Pelvis and Hip Flashcards
3 Bones in Pelvis
1, Ischium- most posterior
- Ilium- most superior
- Pubis- most anterior
- these 3 bones come together at the acetabulum fossa helping move joints
Iliac Crest
top most portion of the pelvis
Pelvic Brim
Made up of arcuate lines and pectineal lines
False Pelvis aka Greater Pelvis
- area between illiac crest and pelvic brim
- also represents inferior end of abdominal cavity
True Pelvis aka Lesser Pelvis
- area between pelvic brim and pelvic diaphragm (pelvic floor), muscular floor
- where pelvic viscera is located
- where the uterus is
Borders of True Pelvis
- Anterior: pubic symphysis
- Superior: Pelvic Inlet
- Posterior: sacrum and coccyx
- Inferior: pelvic floor
Pelvic Inlet
- imaginary but represented by arcuate and pectineal lines
- runs from pubic symphysis to the lumbosacral angle (disc between L5 and S1, aka sacral pomontory)
Peritoneum
- roof of pelvic brim
- false pelvis is the inferior border of the abdominal cavity
Normal Posture
- less energy expended by the body is the most optimal = screwdown mechanism
- simple standing has few muscles contracting
- balanced contraction of antigravity flexors and extensors to maintain erect posture using little energy
Transmission of Body Weight at Hip
- weight is transmitted from lumbar to sacral vertebrate then thru os coxae into femoral heads and lower extremities, stable
Forces of Body Weight
- descending forces: body weight above sacroiliac joint, weight transmitted to sacrum
- sacroiliac joint doesn’t move and is very strong
- body weight transmitted to sacrum -> SI joint -> os coxae -> lunate surface of acetabulum -> femur head
- upward forces: antigravity, lower extremities pushing us up
- balance of forces makes good amount of weight resting and balanced on hip joints
acetabulum
- socket for the head of the femur
- on lateral side of os coxae
- like a cup
Pelvic Bones: Males vs Females
Males:
-adapted for bipedal locomotion (hunting and fighting)
-iliac crests are higher, pelvis looks taller
-sacrum longer
-sacral promontory more prominent
-ischial spine is more projected
-coccyx extends more down and forward
-pelvis is more heart shaped and narrower
-pubic arch is acute angle, V-shaped
Females:
-adapted for child birth
-illiac crests are shorter, pelvis looks shorter
-sacrum shorter
-pelvis is more circular and wider
-pubic arch is obtuse angle, U-shape (broader)
-smoother bones
-acetabula is smaller and farther apart -> broad hips
Normal vs. Anomaly
- bell shaped curve for most human structures and systems
- normal: has broad range with variations
- anomaly: outside of normal
sacral promontory
most anterior projection of sacrum
sacroilliac joint/ligament
- where the auricular surface of ilium meets the auricular surface of sacrum, fits together
- at joints/ligaments have roughened surfaces to increase the surface area for attachment of ligament or muscles through ligament
- bone modifies itself to accommodate to action of muscle
- where transition of weight occurs from spine/sacrum to pelvis
iliac crest
-most superior portion of ilium
ala
- wing on lateral surface of ox coxae
- bowl for false pelvis
anterior superior iliac spine
- anterior protrusions of inferior end of iliac crest
- important for palpating
iliac fossa
- on medial surface of os coxae
- origin of iliacus muscle (fills in cup)
arcuate line of ilium
- where ilium and pubis meet
- buttress that gives pelvis and pelvic brim extra structural integrity
- also merges with pectineal line
iliac tuberosity
-site of attachment for sacroiliac ligament
posterior superior iliac spine
- important landmark for palpation
- create back dimples, skin attachments to PSIS
- if uneven or in different places, the pelvis is tilted and produces shortened leg
Gluteal Lines
- Anterior
- Inferior
- Posterior
- spaces between lines provide gluteal muscle attachment
- gluteus minimus in between anterior and inferior line, adductor of hip
- gluteus medius in between anterior and posterior line, adductor of hip
- gluteus maximus is below posterior line, extensor of hip
Ischial Spine
-projects posteriorly on medial surface
Greater Sciatic Notch
- becomes greater sciatic foramen
- above ischial spine
obturator foramen
- ischial ramus and inferior pubic ramus come together to form this
- lightens up pelvis
- some of the muscles that externally rotate the hip have origins inside the pelvis and pass out through obturator foramen
ischial tuberosity
- rough surface
- holds weight when sitting down
sacroiliac synovial joint
- synovial anteriorly
- fibrous posteriorly
- forms a boney interlocking mechanism reinforced by ligaments to absorb twisting movements
- sacral surface has hyaline cartilage and ilial surface has fibrocartilage
inguinal ligament
- distinction between abdomen above and thigh below it
- it attaches to ASIS superior and laterally and pubic tubercle inferiorly and medially
anterior SI ligament
- injured most often because of thin structure
- not that strong
- attaches sacrum to ilium
sacrospinous ligament
along with sacrotuberous, it opposes forward tilting of sacrum on os coxa during weight bearing, strong, turns greater sciatic notch into greater sciatic foramen
sacrotuberous ligament
- blends with posterior SI ligament
- stabilizes against nutation of sacrum and counteracts against posterior and superior migration of sacrum during weight bearing
posterior sacroiliac ligament
-very strong and tough
-nutation (anterior motion of sacrum) loosens ligament
-counternutation (posterior motion) will make ligament tight
