Elbow and Forearm Flashcards
In the Elbow Joint three are four joints, what are they called?
1- Humero-ulnar joint
2- Radio- humeral joint
3- Proximal Radio-Ulnar joint
4- Distal Radio-Ulnar Joint
What sort of joint is the Humero-ulnar joint?
Synovial Hinge with 1 DOF
What motion occurs at Humero-ulnar joint?
Flexion/Extension
The carrying angle of the Humero-ulnar joint is bias to which side?
Bias to Ulnar side due to the way the trochlea is located.
There are two collateral ligaments located around humero-ulnar joint. what are they called?
Medial and Lateral Collateral Ligament
The normal angulation of the elbow is called what?
the slightly abducted angle is called the Carrying angle which is valgus
If you decrease the Carrying angle of the elbow what is it called to do?
Varus
When there is hyper valgus force the elbow which ligament is stressed?
Medial collateral ligament
When there is hyper varus force on the elbow which ligament is stressed?
Lateral collateral ligament
If the Medial collateral ligament is torn what surgery is performed?
Tommy John surgery
What comes into contract with the Radio-humeral joint?
Fovia of the radial head and capitulum of the humerus
Radio-humeral joint is only comes into contact when what happens?
arm is extended and is weight bearing
The radius and humerus comes into contact without weight bearing when? and where?
Elbow flexion
Radial head fits into the radial fossa of humerus
Which two joints are the union of the radius and the ulnar in the elbow?
Proximal and Distal Radio-Ulnar joint
What is in between the Radial and Ulnar?
interosseous membrane
In between the shafts of the radius and the ulnar what type of joint do we have?
syndesmosis
What is the function of the interosseous membrane?
stabalization and transfer forces between radius and ulnar
Both Radio-ulnar joints have 1 DOF which is what?
pronation/supination
What type of joint only has rotation like the Radio-ulnar joints
Pivot joints
At the Proximal portion of the Radio-ulnar joint is what ligament?
Anular Ligament
What is the Anular Ligament?
surrounds the heads of the joints, runs from the radial notch of the ulnar around the head of the radius. The inner surface is lined with hyaline ligament to decrease friction. Due to the head of the Radius’ constant spin.
What happens when the Anular Ligament is torn?
not able to pronate or supinate the forearm. the radial head wouldn’t be held in place
Along the distal portion of the Radio-Ulnar joint is what two ligaments?
Palmar and Dorsal Radio-ulnar ligament
What are the Palmar and Dorsal Radio ulnar ligament’s function?
Palmar radio-ulnar ligament prevents excessive supination
Dorsal radio-ulnar ligament prevents excessive pronation
Where is the area of the palmar and dorsal radio-ulnar ligaments?
Running from the distal ulnar-styloid process to Ulnar notch is palmar and dorsal on each side.
What are the three anterior arm muscles?
Biceps brachii- supination, elbow flexion, shoulder flexion
Coracobrachialis- just deep to short head of biceps, shoulder flexion, horizontal ADD, and flex ADD
Brachilais- deep to the biceps distally, attaches to anterior aspect of the humerus the distal 2/3. projects inferiorly and inserts into the ulnar tuberosity. ALL types of elbow flexion
what are the attachments of brachialis?
anterior aspect of the humerus the distal 2/3 to ulanr tuberosity
What innervates all three anterior arm muscles and why?
musculocutaneous nerve bc its the anterior aspect of the arm
What innervates all the posterior muscles of the arm?
radial nerve
What action happens with the triceps brachii?
shoulder extension and elbow extension
What action happen with the anconeous?
elbow stabilizer and small elbow extension
What are the attachments of the ancoenous?
Its actually part of the anterior forearm. just inferior to the alecronon process, attaches to the shaft of the ulna to the lateral epicondyle then down to the alecronon.
What are the two common origin points of forearm muscles?
medial aspect (medial epicondyle) and lateral aspect (lateral epicondyle) of the humerus
What type of muscles attach to medial and lateral of the humerus for the forearm muscles?
Medial- are known as flexor muscles
Lateral- are known as extensor muscles
What layers does Flexors have?
Superficial layer, Intermediate layer, and Deep layer
What layers does Extensors have?
Superficial layer and deep layer
All muscles that attach to medial and lateral distal humerus cross to the anterior to humeral-ulnar joint. therefore all the muscles that attach to the medial and lateral epicondyles will be weak what muscles to the elbow?
weak flexors.
How do you stretch the extensors and flexors of the forearm fully?
extend the elbow
What are the four muscles of the superficial layer of the flexors?
Flexor carpi ulnaris
Pronator teres
Palmaris Longus
Flexor carpi radialis
which superficial flexor muscle is most medial?
