"Man-in-a-barrel" is a clinical syndrome of brachial diplegia with preserved muscle strength in the legs.
This most usually occurs as a result of bilateral border zone infarcts in the territories between the anterior and middle cerebral arteries ("watershed infarction"). This may be as a consequence of cerebral hypoperfusion (e.g., during cardiac arrest, cardiac surgery), in which case the prognosis is poor. The clinical picture has also been reported with cerebral metastases. Acute central cervical cord lesions may also produce a "man-in-a-barrel" syndrome, for example after severe hyperextension injury, or after unilateral vertebral artery dissection causing anterior cervical spinal cord infarction. This may follow a transient quadriplegia, and considerable recovery is possible. A neurogenic main-in-a-barrel syndrome has been reported ("flail arm syndrome"), which is a variant of motor neurone disease.
Mohr JP. Distal field infarction. Neurology 1969; 19: 279 (abstract GS7)