Head of the radius

Study entry

Description

Short disc at the proximal end of the radius; the superior surface is concave and the periphery is covered with cartilage.

Relations

Articulates with the capitulum of the humerus and with the radial notch of the ulna; the annular ligament encircles it.

Palpation

It rotates under the thumb, below the lateral epicondyle, in pronation and supination.

Source: cap. 3, «Huesos del antebrazo»

Clinical correlation

Subluxation of the radial head ("nursemaid's elbow")

In preschoolers, above all girls, suddenly pulling the child by the arm with the forearm pronated (swinging in the air, for example) makes the head of the radius slip partly out of the annular ligament. The child cries and does not use the arm, which is held with the elbow flexed and the forearm pronated. The pull tears the distal attachment of the annular ligament at the neck of the radius; the head descends and comes partly out of the ligament's "cup", and the torn piece may be caught between the head of the radius and the capitulum of the humerus; this pinching is what hurts. It is treated by supinating the forearm with the elbow flexed; the ligament heals with a sling for 2 weeks.

Related clinical cases

• Subluxation of the radial head ("nursemaid's elbow")

Other structures in this region

• Conoid tubercle
• Trapezoid line
• Scapular notch
• Glenoid cavity
• Supraglenoid tubercle
• Infraglenoid tubercle
• Subscapular fossa
• Supraspinous fossa