Bones - Radius Flashcards
What type of bone is the radius?
Long bone.
What are the articulations of the radius?
1) Elbow joint - between the head of the radius and the capitulum of the humerus.
2) Proximal radioulnar joint - between the radial head and the radial notch of ulna.
3) Wrist joint - between the distal end of the radius and the carpal bones.
4) Distal radioulnar joint - between the ulnar notch and the head of the ulna.
What are the bony landmarks of the proximal radius?
The proximal end of the radius articulates in both the elbow and proximal radioulnar joints.
1) Head of the radius - a disc shaped structure, with a concave articulating surface. It is thicker medially, where it takes part in the proximal radioulnar joint.
2) Neck - a narrow area of bone, which lies between the radial head and radial tuberosity.
3) Radial tuberosity - a bony projection, which serves as the place of attachment of the biceps brachii muscle.
What the features of the shaft of the radius?
The radius expands in diameter as it moves distally. Like the ulna, it is triangular in shape, with three border and three surfaces.
In the middle of the lateral surface, there is a small roughening for the attachment of the pronator teres muscle.
What are the bony landmarks of the distal radius?
1) Styloid process - lateral side
2) Ulnar notch - medial surface, articulating with the head of the ulna, forming the distal radioulnar joint.
The distal surface of the radius has two facets, for articulationg with the scaphoid and lunate carpal bones. This makes up the wrist joint.
Clinical relevance: common fractures of the radius
1) Colles’ fracture - the most common type of radial fracture. A fall onto an outstretched hand causing a fracture of the distal radius. The structures distal to the fracture (wrist and hand) are displaced posteriorly. It produces what is known as the ‘dinner fork deformity’.
2) Fractures of the radial head - charasterially due to falling on an outstretched hand. The radial head is forced into the capitulum of the humerus, causing it to fracture.
3) Smith’s fracture - caused by falling onto the back of the hand. It is the opposite of the Colles’ fracture, as the distal fragment is displaced anteriorly.
