Popeye sign is a pronounced bulging muscle in the distal aspect of the biceps region of the arm. It is clinically apparent with a complete long head of biceps tendon tear which causes distal migration of the long head of biceps muscle.  

History and etymology

Defined by the distal migration of the long head of biceps muscle which causes an increased peak in the definition of the muscle on elbow flexion, making the arm appear like that of the muscular cartoon character Popeye.

Differential diagnosis

• haematoma
• soft tissue mass e.g. soft tissue sarcoma

Practical points

• actively flexing the elbow can exaggerate the Popeye sign and arm symmetry can be compared
• long standing tears will cause atrophy with fatty replacement of the muscle belly therefore this should be assessed during imaging
• ultrasound requests stating ‘?biceps tendon rupture’ should be discussed with the referrer to clarify between a proximal long head and distal bicep tendon tear, to determine imaging urgency.  Distal tendon tears are usually repaired within two weeks ¹, proximal long head tears are usually not
• often long head of bicep tendon tears occur in the setting of large rotator cuff tears; loss of the subacromial space on radiograph can suggest this as cause
• a methodical approach to shoulder ultrasound will prevent the long head of biceps being overlooked ²
• the long head of biceps and biceps sling/pulley are potential pain generators ³.  Ultrasound-guided long head of biceps tendon sheath injections are often diagnostically performed.