Orthotic Correction of Sitting Abnormality in Achondroplastic Children

Abstract

The spine of the achondroplastic child is poorly structured for weight-bearing (1, 2):

• 1. because the pedicles of the vertebrae are shortened, the distance between the two facet joints and between the facet joints and the vertebral body are less than normal. An abnormally narrowed and shortened weight-bearing structure results;

• 2. the ligamentous support of the spine is also affected adversely, for laxity of ligaments is among the characteristics of achondroplasia;

• 3. shortened ribs compound the problems of maintaining an erect trunk by reducing the bracing against flexion of the thoracic spine which longer ribs normally provide.