The biceps brachii is a muscle located on the front of the upper arm, playing a major role in flexing the elbow and rotating the forearm. A biceps tendon rupture, or tear, occurs when one of the strong tendons connecting this muscle to the bone separates, either partially or completely. This separation disrupts the mechanical connection necessary for muscle function and is often the result of a sudden, forceful event or chronic tendon degeneration. Symptoms are directly tied to which of the three tendons is affected.
Understanding Tear Locations
The severity and functional impact of a biceps tendon tear depend on the location of the injury. The biceps muscle connects to the shoulder joint via two proximal tendons and to the elbow via a single distal tendon. Proximal biceps tendon ruptures, which happen near the shoulder, are the most common type, accounting for approximately 96% of all biceps tears. These injuries typically involve the long head of the biceps, which attaches to the top of the shoulder socket.
The body can often compensate for a proximal tear because the short head of the biceps remains attached, preserving much of the arm’s strength. Conversely, a distal biceps tendon rupture occurs at the elbow, where the single tendon attaches to the radius bone in the forearm. While less common, this type of tear carries a higher risk of functional loss because it severs the muscle’s only connection to the forearm. Distal tears usually happen during an unexpected, forceful extension against a flexed arm, such as during heavy lifting.
Specific Indicators of a Rupture
The immediate sign of a biceps tendon rupture is frequently a sudden, sharp pain in the upper arm or elbow region. This intense pain is often accompanied by the distinct sensation or sound of a “pop” or “snap” when the tendon separates from the bone. The initial severe pain may quickly subside, sometimes replaced by a dull ache, but the injury’s physical indicators remain.
A visible deformity is one of the most recognizable signs, resulting from the muscle belly recoiling after the tendon snaps. For a proximal tear near the shoulder, the muscle retracts downward, creating a prominent bulge in the lower part of the upper arm, often referred to as the “Popeye” muscle deformity. If the tear is distal, near the elbow, the muscle belly retracts upward toward the shoulder, sometimes leaving a gap or indentation in the crease of the elbow.
Bruising (ecchymosis) is another common indicator, developing shortly after the injury. This discoloration often starts in the area of the tear and can spread down the arm toward the elbow. Swelling and tenderness in the affected area will also be present, particularly in the antecubital fossa (the triangular area at the front of the elbow) for a distal rupture.
Functional limitations also provide important clues, distinguishing a tear from a less severe strain. Weakness when bending the elbow (flexion) is expected, but weakness during forearm rotation is particularly telling. A complete distal tear causes a noticeable loss of strength when trying to supinate the forearm, which is the action of turning the palm upward. Even with a proximal tear, some individuals report cramping of the biceps muscle with strenuous use.
Immediate Care and Medical Triage
If a biceps tendon rupture is suspected due to acute pain and a visual deformity, immediate steps should focus on stabilizing the injury and reducing inflammation. The RICE protocol (Rest, Ice, Compression, and Elevation) provides a foundation for initial management. Applying cold compresses to the affected area for 10 to 20 minutes can help limit swelling and manage the initial pain.
The arm should be immobilized using a sling to prevent further movement or stress on the damaged tendon. It is important not to attempt to straighten or manipulate the injured extremity, even if a deformity is present. Over-the-counter pain relievers, such as non-steroidal anti-inflammatory drugs (NSAIDs), can be used to manage discomfort.
An immediate medical evaluation by a specialist, such as an orthopedic surgeon, is necessary to determine the extent of the tear. Distal biceps tendon ruptures often require prompt surgical intervention for the best functional outcome, making timely referral a priority. A doctor will perform a detailed physical examination, looking for the classic signs and testing for specific weaknesses in elbow flexion and supination.
To confirm the diagnosis and determine if the tear is partial or complete, imaging tests such as ultrasound or Magnetic Resonance Imaging (MRI) may be ordered. While partial tears and most proximal tears can often be managed without surgery, a complete tear, especially at the elbow, typically requires a definitive treatment plan. Following the initial triage, the arm should be kept elevated when possible to assist in reducing swelling.