unit 15- posterior forearm and hand
dorsal metacarpal arteries
- branches of the dorsal carpal arch to carry blood to the fingers
first dorsal metacarpal artery
- directly from the radial artery before it crosses through the two heads of the first dorsal interosseous muscle
deep radial nerve
- supplies the extensor carpi radialis brevis and supinator muscles
no- some people only have 3 because not everyone has one going to their pinky finger
does every single person have 4 tendons from their extensor digitorum? explain.
no it inserts on the upper ulna (aka doesn't cross the wrist joint) so it only works on the elbow joint
does the anconeus muscle work on the wrist?
no
does the brachioradialis cross the wrist?
no it only works on the elbow joint (to flex it) because it inserts on the styloid process of the radius which is above the wrist joint (since it doesn't cross the joint it cant work on it)
does the brachioradialis work on the wrist joint?
no! it is purely cutaneous (but that means it does have some visceral efferents aka postganglionic sympathetics for those sweat glands)
does the superficial radial nerve have somatic motor fibers?
anatomical snuff box
edges are tendons of muscles related to the thumb -tendons of abductor pollicis longus and extensor pollicis brevis -tendon of extensor pollicis longus
when it enters the extensor retinaculum it is one tendon but as it emerges from the distal side of the extensor retinaculum and heads towards the pinky finger it is typically 2 separate tendons next to each other
explain the tendons of the extensor digiti minimi
6
how many osteofibrous comparments under the extensor retinaculum are there?
O: lateral epicondyle and ulna, wraps around radius I: lateral surface of the radius A: supinates the forearm N: deep branch of radial nerve
origin, insertion, action, and innervation of the supinator muscle
superficial radial nerve
purely cutaneous to posterolateral surface of the hand
dorsal branch of the ulnar nerve
serves the medial aspect of the digits of the dorsal side
dorsal carpal arch
supplied by the dorsal carpal branches of the radial and ulnar arteries and anterior and posterior interosseous arteries
first compartment
the abductor pollicis longus passes through the ________ ________under extensor retinaculum
medial
the dorsal branch of the ulnar nerve supplies the _____ aspect of the digits of the dorsal side
2nd 3rd
the extensor carpi radialis LONGUS inserts on the base of the _____ metacarpal while the extensor carpi radialis BREVIS inserts on the base of the _______ metacarpal
second compartment
the extensor carpi radialis brevis passes through the ______ ______ under the extensor retinaculum
second compartment
the extensor carpi radialis longus passes through the _________ _______ under extensor retinaculum
extensor retinaculum
the extensor carpi radialis longus passes through the second comparment under the ______ _______
sixth comparment
the extensor carpi ulnaris passes through the _______ _______under extensor retinaculum
medial/ulnar side
the extensor digiti minimi inserts on what side of the extensor digitorum tendon to the pinky finger?
fifth comparment
the extensor digiti minimi passes through the ______ compartment under the extensor retinaculum
fourth compartment
the extensor digitorum passes through the _______ ______ under the extensor retinaculum
medial/ulnar
the extensor indicis inserts on the ______ side of the extensor digitorum tendon to the index finger
fourth compartment
the extensor indicis passes through the______ ______under extensor retinaculum
first comparment
the extensor pollicis brevis passes through the ______ ________ under extensor retinaculum
third compartment
the extensor pollicis longus passes through the _______ _________ and changes direction at the dorsal radial tubercle (Lister's tubercle)
radial artery (before it crosses through the two heads of the first dorsal interosseous muscle)
the first dorsal metacarpal artery comes directly from what?
anconeus muscle
the interosseous recurrent artery remains deep to what muscle?
anconeus (branch from the arm not in cubital fossa) extensor carpi radialis longus brachioradialis muscles
the main trunk of the radial nerve supplies what 3 muscles before it divides?
above the wrist
the posterior branch of the anterior interosseous artery appears where?
supinator
the posterior interosseous artery enters the compartment deep to what muscle?
deep radial nerve
the posterior interosseous nerve is a continuation of what nerve?
anterior aspect
the radial nerve divides on the _______ aspect of the elbow
scaphoid bone
What is the most frequently fractured carpal bone?
