Hip Joint Flashcards
What ligament supports the hip joint anteriorly and what does it do?
Iliofemoral ligament- it limits hip extension
SGluteal intramuscular injection
Superolateral region bilaterally into the gluteus medius
Worst place: lower medial quadrant has a lot of neuroavasculature
Characteristics of gait
- Stride
- Step
- Gait velocity
- Cadence
Stride: initial contact one foot to initial contact same foot
Step: initial contact one foot to initial contact other foot
Gait velocity: stride length/stride time
Cadence: # steps per unit time
Describe blood supply journey from deep artery of the thigh to the synovium
Deep artery
> Medial circumflex femoral artery (MCFA)
> forms an extracapsular ring around the femoral neck
> goes up to the head as retinacular arteries/ascending cervical arteries
> Makes subsynovial intracapsular arterial ring (blood flow going into synovial tissue/into joint.)
Describe blood supply early in development
- Early in development, the epiphysis and the metaphysis of the femoral head have separate blood supplies.
- The two ossification centers have different blood supplies and they develop as the patient matures.
Femoral neck fracture
Disrupts intraosseus blood supply, so you only have supply from the ligamentum teres and the retinacular arteries.
Can lead to osteonecrosis/avascular necrosis: part of the femoral head dies
Hip dislocation
- It takes a substantial force to dislocate the hip because it’s a very stable joint -> expect associated injuries
- Dashboard injury: axial load applied to femur while the hip is flexed
- In a posterior hip dislocation, blood supply through the ligamentum teres and capsule blood supply may be disrupted.
- Hip flexed, internally rotated, adducted
- In an anterior hip dislocation, the anteiror hip capsule is torn or avulsed and the femoral head is levered out anteriorly.
- Externally rotated, abducted
- Reduction asap to restore blood supply
What’s the difference between a trendelenburg sign and a trendelenburg test?
Waddling gait
What makes up the innominate/coxal bone?
Ilium, ischium, pubis
Tri-radiate cartilage
Makes up the acetabulum
What is the articulate surface of the acetabulum called?
Lunate surface (U-shaped)
Evulsion (?) fracture at the ASIS would injure what msucle?
One of the heads of the rectus femoris.
Evulsion fracture at the ischium would injure what muscle?
Hamstrings
What attaches to the lesser trochanter?
Iliopsoas
What attaches to the greater trochanter?
Hip abductors
Lesser trochanter is a posterior/anterior structure
Posterior
The hip joint and the shoulder joint are both ball and sockets. Which one is more stable?
The hip joint - more of the ball (~40%) is covered by the socket, so it relies less on ligamentous support.
The acetabular labrum is a strong, fibrocartilaginous ring. What are its 3 functions?
- Increases femoral head coverage adn contributes to hip joint stability.
- Load transmission
- Regulation of synovial fluid dynamics by maintaning lubrication and vacuum seal .
The angle the femoral neck makes with the shaft is ~___.
The femoral neck is ___ verted.
130 degrees, +/- 7
Anteverted by about 10 degrees
How far does the hip joint capsule extend anteriorly vs posterior?
Anteriorly: it goes all the way tot he intertrochanteric crest
Posteriorly: only partially across the femoral neck
Y ligament of bigelow
Another name for the iliofemoral ligament, which is an anterior capsular reinforcement that is extremely strong at limiting hip extension.
Has lateral and medial fascicle.
What ligament supports the hip joint inferiorly? What does it do?
Pubofemoral ligament attaching between the pubis and the femur- it limits hip abduction
What ligament supports the hip joint posteriorly and what does it do?
Ischiofemoral ligament- limits hip flexion and adduction
This is an inferior view with the femur flexed. What are the two ligaments in red lines?
Pubofemoral (top)
Ischiofemoral (bottom)
What is the intra-articular ligament of the femur?
Ligamentum teres/Round ligament
Where does the ligamentum teres/round ligament attach?
Apex of the cotyloid notch -> fovea of femoral head
Blood supply to femoral head
- Primary: lateral epiphyseal artery (terminal branch of MCFA)
- Also contributing:
-
Inferior metaphyseal artery (terminal branch of LCFA)
- Important for metaphyseal circulation
- Medial epiphyseal artery of ligamentum teres (branch of obturator artery)
-
Inferior metaphyseal artery (terminal branch of LCFA)
What muscles cause hip ABduction?
Gluteus medius and minimus
-Originate on the iliac crest and inserting onto the greater trochanter
How does blood supply change with age?
- BIRTH: neck-to-head blood supply from the mfca, lcfa, and the ligamentum teres
- As the growth plate develops in adolescence, it blocks that intraosseus circulation, forcing the head to rely mostly on the retinacular arteries (posterosuperior & posteroinferior branches)
- At this time, damage to a single vessel can have more serious consequences bc there’s less collateral.
- As the growth plate fuses (skeleton matures as ~14yo in girls and 16 yos), you have anastomoses between retinacular arteries, ligamentum teres, and the intraosseus blood flow from the lfca.
What muscle causes hip flexion?
Iliopsoas attaching from the pelvis to the lesser trochanter
What muscles cause hip ADduction?
Muscles of the medial thigh originating from the pubis and attaching to the shaft of the femur or distal to the knee joint.
- Gracilis
- Pectineus
- Adductor longus
- Adductor brevis
- Adductor magnus
- Obturator externus
What muscles in the hip are responsible for extension?
- Gluteus maximus
- biceps femoris
- Semimembranosus
- Semitendinosus
What muscles are responsible for external rotation?
- Piriformis
- Superior Gemellus
- Inferior Gemellus
- Obturator internus
- Quadratus femoris
Originate in the pelvis and attach to the posterior ridge of the greater trochanter and intertrochanteric region.
What muscles are responsible for internal rotation?
- Gluteus medius (anterior fibers)
- Gluteus minimus
- Tensor fascia latae
- Adductor longus
- Adductor brevis
Antalgic gait
- Weight bearing time on affected limb increases
- Stride length shortened
- Cane in opposite hand
- Opposite side of pelvis rises
Trendelenburg sign
