Pelvis and pelvic joints Flashcards
What are the pelvic bones
Ilium Pubis Ischium Triradiate cartilage Sacru Coccyx
Name the pelvic joints
Sacroiliac joint (b/w ilium and sacrum) Sacrococcygeal symphysis (b/w sacrum and coccyx) Pubic symphysis (between pubic bodies or 2 hip bones) Lumbosacral joint (b/w Lx and sacrum--> it is not an articulation within the pelvis) Hip joint (b/w acetabulum and head of femus--> not part of pelvis)
How many articulations are there within the pelvis
4 articulations:
2 sacroiliac
Sacrococcygeal symphysis
Pubis symphysis
What is a symphysis
a fibrocartilaginous fusion; hence not a joint
What is the function of the pelvis
Transfer weight from upper axial body to lower appendicular body (especially during movements)
Provides an attachment for the muscles and ligaments used in locomotion
Contains and protects the abdominopelvic viscera
What is the greater pelvis
Known as the ‘falsa pelvis’
Located superiorly
Provides support of the lower abdominal viscera (such as ileum and sigmoid colon)
Has little obstetric relevance
What in the lesser pelvis
Also known as the ‘true pelvis’
Located inferiorly
Within the lesser pelvis lies the pelvic cavity anf pelvic viscera
What is the pelvic brim
the outer edges of the pelvic inlet
What is the pelvic inlet
the junction between the greater and lesser pelvis
What are the borders of the pelvic inlet
Posterior–> superior portion of sacrum and sacral wings (ala)
Lateral–> arcuate line of the inner surface of ilium and the pectineal line on superior pubic ramus
Anterior–> pubic symphysis
What are the borders of the pelvic outlet
Anteriorly–> pubic symphysis
Posteriorly–> coccyx
anterolaterally–> ischiopubic ramus
Posterolaterally–> sacrotuberous ligament
Where is the birth canal
between the pelvic inlet and outlet
What is the anatomical or true conjugate
From middle of sacral prominence to posterior superior edge of pubic symphysis
Should be 11cm or more
What is the obstetric conjugate
The shortest of the 3 diameters
Determined from the sacral promontory to the thickest part pf pubic bone
Narrowest fixed distance
should be 10cm or more
What is the diagonal conjugate
From sacral promontory to posterior inferior edge of pubic symphysis
Should be 11.5cm or more
When is the inlet assumed contracted
When any one of the pelvic diameters are less than normal
Where is the iliolumbar ligament
From tip of L5 to posterior aspect of inner lip of iliac crest
What is the function of iliolumbar ligament
Strengthens the lumbosacral joint
Where is the sacrotuberous ligament
From sacrum to tuberosity of the ischium
Posterior surface of sacrum and coccyx and PSIS & PIIS to ischial tuberosity
Where is the sacrospinous ligament
From ischial spine to lateral margins of sacrum, lower sacrum and coccyx to ischial spine
What is the function of the sacrotuberous and sacrospinous ligament
Stabilise SIJ
Sacrotuberous and sacrospinous prevent anterior rotation of sacrum within pelvis
Limit rotation of pelvis and adds attachments for glute max
Rotation of the superior sacrum is counterbalanced by the strong sacrotuberous and sacrospinous ligaments that anchor the inferior end of the sacrum to the ischium, preventing its superior and posterior rotation
Where is the sacrococcygeal ligament
Anterior–> from anterior surface of sacrum to front of coccyx (continuation of the anterior longitudinal ligament)
Lateral portion–> inferior lateral angle of sacrum to transverse process of 1st coccygeal vertebrae
Also has dorsal portions
What and where are the ligaments around the pubic symphysis
Superior pubic ligament-> runs between pubic tubercles
Inferior (arcuate) pubic ligament–> between inferior pubic rami and blends with fibrocartilaginous disc of pubic symphysis
Anterior pubic ligament–> across front of symphysis
Posterior pubic ligament–> membranous structure whihc blends with periosteum
What is the difference between male and female pelvis in terms of primary function
Female pelvis: locomotion and childbirth (adaption by mainly lesser pelvis)
Male pelvis: locomotion
