Lecture 6 8/31/23 Flashcards
What are the three tendons located in the weight bearing digits?
-interosseus
-deep digital flexor (DDF)
-superficial digital flexor (SDF)
What are the three circular retinacula of the weight bearing digits?
-palmar annular ligament
-proximal digital annular ligament
-distal digital annular ligament
Where is the palmar annular ligament located?
palmar surface of the metacarpo-phalangeal joint
What is the role of the palmar annular ligament?
holds the interosseous, DDF, and SDF tendons in place
Where is the proximal digital annular ligament?
palmar surface of the proximal phalanx
What is the role of the proximal digital annular ligament?
holds the DDF and SDF tendons
Where is the distal digital annular ligament?
palmar surface of the middle phalanx
What is the role of the distal digital annular ligament?
holds the DDF
What are the characteristics of the dorsal ligaments of the weight bearing digits?
-paired, with one on each surface of the foot
-allow for claw retraction in cats
When declawing a cat (removing distal phalanx), what structures must be cut?
-both dorsal ligaments
-DDF
-both collateral ligaments
-common digital extensor
-lateral digital extensor (lateral digits only)
Why is the cat’s distal phalanx to the side of the middle phalanx, while a dog’s distal phalanx is directly below the middle phalanx?
having the distal phalanx on the side allows the cat to retract its claws
How do cats retract their claws?
-when the DDF contracts, cat’s claw extends and dorsal ligaments stretch
-when DDF relaxes, dorsal ligaments relax and retract claw
What is luxation?
when bones come entirely out of the joint (dislocation)
What is subluxation?
when bones come partially out of the joint
Why do the ulna and radius move laterally during luxation of the cubital joint?
-medial epicondyle of the humerus has a corner, while the lateral epicondyle is curved
-easier for curved portion of ulna to slip on lateral epicondyle
How does the genual joint between the femur and the tibia stay together?
-ligaments
-fibrocartilaginous pads
What are the characteristics of the menisci?
-medial and lateral
-C shaped, with a thicker outer portion
-stabilize joint and act as cushion
-both anchored to tibia via ligaments
-lateral meniscus also anchored via ligament to femur
Where are menisci most likely to be damaged?
on the inside of the C shape, which is thinner
What happens when the meniscus is damaged?
-bucket handle tear occurs
-nervous endings in meniscus cause animal to feel pain
-meniscus must be removed
Why is it possible for one meniscus to be removed?
as long as the other one remains, it provides enough stability for the entire joint (although not as stable)
How do the medial and lateral menisci differ in relation to the medial and lateral collateral ligaments?
-medial meniscus is attached to medial collateral ligament with connective tissue
-lateral meniscus is not attached to lateral collateral ligament
Which ligaments stabilize the medial meniscus to the tibia?
-cranial tibial ligament of medial meniscus
-caudal tibial ligament of the medial meniscus
Which ligaments stabilize the lateral meniscus to the tibia?
-cranial tibial ligament of the lateral meniscus
-caudal tibial ligament of the lateral mensicus
Which ligament connects the two menisci?
transverse ligament
Which ligament stabilizes the lateral meniscus to the femur?
meniscofemoral ligament
Which ligaments connect the tibia and the femur?
-cranial cruciate ligament
-caudal cruciate ligament
What are the extra-capsular ligaments of the genual joint?
-medial collateral ligament
-lateral collateral ligament
What is the role of the cranial cruciate ligament?
prevent tibia from moving cranially
What is the role of the caudal cruciate ligament?
prevent tibia from moving caudally
What happens when the cranial cruciate ligament ruptures?
observe cranial drawer sign (tibia moves front)
What happens when the caudal cruciate ligament ruptures?
observe caudal drawer sign (tibia moves back)
What ligaments must be cut to remove the medial meniscus?
-transverse ligament
-cranial tibial ligament of medial meniscus
-caudal tibial ligament of medial meniscus
-must blunt dissect medial meniscus away from medial collateral ligament
What ligaments must be cut to remove the lateral meniscus?
-transverse ligament
-cranial tibial ligament of the lateral meniscus
-caudal tibial ligament of the lateral mensicus
-meniscofemoral ligament
