Table 3.

The actual and clinical positions of the sural nerves and their relationship with the midpoint of the Achilles tendon.

	Checkpoint 1			Checkpoint 2			Checkpoint 3
	CP	AP	Half of WAT	CP	AP	Half of WAT	CP	AP	Half of WAT
Mean	2.84	0.94	1.73	3.11	2.11	1.46	3.27	2.45	1.23
SD	0.37	0.19	0.19	0.35	0.34	0.159	0.44	0.46	0.17

Checkpoint 1: 10 cm proximal to calcaneal insertion; checkpoint 2: 8 cm proximal to calcaneal insertion; checkpoint 3: 6 cm proximal to calcaneal insertion. Take the midline of Achilles tendon as the “0” point. CP: clinical position: the distance from the sural nerve located by body surface location point to the midpoint of Achilles tendon; AP: actual position: the distance from the sural nerve located by ultrasonography to the midpoint of Achilles tendon; WAT: width of Achilles tendon: the distance from the medial edge to the lateral edge of the Achilles tendon on each plane.