Can back pain caused by symptom-giving sacroiliac joint relaxation ...

The sacrotuberous ligament
The sacrotuberous ligament can be divided
into three parts [58, 24, 35]:
o The superior part extends from the
sacral inferior lateral angle to the PSIS.
This part comprises fibres of the gluteus
maximus muscle and of the deep lamina
of the thoracolumbar fascia.
Fig. 1B: Sacrotuberous ligament [35]
o The medial part extends spirally from
the lateral aspect of the sacrum and the coccyx to the ischial tuberosity.
o The lateral part extends from the posterior superior iliac spine to the ischial
tuberosity and is connected with the piriformis muscle. This part does not
directly span the SIJ but represents an intraosseous bracing of the coxal bone
between ischium and ilium.
Klein and Sommerfeld [24] specify the following main functions of the sacrotuberous
ligament in the pelvis:
o support of the dorsal intrinsic ligaments
o closure of the pelvic floor
o region of insertion for the gluteus maximus muscle, the thoracolumbar fascia
and parts of the tendon of the hamstring muscle
o damper of the sacral nutation (see chapter 1.2.3.) [24, p. 149]
The sacrospinal ligament
The sacrospinal ligament extends from the lateral margin of the sacrum and the
coccyx to the ischial spine. It stabilises the coccyx in the frontal plane, closes the
pelvic floor and serves as a nutation damper like the sacrotuberous ligament. [24, 35,
58]
Master’s Thesis Wolfgang Aspalter 13