Hand Flashcards
When you talk about the (elbow/hand), we know that its’ importance for fine motor tasks is what defines it.
hand
The (shoulder/hand) is a sensory organ and an effector organ.
hand
As a (motor/sensory) organ, the hand allows us to have an intricate perception of our environment right, we can touch and feel things and recognize what that object is without even looking at it.
sensory
There’s (a lot/not a lot) of nervous system inputs both back and forth between the brain and the hand.
a lot
The hand is also an (sensory/effector) Organ because you’re able to complete complex tasks with your hands. Think of Kodali’s anatomy professor lab practical he had to do when he had to reach inside the bone box and identify the bone without looking. What was happening there is that his hand was reaching in and his brain knows all the anatomy information and he has to now make sense of the input he was getting from his hand . So that’s how some of those very routine tasks that we take for granted, are happening, there’s like a big connection between the hand in the brain.
effector
The CMC joint at the thumb is (the same as/different than) the CMC joints from digits 2-5.
different than
The CMC joint at (the thumb/digits 2-5) gets its’ stability from the joint capsule and the supporting ligaments
the thumb
The ligaments can guide the motion of the thumb. So if they’re appropriately tight in their position they will help guide some motion. So medial rotation at the cmc joint is coupled with either ___ or ____ . A lateral rotation couples with ___ or ____.
flexion or abduction; extension or adduction
The thumb is rotated almost 90 degrees from the other CMC joints which is why flexion/extension occurs in the ___ plane and abduction and adduction occurs in the _____ plane for these movements at the thumb.
frontal; sagittal
CMC joints 1, 4, & 5 is (less/more) mobile than the CMC joints 2 and 3.
more
The ____ pillar is a mechanism that we have that enhances grip strength and also provides a very firm attachment to the ECRL, ECRB, and the FCR. Because this is a very sturdy area, the attachment of the muscle to a very sturdy area allows those muscles to operate very efficiently and with strong force. When you squeeze an object you do not feel as much movement in the CMC joints 2 and 3 compared to CMC joints 4 and 5 and that sturdy joint is where a lot of those major wrist extensors and flexors attach and that allows them to operate efficiently.
central
Stability for the __& __ joints comes from the bone, capsule & ligaments, & the volar plate. The stability of these joints is critical to the biomechanics of the hand overall.
MCP & IP
As you flex the (IP/MCP) joints those ligaments start to get stretched out and more taught. So increased tension in flexion leads to increased (mobility/stability) because of the ligaments. One way of visualizing this is if you take your finger and you abduct them. Now take your MCPS and flex them and you’ll see that it is much harder and that is because that joint is more stable because of the ligamentous tension.
MCP; stability
For the (MPS/IPS), the collateral ligaments is taught throughout the range of motion and that makes sense if you look at your finger. Can you ever abduct at that joint? No matter where you are you can’t really abduct, so the ligaments are (mobile/stable) throughout the range of motion, they’re just tight all the time. You’re not going to have that wiggle room where you can abduct at the IP joints. If you abduct too far you’re actually going to tear the ligament.
IPS; stable
All of the collateral ligaments are important to maintain (mobility/stability) in order to grasp things.
stability
Metacarpals _ and _ makeup the central pillar.
2 and 3
At the thumb MCP joint there is virtually no (flexion/abduction) and it is very stable. If you stabilize the first metacarpal and you try to wiggle it sideways you will see it is very stable.
abduction
From the thumb going to the 5th MCP joint there is more and more (mobility/stability) available and it provides additional range for opposition in order to grasp objects. I am able to manipulate the grasp around a lot of different sized objects because of the mobility that (increases/decreases) through the MCP joints as I move from the thumb to the 5th finger.
mobility; increases
The volar plate enhances joint (mobility/stability) by limiting (hyperflexion/hyperextension).
stability; hyperextension
The MCPS are taught in (flexion/extension) and slacking in (flexion/extension).
flexion; extension
The volar plate is more responsible in (flexion/extension) for stability, so it is going to prevent hyperextension
extension
The volar plate gets more taught during (flexion/extension).
extension
The volar plate buckles in (flexion/extension) and the different layers fold on over themselves and become redundant tissue.
flexion
If the volar plate stays in fixed flexion (the finger stays fixed) you’re going to get a contracture and those fibrous ends tend to stick together and when that happens the flexor tendons can tend to stick to the volar plate as well so you lose even more function because now the flexor tendons can’t glide normally like they would. As a result you will have very limited ability to (flex/extend).
extend
Just because muscles are finger flexors as their primary goal does not mean that they do not have the ability to also flex the wrist.
Got it
In order to isolate the muscle force for the finger flexors, the (flexors/extensors) of the wrist have to turn on in order to negate the flexion that is generated from the finger flexors of the wrist in order to generate the most force to have good grip strength. So if I am flexing my fingers my wrist has the potential to go into flexion. So in order for those finger flexors to work efficiently the (flexors/extensors) of the wrist have to turn on.
extensors; extensors
The (intrinsics/extrinsics) of the thumb allow us to kind of place our thumb in order to put different pressure on different objects. Prehension is the act of holding on to something. Those (intrinsics/extrinsics) of the thumb are what allow you to place your thumb in more specific grasps.
extrinsics; extrinsics
The lumbricals (flex/extend) at the (MCP/IP) and keep it straight.
flex ; MCP
For class all we need to know is that we have flexor tendon sheaths and they’re made up of these pulleys. When a pulley is ruptured and you try and flex the distal IP joint and there’s nothing tethering this down here, so you can have this bowstring tendon and with that you are going to get (increased/reduced) grip strength and (increased/reduced) flexion ROM because now the tendon does not have a great leverage in order to move the distal segment.
reduced; reduced
Remember the example in the second week of class when the surgeon moves the tendon further away and it increases its’ moment arm? We said the potential consequences of that would be decrease in strength and decreased ROM overall and the reason why was because the joint is set up in a particular way where now it doesn’t have the capability of contracting as well, and so, even though it has a bigger internal moment arm, it is not as efficient. You’ll lose ROM in that situation and that is kind of what is going on with the flexor tendon sheaths with the ruptured pulleys.
Got it
The extensor indicis and extensor digiti minimi work to provide a little extra independent function. Instead of just a common extensor tendon for all of my digits, I also have the ability to extend at the _ ray and the _ ray. You can extend those individually so it allows for more function and dexterity, not necessarily more strength.
2nd; 5th
If the extensor digitorum is cut, the biggest deficit you will see is extension in what joint?
The MCP joint
The anatomy of the extensor mechanism is that we have this dorsal hood that also blends in with the extensor digitorum tendon over the dorsum of the __ joint.
MCP
There are some fibers that continue along the way of the extensor digitorum and those fibers continue to what two bands?
The central band and the lateral band
As far as the central band goes, it transmits extensor force from the extensor digitorum across the __ joint
PIP
The lateral bands transmit extensor force from the extensor digitorum, lumbricals, and the interossei across what two joints?
PIP & DIP joint
The interossei help function in (flexion/extension) of the PIP and DIP joints.
extension
If fibers come down anterior to the axis of rotation at the MCP joint, they will pull it into (flexion/extension).
flexion
Remember that in the extensor mechanism there will be MCP (flexion/extension) and IP (flexion/extension).
flexion; extension