Classic history and presentation: Common signs and symptoms include nuchal rigidity, neck and shoulder muscle hypoplasia, muscle atrophy, and limited ROM of the shoulders. It is often diagnosed as a component of other congenital disorders, such as Klippel-Feil syndrome.
Prevalence:
- Age – Severe cases are diagnosed at birth, but diagnosis is often delayed in mild or moderate cases lacking other abnormalities. Later presentations typically occur in the pediatric age group, often during scoliosis screening.
- Sex / gender – 3:1 female-to-male ratio
Grade / classification system: Cavendish classification is most often used.
- Grade 1 (very mild)
- Shoulders level
- Deformity not visible when dressed
- Grade 2 (mild)
- Shoulders slightly uneven
- Minor deformity visible when dressed: lump in web of neck
- Grade 3 (moderate)
- Shoulder elevated by 2-5 cm
- Obvious deformity when dressed
- Grade 4 (severe)
- Shoulder is elevated > 5 cm
- Superior angle of scapula lies close to occiput