Atlas of Acupuncture

3 Anatomical Orientation

Lumbosacral junction

Following orientation in the lumbar region with the help of the

iliac crests (
Iliac crest), the lumbosacral joint can be located

by counting the spinous processes in an inferior direction. It can

generally be felt as a marked ‘kink’ or depression, followed by

the smaller spinous processes of the slightly convex median

sacral crest directly below.

Caution:Note that (according to the literature in up to 15% of

cases) there can be lumbarization of the 1st sacral vertebra or

sacralization of L5. In these cases there will be either four or six

lumbar vertebrae.

Posterior superior iliac spine (PSIS)

(
Figs 3.73, 3.74)

Another important landmark on the lower back is the posterior

superior iliac spine (PSIS), which forms the posterior end of the

iliac crest lateral to the upper sacral region. The PSIS can often

be identified by two superficially visible dimples. It is best

located by palpating from an inferior in a superior direction. If

the dimples are not visible, they can be located by palpating

3 cun from the rima ani in a superior and lateral direction at an

angle of 45°, until a marked bony ridge can be felt.

Generally, the PSIS is located at the level of the space between

the 1st and 2nd sacral foramina, so that 
BL-27is located

directly medial or slightly superior and medial to the PSIS,

while 
BL-28is located just inferior and medial to the PSIS.

BL-27

BL-28

Fingers on the PSIS

Lumbosacral

junction

Sacrum

PSIS

Tuffier’s line Iliac crest

L4

T5

Fig. 3.73

Fig. 3.74