Lower Limb joints Flashcards
Wilson
What is the mechanical axis of the femur?
87 degrees
What is the anatomical axis of the femur?
84 degrees
The hip joint centre is located where?
Middle of the head of othe femur
What is the anatomical and mechanical axis of the tibia?
93 degrees
A medial deviation from the axis of the bone is known as the?
Vara (varus)
A lateral deviation from the axis of the bone?
Valga (Valgus)
What is the normal angle of inclination of the femur?
120 degrees
(range is 120-135 degrees
thus creating Ward’s triangle
What is a coxa valga?
when the Ward’s trinagle angle of the femur increases to more than 135 degrees
(this is an excessive slant)
What is a coxa vara?
When the Ward’s triangle angle degreases to less than 120 degrees.
congenital = 90 degrees
aquired = less than 90 degrees
This joint is a synovial joint of the ball and socket variety. It is formed between the head of the femur and the acetabulum of the innominate bone (pelvic girdle).
Hip joint
(more stable than the glenohumoral joint)
What is a ball and socket joint?
A oint that can move in all 3 planes
Coronal
Sagital
Axial
Which three bones fuse to form the acetabular fossa
ilium, ischium, pubis
Innominate
(Pelvic girdle)
Areas of thick fibers that go in one direction are known as?
Ligaments
The hip joint is surrounded by what? and what is that thing lined with?
It is surrounded by an articular capsule that is lined with a synovial membrane. And the articular surfaces are covered with hyaline cartilage.
Thickning of the articular capsule forms what?
Intrinsic ligaments
What are the intrinsic ligaments of the hip joint?
Anteriorly
Iliofemoral ligament
pubofemoral ligament
Posteriorly
Ischiofemoral ligament
Which ligament of the hip joint is the strongest and most important because it supports the hip joint in erect posture?
Iliofemoral ligament
The articular capsule of the hip joint is composed of what type of fibers?
parallel fibers
What happens to the fibers in the articular capsule during flexion and extension?
The fibers unwind during flexion
Extension causes the fibers to spiral (become oblique) = draws acetabulum and femur closer together like a screw. = hip stability
When do you have the maximal contact between the head of the femur and the iliofemoral ligament.
during extension
Allows you to stand with mild muscle activity
What is the infamous ligament of the hip that has an artery running through it?
Ligament of the head of the femur with Acetabular artery
(presence of the artery is variable and may not be patent)
This ligament runs in the acetabular fossa
Add image for slide 16
CT scan Though Hip
A. Acetabular fossa
B. Obturator internus
C. Head of femur
D. Gluteus maximus
What occurs when yo fracture the neck of the femur and why?
Shotening and lateral rotation of the affected limb
Hip injuries cause its myotatic unit to spasm which provides protective splinting. Stonger muscle (lateral rotators) will over power weaker muscle (medial rotators)
What are the medial rotators of the hip?
Gluteus medius (anterior fibers)
Gluteus minimus
Tensor of fascia lata
(towards anterior superior iliac spine)
What are the lateral rotators of the hip?
Quadratus femoris
Gluteus maximus
Piriformis
Ticeps Coxae
Obturator internus
Obturator externus
(toward posterior superior iliac spine)
Where is the center of rotation?
Also known as the fulcrum!
head of femur and lever formed by head, neck, and greater trochanter of femur
Which vessels are the main blood supply for the femur?
Media femoral circumflex
Lateral femoral circumflex
(they pierce the capsule and radiate towards the head of the femur)
Why are proximal fractures of the femoral neck worse than distal fractures?
arterires run throufh the proximal neck to reach the head not the distal neck. Therefore, and proximal fracture will interupt blood supply which would make it difficult to heal. This can lead to avascular nevrosis
More proximal the fracture -= the worse the prognosis
Image from slide 24
Fractures of the femur
A. Subcapital fracture line (poor prognosis)
B. Cervical fracture line
C. Basal fracture line
D. Pretrochanteric fracture line (goes thorugh greater and lesser trochanter, good progosis)
Posterior dislocation of the hip results in?
Shortning of the limb
Medial rotation of the hip
This is because the normal relationship between the femur and bone is changed. Had of femur is now located posteriorly and the lateral rotators are located medially, so when the muscle contracts they would actually cause a medial rotation and not a lateral rotation.
What is the major complication of a disclocated hip?