Flexor carpi ulnaris. originates on the medial epicondyles runs medially and attaches to Hook of Hamtae and ends on the base of the the 5th metacarpal.
Which carpal bone is inbedded in the superficial flexor carpi ularis tendon?
pisiform
what nerve is just deep to the flexor carpi ulnaris?
Ulnar nerve which also innervates the flexor carpi ulnaris
What action does flexor carpi ulnaris do?
wrist flexion and ulnar deviation (palmar adduction)
If the flexor carpi ulnaris contracted alone without any other muscles?
combination of forearm flexion and ulnar deviation
Just lateral to the flexor carpi ulnaris is what muscle?
palmaris longus
Whats unique about palmaris longus muscle?
thin long belly and very long tendon
What are the attachments for palmaris longus?
originates medial epicondyle, travels superficial to the carpal tunnel and then blends in with the thick palmar apeneurosis
What motion does palmaris longus provide?
very weak wrist flexor due to the thinness. Not everyone has it. you can live without it, its very vistidual.
How can you find the palmaris longus if you had it?
resist the forearm flexion and active the palmar apeneurosis by tensing the palm with all fingers together.
How many muscles does the ulnar nerve innervate?
1.5 Flexor carpi ulnaris and half of flexor digitorum profundus
since you know only 1.5 muscles are innervated by the ulnar nerve what can you assume innervates the palmaris longus?
Median nerve
What muscle is lateral to palmaris longus?
Flexor carpi radialis
what are the attachments of flexor carpi radialis?
originating on the medial epicondyle of the humerus, travels distally, and continues into the hand into the bases of 2nd and 3rd metacarpals.
What does runs just lateral to the flexor carpi radialis run in the level on the wrist?
Radial artery
what action does flexor carpi radialis do?
Wrist flexion and radial deviation (palmar abduction)
What needs to happen for uniform wrist flexion?
Both Flexor carpi ulnaris and flexor carpi radialis needs to contract. If not there will be slight deviation
What are the attaches and orientation of the Pronator teres?
originates on the medial epicondyles sweeps across the forearm, and ends mid shaft on the radius.
What is the only muscle to not reach the wrist level of the superficial flexor muscles?
Pronator Teres
What nerve runs in between the two head of the pronator teres?
Median Nerve. it is also innervated by the pronator teres
What motion does the pronator teres provide?
pronation
What is the one muscle of the intermediate layer of the flexor?
Flexor digitorum superficialis just deep to all the superficial layer of the flexor
What are the attachments of the flexor digitorum superificalis?
originates on the medial epicondyle, projecst downward under the superficial layer, right under it is the median nerve, and transmits into the hand via the carpal tunnel (all 4 tendons) and then into the middle phalanges of digits 2, 3, 4, and 5.
What are the actions of the flexor digitorum superficialis?
Wrist flexion, metacarpal phalangeal joint flexion, proximal interphalangeal joint flexion of digits 2-5
What are the muscles of the deep layer in the flexors?
Flexor digitorum profundus
Flexor pollicis longus
Pronator quadratus
Where do all the deep layer flexors originate from?
medial epicondyle but the flexor digitorum profundus (originates on proximal ulnar on the coronoid process)
what are the attachments of Flexor digitorum profundus?
Originates from the proximal aspect of the ulnar on the coronoid process, then into carpal tunnel (all 4 tendons) then the tendons attaches to the distal phalanges of 2, 3, 4, 5 digits
What innervates the flexor digitorum profundus?
ulnar nerve (medial half) anterior interosseous nerve branch of the median nerve (lateral aspect)
What action does the flexor digitorum profundus provide?
wrist flexion, metacarpal phalanges flexion, proximal interphalanges flexion, distal interphalanges flexion.
A tear of the flexor digitorum profundus will result in what?
jersey fingers, where the tip of the finger won’t flex
More lateral to the flexor digitorum profundus is what other deep layer flexor muscle?
flexor pollicus longus
what is the orientation of the flexor pollicus longus?
unipennate, its tendon runs vertically and the muscle fibers run obliquely
flexor pollicus longus attachments are what?
originates more distally near the interosseous membrane on the distal radius, and runs through the carpal tunnel (1 tendon), and along the 1st digit and attaches to the distal phalange of the thumb.
what action dude to flexor pollicus longus?
slight wrist flexion, and more importantly first digit flexion
flexor pollicus longus is innervated by what?
anterior interosseous nerve
What muscle runs right along the interosseous membrane in between the ulnar and radius?
Pronator quadratus
What innervates the pronator quadratus?
anterior interosseous nerve
what runs up until the pronator quadratus
anterior interosseous nerve, artery, and vein
How many layers are there for the extensors ?
Superficial and deep layer
Why is the brachioradialis a good muscle to landmark?
