Espiral AtlasNeck of the radius
collum radii
Study entry
Description
Constriction just below the head of the radius.
Relations
The deep branch of the radial nerve winds around the neck as it pierces the supinator.
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")