Measurement of force to obstruct the cervical arteries and distribution of tension exerted on a ligature in hanging.

We experienced suicidal hanging cases without a ligature in front of the neck. We conducted several anatomical autopsies and the magnetic resonance imaging (MRI), and studied the dynamics behind hanging by applying an apparatus to cadaver and creating a dummy. MRI revealed that the vertebral artery protrudes diagonally upward from the second vertebra to the first one. We also found that this area was not covered with any bony tissue. The average length between the first and second transverse processes was 2 cm. We measured the minimum required force to obstruct the blood stream in both carotid and vertebral arteries exerting 130 mmHg. The required force was 6 kg for the carotid artery and 7 kg for the vertebral artery. Compared to the reported cases, there was not a significant difference in the force to obstruct the carotid artery, however, that of the vertebral artery was lower than the force reported so far. With an experiment of pressure sensitive plastic-sheet, we learned the lateral sides of the neck are compressed more. The results obtained from this study show that the complete and fatal obstruction of the carotid and the vertebral arteries may easily occur when the ligature transects at the lower part of mandible angle.