According to the concept of sagittal spinal balance, the alternating curves of cervical and lumbar lordosis and thoracic and sacral kyphosis enable the head to be positioned over the trunk and pelvis.
Veins of the madial-caudal cervical segment of the esophagus and trachea were drained into the esophatracheal vein trunk.
回流食管和气管颈段中后部血液的静脉汇入食管气管静脉干；
3
The postganglionic neurons were mainly located in the stellate ganglion (61.99%), anterior and middle cervical ganglia, and T_2-T_5 ganglia of the sympathetic trunk, bilaterally.