Entrapment of sciatic nereve
(sensory motor dysfunction)
This joint is a synovial joint. It ariculates between condyles of the femur and tibia. It forms a hinge joint with limited degree of rotation.
knee joint
What is a hinge joint?
uniaxial joint
can go anterior and posteriorly in the axial position
The articulation between which two bones is a synovial joint of sliding variety?
Patella and femur
When you are standing erect what is happening with you knee?
There is a slight degree of rotation which allows you to lock the knee in place with mild muscle contraction.
What are the intrinsic ligaments of the knee joint?
Tibial (medial) collateral ligament
articular capsul
This joint is supported by extrinsic, intrinsic, and intra-articular ligaments.
knee joints
What are the intra-articular ligaments of the knee?
Anterior cruciate ligament
Posterior cruciate ligament
What are the extrinsic ligaments of the knee>
Fibular (lateral) collatral ligament
Patellar ligament
Which ligament provides stability in the knee joint and if ruptured you have loss of function in the knee?
Posterior cruciate ligament
How do you test if a person ruptured their ACL?
Patient lays down with a flexed leg and you pull the leg towards you. If there is a great shift anteriorly then this is known as the postive anterior drawers sign. Thus confirming that the ACL is torn
How do you test if a person ruptured their PCL?
Patient lays down with a flexed leg and you push the leg away from you. If there is a great shift posteriorly then this is known as the postive posterior drawers sign. Thus confirming that the PCL is torn
Hyperextension of the knee causes what?
ACL injury
Hyperflexion of the knee causes what?
PCL injury
What is interposed between the condyles of the femur and tibia?
Medial Meniscus
Lateral meniscus
(articular cartilage that makes the joint deeper)
What is directly attached to the medial meniscus?
Tibial Collateral ligament
(they form one system therefore this ligament is part of the capsule
What is the unhappy triad?
- Tearing of the ACL
- Tearing of the TBL (tibial collateral ligament)
- Tearing ot the medial meniscus
This occurs when the foot is planted on the gound and you have a lower extermity internal rotation (impact comes from the lateral side, person falls medially)
Medial angle of the knee joint increases and lateral angle decreases
What is it called when the distal end of the femur devialtes medially and the head of the tibia deviates medially?
knocked knee!
Tibia displays -> genu valgum
Femur displat-> Coxa vara
What is it call when the distal end of the femur and the head of the tibia deviates laterally?
Bow leg!
Tibia dispalys -> genu varum
Femur displays -> coxa valga
(INWARD BEND)
What is the valgus stress test?
Test for torn MCL
Bend leg to where the foot goes laterally and the knee goes medially
Rupture of the medial collateral ligmament shifts the forces to the lateral condyles and leads to a torn lateral meniscus and torn ACL and impaction of the lateral femoral condyle or wedge fracture of the lateral tibial plateu.
What is the Varus test?
Test for torn LCL
Leg goes medially while knee goes laterally
Rupture of the lateral collateral ligament. This is rare but can occur when a mortorcycle fall on the medial side of the knee
Which direction is the patella typically dislocated?
Laterally
This happens often in women because of their wideer hips and thus greater (Q) angle between femur and line of gravity (that passes through the tibia)
Q angle is small is men
Larger Q = more probable dislocation
What happens to the Rectus femoris when the hip sizes change?
Small hip = Rectus femoris pulls straight up
Large hip = Rectus femoris pulls up at an angle
What is the Q ange?
Angle formed between the ASIS and the line of gravity
This joint is a synovial hinge joint formed by the articulations of the distal ends of the tibia and fibula (and their malleoli) which form as deep socket around the talus
Ankle joint
Which plane does the ankle joint act in?
Sagital plane
What are the lateral ligaments of the ankle joint?
Anterior talofibular ligament
Posterior Talofibular ligament
Calcaneofibular ligament
Forced inversion of the foot tears the lateral lligaments of the angle. This is known as a?
Sprained ankle
Most common joint injury
What are the medial ligaments of the ankle joint?
Deltoid - several ligaments combined; attaches to the medial malleolus
What is Pott’s fracture?
Forced eversion of the ankle = tearing of the medial liganments of the ankle joint
- Blow from the lateral side
- Medial malleolus is avulsed (fractured) by the strong deltoid ligament
- Ankle becomes unstable and dislocated on the medial side (medial malleoulus and deltoid ligament seperate)
- Torqu on the fibula results in a fibula fracture
