77-year-old patient presenting with predominant pain at the lateral aspect of the right humerus. Symptoms may include local tenderness, radiation, movement-related pain, or weakness. Ultrasound examination performed to evaluate both neural and shoulder-related pain sources.
Ultrasound examination of the right shoulder and humerus was performed according to the ESSR shoulder protocol, with additional assessment of the rotator interval (SGHL, CHL), humerus, deltoid muscle, and radial nerve.
At the level of the lateral mid-humerus near the intermuscular septum, the radial nerve demonstrates moderate neuropathic change. The nerve is enlarged in cross-sectional area and appears more hypoechoic than expected, consistent with nerve irritation or entrapment.
There is moderate to severe subacromial-subdeltoid (SASD) bursitis.
The supraspinatus tendon demonstrates a moderate full-thickness tear involving part of the tendon width, located in the anterior tendon portion.
These three abnormalities may all contribute to pain perceived at the lateral humerus.
1. Final diagnosis
Right lateral humeral pain with three potential pain generators: moderate radial neuropathy at the lateral mid-humerus, moderate to severe SASD bursitis, and moderate partial-width full-thickness supraspinatus tear.
2. Differential diagnosis
Consider referred pain from cervical pathology or myofascial pain if symptoms are not fully explained by the identified lesions.
3. Teaching points
Lateral arm pain is not always caused by the shoulder alone. Rotator cuff pathology, bursitis, and peripheral nerve entrapment can produce overlapping symptom patterns. Targeted clinical testing or diagnostic injection can help identify the dominant pain generator.
4. Injury/disease information
The radial nerve may become irritated where it courses along the humerus and through fascial septa. SASD bursitis and supraspinatus tears commonly cause referred pain to the lateral upper arm. Multifactorial pain presentations require correlation between imaging findings and symptom provocation.
5. Clinical recommendation:
Further evaluation is recommended to determine which of the three findings is the primary source of symptoms. This may be achieved through focused clinical examination, selective ultrasound-guided diagnostic injection, or other appropriate diagnostic strategies.
Marc is founder of, and trainer at, SonoSkills. SonoSkills is an organization dedicated to MSK ultrasound education. He's also an MSK Sonographer at EchoConsult in Roermond, the Netherlands.
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