Tay chân, bao gồm cả bàn tay và bàn chân vắng mặt và vắng mặt biến dạng của một bàn tay, chân tay hoặc chân có thể kết quả như là một phần của hội chứng hoặc có thể là một bất thường bị cô lập đã xảy ra như là kết quả của một sự gián đoạn trong chuỗi phát triển hay một sự kiện thiếu máu cục bộ. | 122 EXAMINATION OF THE NEWBORN Limbs including hands and feet Absence and deformity Absence of a limb hand or foot can result as part of a syndrome or may be an isolated abnormality that has occurred as a result of either a disruption in the sequence of development or an ischaemic event. Deformity can result from those same causes or as a result of intrauterine position. Deformity resulting from congenital absence of the fibula or radius can be associated with other abnormalities . low platelet count thrombocytopenia . It can also result from congenital contractures arthrogryposis . It should be noted that for all cases of limb deformities other than those that are postural early referral to an orthopaedic surgeon is essential. Hands Non-pitting oedema lymphoedema of the hands and feet is associated with both Turner s and Noonan s syndromes see p. 158 . The baby should be examined carefully for other features associated with the syndromes and blood should be collected for chromosome analysis. The lymphoedema should settle with time. Palmar creases Single palmar creases are associated with Down s syndrome see p. 157 but beware because 10 of the normal population have a unilateral single palmar crease and 5 have bilateral single palmar creases. Feet The feet may be abnormally positioned. Talipes equinovarus describes feet which are plantarflexed turned downwards and inwards whereas talipes calcaneovalgus describes feet which are dorsiflexed turned upwards and outwards . ABNORMAL FINDINGS AND CONGENITAL ABNORMALITIES 123 Digits Polydactyly Extra digits can occur spontaneously as a familial trait or as part of a syndrome. Enquire whether polydactyly is a familial trait if not examine the baby carefully for other abnormal features. Bilateral polydactyly is often associated with renal anomalies so arrange a renal ultrasound scan to exclude these. A radiograph of the hand will reveal whether the extra digit has a bony component. If the extra digit has a bony component
