Elbow and Knee Joints Flashcards
Which kind of joint are elbow and knee joints ?
Hinge Joints
What are some characteristics of all hinge joints ?
- articular surfaces are reciprocally shaped
- strong collateral ligaments
- muscles are grouped at the sides of the joint where they do not interfere with movement
What are the 2 joints making up the elbow joint ?
Humero-radial and humero-ulnar joints
What movements does the proximal radio-ulnar joint allow for?
Supination and pronation
The knee joint allows for free movement in how many planes ?
One plane
Describe the main features of the elbow joint capsule.
- Single fibrous capsule for 3 joints
- lined by synovial membrane
- attaches to the articular margins
- strengthened by radial and ulnar collateral ligaments
What are the weak areas of the elbow joint capsule ?
Capsule is weaker anteriorly and posteriorly
Does the radial collateral ligament attach to the radius ?
No
What are ligaments surrounding the elbow joint ? What is the role of each ?
Anular ligament: holds the radial head in place, but allows its rotatory movement for supination and pronation
Interosseal membrane: holds the radius and ulna together and transmits forces from the radius to the ulna; muscle attachment
What is the possible result of an excessively forceful pull on the hand ?
Dislocation of the radial head from the anular ligament
Which joints are in use during pronation and supination ?
Proximal and distal radio-ulnar joints
Describe the main features of the knee joint capsule.
- fibrous
- lined by synovial membrane
- attaches to the articular margins
- has collateral ligaments supporting the sides of the joint
- has intra- articular ligaments and cartilages
- INCOMPLETE (Anteriorly, replaced by the quadriceps tendon (patellar ligament), the patella and fat pads on either side of patellar ligament)
What are the augmentations of the knee joint capsule ?
- ANTERIORLY, by the iliotibial tract and patellar retinacula from quadriceps
- POSTERIORLY, by the oblique popliteal ligament (expansion of the semimembranous) and the arcuate popliteal ligament
What bursaes communicate with the articular cavity of the knee joint ?
- Suprapatellar bursa
- popliteus bursa
- anserine bursa
- gastrocnemius bursa
What are the collateral ligaments of the knee joint ? What is their respective role ? Where do they extent from, and where do they extend to ? Are they fused to the joint capsule (if yes, anything else they are fused to ?) ?
Lateral (Fibular) ligament:
- prevents adduction of leg
- from Lateral femoral epicondyle to Head of fibula
- Not fused to joint capsule
Medial (Tibial) ligament:
- prevents abduction of leg
- from Medial femoral epicondyle to Tibial condyle
- fused to joint capsule and medial meniscus
Where is the tendon of popliteus found ?
Between the lateral fibular ligament and the knee capsule
Allocate each of the following characteristics to either medial, or lateral collateral ligament of the knee: broad, strong, flat
Medial collateral ligament: broad, flat
Lateral collateral ligament: strong
How many menisci are there around the knee joint ? What is their names ?
2
Medial meniscus and Lateral meniscus
Which connective tissue are menisci usually made of ?
Fibrocartillage
What are the functions of the medial and lateral menisci of the knee ?
- Increase the congruence of articular surfaces
- Dissipate the forces/stress on articular cartilage
- Absorb shock
- Decrease friction
- Participate in locking of knees
- Proprioception
Where, and how are the medial and lateral menisci of the knee connected ?
Anteriorly, by the transverse ligament of the knee
Where do the medial and lateral menisci of the knee move during flexion and extension of the knee?
They move antero-posteriorly
Describe the vascularity of the menisci of the knee.
Inner 2/3 is avascular, outer 1/3 partially vascular
Where are the horns of the menisci of the knee attached to ?
To the intercondylar region of the tibial plateau
What are surrounding structures attached to the medial and lateral menisci of the knee respectively ?
Medial meniscus: to the joint capsule AND to the medial collateral ligament
Lateral meniscus: to the joint capsule and to the tendon of the popliteus muscle but NOT to the lateral collateral ligament
Where does the Meniscofemoral ligaments extend from and to ?
From the posterior horn of lateral meniscus, to medial condyle of femur
What are the two cruciate ligaments of the knee called ?
Anterior and posterior cruciate ligaments
What are the functions of the anterior and posterior cruciate ligaments respectively ?
Anterior cruciate ligament:
- Prevents anterior movement of tibia and hyperextension
- Act as a pivot for rotatory movements between the bones
Posterior cruciate ligament:
- Prevents posterior movement of tibia (walking downhill)
- Act as a pivot for rotatory movements between the bones
True or false: Parts of the cruciate ligaments of the knee are taut in all positions of the joint.
True
What do the Q-angle and the Carrying angle refer to respectively ?
Q-angle: angle between the anatomical axis of the femur and that of the tibia
Carrying angle: angle between the long axes of arm and forearm.
Is the carrying angle more pronounced in males or females ? Why ?
More pronounced in the female to account for the wider pelvis
What is the carrying angle approximately equal to, in males, and in females ?
10-15 degrees in males
>15 degrees in females
Where do flexors of the elbow and knee pass, relative to the elbow and knee joint respectively ?
Anterior to the elbow joint
Posterior to the knee koint
What are the flexors of the elbow ?
Main: Brachialis (and control the extension produced by gravity)
Also: Brachioradialis (when the forearm is midway between pronation and supination), Biceps brachii (esp. when supinated), Pronator teres and the wrist/digit flexors (Palmaris longus, flexor carpi radialis, flexor digitorum superficialis)