II: Biomechanics Of The Pelvis (PART 2/2 - evaluation) Flashcards
Landmarks to observe in posture

- iliac crests
- PSISs
- greater trochanters
- gluteal folds
- pelvic tilt
What boney landmarks are you palpating for in prone?
- Iliac crests
- PSIS
- sacral base, borders and apex
- coccyx

Dr.’s thumbs on PSIS & sacral tubercle and Pt. flexes ipsilateral hip . This is a Gillet’s test for assessing:

- upper joint flexion
- Dr’s thumbs should approximate as ilium flexes on the sacrum and the PSIS move posteriorly and inferiorly
Dr.’s thumbs on PSIS & sacral tubercle Pt. flexes contralateral hip. This is a Gillet’s test for assessing:

- upper joint extension
- Dr’s thumbs should separate as sacrum counternutates relative to the ilium and the sacral tubercle moves inferiorly
Dr.’s thumbs on sacral tubercle or side of sacral apex & area of PIIS. Pt. flexes ipsilateral hip. This is a Gillet’s test for assessing

- lower joint flexion
- Dr’s thumbs should separate as the ilium flexes on the sacrum and the PIIS moves inferiorly and anteriorly
Dr.’s thumbs on sacral tubercle or side of sacral apex & area of PIIS. Pt. flexes contralateral hip. This is a Gillet’s test for assessing

- lower joint extension
- sacral contact thumb should move inferiorly relative to PIIS contact as sacrum counternutates relative to ilium
Motion palpation for standing is called
Gillets test
What are the major mechanical functions of the pelvis?
attach spine to and transfer weight to lower extremity
shock absorption
gyroscopic action during gait
important in birth process in females
The pelvis consists of what 3 joint complexes?
2 SI joints
1 pubic symphysis
What joint classification is the pubic symphysis?
fibrocartilaginous amphiarthrosis
The articular surface of the SI joint is primarily in what plane?
sagittal (about 10 degrees to sagittal)
Describe the articular surface of the SI joint?
auricular shaped
cephalad portion = “upper joint”
caudad portion = “lower joint”
Describe the iliac surface of the SI joint?
central convex ridge covered in fibro cartilage
What is the large, rough, bony surface posterior to the SI joint that serves for ligamentous attachment?
iliac tuberosity
Describe the sacral surface of the SI joint?
central concavity that is covered in hyaline cartilage that is 3 times thicker than firbocartilage of iliac surface
What are the intrinsic ligaments that bind the sacrum to the ilium?
anterior superior ligaments
anterior inferior ligaments
posterior sacroiliac ligaments
interosseous SI ligaments
What are the extrinsic ligaments that bind the sacrum to the iliac?
sacrotuberous
sacrospinous
iliolumbar
What muscles are related to pelvic biomechanics?
multifidis, erector spinae via SI ligament
hamstrings, gluteus max and piriformis vis scarotuberous l.
psoas via anterior joint capsule
quadratus lumborum vis iliolumbar l.
Describe the innervation of the SI joint?
exact innervation is debated but has both pain and proproceptive innervation
What are the most functionally important anatomy features of the SI joint?
it is synovial diarthrodial
auricular shaped joint surface
corresponding groove/ridge on joint surface
locking sacral wedge shape, interlocking sacral S configuration
strong posterior SI ligaments resist distraction and translation
muscles that insert into joint capsule and pelvis add stability
Describe SI joint development at birth?
joints are undeveloped, smooth, flat and glide in any direction
start to develop with walking
Describe SI joint development during teens?
roughening of surfaces, development of grooves and ridges
this occurs more pronounced in males than females
Describe SI joint development in the 3rd and 4th generation of development?
joint surfaces become irregular
enlargement of iliac tuberosity
joint surfaces begin eroding
possible osteoarthritis on iliac surface
Describe SI joint development in the 5th and 6th generation?
joint surface continues to become more irregular
possible osteoarthritis developing on sacral surface
osteoarthritis continuing on iliac surface
development of joint adhesions, osteophytes and fusion

















