Arm, Elbow, Forearm Flashcards
What muscle group attaches to the medial epicondyle?
Anterior forearm muscles
What muscle group attaches to the lateral epicondyle?
Posterior forearm muscles
3 characteristics of the distal humerus
Humeral torsion (allows greater range of motion), Anterior curve on distal end (allows more flexion than extension) Oblique inferomedial joint axis (allows for valgus alignment)
Definition of varus
Medial deviation of distal segment relative to proximal segment
Definition of valgus
Lateral deviation of distal segment relative to proximal segment
What is the degree of valgus in the elbow?
10-15 degrees valgus
Function of the fossa below the radial notch on the ulna
Allows radial tuberosity to change position in pronation and supination
What are the 3 joints in the elbow joint complex?
Humeroulnar (Hinge joint), Humeroradial(Ball and socket joint) and Proximal radioulnar joints (Pivot joint)
What is the functional classification of the elbow joint?
Uniaxial Synovial hinge joint
At which degree does the olecranon engage in the olecranon fossa?
0 degeree extension to 20 degrees flexion
What are the 2 synovial bursae present in the elbow joint?
Olecranon and subtendinosus bursa
What is the function of the subtendinous bursa?
Reduce friction between tendon of triceps brachii and the joint
What are the collateral ligaments in the elbow?
Lateral collateral ligament complex and Medial (Ulnar) collateral
What is the function of the anular ligament of radius?
Principal stabiliser of proximal radioulnar joint
Reinforce joint capsule laterally
allow radial head to slide against radial notch of ulna and pivot on capitulum during pronation and supination
What movement tauts the anterior capsule?
Extension
What force does the anterior capsule resist?
Valgus
Why is the posterior capsule less stable?
It is loose to allow full range of motion.
What are the 2 types of stability?
Static stability and dynamic stability
What structures provide passive stability to the elbow joint?
Articular surfaces, joint capsule, ligaments and interosseous membrane.
What are the muscles that cross the elbow joint?
Biceps, Triceps and brachialis
Which ligaments are primary constraints?
Anterior medial collateral ligament, Lateral collateral ligament complex, Ulnohumeral articulation
What structures are secondary constraints?
Radiohumeral articulation, Common flexor-pronator tendon, Common extensor tendon and capsule
What are the boundaries of the cubital fossa?
Imaginary line between medial and lateral epicondyles (Superior), Lateral boundary of pronator teres (Medial), Medial border of brachioradialis (Lateral)
What are the main contents of the cubital fossa?
Radial nerve (C5-T1), Tendon of biceps brachii, Brachial Artery and median nerve (C6-T1)
What are the boundaries of the cubital tunnel?
Ligament between medial epicondyle and olecranon (Roof), Elbow joint capsule and medial collateral ligament of elbow (Floor)
What nerve travels through the cubital tunnel?
Ulnar nerve
What does the medial collateral ligament consist of?
Anterior and Posterior medial collateral ligaments and transverse band
What force does the MCL resist
Valgus
What is the function of the AMCL?
Major joint stabiliser, taut through full ROM
Where does the AMCL insert?
Coronoid process
What is the function of the PMCL?
Taut in flexion, lax in extension
Where does the PMCL insert?
Olecranon process
Does the transverse band contribute to joint stabiltiy?
no
What does the lateral collateral ligament complex consist of?
Radial collateral ligament, annular ligament, lateral ulnar collateral ligament
Where does the Radial collateral ligament attach to?
Lateral epicondyle of humerus and blends with anular ligament
What force does the lateral collateral ligament complex resist?
Varus and posterolateral instability