It will notify the extensor compartment bc it is the closest muscle to the flexor compartment that is actually originating from the lateral epicondyle
What are the attachments of the brachioradialis
originates on the lateral supracondylar ridge. (most proximal of all extensors) projects along the lateral aspect of the forearm, attaches to the radius just proximal to the radiostyloid process.
what nerve travels just deep to the brachioradialis?
traveling just deep to it is the superficial radial nerve
what action does the brachioradialis produce?
elbow flexion no action in the forearm!!!! bc it doesn’t attach past the wrist
What muscle travels just medial to the brachioradialis?
extensor carpi radialis longus ECRL
What are the attachments of the ECRL?
fibers blend into the lateral epicondyle, inserts into the base of the 2nd metacarpal
what action does ECRL do?
Radial deviation and wrist extension
what nerve innervates all the extensors?
some sort of radial nerve
once the deep radialis nerve enters the Supinator what nerve does it become?
posterior interosseous nerve
supinator, brachioradilis, extensor carpi radialis longus are the only extensors that are not innervated by which nerve?
posterior interosseous nerve
What extensor muscles does the Deep radial nerve innervate?
Brachioradialis, ECRL, and Supinator
what muscle is just medial to the ECRL?
ECRB extensor carpi radialis brevis
what are the attachments of ECRB?
originates in the lateral epicondyle, insert into the base of the 3rd metacarpal
what action does ECRB provide?
wrist extension, and radial deviation slight due to the very medial positioning on the forearm.
What muscles travels medial to ECRB?
extensor digitorum
What does the extensor digitorum not do?
extend the digits
what are the attachments of the extensor digitorum?
originates on the lateral epicondyle, its 4 tends will enter the wrist dorsally then barely cross the proximal interphalangeal joints. inserts into the middle phalanges of digits 2, 3, 4, and 5
what actions does the extensor digitorum actually prodive?
extends the wrist, extend the metacarpal phalangeal joints, and very slight extension of proximal interphalangeal joints
what muscle looks like an extension of the extensor digitorum?
extensor digiti minimi
where does the extensor digiti minimi attach to?
tendon to base of the middle phalange of digit 5
where does the extensor carpi ulnaris attach to?
base of the 5th metacarpal of the dorsal surface
what motion does the extensor carpi ulnaris provide?
ulnar deviation and extension
what innervates the extensor carpi ulnaris?
posteior interosseous nerve
What is the difference between extensor carpi radialis longus/brevis and flexor carpi radialis in respect to their attachments?
one muscle -Flexor carpi radialis attaches to base of metacarpal 2 and 3 digits
two muscles Extensor carpi radilais longus and brevis attaches to base of 2 and 3 digits
what happens when extensor carpi radialis longus, extensor carpi radialis brevis, extensor capri ulnaris were to contract what happens?
wrist extension evenly
How do you find the supinator?
deep to ECRB Extensor digitorum and follow it up all the way to the lateral epicondyle and split the extensor wad
what is the attachment of the supinator?
lateral epicondyle to neck of the radius and radial tuberosity
what innervates the supinator
deep radial nerve
when does the supinator supinate?
unlike the biceps brachii, it supinates in all positions where as biceps only supinate when flexed
If you take the extensor digitorum and move it to the side what two muscle bellies are there deep to it?
Extensor indicies and extensor pollicis longus
Extensor indicies and extensor pollicis longus: which is ulnar side and which is radial side?
extensor indicies is on the ulnar side
extensor pollicis longus is on the radial side
The extendor indicies enters the hand as a tendon to the 2nd digits under what other tendon?
extensor digitorum
where does the extendor indicies attach to? hint: same as extensor digitorum.
base of the middle phlange of the 2nd digit
extensor pollicis longus loops around what bony landmark?
Lister’s tubercle
where does the extensor pollicis longus attach to?
distal phalanx of the thumb
extensor pollicis brevis and abductor pollicis longus have close muscle bellies that loops around what bone and originates in what region?
originates near the interosseous membrane and loops around the radius
where does the extensor pollicis brevis attach to?
dives under the dorsum the of the 1st digit attaches to the distal phlange of 1st digit
How can you differentiate extensor pollicis brevis and abductor pollicis longus?
abductor pollicis longus dives anteriorly to the base of the 1st digit whereas the extensor pollicis brevis attaches to the dorsal distal phlange of 1st digit
what forms the borders of the anatomical snuff box?
extensor pollicus longus, extensor pollicis brevis, and abductor pollicis longus
If someone had radial nerve lesion at the level of the elbow, what problem would they have? what about at the level of the wrist?
Level of elbow: problem with elbow extension
level of wrist: wrist drop or waiters tip position
Axillary nerve travels through what?
quadrangular space
when can the axillary nerve be compressed?
during surgical neck fracture and prolonged compression due to crutches
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