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Triceps is maximally efficient with the elbow flexed 20–30°. As the angle of flexion increases, the position of the olecranon approaches the main axis of the humerus which decreases muscle efficiency. In full flexion, however, the triceps tendon is "rolled up" on the olecranon as on a pulley which compensates for the loss of efficiency.
The olecranon (/ oʊ ˈ l ɛ k r ə n ɒ n /, from Greek olene 'elbow' and kranon 'head'), is a large, thick, curved bony process on the proximal, posterior end of the ulna.It forms the protruding part of the elbow and is opposite to the cubital fossa or elbow pit (trochlear notch).
The humeroulnar joint (ulnohumeral or trochlear joint [1]) is part of the elbow-joint. It is composed of two bones, the humerus and ulna, and is the junction between the trochlear notch of ulna and the trochlea of humerus. [1] It is classified as a simple hinge-joint, which allows for movements of flexion, extension and circumduction.
In anatomy, flexor is a muscle that contracts to perform flexion (from the Latin verb flectere, to bend), [1] a movement that decreases the angle between the bones converging at a joint. For example, one's elbow joint flexes when one brings their hand closer to the shoulder , thus decreasing the angle between the upper arm and the forearm .
The elbow joint is a complex of three joints — the humeroradial, humeroulnar, and superior radioulnar joints — the former two allowing flexion and extension whilst the latter, together with its inferior namesake, allows supination and pronation at the wrist. Triceps is the major extensor and brachialis and biceps the major flexors. Biceps ...
Is a simple hinge-joint, and allows of movements of flexion and extension only. Humeroradial joint: head of the radius: capitulum of the humerus: Is a ball-and-socket joint. Superior radioulnar joint: head of the radius: radial notch of the ulna: In any position of flexion or extension, the radius, carrying the hand with it, can be rotated in it.
These three muscles act as flexors at the elbow joint. [5] The extensor carpi radialis brevis and longus are both weak flexors at the elbow joint. Brevis moves the arm from ulnar abduction to its mid-position and flexes dorsally. Longus is a weak pronator in the flexed arm and a supinator in the outstretched arm.
When pronated, the brachioradialis is more active during elbow flexion since the biceps brachii is in a mechanical disadvantage. With the insertion of the muscle so far from the fulcrum of the elbow, the brachioradialis does not generate as much joint torque as the brachialis or the biceps. It is effective mainly when those muscles have already ...