“中间支”是啥意思？

Nociceptive nerve endings are located in both the capsule and synovial membrane of the facet joints [20, 21].Nociceptive signals from the facet joints are transmitted through the medial branch nerves, which also supply the motor innervation of the multifidus muscle as well as interspinous and supraspinous ligaments. Medial branch nerves originate from the posterior ramus which also divides into the lateral and intermediate branches, and in turn, the medial branch divides into two branches that supply the facet joint at the same level and the joint at the level below [21, 22].

伤害性神经末梢位于小关节的关节囊和滑膜内[20-21]。来自小关节的伤害性信号通过内侧支神经传递，内侧支神经也为多裂肌、棘间韧带及棘上韧带提供运动支配。内侧支神经起源于脊神经后支（后支分为外侧支和中间支）。内侧支再分为两支，分别支配相同节段的小关节和下一节段的关节[21-22]。

脊神经后支分为外侧支和内侧支，那“中间支”是啥意思？