So the main cause of a subdural hemorrhage is a rupture of the bridging veins located in the subdural space.

硬膜下出血的主要原因就是硬膜下隙中的桥静脉破裂。

Regardless of the mechanism, once a bridging vein is torn, the blood pools in the subdural space and creates a hematoma.

无论何种机制，一旦桥静脉破裂，血液就会积聚在硬膜下隙形成血肿。

After the brain tissue has taken up the oxygen and nutrients, the blood drains into superficial cerebral veins, or bridging veins, that also sit in the subarachnoid space.

在大脑吸收了血液中的氧气和营养后，血液回流至大脑浅静脉，也称为桥静脉；它们也在蛛网膜下隙中。

And that means that the bridging veins are stretched across a wider space, where they are largely unsupported, kind of like a rickety bridge across a mountain pass.

这意味着桥静脉所在的空间将被拉宽，血管所受支撑会减弱，就像两座大山间摇晃的吊桥一样。

An acute-on-chronic bleeding is a combination of hyperdense and hypodense, which is seen in individuals who have a rebleed in the bridging veins after a chronic hematoma has already formed.

慢性区域的急性出血则是两者混合：这可能在慢性血肿已经形成，而桥动脉再次出血的患者中见到。

Right after that, the head moves backwards and hits the headrest, causing the brain to impact the back of a skull that rapid back-and-forth movement once again causes damage to the bridging veins.

在那之后，头部又会向后运动撞到头垫，这使大脑又由于惯性撞到颅骨后侧，如此快速的来回运动会损伤桥静脉。

Since the damaged bridging veins are under low pressure, the bleeding can be slow, which causes delayed onset of symptoms, which might develop over the course of days to weeks, as the hematoma gradually expands.

由于损伤的桥静脉通常压力很低，出血会比较缓慢，这会让症状出现延迟：随着血肿缓慢增大，症状在数日至数周内缓慢发展。

Subdural hematomas are common in head traumas like falling in a wet bathtub and whacking your head, or in Shaken Baby Syndrome, where a baby is violently shaken, making their head whip back and forth, which damages the bridging veins.

硬膜下血肿在头部外伤中很常见，比如在浴缸中摔倒撞到头，或是婴儿摇晃综合征：即当婴儿受到强力摇晃时，其大脑来回的摇晃，损伤了桥静脉。