_Diagnosis._--When teno-synovitis occurs independently of disease of the ankle, the swelling is confined to one aspect of the joint. In sarcoma of the lower end of the tibia, the swelling lacks the uniform distribution of that met with in joint disease. In Brodie's abscess of the lower end of the tibia there may be swelling of the ankle, but there is an area of special tenderness on percussion over the bone. _Treatment._--The foot is immobilised at a right angle to the leg by splints or plaster of Paris; if articular symptoms are absent or have subsided, a Thomas' knee splint should be applied to enable the patient to move about without bearing his weight on the affected foot (Fig. 125). To inject iodoform, the point of the needle is inserted below either malleolus, and is then pushed upwards alongside of the talus. If localised disease in one of the bones is recognised before the joint is infected, it should be eradicated by operation. When the disease is diffuse and resists conservative treatment, excision should be performed, the articular surfaces of the constituent bones being removed, and if necessary the whole of the talus. Amputation is only called for in adults with rapidly progressing disease and diffuse suppuration, and in cases which have relapsed after excision. The other diseases of the ankle include _pyogenic_, _gonorrhœal_, _rheumatic_, _gouty_, and _hysterical_ affections, _arthritis deformans_, and _Charcot's disease_. The last-named is generally associated with a rapid and painless disintegration of the bones of the ankle and tarsus, resulting in great deformity and loss of the arch of the foot--sometimes associated with perforating ulcer of the sole. Tuberculous disease in the #tarsus#, #metatarsus#, and #phalanges# has been considered in the chapter on Diseases of Bone. CHAPTER X DEFORMITIES OF THE EXTREMITIES The origin of deformities: (1) Those arising before birth; (2) those produced during birth; and (3) those acquired after birth. Palsies of children: _Anterior Poliomyelitis_. Cerebral palsies: _Spastic paralysis_. THE LOWER EXTREMITY: Congenital dislocation of hip--Snapping hip--Paralytic deformities--Contracture and ankylosis of hip--Coxa vara and coxa valga--Congenital dislocation of knee and patella--Genu recurvatum--Paralytic deformities--Contracture and ankylosis of knee--Genu valgum and genu varum--Congenital deformities of leg--Bow-leg--Club-foot: _Talipes equino-varus_; _Pes equinus_; _Pes calcaneus_; _Pes calcaneo-valgus and varus_; _Pes cavus_; Flat-foot and pes valgus--Painful affections of heel--Metatarsalgia--Hallux valgus and bunion--Hallux varus--Hallux rigidus and flexus--Hammer-toe--Hypertrophy of toes--Supernumerary toes--Webbed toes.