Exam 4

• elbow complex is made up of 3 bones, 3 ligaments, 2 joints, and 1 capsule
• the three bones of the elbow complex is the radius, ulna, and humerus
• the longitudinal axes of the humerus and forearm form the carrying angle
• the carrying angle occurs because the distal end of humerus isn't lever and the medial side of the humerus is lower than the lateral
• the ulnar collateral ligament provides valgus support
• the ulnar collateral ligament attaches on the medial epicondyle of the humerus and runs obliquely to the medial sides of the coronoid process and olecranon process of ulna
• radial collateral ligament provides varus support
• the radial collateral ligament attaches proximally on the lateral epicondyle of the humerus and distally on the annular ligament and the lateral side of the ulna
• annular ligament attaches anteriorly and posteriorly to the radial notch of the ulna, encompassing the head of the radius and holding it against the ulna
• humeroradial joint concave surface is the radial fovea and the convex surface is the humeral capitulum
• the humeroulnar concave surface is the trochlear notch and the convex surface is the humeral trochlea
• majority of the movemetn of the elbow joint comes from the humeroulnar joint
• 100 degrees of ROM is needed to complete activities of daily living
• the elbow complex ranges of motion: active is 145 degrees and passive is 160 degrees
• Elbow flexors include biceps brachii, brachialis, brachioradialis, pronator teres
• elbow extensors include the triceps brachii and anconeus
• the brachialis is the primary elbow flexor and is the only flexor that inserts onto the ulna
• the triceps brachii have three heads: the long, lateral, and medial heads
• the lateral head of the triceps is the strongest yet inactive unless against resistance
• the long head descends between teres minor and major to join the other two heads
• the medial head of the triceps are labeled the "workhorse" which is active in all positions
• elbow injuries include lateral epicondylitis, medial epicondylitis, little league elbow, and nursemaid's elbow
• little league elbow is caused by overuse and occurs in young baseball players that haven't reached skeletal maturity
• proximal radioulnar joint is the articulation of radial head and radial notch. It is classified by the pivot joint.
• The proximal radioulnar joint is responsible for the initation of supination and pronation
• radial head is held against the ulna by the annular ligament 75%, radial notch 25% and small support by quadrate ligament
• quadrate ligament reinforces inferior part of capsule, stabilizes proximal radius against the radial notch, and restricts excessive supination
• the interosseous membrane's purpose is to keep the radius and ulna from separating and provides more surface area for muscles
• distal radioulnar joint is the articulation of ulnar head and ulnar notch and includes the articular disc. It is known as a pivot joint.
• the arthrokinematic motions of the distal radioulnar joint are roll and slide
• primary supinators are the biceps brachii and the supinator
• the biceps brachii are most effective in supination when elbow is flexed at 90 degrees
• assistive supinators include: brachioradialis, extensor pollicus longus, extensor indicis, and radial wrist extensor
• the primary pronators are the pronator teres and the pronator quadratus
• the assistive pronators are the flexor carpi radialis and palmaris longus
• the pronator teres is a superficial muscle covered by the brachioradialis, smaller in size, and has a diagonal line of pull
• the pronator quadratus is located on the anterior surface of forearm and works with pronator teres to pronate the forearm
• The brachioradialis is deemed the "halfway muscle" because it helps with both pronation and supination
• The wrist is made up of the radiocarpal joint and the midcarpal joint
• The radiocarpal joint is a synovial joint classified as a condyloid joint