Lec 17(cheat sheet) Flashcards
(22 cards)
What type of joint is the elbow?
Ginglymus (hinge) joint, allowing flexion and extension.
What type of joint is the radioulnar joint?
Trochoid (pivot) joint, allowing supination and pronation.
Which bones make up the elbow joint?
Humerus, ulna, and radius (mainly humeroulnar and radiohumeral articulations).
Which bones make up the radioulnar joint?
Radius and ulna.
What motion occurs at the radioulnar joint?
Supination and pronation of the forearm.
Which bone rotates over which in supination/pronation?
Radius rotates over the ulna.
What is the “lock-unlock” mechanism at the elbow?
Full extension locks the olecranon into the fossa for stability; unlocking occurs at ~20° flexion, increasing side-to-side laxity.
What does the ulnar collateral ligament do?
Provides medial support; prevents abduction.
What does the radial collateral ligament do?
Provides lateral support; resists varus forces.
What does the annular ligament do?
Encircles the radial head and holds it in place during rotation.
What is the function of the biceps brachii?
Flexes elbow, supinates forearm, weak shoulder flexion.
What is the function of the brachialis?
True elbow flexion.
What is the function of the brachioradialis?
Elbow flexion, pronation/supination to neutral.
What is the function of the pronator teres?
Pronation, weak elbow flexion.
What is the function of the pronator quadratus?
Pronation of forearm.
What is the function of the triceps brachii?
Elbow extension; long head assists in shoulder extension and adduction.
What is the function of the anconeus?
Elbow extension.
What is the function of the supinator?
Supinates the forearm.
What is an open chain movement example for the elbow?
Bicep curl (distal segment: forearm, not fixed).
What is a closed chain movement example for the elbow?
Push-up or pull-up (proximal segment: upper arm, hands fixed).
During a bicep curl, what happens at the elbow?
Elbow flexion, concentric contraction of biceps brachii, brachialis, and brachioradialis. Segment moved: forearm.
During the lowering phase of a push-up, what happens?
Eccentric elbow extension, triceps brachii and anconeus are active. Segment moved: upper arm toward the ground.
