Lecture 39 - Hip and Pelvis Flashcards
What are the 6 structures that make up the hip/pelvic region
- L4-L5 vertebrae
- 2 Ilia
- Sacrum
- Pubic bones
- Sacroccygeal joint
- Hip joints
How is the L4-L5 vertebrae tethered to the ilia
By the iliolumbar ligament
What happens if pelvis demonstrates increased motion in front plane during gait
It can put added stress upon the lumbar spine and associated segments
Describe the 2 ilia
They are paired, symmetrical and contain an anterior and posterior superior iliac spine that comprise the superior and posterior innominate bone
Provide 4 characteristics of the sacrum
- They are unpaired
- Consist of 5 fused vertebrae
- Highly variable shape
- They are key for stability
Name 3 characteristics of the pubic bones
- Makes up the anterior and inferior portion of the innominate bone
- The 2 pubic bones articulate in the cartilaginous pubic
- Pubic bones are covered in thin hyaline cartilage separated by a fibrocartilaginous disc
What is the sacrococcygeal joint
It is where the sacrum and coccyx are joined via fibrocartilaginous disc
List 3 characteristics of the hip joint
- Simple synovial joint
- Unmodified ovoid
- Contains acetabulum
Acetabulum
Place where the bones of the ischium, ilia, and pubic bones meet
What are the 2 systems of the pelvic girdle
- Load transfer system: During walking, running, jumping the load must be transferred from one leg to the other and from upper to lower body
- Force generator: Rotational force during gait (mainly midstance to terminal stance) is the force that re-supinates the foot helping to form the stable arch system
How many degrees of motion is the hip joint
3 degrees of motion (similar to GH joint)
What are 3 differences between hip joint and GH joint
1) Hip has deep acetabulum (true socket) that surround femoral head
2) thick capsule with extrinsic ligamentous system
3) Can manage tremendous forces and loads imposed during weight-bearing activities
**less likely to dislocate
The acetabulum is formed by (3)
1) ilium (40%)
2) Ischium (20%)
3) Pubic (20%)
The articular surface of the acetabulum is the
Lunate fossa
How does the acetabulum face
Forward, downward and outward (ventral, caudally, laterally)
How does the head of the femur face
Forward, upward and inward
Describe the shape of the head of the femur
2/3 of a sphere covered by hyaline cartilage (except fovea)
Describe the difference between a young and older hip joint
What are the 3 ligaments of the hip
- Iliofemoral
- Ischiofemoral
- Pubofemoral
Iliofemoral ligament (ligament of Bigelow)
Inverted Y (superior and inferior band) that connects the pars inferioris and pars superioris
Where does the pubofemoral ligament attach to
Goes from superior ramus of pubis to intertrochanteric fossa
Where does the ischiofemoral ligament go to
Runs from posterior acetabular rim and labrum and spirals superiorly to run to the zona orbicularis and greater trochanter
Ligamentum teres function
It is an intrinsic ligament that is loaded with mechanoreceptors and acts as a conduit for neurovascular supply to the femoral head, and maintains the reduction of the humeral head
Labrum function
Makes up the outer margin of the acetabulum and attaches to joint capsule to assist in maintaining fluid pressurization and provide proprioceptive sensory information for hip position and movement
Side note: (labrum tear in hip results from repetitive use (younger pop.) vs trauma in shoulder labrum)
2 characteristics of the joint capsule and synovium
1) Runs from outer rim of the acetabulum to the neck (like a sleeve)
2) Capsule is thickest and strongest superiorly and anteriorly
Name 6 types of bursae
- Iliopectineal bursa
- Trochanteric bursa
- Ischial bursa
- Iliospsoas bursa
- Gluteus medius bursa
- Ischiogluteal bursa
Describe the blood supply of the head and neck of the femur
Supplied by the medial and lateral femoral circumflex (extracapsular arterial ring) that branches from femoral or profunda femoris
T or F: Nerve supply to a joint is derived from the nerve supply of any muscle that crosses that joint
T
Name the 5 flexor muscles of the hip
Name the 4 adductors of the hip
Name the 4 extensors of the hip
Name the 3 abductors of the hip
Name the 2 internal rotators of the hip
Name the 7 external rotators of the hip
Describe palpation of the anterior hip dont need to know just to help
Describe palpation of the posterior hip dont need to know just to help
Describe dynamic stability of the hip
Posterior fibers of the gluteus medius and the gluteus minimus decelerate hip adduction (working eccentrically) and hip internal rotation
Describe trendelenburg’s sign **IMPORTANT *8
This is when features of lateral balance control fail where the pelvis falls on the unsupported side when individual stands on affected limb. Results in person walking with lurching or waddling gait
Compare a positive vs negative Trendlenburg’s test IMPORTANT
Positive: Hip abductors cant control dropping of pelvis when opposite leg is raised
Negative: Hip abductors are acting normally tilting the pelvis upwards when opposite leg is raised off ground
When would Trendelenburg gait be observed
Verry common in osteoarthritis and other lower extremity pathologies like patella-femoral syndrome, ACL tears, and ankle instability
Describe some characteristics of force on the acetabulum
1) Acetabulum are accepting loads with function at hip (especially during gait execution)
2) Acetabular architecture allows distribution of stress across acetabulum to support 1.8-3.8 times individuals body weight
3) Any force greater then 3 times body weight puts joint at risk of early degeneration
4) If one muscle decreases in function across the joint, compression force across cartilage can exceed 4 times an individuals body weight = early degeneration
Describe what happens with acetabular or femoral head dysplasia
Results in reduced coverage of femoral head by acetabulum and altered joint congruency resulting in altered locomotor performance and joint compression force pattern changes. These changes along with increased joint laxity and instability put the joint at increased risk for degeneration that could produce femoral head flattening and notching
Compare healthy hip joint vs a hip joint with osteoarthritis
