1. Functional Anatomy Of The Pelvis Flashcards
SI pain is often described by the patient as _____
Low back pain
What kind of joint is the SI?
Diarthrosis
Synovial
What kind of joint is the pubic symphysis?
Fibrocartilaginous
Amphiarthrosis
The SI joint is boot shaped. The upper half (leg) of the blood articulates at the level of ______
S1
The SI joint is boot shaped. The lower half (foot) of the blood articulates at the level of ______
S2-S3
The sacral surface of the SI joint (S1-S3) is covered in _____
Hyaline cartilage
The cartilage covering which SI joint surface is 3 times thicker.
Sacral surface is three times thicker than iliac surface
The iliac surface of the SI joint is covered in _____ cartilage
Fibro
The sacral surface of the SI joint is what shape?
Has a central groove/concavity
The iliac surface of the SI joint is what shape?
Has central ridge or convexity
The sacral surface of the SI joint is ____ shape superior to inferior and ____ shape anterior to posterior
wedge, S
What is the large rough bony surface for ligamentous attachment for the SI joint and where is it located?
Iliac tuberosity, located superior and posterior to iliac surface of SI joint
Describe SI joints at birth
joints undeveloped, smooth and flat, glide in any direction; stability provided by ligaments
Start to develop with walking
Do male or female teens have more pronounced roughening of surfaces and development of grooves and ridges in the SI joint?
Male
What does joint surface erosion and possible osteoarthritis begin in the SI joint?
In the 3rd and 4th decades of life
The osteoarthritis that begins to occur in the 3rd and 4th decade of life occurs on which surface of the SI joint and why?
Iliac surface, because the cartilage is a third the thickness of the sacral surface
When does osteoarthritis develop on the sacral surface of the SI joint?
5th and 6th decade
Other than osteoarthritis, what other dysfunction of the SI joint can develop in the 5th and 6th decades of life?
Joint adhesion
Osteocytes
Fusion
There is a high prevalence of bony ankylosis in the 7th decade and beyond. What is the prevalence in males vs. females?
Male 27.7%
Females 2.3%
There is a high prevalence of bony ankylosis in the 7th decade and beyond in men and it appears to be age dependent. What percentage of males 20-39 years of age have it?
5.8%
There is a high prevalence of bony ankylosis in the 7th decade and beyond in men and it appears to be age dependent. What percentage of males 60-79 years of age have it?
31.1
There is a high prevalence of bony ankylosis in the 7th decade and beyond in men and it appears to be age dependent. What percentage of males 80+ years of age have it?
46.7%
Fusion of the SI joint mainly occurs in the _____ part.
Superior
What is the function of intrinsic SI ligaments?
bind sacrum to the ilium, limit movement and provide significant
support.
What are the intrinsic ligaments of the SI joint?
Posterior SI ligament (includes interosseous and dorsal ligaments)
Anterior SI ligament
Joint capsule
Which of the posterior sacroiliac ligaments is the major posterior stabilizer?
Interosseous
The dorsal ligaments are smaller and not as critical
The dorsal ligaments of the SI joint limit _____ movement of the sacral base?
Anterior/nutation
The dorsal ligament of the SI joint span from where to where?
The sacrum to the PSIS and iliac tuberosity
The anterior SI ligament is a thickening of the ____
Anterior joint capsule
The joint capsule is more developed ______
Anteriorly
What are the extrinsic ligaments of the SI joint?
Sacrotuberous
Sacrospinous
Where does the sacrotuberous ligament span?
From the sacrum to the ischial tuberosity
What is the function of the extrinsic ligaments of the SI joint?
The sacrospinous and sacrotuberous ligaments limit posterior movement of the sacral apex (nutation)
Where does the sacro spinous ligament span?
From the inferior lateral edge of the scrum and the upper edge of the coccyx to the ischial spine
What kind of cartilage is the interpubic disc of the pubic symphysis?
Fibrocartilaginous
What muscles act on the SI joint?
None directly cross the joint and therefore none act on it directly, but many influence the mechanical behavior of the joint or respond to stresses applied to it including
- erector spinae
- QL
- iliopsoas
- piriformis
- gluteals
muscles can react to SI stress causing ____ and ____.
spasms, trigger points
abnormal muscle tension may limit overall SI movement leading to _____
joint dysfunction
What is the innervation of the SI joint?
Exact innervation is debated, but neural elements have been identified in the joint capsule and adjoining ligaments suggesting innervation for both pain and
proprioception
