A mother pulls her 3-year-old daughter's arm to lift her off the ground. The child immediately cries and holds the left upper limb adducted and internally rotated, refusing to use it. The forearm is held mildly pronated. There is no swelling or deformity. The structure responsible for this injury is:
- A The lateral collateral ligament of the elbow
- B The annular ligament, which slips proximally over the radial head ✓
- C The biceps tendon inserting on the radial tuberosity
- D The proximal radioulnar joint capsule
Correct answer: B. The annular ligament, which slips proximally over the radial head
Explanation
Pulled elbow, or radial head subluxation, occurs when sudden longitudinal traction on a pronated extended arm allows the immature annular ligament to slip over the radial head and become interposed in the radiocapitellar joint. It occurs below age 5 because the annular ligament is still weakly attached. Reduction by supination and flexion produces an immediate click and relief. No immobilisation is needed and recurrence risk relates to ligament laxity.
Reference: Tachdjian's Pediatric Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.