Lecture 11 - Pelvic Girdle Flashcards
What are the functions of the pelvic girdle?
- Weight bearing
- Transfers weight from axial to lower appendicular skeleton
- Attachment point for muscles
- Contain and protect abdominal contents and reproductive organs
What are the 4 bones of the pelvic girdle?
- ilium
- ischium
- pubis
- sacrum
What is the ilium?
- The superior portion of the hip bone
What is the anterior superior/inferior iliac spine?
- part of the ilium
- Anterior Superior Iliac Spine (ASIS): Rounded, anterior end of the iliac crest
- Anterior Inferior Iliac Spine (AIIS): Small, bony projection located on the anterior margin of the ilium, below the ASIS
What is the posterior superior/inferior iliac spine?
- part of the ilium
- Posterior Superior Iliac Spine (PSIS): Rounded, posterior end of the iliac spine
- Posterior Inferior Iliac Spine (PIIS): Small, bony projection located at the inferior margin of the auricular surface on the posterior ilium
What is the auricular surface of the ilium?
- Roughened area located on the posterior, medial side of the ilium of the hip bone
- Articulates with the auricular surface of the sacrum to form the sacroiliac joint
What are the 6 landmarks of the ilium?
- iliac crest
- anterior superior/inferior iliac spine
- posterior superior/inferior iliac spine
- auricular surface
What is the iliac crest?
- Curved, superior margin of the ilium
What is the ischium?
- Posteroinferior portion of the hip bone
What are the 4 landmarks of the ischium?
- ischial Tuberosity
- ischial ramus
- lesser sciatic notch
- ischial spine
What is the ischial Tuberosity?
- Large, roughened protuberance that forms the posteroinferior portion of the hip bone
- Weight bearing region of the pelvis when sitting
What is the ischial ramus?
- Bony extension projecting anteriorly & superiorly from the ischial Tuberosity
- Joins with the inferior pubic Remus to form the ischiopubic ramus
What is the lesser sciatic notch?
- Shallow indentation along the posterior margin of the ischium, inferior to the ischial spine
What is the ischial spine?
- Pointed, bony projection from the posterior margin of the ischium that separates the greater sciatic notch & lesser sciatic notch
What is the pubis?
- The anterior portion of the hip bone
What are the 7 landmarks of the pubis?
- pubic body
- pubic tubercle
- superior/inferior pubic ramus
- pectineal line
- pubic arch
- ischiopubic ramus
What is the pubic body?
- Enlarged, medial portion of the pubis region of the hip bone
What is the pubic tubercle?
- Small bump located on the superior aspect of the pubic body
What is the superior/inferior pubic ramus?
- Superior Pubic Ramus: Narrow segment of bone that passes laterally from the pubic bone to join the ilium
- Inferior Pubic Ramus: Narrow segment of bone that passes inferiority & laterally from the pubic bone
What is the pectineal line?
- Narrow ridge located on the superior surface of the superior pubic ramus
What is the pubic arch?
- Bony structure formed by the pubic symphysis, & the bodies & inferior pubic rami of the right & left pubic bones
What is the ischiopubic ramus?
- Narrow extension of bone that connects the ischial Tuberosity to the pubic body
- Formed by the junction of the ischial ramus & inferior pubic ramus
What is Innominate bone fusion?
- Starts off as triradiate cartilage in the acetabulum
- Fuses after puberty to become one solid bone
What are the gluteal lines?
- On the lateral/external aspect of the ilium
- Three distinct lines can be identified:
- Inferior Gluteal Line
- Anterior Gluteal Line
- Posterior Gluteal line - Important as landmarks in describing the muscle attachments for the gluteal muscles
What is the acetabulum?
- Large, cup-shaped cavity located on the lateral side of the hip bone so the femur can attach
- Formed by the junction of the ilium, pubis, & ischium portions of the hip bone
- contains the Acetabular Fossa, Lunate Surface, Acetabular Notch, Transverse Acetabular Ligament
What is the orientation of the Innominate bone?
- Superiorly: iliac crests
- Laterally: acetabulum
- Posteriorly: greater sciatic notch, ischial tuberosity
- Inferiorly: obturator foramen
What are the pelvic divisions?
- Lesser/True Pelvis: Inferior to the iliopectineal line, Houses reproductive organs & bladder
- Greater/FalsePelvis: Superior to the iliopectineal line, Formed by the blades of ilium, Houses digestive organs (parts of small and large intestines)
What is the pubic symphysis?
- The point where the two pubic bodies join anteriorly
- Joined by two very strong ligaments superiorly and inferiorly with Fibrocartilagenous disc in between to allow minimal movement
- Softens and loosens in late pregnancy
What are the functions of the pelvic ligaments?
- Pelvic girdle is under constant strain except when the body is recumbent
- Ligaments are important for:
- Transmission of body weight - Securing the sacroiliac joint during movement in other areas of the body
What are the 3 pelvic ligaments?
- iliolumbar ligament
- sacrotuberous ligament
- sacrospinous ligament
What is the iliolumbar ligament?
- runs from the Iliac crest to the transverse process of L5
- Helps stabilize the lumbosacral spine on the pelvis
What is the sacrotuberous ligament?
- Runs between the inferior sacrum & the ischial Tuberosity
- Assists in pelvic stability, prevents the sacrum from tipping forward when downward pressure is applied to the spine
What is the sacrospinous ligament?
- Passes from the lateral sacrum & coccyx to the ischial spine
- Assists with pelvic stability, works with the sacrotuberous ligament to prevent rotation of the illum past the sacrum thus preventing excessive twisting of the pelvis
What is the sacro-iliac joint?
- Between the auricular surface of the ilium and the auricular surface of the sacrum
- Supported by very strong anterior and posterior Sacroiliac Ligaments
- Transmits forces from the lower limbs to the vertebral column
- is a synovial plane joint
What are the sex differences in the pelvis?
- Slope of Iliac Spine, Male: more upright, Female: more angled
- Width between Ischial Tuberosities, Male: narrower, Female: wider
- Inlet, Male: oval or heart shaped, Female: round
- Outlet, Male: smaller, Female: larger
- Sacral Shape, Male: longer, Female: shorter