Lecture 6.2 Flashcards
What kind of joint is the elbow joint?
Compound, hinge joint; elbow and proximal radioulnar joint in the same capsule..
Does the elbow joint have an articular disk/meniscus?
No
What is the blood supply of the elbow joint?
Branches of the brachial artery
What is the nerve supply of the elbow joint?
Musculocutaneous nerve
Radial nerve
Ulnar nerve
What are the main stabilizing ligaments of the elbow joint?
Radial collateral ligament
Ulnar collateral ligament:
Where does the ulnar collateral ligament originate and insert?
Goes from medial epicondyle and produces 3 bands:
Anterior: inserts onto coranoid process
Posterior: olecranon process of ulna
Oblique: coranoid and olecranon process.
Where does the radial collateral ligament insert?
Radial collateral ligament blends with the annular ligament.
What type of deviation does the forearm have?
Distal end of forearm deviates laterally compared to the proximal end. (valgus deviation)
Why is the ulnar collateral ligament the main stabilizing ligament of the elbow joint?
The ulnar collateral ligament prevents excessive valgus deviation.
*If varus deviation was the deviation of the forearm the ligaments there would have been the main stabilizing ligaments.
What can be found in the fossae of the olecranon, coranoid, and radial fossae to cushion the entry of their processes?
Olecranon, radial, and coranoid processes have fat pads.
Where can the olecranon bursa be found? What is its function?
olecranon bursa is between the skin and olecranon process this prevents excessive friction at that region.
Which muscles articulate during flexion at the elbow joint?
Flexion occurs mostly between humerus and the ulna.
When does the radius contact the humerus during flexion?
Radius contacts humerus only at closely packed position.
What is the closely packed position of the radius during flexion?
90 degrees flexion and midway between pronation and supination.
Why is there a valgus angle during extension?
The trochlear is angled obliquely.
What is the carrying angle? Is it greater in males or females?
Carrying angle is formed between shaft of the humerus and the ulnar. This angle is greater in females than in males (in females >15 degrees, in males it is between 10 -15 degrees).
Is carrying angle greater in adults or children?
adults
What is the function of the anconeus?
anconeus pulls skin out of the way during tricep extension
What articulates in the proximal and distal radioulnar joints?
Proximal radioulnar joint is between radial notch of the ulna and the radial head.
Distal radioulnar joint is between ulnar notch and the ulnar head.
What type of joint is the radioulnar joint?
pivot joint
What is the motion that takes place at the radioulnar joints?
pronation and supination
How are the fibers of the interosseus membrane arranged?
Interosseus membrane fibers are oriented obliquely and this directs the force obliquely.
How much of the force transmitted from ulnar to the radius proximally and distally?
proximally only 20% of force is transmitted to radius.
Distally 80% is transferred to radius,
What is a likely consequence of fracture at one end of the radius or the ulna?
Fracture at one end may lead to dislocation at the other end.
What is a sacciform recess?
Capsule is lax inferiorly at the neck of the radius which forms the sacciform recess allowing smooth movement of radius against ulna.
What ligaments stabilize the proximal radioulnar joint?
The annular ligament
The quadrate ligament (goes inferiorly and inserts onto the neck of the radius)
Interosseus membrane
What is a pivot joint?
Pivot joint is where a joint moves within a ring against another ring.
What is the ring in the proximal radioulnar joint?
The annular ligament.
What is the main nerve supply of the proximal radioulnar joint?
Median nerve
Musculocutaneous nerve
Radial nerve
What is the blood supply of the proximal radioulnar joint?
Deep radial and radial artery branches.
What kind of joint is the distal radioulnar joint?
pivot joint; synovial
What ligaments reinforce the distal radioulnar joint?
Anterior and posterior radioulnar ligaments
interosseus membrane
What is the nerve supply of the distal radioulnar joint?
Median interosseus nerve
Radial interosseus nerve
What is the blood supply of the distal radiounar joint?
Anterior interosseus artery
Posterior interosseus artery.
What is the most stable position for the distal radioulnar joint?
Midprone postion
How is rotation different at the proximal and distal radioulnar joints?
distally radius moves completely anteriorly to ulnar.
Proximally radial rotation is limited by capitulum and the annular ligament.
What are the origin and insertion of the pronator teres?
Origin the medial epicondyle
Insertion the shaft of the radius.
What are the origin and insertion of the pronator quadratus?
from shaft of radius to shaft of ulna.
What muscles assist in pronation?
FCR
PL
Brachioradialis (when forearm is midprone)
What muscles assist in supination?
Extensor pollicis longus
Extensor carpi radialis longus
What is another function of supinator?
supinator also is pierced by the radial nerve
What can happen to proximal radioulnar joint when falling on a flexed elbow? What age groups are more likely to get this injury?
dislocation (more common in children due to lax ligament)
What happens during a dislocation of the proximal radioulnar joint?
Radial head gets displaced -> muscle pulls radial head superiorly after it leaves the annular ligament.
How is a dislocation of the proximal radioulnar joint reduced?
While in flexion:
Supinate forearm -> Push proximally
What are some things that can go wrong with the H-U and R-U joints?
olecranon bursa can get inflamed.
Epicondylitis can occur depending on which is overused. (flexor compartment uses medial epicondyle and extensor compartment uses lateral epicondyle)
What structures can be affected by an avulsion fracture in the H-U and R-U joints?
Avulsion fractures can affect:
medial epicondyle
olecranon process
coranoid process
styoloid process
What is the resultant condition from a supracondylar fracture?
Volkmann’s ischaemic contracture (thinning of forearm muscles causing contracture)
