Arm, elbow & forearm Flashcards
(24 cards)
What are the three factors of the humerus alignment?
- humeral torsion
- anterior curve distal end
- oblique inferomedial joint axis (causes valgus elbow alignment)
what is the alignment of the elbow?
valgus (laterally deviated) 10-15 degrees
what are the separate articulations within capsule of the elbow joint complex?
- humeroulnar joint
- humeroradial joint
- proximal radioulnar joint
what are the articulations of the humeroulnar joint?
trochlea of humerus and the trochlear notch of ulna
what are the articulations of the radiohumeral joint?
capitulum of humerus and the head of the radius
what is the difference between a primary and secondary constraint?
A primary constraint is defined as a constraint where release of that structure causes laxity of the joint. A secondary constraint is a constraint where release alone is insufficient to cause laxity, but where release after division of primary constraint increases the laxity of the joint.
what are the primary constraints of elbow joint complex?
ulnohumeral articulation (valgus and varus) anterior medial collateral ligament (valgus) lateral collateral ligament complex (varus)
what are the secondary constraints of the elbow joint complex?
radiohumeral articulation (valgus) common ext tendon (varus), capsule (valgus), common flex-pron tendon (valgus)
what are the parts of the medial collateral ligament?
- anterior band (AMCL) - well defined
- posterior band (PMCL) - weaker
- transverse band (TMCL) - no contribution to elbow joint stability
what is the primary restraint to valgus force especially in flexion?
anterior medial collateral ligament
what comprises the lateral collateral ligament complex?
- lateral/radial collateral ligament (LCL or RCL)
- annular ligament (AL)
- lateral ulnar collateral ligament (LUCL)
what is the primary varus constraint?
lateral collateral ligament complex
which elbow flexors produce the most force (PCSA)?
- brachialis
- bicep brachial
- pronator teres
- brachioradialis
which elbow flexors have the greatest moment arm?
- brachioradialis
- biceps brachii
- brachialis
- pronator teres
what are the two primary elbow flexors?
biceps brachii and brachialis
what are the three components of integrated forearm function?
- proximal radioulnar joint and annular ligament
- interosseous membrane/ligament
- distal radioulnar joint and TFCC
what are the articulations of the proximal radioulnar joint (PRUJ)?
head of the radius articulates with radial notch of ulna
what type of joint is the proximal radioulnar joint and what is its primary and secondary stabilisers?
synovial pivot joint
primary stabiliser = annular ligament
secondary stabiliser = interosseous membrane
what are the functions of the interosseous membrane and ligament?
- attaché,ent site for muscles
- hinge for forearm rotation
- stabilise proximal and distal radioulnar joint
- distribute load from radius to the ulna in the proximal forearm
What are the articulations of the distal radioulnar joint (DRUJ)?
vertical part = distal ulna articulates with ulnar notch of radius
horizontal part = distal ulna articulates with triangular fibrocartilage disc
what type of joint is distal radioulnar joint (DRUJ) and what are its primary stabilisers?
synovial plane joint
primary passive stabilisers = triangular fibrocartilage complex (TFCC) includes triangular fibrocartilage and dorsal & palmar radioulnar ligaments
what are the supinator and pronator muscles?
supinators; biceps brachii & supinator
pronators: pronator teres & pronator quadratus
(brachioradialis is an accessory pronator from a supinated position to a neutral position)
what are the superificial muscles of the forearm (anteromedial compartment)?
Pronator teres
FCR (flexor carpi radialis)
Palmaris longus
FCU (flexor carpi ulnaris)
what are the cubical fossa margins?
line between later and medial epicondyles, bracioradialis, pronator teres
