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82 terms

The Elbow

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provide mobility for the hand in space and provide stability for skilled or forceful movements of the hand
What is the function of the elbow?
humeroulnar, humeroradial, radioulnar (proximal)
What are the three joints of the elbow?
1, flexion/extension
How many degrees of freedom does the humeroulnar joint have? What movements can it do?
anterior roll, anterior glide
Describe the rolls and glides of the humeroulnar joint.
coronoid process enters the coronoid fossa
What happens when the humeroulnar joint goes into flexion?
olecranon process enters olecranon fossa
What happens when the humeroulnar joint goes into extension?
distal end of humerus bulges anteriorly 45 degrees
What allows the humerus and ulna to be almost parallel before the coronoid process enters the fossa?
2, flexion/extension and pronation/supination
How many degrees of freedom does the humeroradial joint have? What are its main actions?
radius and capitulum of the humerus
What two structures articulate at the humeroradial joint?
1, pronation/supination
How many degrees of freedom does the radioulnar joint have? What is its main action?
convex on concave, superior roll, inferior glide
Describe the arthrokinematics of the radioulnar joint, and the rolls and glides.
1/5
How much of the radio ulnar joint is bony contact?
4/5
How much of the radioulnar joint is made of the annular ring (annular ligament)?
carrying angle
in anatomical position, the forearm is held in an abducted position
valgus
is the normal carrying angle a varus or valgus position?
10-15 degrees
What is the normal carrying angle for women?
5-10 degrees
What is the normal carrying angle for men?
hand to mouth movement
What is the most likely reason for the carrying angle?
cubitis valgus
What is the name for a carrying angle greater than 20 degrees?
cubitis varus
What is the name for a carrying angle less than 5 degrees?
MCL, LCL and annular ligament
What are the three main ligaments of the elbow joint?
anterior, posterior and oblique
What are the three parts of the MCL?
valgus
What type of force does the MCL prevent?
MCL
in order for the last 20 degrees of elbow flexion to be reached, what ligament must be stretched?
LCL
Which elbow ligament is fan shaped?
anterior, intermediate, posterior
what are the three fibers of the LCL?
varus
What type of force does the LCL prevent?
LCL
What elbow ligament also supports the annular ligament and the radioulnar joint?
radial head
What structure does the annular ligament surround?
it is lined with articular cartilage
what is unusual about the annular ligament?
nurse maid's elbow
What injury results from pulling the radial head out of the annular ligament?
interosseus membrane
What is the name given to the collaginous sheet running between the radius and the ulna?
provides stability for the proximal and distal radioulnar joint
What is the function of the interosseus membrane?
neutral
In what position is the interosseus membrane taut?
pronation/supination, muscles
When is the interosseus membrane relaxed? What is supporting the system in this position?
3 joints in one capsule
What is unusual about the elbow joint capsule?
brachialis
What is the main flexor of the elbow?
brachialis, brachioradialis, biceps brachii
What are the three flexor muscles of the elbow?
spurt
Is the brachialis muscle a shunt or spurt muscle?
100 degrees of flexion
In what position can the brachialis produce the greatest torque?
crosses as a muscle
What is special about how the brachialis crosses the elbow joint?
shunt
Is the brachioradialis muscle a shunt or spurt muscle?
supination in extreme pronation or pronation in extreme supination
Other than flexion, what type of movents can the brachioradialis produce?
spurt
is the biceps brachii a shunt or spurt muscle?
80-100 degrees of flexion
In what position can the biceps brachii produce the greatest torque?
pronator teres
What muscle acts as an accessory flexor of the elbow?
myositis ossificans
calcium infiltrates the muscle, causing it to no longer work
triceps and anconeus
What are the elbow extensor muscles?
90 degrees of elbow flexion
When does the triceps generate the most isometric torque?
pronator teres and pronator quadratus
What are the pronator muscles of the elbow?
pronator teres and pronator quadratus
What muscles act as the supporting structures when the interosseus membrane is lax?
pronator quadratus
What muscle maintains compression on the distal radioulnar joint?
pronator teres
What muscle maintains compression on the proximal radioulnar joint?
supinator and biceps brachii
What muscles supinate the elbow?
90 degrees of elbow flexion
In what position is the biceps brachii the most efficent supinator?
ECRL, ECRB, FCU
What muscles are considered secondary elbow flexors?
anconeus
What muscle is considered a secondary elbow extensor?
APL, EPB, extensor indices
What muscles are considered secondary elbow supinators?
FCR, ECRL
What muscles are considered secondary elbow pronators?
ulnar
what nerve is found in the sulcus between the median epicondyle and the olecranon?
brachial artery
What is the major vascular supply to the lower arm?
130-140 degrees, soft
What is the normal ROM for elbow flexion? feel?
0 degrees, hard
What is the normal ROM for elbow extension? feel?
85 degrees
What is the normal ROM for elbow supination and pronation?
firm
What is the end feel for supination?
hard
What is the end feel for pronation?
extension with supination
What is close packed position for the humeroulnar joint?
45 degrees of flexion
What is loose packed position for the humeroulnar joint?
glide same as roll
Describe the rolls and glides of the humeroulnar joint?
70 degrees of flexion, 45 degrees of pronation
What is close packed position for the humeroradial joint?
extension with supination
What is loose packed position of the humeroradial joint?
glide same as roll (concave on convex)
Describe the arthrokinemetics of the humeroulnar joint?
superior roll, inferior glide, convex on concave
Describe the rolls and glides and arthrokinematics of the proximal radioulnar joint
hyperextension
What is generally the cause of elbow dislocation?
MCL
What ligament is usually ruptured during elbow dislocation?
ulnar nerve and brachial artery
What other structures may be damaged during elbow dislocation?
lateral epicondylitis
What is the clinical name for tennis elbow?
extensor tendon overload
What is the cause of lateral epicondylitis?
medial epicondylitis
What is the clinical name for little league elbow?
resisted wrist flexion and pronation
What can aggrivate the pain of medial epicondylitis?
gravity, tightening pecs to lock out arm
How could you extend your elbow if the radial nerve was damaged?
brachialis
What muscle is always active in elbow flexion regardless of speed of movement or presence of load?