5 2
_____ superficial layer muscles take origin from a common tendon on the lateral epicondyle while _____ take origin from the supracondylar line above it
posterior interosseous nerve
all of the deep layer muscles (besides the supinator) are innervated by what?
radial nerve and its branches
all of the posterior forearm muscles are innervated by what?
lateral epicondyle supracondylar line/ridge
all superficial layer muscles take partial origin from a common tendon from the ______ _______ (5) or the ________ ________ (2) above it
L: tendons of abductor pollicis longus and extensor pollicis brevis M: tendon of extensor pollicis longus
borders of the anatomical snuff box : lateral border: medial border:
long extensor of the thumb
content of 3rd compartment
tendon of the extensor digiti minimi muscle
content of 5th compartment
tendon of extensor carpi ulnaris muscle
content of 6th compartment
the tendon splits into 3 parts - one central split and then 2 bands on either side.. the central split inserts on the middle phalanx while the 2 lateral slits travel down further to insert on the distal phalanx (looks similar to the FDS splitting and FDP traveling through)
describe what happens to the tendons of the extensor digitorum as they go to insert on the digits
skin and fascia
what forms the roof of the snuff box?
superficial radial nerve deep radial nerve (posterior interosseous nerve - a continuation of the deep radial)
2 branches of the radial nerve when it divides on the anterior aspect of the elbow
two extensor carpi radialis muscles (longus and brevis)dorsa
2 contents of the 2nd compartment
tendons of extensor digitorum and extensor indicis muscles
2 contents of the 4th compartment
long abductor and short extensor of the thumb
2 contents of the first compartment
supinator abductor pollicis longus extensor pollicis brevis extensor pollicis longus extensor indicis
5 muscles of the deep layer of the posterior forearm/hand from most proximal to most distal
brachioradialis extensor carpi radialis longus extensor carpi radialis brevis extensor digitorum extensor digiti minimi extensor carpi ulnaris aconeus
7 muscles of the superficial layer of the posterior forearm/hand
no-- the radial nerve innervates a portion of the back of the hand where the median nerve was on the front (the median nerve only innervates the distal phalanx area of the 3.5 fingers) the ulnar nerve still has about its same 1.5 digit innervation area
is the cutaneous supply of the dorsal aspect of the hand the same as the palmar aspect?
no -- there are insertions on all the other metacarpals though
is there a muscle from the posterior compartment of forearm that inserts on the 4th metacarpal?
extensor carpi radialis longus extensor carpi radialis brevis extensor digitorum extensor digiti minimi extensor carpi ulnaris anconeus (on top)
list the 6 muscles of the superficial layer of the posterior compartment from most lateral to most medial
listers tubercle
name for the dorsal radial tubercle
extensor expansion
name for the four tendons from the extensor digitorum muscle spread out over the metacarpophalangeal joint
O: radius, ulna and interosseous membrane I: base of first metacarpal A: abducts and extends the thumb N: posterior interosseous nerve
origin, insertion, action and innervation of the abductor pollicis longus
O: lateral epicondyle I: on the olecranon and upper one-fourth of ulna A: extends the elbow N: main trunk of the radial nerve (from the ARM not in the cubital fossa)
origin, insertion, action and innervation of the anconeus muscle
O: lateral supracondylar ridge I: distal radius above styloid process A: flexes forearm at elbow N: main trunk of the radial nerve
origin, insertion, action and innervation of the brachioradialis
O: lateral epicondyle I: base of third metacarpal A: extends and abducts the wrist N: deep branch of the radial nerve
origin, insertion, action and innervation of the extensor carpi radialis brevis
O: lateral supracondylar ridge I: base of second metacarpal A: extends and abducts the wrist N: main trunk of the radial nerve
origin, insertion, action and innervation of the extensor carpi radialis longus
O: lateral epicondyle I: on base of fifth metacarpal A: extends and adducts the wrist N: posterior interosseous nerve
origin, insertion, action and innervation of the extensor carpi ulnaris
O: lateral epicondyle I: on extensor expansion of little finger A: extends the little finger N: posterior interosseous nerve
origin, insertion, action and innervation of the extensor digiti minimi
O: lateral epicondyle I: as extensor expansions to middle and distal phalanges of four fingers A: extends the medial four fingers and also extends the wrist N: posterior interosseous nerve
