Dropped head syndrome (DHS) is characterized by severe neck extensor weakness, resulting in chin-on-chest deformity in the standing or sitting position, which is correctable by passive neck extension.

Classically, DHS can be found in various neurological, neuromuscular, or orthopedic disorders [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], as detailed in Table 1.

In 2019, a literature review [8] highlighted the most frequent etiologies: more than two thirds of DHS appear to be related to four main diagnoses: isolated weakness of the neck extensor muscles (31.8%), Parkinson's disease (20.2%), autoimmune myasthenia (12.4%), and amyotrophic lateral sclerosis (7%). One third of the remaining cases is related to various pathologies, often reported as “cases reports”, including polymyositis [6], focal myositis [13], nemaline myopathy [14], Lambert-Eaton syndrome [5], Chronic inflammatory demyelinating polyneuropathy (CIDP) [15], hypothyroidism [11], cervical post-radial disease [9], or cervical myelopathy [3].

Currently, patient management relies primarily on the treatment of etiology. In addition, symptom is treated through medical management including rehabilitation to strengthen neck extensor muscles, postural and proprioceptive work (more or less associated with ortho-prosthetic equipment) [16]. Surgical management is only considered in case of a failure of medical treatments: techniques and results differ according to series (approach, release of anterior muscle planes, extent of arthrodesis) [17], [18], [19].