Assessment of cervical venous blood flow and the craniocervical venus valve using ultrasound sonography

Abstract Severe congestion with petechiae and/or small hemorrhages over a wide area consisting of the subcutaneous and mucous level of the head and neck is observed in most cases of strangulation and positional asphyxial death. Congestion present above the strangulation mark is accepted as a vital reaction. Although the congestion results from a disturbance of cervical venous flow, only a few reports concerning a relationship between venous flow and posture were found in the literature. We assessed the physiological situation of cervical venous return and movement of the craniocervical venous valve for many types of valve with respect to posture using color-duplex ultrasound sonography (US). We measured the Doppler wave of cervical veins consisting of internal jugular vein (IJV), external jugular vein (EJV) and vertebral vein (VV) and the motion of IJV valves in three positions on a seat which could be manually moved through +90° to −90. The diameter of IJVs and EJVs were thicker in a head-down position, moderate in a supine position and flat in a sitting position. The diameter of VVs was thick in a sitting position, moderate in supine position and unclear in an upside-down position because of difficulty in scanning owing to very slow velocity and deep lying position. The velocities were high in a sitting position, but very slow and intermittent in an upside-down position. The EJV which is markedly congested in some cardiac tamponade cases and drains mainly the facial superficial region is very important in legal medicine but has not often observed in previous reports. We confirmed that cervical venous return (IJV, EJV, VV) changes its route according to the posture. The motion of IJV valves was very complicated and varied in three positions, even after the Doppler wave and the motion of valve became stable. Asphyxia and strangulation should be studied taking the complex venous structure into consideration. We could not find any consistent explanation for venous valve motion and further studies on the valves are necessary to understand the venous reflux in some diseases in legal medicine.