origin, insertion, action and innervation of the extensor digitorum
O: ulna and interosseous membrane I: on extensor expansion of index finger 15-5 A: extends the index finger N: posterior interosseous nerve
origin, insertion, action and innervation of the extensor indicis
O: radius and interosseous membrane I: base of the proximal phalanx of thumb A: extends metacarpophalangeal and carpometacarpal joints of the thumb N: posterior interosseous nerve
origin, insertion, action and innervation of the extensor pollicis brevis
O: ulna and interosseous membrane I: base of the distal phalanx of thumb A: extends interphalangeal, metacarpophalangeal and carpometacarpal joints of the thumb N: posterior interosseous nerve
origin, insertion, action and innervation of the extensor pollicis longus
6 (brachioradialis doesn't really count) 5
there are ____ muscles in the superfiical layer and _____ muscles in the deep layer
2 (superficial and deep)
there are ______ layers of muscles in the posterior forearm and hand
muscular branches
there are numerous ________ _______of radial artery
dorsal digital arteries
there are one of these arteries on each side of each finger
interosseous recurrent artery
this artery remains deep to the anconeus muscle
posterior interosseous artery
this blood vessel enters the compartment deep to the supinator muscle
abductor pollicis longus extensor pollicis brevis
what 2 deep layer muscles pass through the first compartment under the extensor retinaculum?
extensor carpi radialis brevis supinator (then it becomes the posterior interosseous after this)
what 2 muscles are innervated by the deep radial nerve?
extensor carpi radialis longus extensor carpi radialis brevis
what 2 superficial layer muscles pass through the second comparment under the extensor retinaculum
brachioradialis extensor carpi radialis longus anconeus (from the ARM not in the cubital fossa/forearm)
what 3 superficial layer muscles are innervated by the main trunk of the radial nerve?
extensor digitorum extensor digiti minimi extensor carpi ulnaris
what 3 superficial layer muscles are innervated by the posterior interosseous nerve?
radial artery 2 extensor carpi radialis tendons (longus and brevis)
what 3 things pass through the anatomical snuff box?
tendons of abductor pollicis longus extensor pollicis brevis
what are the 2 tendons that from the lateral (radial) border of the snuff box?
styloid process scaphoid bone little bit of the trapezium and 1st metacarpal
what forms the floor of the snuff box?
dorsal carpal branches of the radial and ulnar arteries anterior and posterior interosseous arteries
what is the dorsal carpal arch supplied by?
tendon of extensor pollicis longus
what is the medial (ulnar) border of the snuff box?
supinator (deep branch of radial nerve)
what is the only muscle of the deep layer not innervated by the posterior interosseous nerve?
it WRAPS AROUND the radius from the lateral epicondyle to insert on its lateral surface (this is how it can cause supination)
what is the supinator muscle's relationship to the radius?
it is innervated by the main trunk of the radial nerve but it's innervation comes from the ARM not the forearm (not in the cubital fossa)
what is unique about the innervation of the anconeus muscle?
anconeous
what muscle assists the triceps with elbow extension?
extensor carpi radialis brevis
what superficial layer muscle is innervated by the deep branch of the radial nerve?
it FLEXES the elbow (typically posterior compartment muscles are extensors)
what's unique about the brachioradialis? (one of the reasons it's kind of weird to compartmentalize it into the posterior compartment of the forearm)
the extensor retinaculum is bound down in places along its expansion across the wrist and therefore it creates 6 smaller compartments versus the flexor retinaculum which was not bound down in the middle and only created 1 central compartment aka the carpal tunnel
whats a difference between the extensor retinaculum and flexor retinaculum?
after it passes through the two heads of the supinator muscle and emerges on the posterior side
when does the deep radial nerve changes its name to the posterior interosseous nerve
dorsal radial tubercle (listers tubercle)
where does the extensor pollicis longus change directions?
pinky (extensor digiti minimi- superficial layer) index (extensor indicis - deep layer)
which 2 fingers have their own separate extensors besides the ones from the extensor digitorum? name the extensors
3rd (extensor pollicis longus) 5th (extensor digiti minimi) 6th (extensor carpi ulnaris)
which 3 compartments only have 1 tendon in them? (name the tendon)
extensor pollicis longus
which muscle of the posterior comparment undergoes a change of direction via the dorsal radial tubercle?
