AMC is the clinical description of a congenital syndrome with an estimated incidence of 1:3,000-10,000 [25,30,38]. Already within the uterus, the movement frequency of the foetus is reduced due to multiple – mostly symmetrical – joint contractures. Primarily, the great joints of extremities, the spine  but also the otolaryngologic region [10,11] are affected - with varying severity. Furthermore, a reduced muscle mass and a merely developed subcutaneous tissue are notable. During growth, numerous deformities are generated. Other organ systems can be involved (CNS, cardiovascular system, lungs, gastrointestinal tract, urogenital tract, abdominal wall). In most cases, patients develop normal intelligence.
Details of the cause of this nonprogressive disease are not clear. The reduced frequency of foetal movements seems to be significant – for different reasons . Among others, external factors (e.g. oligohydramnion, uterine septi), primarily metabolic changes in muscle cells (“myopathic form”) or a disturbance of the anterior cornual cells of the spinal cord (“neuropathic form”) are discussed as possible triggers. Thus it is not surprising that numerous syndromes can be associated with AMC (e.g. Freeman-Sheldon syndrome [1,2], Brown syndrome , Bruck syndrome , ARC syndrome [5,46]). Even maternal diseases (Myasthenia gravis [7,44]) or drug consumption during pregnancy [6,31] as well as maternal/fetal infections as caused by de zika virus  can lead to AMC of the unborn.
The clinical classification can be performed according to three degrees of severity (“Munich classification”) :
Type 1: Primary affection of the extremities, possibly neck and trunk muscles; e.g.:
- Primary affection of hands and feet; part of this is the contractural arachnodactylia (so called distal arthrogryposes; autosomal dominant)
- Affection of all extremities – including shoulder and hip joint (60-80%) with symmetrical internal rotation of the shoulders, fixed extended elbows, flexion and extension contractures of the knee joints, as well as lower legs of cylindrical shape, talipes equinovarus (approx. 85%) (so called amyoplasia; in most cases sporadical).
Type 2: Primarily midline malformations; affections of extremities (vide type 1) as well as malformations of different organs (e.g. diaphragmatic hernia, pronounced scoliosis), pterygium. A differentiation of further subgroups in distal arthrogryposis is carried out.
Type 3: Further dysmorphic disorders and malformations; disorders of the CNS.
These are multifaceted syndromes of which AMC is just one aspect; the syndrome severity is originated by the additional malformation.
Frequently, patients with AMC have to undergo recurrent surgical interventions. In this context, several anaesthesiologic particularities have to be observed.