Oblique Cord, Anterior View

Description

Running obliquely across the proximal anterior forearm, the oblique cord (chorda obliqua) spans from the ulna just distal to the ulnar tuberosity toward the radius inferior to the radial tuberosity, crossing superficial to the proximal interosseous membrane. Nearby anterior landmarks include the distal tendon of biceps brachii inserting on the radial tuberosity and the brachialis inserting on the ulnar tuberosity and coronoid process, with the flexor-pronator mass arising from the medial epicondyle coursing distally. Proximally, the relationship to the proximal radioulnar joint and radial neck is apparent, with the cord angling inferolaterally from ulna to radius. Small but specific. This anterior perspective matters when teaching forearm rotation mechanics and the layered stabilizers that complement the annular ligament and interosseous membrane. The oblique cord is often discussed as a potential restraint to distal traction on the radius, a point that comes up in the context of radial head subluxation (nursemaid’s elbow) and when interpreting why proximal radioulnar stability may persist despite partial disruption of the interosseous membrane. Surgeons approaching the proximal radius for radial head arthroplasty, biceps tendon repair, or exposure after a Monteggia-pattern injury benefit from an accurate mental map of this band’s course to avoid misidentifying it as scar, an anomalous slip, or part of the interosseous membrane. Use this artwork in upper limb anatomy lectures, orthopaedic teaching files on elbow and forearm instability, and surgical atlases that describe anterior approaches to the proximal radius and ulna. It also fits radiology education as an anatomic correlate when explaining why certain proximal forearm bands may be subtle or absent on routine MRI without dedicated sequences. Anatomical accuracy verified by SciePro's Medical Advisory Board.