Radius (bone)

The radius (Latin - anat. Spoke for ) is a bone of the forearm. The spoke is thumb- side of the slope, in mammals stronger than the cubital, which it faces there, and a typical long bone.

Anatomy

Top

The directed towards the center of the body ( proximal ) end of the spoke ( epiphysis proximalis radii ) is of the coated with hyaline cartilage spoke head (caput radii ) is formed, which acts like a wheel, the spokes on the neck ( collum radii ) is presented. This has, on its articular surface with the upper arm bone (humerus ) an indentation ( fovea capitis radii ) for the humeral head ( capitellum ). Furthermore, it forms a part of joint ( articulatio humeroradialis ) of the elbow joint ( articulatio cubiti ). In addition, the spoke head embraces a coronary joint surface ( articular circumferentia ) for the articulation with the ulna.

Slightly below the spokes neck one finds a significant roughening, called spokes leg bump ( radial tuberosity ). This forms the point of attachment of the main tendon of the biceps brachii muscle ( biceps brachii ). When Umwendebewegung inside, so thumbs towards the body ( pronation ) and thus palm lying down ( on the back ) facing down, the string is wound around the body of the spoke, like a yarn that is wound up on a hand spindle.

Body

The central portion of the spoke is referred to as spokes or spoke shaft ( Corpus radii ).

The spoke is on the forearm together with the yard a functional unit. This becomes apparent inter alia anatomically that both bones coupled to one another in various ways. For one, they have at their facing the center of the body and away from the center of the body (distal) end of each hinged connection to each other and to the other almost the entire length spanned by a fairly stable adhesive tape between the two on ( interosseous membrane ). This relatively tight train occurs at the spoke at the Elle to side directed toward an edge ( Margo interosseous ). This is easily felt through the skin.

Also on the front of the spoke one can define a rather sharp edge ( anterior border ). Its formation can in turn be explained by a certain train through the deep flexors of the forearm. These same namely to use the front edge part as a source surface.

On the back of the spoke are also found an edge ( Margo posterior). This is usually not so sharp as fewer train is applied to it. At the far end of the body center of the top of the rear edge is caused by the approach of Auswärtsumwenders (musculus supinator ) and continued distally by fibrous bands of the Strecker.

Despite his almost cylindrical body you can define on the spoke different surfaces at the edges due to the just described.

The front surface ( Facies anterior) the bone located between the front edge surface and the edge lying between the two bones of the forearm. It is used for medium and deep layer of the forearm with the adhesive tape between the two bones as origin.

Between the front and rear edge there is also an area that is referred to as a lateral surface (facies lateralis). Here arise some fibrous bands of the forearm muscles.

A back surface ( posterior surface ) is defined as the area that is defined by the rear edge and the edge between the two bones. Also this serves several forearm muscles, in this case, the extensors, along with the band adhesion between the two bones as a source surface.

The spoke widens steadily away from the center of the body so that its distal end of the body center joint covered with cartilage, a joint surface ( articular facies carpi ) for the carpal bones (ossa carpi ) has.

Bottom

On the bottom side projects a bony prominence on the articular surface of the carpal bones. This projection is called the styloid process ( radial styloid ). In him is the brachioradialis muscle ( musculus brachioradialis ).

The walk from the center of the body end of the spoke ( epiphysis distalis radii ) has, on the outer side of the notch ( sigmoid notch ) for the ulna head (caput ulna ) on. It forms with the ulna, the distal ulnar joint.

Peculiarities in animals

In the animals that can perform in the forearm no Umwendebewegungen ( pronation and supination ) (eg, ungulates ) is the radius bone of the ulna fused ( synostosis ).

Adjacent joints

The spoke is involved in a total of four different sub- joints. Firstly, it is related to the humerus by means of the upper-arm spokes - joint ( articulatio radiohumeral radialis ) of the elbow joint ( articulatio cubiti ) and another with the carpal bones by means of spokes - wrist ( radiocarpal joint ) in combination. Furthermore, the radius and ulna have two hinged connections with each other. First, the center of the body located toward ulnar joint ( radioulnar joint Proximal ), which is sometimes counted the elbow joint, and on the other the distal ulnar joint ( distal radioulnar joint ).

Diseases

• Essex - Lopresti injury
• Radius fracture
• Radial head fracture
• Radial head subluxation