ABSTRACT
Examination of the recipient artery and any blood coagulation material within the artery
has often been used to separate in situ thrombosis from embolism. Figure 1 shows an artery
distended with an embolus, and Figure 2 shows the embolic clot that was removed from
the artery. Kubik and Adams (1), in their classic report on basilar artery thrombosis
published in 1946, paid particular attention to distinguishing embolism and thrombosis
at necropsy. “Thrombosis of the basilar artery could usually be recognized at a glance.
The thrombosed portion of the vessel was distended, firm, and rigid and the thrombus
could not be displaced by pressure. . . . In embolism, the embolus was usually lodged in the distal portion of the artery.” In all cases attributed to in situ thrombosis, there was
extensive underlying atherostenosis of the basilar artery with severe luminal narrowing
by plaque. In some patients, microscopic analysis of thrombi revealed that different por-
tions of the clots must have formed at different times. Embolic plugs occasionally lodged
in regions of the artery that were narrowed by atheromatous plaques. The presence of
plaques alone did not separate thrombosis from embolism. Focal regions of layered
thrombi could be superimposed on firm nonadherent emboli (1).
