Chapter 6 Sacrum and Innominate Anatomy Flashcards
When do the 3 bones of the innominate fuse?
20 years old
Anterior portion of 1st segment (S1)?
Sacral promontory
Sacral base?
Top (most cephalad) part
In somatic dysfunctions, what can be recorded as shallow (posterior) or deep (anterior)?
Sacral base or sacral sulci
How can you record the sacral ILA’s?
Shallow (posterior), deep (anterior), superior or inferior
The SI joint is an inverted “L” joint with 2 arms converging anteriorly. Where do these arms join?
S2
2 types of pelvic ligaments/
True and accessory
True pelvic ligaments?
Anterior, posterior and interosseous SI ligaments
Accessory pelvic ligaments?
Sacrotuberous, sacrospinous, iliolumbar ligaments
What ligament divides the greater and lesser sciatic foramen?
Sacrospinous ligament
Which ligament is the 1st to become painful in lumbosacral decompensation?
Iliolumbar ligament
Types of pelvic muscles?
Primary and secondary
Primary pelvic muscles?
Make up pelvic diaphragm–levator ani, coccygeus
Secondary pelvic muscles?
Iliopsoas, obturator internus, piriformis
Origin/insertion of piriformis?
ILA, greater trochanter
Action of piriformis?
Ext rot, extend thigh, abducts thigh with hip flexed
Innervation of piriformis?
S1 and S2 nerve roots
What are S/S of sciatica due to hypertonic piriformis?
Pain from buttock radiating down thigh but not past knee
Axis upon innominates rotate?
Inferior transverse axis (S4)
4 types of sacral motion?
1) Dynamic motion
2) Respiratory motion
3) Inherent (craniosacral) motion
4) Postural motion
Location of transverse axis for resp and inherent motion of sacrum?
S2 (superior transverse axis)
Craniosacral flexion induces what sacral motion?
Counternutates (rotates posterior)
Craniosacral extension induces what sacral motion?
Nutation (rotates anterior)
Axis during dynamic sacral motion (walking)?
Oblique axes
