The content of the transverse foramen of the seventh cervical vertebra.

In human anatomy, the vertebral artery, in its passage from the subclavian artery to the foramen magnum of the skull, enters the transverse foramina of the vertebral column generally at the level of the 6th cervical vertebra. Nevertheless, even though avoided by the vertebral artery, also the 7th cervical vertebra (C7) contains a transverse foramen. The content of this transverse foramen in C7 has been unclear, with different descriptions found in textbooks and in original literature. Here, we have revisited the content of the transverse foramen in C7 by macroscopic dissection of 32 human specimens. We found that the 7th transverse foramen never contained the vertebral artery. Instead, it enclosed in 35 % of the cases both vertebral vein and vertebral nerve, in 20 % of the cases only the vertebral nerve, in 11 % of the cases only the vertebral vein, and in 34 % of the cases it contained no macroscopically visible neurovascular structure at all but only adipose connective tissue.