TEC1 - Semester 2: Pelvic biomechanics Flashcards
(48 cards)
What are the bones of the pelvis?
Sacrum, Coccyx, Ilium, Pubis, Ischium
Describe the structure of the sacrum.
- triangular shaped
- part of the axial skeleton, but also helps completes pelvic ring
- 5 fused vertebrae
- articulates with L5 (S) and pelvic bones (L)
What are functions of the sacrum?
- strong foundation for pelvic girdle
- stable base for spine
- large area for attachment of muscles and ligaments
- protection of pelvic contents
What does the sacrum contain?
- encloses sacral canal
- contains cauda equina + spinal meninges
Describe the structure of the coccyx.
- is remnant of a tail
- triangular shaoed
- 3-5 fused vertebrae
Which bones form the “Innominate”?
ilium, pubis, ischium
Describe the ilium’s structure.
- fan shaped
- comprises superior 2/3 of the pelvic bone
- superior 2/5 of acetabulum
Which landmarks can one find on the ilium?
iliac crest, ASIS, AIIS, PSIS, PIIS
Describe the structure of the pubis.
- anterior part of pelvic bones
- has a body and 2 rami (S and I)
Which landmarks can one find on the pubis?
pubic tubercle, pubic crest, iliopubic ramus, ischipubic ramus
Describe the structure of the ischium.
- L-shaped
- has a body and one ramus
Which landmarks can one find on the ischium?
body, rami, ischial tuberosity, ischial spine
Describe the acetablulum.
- hemispherical cavity articulating with head of femur
- directed L, I and A
- stable joint due to deep concavity
What is the acetabulum formed by?
fusion of pubis, ischium and ilium
Pubis: A and I 1/5
Ischium: P and I 2/5
Ilium: remaining 2/5
What are the muscles of the pelvis?
tensor fascia latae, iliopsoas, gluteus max. med. & min.
What are the joints of the pelvis?
SI-joint, Symphysis pubis, Sacrococcygeal joint
Which joints are functional (=move)?
both SI Joints & pubic symphysis
Which types of joints can the SI joint be divided in?
- Fibrous syndesmotic joint
- Synovial plane gliding joint
Describe the fibrous syndesmosis.
amphiathrotic sacroiliac ligaments bind the tuberosities of the ilium to the sacrum
Describe the synovial sacroiliac joint.
alar surface of sacrum articulates with medial auricular surface of ilium
Does the SI joint have a self-locking mechanism?
yes
What does that mechanism serve for?
to reduce weight bearing efforts. helps with stability in push-off phase of gait
What is the closed-packed position?
= locked position
- maximal contact of articulating surfaces
- joint ligaments and capsule are tight
- no joint play
- very stable position
What is the loose-packed position?
- joint surfaces maximally separated
- joint capsule and ligaments relaxed
- a lot of joint play
- resting position