Sprengel's deformity is a defect of ?

In sprengel&;s deformity scapula fails to descend down from its initial high position in the embryo. Here scapula lies superiorly. It is hypoplastic & improperly shaped . It is associated with other congenital anomalies like cervical rib. * Etiology - due to imperfect descend of shoulder girdle by 3rd month or a band of muscle from skull to the scapula ,which has failed to grow. * pathology- scapula may be normal ,broad or high & there could be other features like hemiveebra,wedging of veebra .Among muscles trapezius may be absent , rhomboids & a thin band represents elevator scapulae . * clinical features - scapula high by 2-10 cm ,no functional impairment, shoulder girdle movements normal, toicollis in 10%, crania bifida, spinal bifida may be present. * Cavendish grading Group 1 : very mild Group 2: mild ,shoulder slightly unaligned Group 3:moderate ,shoulder high Group 4:severe , with superior angle of scapula near the occiput * radiograph - to diagnose the condition * treatment - mild deformity no treatment, severe case - surgery after 3 years , consist of release of muscle from scapula / transfer of origin of trapezius muscle. REF:Textbook of ohopedics, John Ebenezer, 4th editions ,pg.no.489