Ortho/ Muscle Flashcards
(242 cards)
Two exam test to check for hip laxity?
- Ortaloni Test
- Barden Test
Ortaloni test typically performed in lateral but consider in dorsal recumbency if sedated. Typically gone in older dogs due to fibrous and thickening.
What are the Ortaloni and Barden Test assessing?
Joint Laxity.
Normal amount of laxity that can be noted is 2 - 3 mm.
The design of the screw hole allows for a displacement of up to ___ mm per hole in the DCPs 3.5 and 4.5 and up to ___ mm in the DCP 2.7.
1.0 mm
0.8 mm
Screws in LC-DCP can be inclined sideways to a maximum of ___ degrees and in a longitudinal direction up to ___ degress.
7 degrees
40 degrees
As opposed to 25 degress for DCP
What are the different modes DCP/LC DCP plates may function as
- compression
- neutralization, bridging
- buttress
What influences implant bending strength and stiffness?
Area moment of inertia
The area moment of inertia is a geometrical property that reflects how a cross-section’s area is distributed about an axis.
For a nail, how is the moment of inertia calculated?
Using the radius to the fourth power
This calculation emphasizes how the distribution of material affects the nail’s resistance to bending.
For a plate, how is the moment of inertia calculated?
Using the thickness to the third power
This reflects the relationship between the thickness of the plate and its structural strength.
The area moment of inertia of a solid section of an 8 mm interlocking nail is approximately how many times that of a 3.5 mm dynamic compression plate (DCP)?
6.8 times
This indicates the significantly greater resistance to bending of the larger nail compared to the DCP.
The area moment of inertia of a solid section of an 8 mm interlocking nail is approximately how many times that of a 3.5 mm broad dynamic compression plate?
3.5 times
This comparison shows the difference in bending strength between the interlocking nail and the broad DCP.
Where are interlocking nails placed in relation to the bone?
Near the neutral axis
The neutral axis is the line in the cross-section of a beam or structural element where the material experiences no tension or compression.
What type of forces are interlocking nails subjected to during weight bearing?
Compressive forces
Compressive forces push the material together, as opposed to tensile forces that pull it apart.
What moments are interlocking nails less subjected to during weight bearing?
Bending moments
Bending moments occur when an external load is applied to a beam, causing it to bend.
What types of mechanical forces does the locking mechanism of interlocking nails provide stability against?
torsion and compression
Torsion refers to twisting forces, while compression refers to forces that push or pull an object together.
What does the intramedullary location of the nail eliminate the risk of?
screw pull-out
Screw pull-out is a mode of failure where screws become disengaged from the bone, which is more common with plates, especially in weaker bone.
What are the active (dynamic) stabilizers of the shoulder joint?
The active stabilizers of the shoulder joint include:
* infraspinatus
* supraspinatus
* subscapularis
* teres minor muscles
* biceps brachii
* long head of the triceps brachii
* deltoideus
* teres major muscles to a lesser extent
These muscles work together to provide stability and movement at the shoulder joint.
What are passive mechanisms for stabilization of the shoulder joint?
Passive mechanisms do not require muscle activity and include:
* limited joint volume
* adhesion/cohesion mechanisms
* concavity compression
* capsuloligamentous restraints
What does limited joint volume refer to in the context of shoulder stabilization?
limited joint volume is a stabilizing mechanism in which the humeral head is held to the socket by the relative vacuum created when they are distracted
What are adhesion/cohesion mechanisms in shoulder joint stabilization?
“adhesion/cohesion mechanisms” refer to the stabilizing effect created by the molecular attraction between the synovial fluid within the joint and the surfaces of the humeral head and glenoid, essentially acting like a “suction cup” effect that holds the joint surfaces together when they come into contact, providing stability to the shoulder joint; this stability is dependent on the fluid’s ability to adhere to the joint surfaces and its cohesive properties within itself.
What structures are included in capsuloligamentous restraints?
Capsuloligamentous restraints include:
* glenohumeral ligaments
* joint capsule
* labrum
* tendon of origin of the biceps brachii muscle
Where are the extensors of the carpus and digits located?
They are located at the craniolateral position on the forearm.
What is the common origin point for most extensors of the carpus?
lateral epicondyle of the humerus
Which nerve innervates the extensors of the carpus?
radial n.
C6- T2
Which extensor is the most medial?
Extensor carpi radialis