palpated below PSIS
interosseus sacroiliac ligament
- forms major connection between sacrum and os coxa
- strong and short ligament that is deep to posterior sacroiliac ligament
- resists anterior and inferior movement of sacrum
- stronger than bone
Tests of Slight Movement
- bony movements or palpations to provoke pain in same quality and location that they feel before
- 3 or more positive provocation tests that provoke pain to diagnose correctly
FABER
positive test occurs when groin pain or butt pain produced
Compression
- stresses posterior SI ligament (push together)
- increased feeling of pressure
- positive result replicates patients symptoms
Thigh Thrust
- produces shear force at SI, patient tries to resist
- positive test for pelvic girdle pain if axial pressure provokes pain on SI joint
Distraction/Gapping
- stresses anterior SI ligament
- pull apart, SIJ dysfunction
Gaenslen
- extends one SI and flexes othe SI; simultaneously stresses both SI joints
- push one leg against chest and push other down on table
acetabular fossa
- deepest portion of acetabulum
- not articular
- not weight bearing in hip joint
lunate surface
- crescent moon shaped
- thick, elevated, dense, bigger portion of acetabular fossa
- articular surface
- hyaline cartilage lays on surface
- receives weight bearing
acetabular rim
-large and sharp compared to shoulder
acetabular notch
- inferior part of acetabular fossa
- no more ridge
labrum
-cartilaginous ring on acetabular ring that deepens hip socket (acetabular fossa)
ligament of head of femur
- pathway of access of blood and nerve to head of femur
- only vascular supply to femur, scary injury
- attaches from Fovea of the head to acetabular notch and tranverse acetabular ligament
- limits adduction (minimally)
hip joint
synovial ball and socket join between acetabulum and head of femur
transverse acetabular ligament
- layer that closes off acetabular notch
- creates acetabular foramen to allow head of femur to pass through
femoral head
- about 2/3 of sphere
- fits into acetabular socket tightly
- covered by hyaline cartilage, cartilage is thicker superiorly because it rubs againsts lunate cartilage
Capsule
- attaches to acetabular labrum, surrounding bone and transverse acetabular ligament
- tough, strengthened by accessory ligaments that give stability to joint
- capsule is attached distally to intertrochanteric line and intertrochanteric crest (elevated ridges) of femur
Iliofemoral ligament
- important support ligament of hip joint
- anterior view of os coxa and femur
- attaches to lateral surface of ischium and extends down on proximal surface on intertrochanteric line of femur
- inverted shape of Y
- spiral path of fibers from AIIS to intertrochanteric line
pubofemoral ligament
- comes from pubis and blends with interfemoral ligament
- resists/limits abduction
ischiofemoral ligament
- important support ligament of hip joint
- comes from posterior ischial acetabulum, spirals anteriorly over femoral head and attaches to superior part of femoral neck
- posteroinferior part of capsule is not reinforced with ligaments-weak spot, femur pushed posteriorly in injuries/car accidents
iliofemoral ligament function
- screw down mechanism: standing erect we have tightening of ligaments and squeeze head of femur deeper into acetabulum
- hyperextension of hip screws head tightly into fossa and creates strong stability
- tight in extension to balance forward roll on hip joint
ischiofemoral ligament function
- screw down mechanism
- tightest in hyperextension
nutation
- anterior pelvic tilt
- nodding forward
- interosseous sacroiliac ligament acts as axis through pelvis
- forward moving and lowering of sacral promontory and backward/elevation of tip of coccyx
- opens pelvic outlet and spreads pubic symphysis
counternutation
- posterior pelvic tilt
- coccyx forward and backward/elevation of sacral promontory
- closes pelvic outlet and increase pelvic outlet
Anterior Tilt
-contract back extensors and hip flexors
Posterior Tilt
-contract hamstrings posteriorly and erector abdominis anteriorally
Muscle Balance
anterior and posterior tilts are balanced,
-anteior, inferior muscles are balanced with poster, superior muscles
Muscle Balance
- if abs and hamstrings are stretched out and weak and hip flexors and back extensors are strong but tight
- See LEcture 2 slide 24
- strong muscles pull pelvic toward it and produces pathological pelvic tilt
leg length discrepancy
- pelvic tilt occurs in lateral plane
- tilted to one side of the body
- produces compensatory skuliosis, curve of spine
Center of gravity in Posture
-passes posterior to hip joint, increasing the tendency for pelvis to roll backwards (hyperextend), stable with no energy expedenture
- hip ligaments screw down mech forcing femoral head deeper in acetabulum
- hip, knee, and ankle are all close packed at full extension
which stabilizes lower extremity and allows weight bearing with minimal energy expense
Unbalanced Posture: Lordosis
- increased anterior lumbar curve from neutral
- deep curve in lumbar spine
- anterior pelvic tilt
Unbalanced Posture: Kyphosis
- increased posterior thoracic curve
- humpback
- head and lumbar spine is thrust forward
- thoracic spine thrust back
- neutral pelvis
- knee joint hyperextended
Unbalanced Posture: Flat Back/Sway Back
- decreased anterior lumbar curve (flat back)
- posterior pelvic tilt
- head and neck forward
Proper Posture
-rectus abdominis pull up on pubis and hamstring pull down on ilium and ischium to initiate posterior rotation (extension) for screw down mech
