3. The prognosis of the bladder paralysis has been established by review up to six years after removal of the disc prolapse. No evidence of recovery of complete bladder paralysis has been found, but the consequences of persistent bladder paralysis have been much less severe than previous reports have stated. Reasons have been suggested for this.

4. Principles of recognition and management of bladder paralysis due to cauda equina lesions have been stated and methods suggested.

1. The theories that have been advanced to explain the occurrence of traumatic tetraplegia in patients without evidence of vertebral column injury are reviewed.

2. Traumatic tetraplegia of delayed onset is described in a middle-aged man with ankylosing spondylitis. There was no injury of the vertebral column.

3. The reasons are given for suggesting that the tetraplegia was caused by injury to the arterial supply of the cord.