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53 Cards in this Set
- Front
- Back
The long extensor tendons include |
-Extensors of the wrist -Extensors of the digits |
|
Extensors of the wrist are |
-ECRL -ECRB -ECU |
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Extensors of the digits are |
-EDC -EDM (extensor digiti minimi) -APL (abductor policis longus) -EPB -EPL -EI (extensor incidius) |
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These tendons pass the wrist to attach to the carpal bones, metacarpal bone, or the dorsum of the fingers. |
The long extensors tendons |
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At the wrist, the long extensor tendons pass under the EXTENSOR RETINACULUM through WHAT |
dorsal fibrous compartments I-VI |
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Extension of the wrist can also be called |
dorsi flexion of the wrist. |
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What is the name of a strong fibrous band that holds the extensor tendons in place? |
The extensor retinaculum |
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The extensor retinaculum attaches to what? (laterally and medially) |
-Laterally: the distal end of the radius -Medially: the styloid process of the ulna, the triquetrum and pisiform bones |
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The extensor retinaculum functions as a pulley to prevent WHAT? |
Bowstringing of the long extensor tendons during wrist extension (dorsiflexion) |
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How many compartments of the extensor retinaculum is there? |
6! (I-VI) |
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The long extensor tendons pass through the six compartments, which are listed from _________ to __________. |
lateral to medial |
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Compartment I muscles |
APL and EPB |
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Compartment II muscles |
ECRL and ECRB |
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Compartment III muscles |
EPL |
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Comparmtnet IV |
EDC and EI |
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Compartment V muscles |
EDM |
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Compartment VI muscles |
ECU |
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From the forearm _____ and ______ cross over diagonally. |
ECRL and ECRB |
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Each compartment of the extensor retinaculum forms an |
osseofibrous tunnel |
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When passing through the osseofibrous tunnel (under the extensor retinaculum), the tendons in each compartments are surrounded by |
synovial sheaths, which protect them against friction. |
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After passing through the extensor retinaculum, the tendons of the extensors of the digits continue (proximally or distally) |
Distally |
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Digits 3 and 4 get how many tendons each? |
One! (EDC only) |
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Digits 2 and 5 get how many tendons each? |
Two! (EDC plus EI and EDM, respectively) |
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SO, the middle finger (digit III) and the ring finger (digit IV) only get |
the EDC tendon |
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BUT, the pointer finger (digit II) gets the |
EDC tendon and the EI tendon |
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AND the pinky finger (digit V) gets the |
EDC tendon and the EDM tendon |
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In the pointer finger (digit II) and the pinky finger (digit V), the ___ tendons are radial (lateral) to the accessory long extensor tendons (____ and ____). |
EDC tendons are radial/lateral to the long extensor tendons (EI and EDM) |
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In the pointer finger (digit II), the ___ tendon is ulnar (medial) to the ___ tendon |
EI is ulnar to the EDC |
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In the pinky finger (digit V), the ___ tendon is ulnar to the ____ tendon |
EDM tendon is ulnar to EDC |
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EDC is always ______ to other tendons |
RADIAL |
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OTHERS = |
ULNAR |
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Just proximal to the MP joints the tendons of the EDC communicate through tendinous junctions. What is this called? |
Juncturae Tendinum |
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What does the juncture tendinum prevent? |
Digits 3 and 4 from being able to extend individually |
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Distal to the MP joints, on the dorsum of the digits, the long extensor tendons of the digits (EDC, EI, EDM) do what? |
Expand and become flat |
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They are joined by the tendons of the intrinsic hand muscles (interossei and lumbricals) to form the _______________ which extends from the MP joint to the base of the distal phalanx. |
digital extensor expansion |
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What is a structure on the posterior surface of all digits that is made rfom the expansion of the tendons of the long extensor muscles of the digits called? |
Extensor Expansion |
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What muscles does the extensor expansion include? |
EDC, EI, and EDM |
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What tendons make up the thumb extensor expansion ? |
EPL and EPB |
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In the fingers (NOT in the thumb), the tendons of the lumbricals and interossei muscles joint the extensor expansion at the (same/different) levels. |
Different! |
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The LUMBRICALS join more DISTAL than the |
interossei muslces! |
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The portion of the extensor expansion where the tendons of the long extensor muscle of the digits are held down to the bone at the level of the MP joint by a structure called the |
Extensor hood (or sagittal bands) |
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What part of the extensor expansion extends the MP joints? |
Extensor hood |
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This structure holds down the tendons as they come into the MP joint (it is the part that extends the MP joint) |
Extensor hood |
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Where are the following structures founds? -Extensor hood (sagittal bands) -Central tendon (central slip) -Lateral bands (slips) -Terminal tendon -Interossei muscles -Lumbricals |
The posterior surface of the digits |
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This structure is part of the extensor expansion and inserts into the base of the middle phalanx. |
Central tendon (central slip) |
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What joint does the central tendon (central slip) extend? |
the PIP joint (because it extends to the middle phalanx) |
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Prior to the insertion of the central tendon into the middle phalanx, the tendons divide into |
two lateral bands (slips) |
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The lateral bands then rejoin distally, to form the |
terminal tendon |
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Which part of the extensor expansion inserts into the base of the distal phalanx? |
terminal tendon |
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Which tendon extends the DIP joint? |
Terminal tendon |
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The interossei muscles insert into the extensor expansion at the level of the |
extensor hood (more proximal) |
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The lumbricals insert just distal to |
the extensor hood (more distal) |
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When contracting, the intrinsic muscles (lumbricals and interossei) perform a combined movement of |
MP flexion and PIP + DIP extension
(The line of pull is from the palmar surface to the dorsal surface anterior to the MP joint) |