DiagnosticTree/Olecranon
Olecranon / Posterior Elbow Pain — Diagnostic Algorithm
This algorithm uses a Bayesian scoring model to rank the two myofascial trigger point (TrP) sources of posterior elbow and olecranon pain most likely to be responsible. It is designed to be used after structural diagnoses have been considered (see red flags and broad differential on Pain:Olecranon).
The two muscles in this model were selected from Travell & Simons because they are the primary TrP sources with direct referred pain to the olecranon process specifically:
- Muscle:Triceps_Brachii — attachment TrP at the distal insertion, just above the olecranon; always secondary to a central TrP in one of the triceps heads; produces focal olecranon tenderness
- Muscle:Serratus_Posterior — serratus posterior superior; refers pain in a wide arc from deep under the scapula, through the posterior deltoid and long head of triceps, with accent at the olecranon in the spillover zone; continues into the ulnar forearm and 5th digit
Muscle summary
| Muscle | T&S Bold? | Prior | Key referral to olecranon |
|---|---|---|---|
| Triceps Brachii (distal attachment) | Yes | 0.60 | Attachment TrP directly over the olecranon; always secondary to a central TrP; focal spot tenderness only |
| Serratus Posterior Superior | No | 0.40 | Olecranon is part of a wide pattern: deep scapular pain → posterior triceps → olecranon accent → ulnar forearm → 5th digit |
Structural differential (non-TrP)
These diagnoses must be excluded or identified before proceeding to TrP scoring. Patients with visible bursal swelling, loss of elbow extension, or pain only at terminal arc do not belong in this algorithm.
- Olecranon bursitis — fluctuant swelling at olecranon; may be painless (aseptic) or erythematous with fever (septic); TrP4 tenderness is deep to the aponeurosis with no fluctuance
- Distal triceps tendon rupture — loss of active extension; palpable gap; flake sign on X-ray; positive modified Campbell Thompson test
- Elbow osteoarthritis — pain only at terminal extension or flexion; mid-range comfortable; osteophytes and stiffness
- C8–T1 radiculopathy — objective neurological deficit required to diagnose; serratus posterior superior refers numbness into C8–T1 distribution without neurological deficit
Source
Structural differential adapted from: Chung HJ et al. Differential Diagnosis of Elbow Pain. PMCID: PMC12093526 (2025).