It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna. The ulna is usually slightly longer than the radius, but the radius is thicker. Therefore the radius is considered to be the larger of the two. At the wrist, the radius forms a joint with the ulna bone.
The following muscles originate from the ulna[19][20]:
- Pronator teres – the medial surface of the coronoid process.
- Flexor carpi ulnaris – olecranon process.
- Flexor digitorum superficialis – coronoid process.
- Flexor digitorum profundus – anteromedial surface.
- Pronator quadratus – distal anterior shaft.
The olecranon (previously the olecranon process) of the ulna is the most proximal part of the bone. It is a massive, blunt process.
Anterior view. The distal radioulnar articulation (inferior radioulnar joint) is a synovial pivot-type joint between the two bones in the forearm; the radius and ulna. It is one of two joints between the radius and ulna, the other being the proximal radioulnar articulation.
The forearm consists of two bones, the radius and the ulna, with the ulna is located on the pinky side and the radius on your thumb side.
Figure 6.44. Ulna and Radius The ulna is located on the medial side of the forearm, and the radius is on the lateral side.
The distal radius rolls and slides in the same direction relative to the ulnar head. During pronation, the radial head spins within the proximal radioulnar joint in the direction of the thumb within its “home” created by the annular ligament and the radial notch of the ulna (Fig.
Anatomical terms of boneBeneath the neck of the radius, on the medial side, is an eminence, the radial tuberosity; its surface is divided into: a posterior, rough portion, for the insertion of the tendon of the biceps brachii. an anterior, smooth portion, on which a bursa is interposed between the tendon and the bone.
Ulnar head (caput ulnae) is a small rounded eminence at the distal end of the ulna. Its inferior surface articulates with the articular disc cartilage of the wrist, and its lateral surface articulates with the ulnar notch of the radius during pronation and supination of forearm, wrist, and hand.
Many muscles in the arm and forearm attach to the ulna to perform movements of the arm, hand and wrist. Movement of the ulna is essential to such everyday functions as throwing a ball and driving a car. The ulna extends through the forearm from the elbow to the wrist, narrowing significantly towards its distal end.
Ulnar wrist pain occurs on the outside (pinkie-finger side) of your wrist. The ulna is the arm bone that ends at the wrist on this side.
Anatomical PartsThe articular surface for the ulna on the lower extremity of the radius is called the ulnar notch (sigmoid cavity) of the radius; it is narrow, concave, smooth, and articulates with the head of the ulna.
The ulna is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. It runs parallel to the radius, the other long bone in the forearm.
The radial head is at the top of the radius bone, just below your elbow. A fracture is a break in your bone. The most common cause of a radial head fracture is falling with an outstretched arm.
The radius and the ulna constitute as the bones of the forearm. The antebrachial region, as it is clinically known, spans the length of the region which extends roughly from elbow to wrist. With all of the 20 muscles of the forearm they support, these bones are essential for the functioning of the upper extremity.
The main function of the ulna, along with the radius, is to assist with rotation. This rotation allows for the maximal function of the wrist and hand due to the increased range of motion. The sole motion of the elbow joint is flexion and extension, otherwise known as bending and straightening the arm.
The
humerus (/ˈhjuːm?r?s/, plural: humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the
radius and ulna, and consists of three sections.
Distal humerus.
| Lower extremity of humerus |
|---|
| TA2 | 1180 |
| FMA | 13303 |
| Anatomical terms of bone |
The humerus articulates with the forearm bones to form the elbow joint, and the forearm bones articulate with each other to form the proximal radio-ulnar joint. The anular ligament, together with the radial notch of the ulna, provides a perfectly fitting socket for the head of the radius to rotate in.
The styloid process of the ulna extends distally and is the site of attachment for ligaments found in the wrist.
The rotator cuff are the muscles that stabilize movement of the shoulder. The pectoralis minor and pectoralis major are large muscles of the chest that participate in many movements, including flexion of the humerus.
Most clavicle fractures occur when a fall onto the shoulder or an outstretched arm puts enough pressure on the bone that it snaps or breaks.
The radius is a long bone in the forearm. It lies laterally and parallel to ulna, the second of the forearm bones. The radius pivots around the ulna to produce movement at the proximal and distal radio-ulnar joints.
The scaphoid and lunate bones articulate directly with the distal end of the radius, whereas the triquetrum bone articulates with a fibrocartilaginous pad that spans the radius and styloid process of the ulna. The distal end of the ulna thus does not directly articulate with any of the carpal bones.
It is the site of insertion of the tendon of the triceps brachii muscle. The coronoid process extends anteriorly from the distal base of the trochlear notch. The radial notch, for articulation with the head of the radius, is a curved surface that lies laterally along the base of the trochlear notch.
Long bones are mostly located in the appendicular skeleton and include bones in the lower limbs (the tibia, fibula, femur, metatarsals, and phalanges) and bones in the upper limbs (the humerus, radius, ulna, metacarpals, and phalanges).
The following measurements were taken: maximum humeral length (mean: 33.4cm in males; 30.7cm in females), vertical humeral head diameter (mean: 5.0cm in males, 4.4cm in females), humeral epicondylar width (mean: 6.6cm in males; 5.8cm in females), maximum ulnar length (mean: 26.5cm in males, 23.8cm in females), proximal
The radius articulates proximally at the elbow with the capitulum of the humerus and the radial notch of the ulna. It articulates at its distal end with the ulna at the ulnar notch and with the articular surfaces of the scaphoid and lunate carpal bones.
It occurs at the junction of the antero-inferior surface of the coronoid process with the front of the body. It provides an insertion point to a tendon of the brachialis (the oblique cord of the brachialis is attached to the lateral border).
Supination and PronationIn this position, the radius and ulna are parallel to each other. When the palm of the hand faces backward, the forearm is in the pronated position, and the radius and ulna form an X-shape. Supination and pronation are the movements of the forearm that go between these two positions.
