Biomech unit 4 Upper limb & Spine - deck 4 Flashcards
What is the range of motion of each of the carpometacarpal, metacarpophalangeal and interphalangeal joints of the fingers is dependent on?
Their bone structure and the surrounding ligaments.
State the movements permitted in the 2nd to 5th CMC joints in the fingers
- The 2nd and 3rd CMC joints are basically immobile
- The 4th and 5th CMC joints permit a small amount flexion-extension
What is the range of motion permitted by the 4th and 5th CMC joints in the fingers ?
10 to 15 degrees at the 4th and 20 to 30 degrees at the 5th
What movements do the MCP joints of the fingers allow?
Flexion-extension & Abduction-adduction
What is the range of flexion-extension of the MCP joints in the fingers?
- Max flexion is 90 degrees
- Extension varies considerably depending on the laxity of an individuals ligamnets
What movements are permitted by the DIP and PIP joints of the fingers?
Only flexion-extension
Which of the DIP or PIP joints allows the most amount of flexion?
The PIP joints
What is the range of flexion allowed by the PIP and DIP joints of the fingers ?
- PIP joints allow 100-110 degrees
- The DIP joints allow 90 degrees
What is extension beyond the neutral position, with the fingers straight termed ?
Hyperextension
What is range of extension permited by the DIP and PIP joints in the fingers?
It varies considerably between individuals and is dependent largely on ligament laxity just like in the MCP joints
How does the structure and function of the MCP, PIP and DIP joints of the thumb compare to those of the fingers?
Structure and function is the same
However the MCP does not generally allow as large an amount of flexion as those of the fingers. The range varies from 30 to as much as 90 degrees. The amount of extension though is generally greater with normally around 15 degrees being possible.
What joint of the thumb is of particular importance functionally?
The carpometacarpal (CMC) joint
In what plane are flexion and extension of the thumb in terms of movement permitted by the CMC joint ?
In the plane of the palm
Define what flexion and extension of the thumb permitted by the CMC joint is
- Flexion is when the thumb moves across the palm
- Extension is when the thumb moves away to the side from the palm
Remember that the movements of the thumb are described in relation to the plane of the palm (of the hand)
Believe the CMC joint allows this movement
What is the range of motion of flexion-extension of the thumb permitted by the CMC joint ?
- 15 degrees of flexion
- 20 degrees of extension
Describe what abduction of the thumb is and state the range of motion in degrees
- This is when the thumb moves away from the hand
- range of motion = 60 degrees
Believe the CMC joint allows this movement
Is rotation of the thumb possible?
Yes to a small degree
(believe it is allowed by the CMC joint of the thumb)
Describe the movements of the thumb which together achieve adduction of the thumb
- Flexion and rotation of the carpometacarpal joint and flexion of the metacarpophalangeal and interphalangeal joints (shown in fig. C&D)
- Adduction = if the thumb is moved across the palm so that the tip touches the base of the little finger
How do the muscles in the forearm control movements of the digits?
Their distal tendons cross the wrist and are then inserted onto the digits
e.g. the flexor digitorum profundus originates from the anterior aspect of the ulna and has insertions on the distal phalanges, allowing it to flex the distal interphalangeal joints
As the wrist changes position how does it affect the muscle tendons which cross the wrist ?
- It alters the functional lengths of the muscle tendons
- e.g. when the wrist is straight the fingers can be easily clenched into a tight fist, however, if the wrist is flexed first of all then it becomes difficult to fully flex the fingers.
What is the the range of wrist flexion is dependent on?
Whether the fingers are straight or flexed. (this is the same idea as when wrist position changes the functional length of the muscle tendons so does finger position)
e.g. With the fingers extended the wrist can flex to almost 90º, but with the fingers clenched into a fist the range of wrist flexion is significantly reduced
What bones form the spine spliting the bones into regions and state the number of each in each region ?
- 24 unfused vertebrae (7 cervical, 12 thoracic, 5 lumbar)
- The sacrum (5 fused vertebrae) and the coccyx (4 fused vertebrae)
State the 5 regions of the spine
- cervical
- thoracic
- lumbar
- sacrum
- coccyx
What are the main differences between each region of the spine ?
The vertebrae are slightly different in structure, as is the overall structure, function and range of motion in each region
