The length from the part of venae jugularis externa up 2.0 cm above collarbone to the middle part of venae cava superior is 13 .8+ 2.9cm on the left side and 11.5+ 1.8cm on the right side.

• 颈外静脉距锁骨上方2.；0cm处至上腔静脉中段之间长度；左侧13