A system comprising: (a) a pair of devices (103), wherein each device has an appropriate size and shape to restrict blood flow egressing from the head of a subject when the devices are placed against the neck of the subject； and (b) a shirt (137) comprising an integral collar (138), wherein the collar (i) comprises an elastic material, (ii) comprises the devices, and (iii) in combination with the devices, is adapted to apply a compressive pressure of about 5 mm Hg to about 70 mm Hg to a pair of neck veins when the collar is fitted to the neck of the subject. rain injury and injuries to the spinal column.
