What is the likely diagnosis and recommended evaluation and management for medial (ulnar) elbow pain that seems to originate from chest compression of the ulnar nerve, such as thoracic outlet or pectoralis minor syndrome?

Medial Elbow Pain with Suspected Proximal Neurogenic Origin

This presentation most likely represents neurogenic thoracic outlet syndrome (nTOS) with pectoralis minor compression causing referred ulnar-distribution symptoms to the elbow, rather than primary medial epicondylitis. 1, 2

Understanding the Clinical Picture

The key distinction here is recognizing that true medial epicondylitis (golfer's elbow) is a local tendinopathy, whereas your description suggests a proximal compression syndrome radiating distally. When "epicondylitis" symptoms stem from chest compression, you're dealing with:

• Pectoralis minor syndrome - compression of the brachial plexus (particularly the lower trunk/medial cord that forms the ulnar nerve) under the pectoralis minor muscle in the retropectoralis minor space 1, 2
• This compression occurs in one of three anatomical spaces where TOS develops: the interscalene triangle, costoclavicular space, or pectoralis minor space (subpectoral tunnel) 1
• Repetitive overhead activity combined with scapular dyskinesia leads to pectoralis minor shortening, decreased retropectoralis minor space volume, and subsequent brachial plexus compression 2

Diagnostic Evaluation Algorithm

Initial Imaging

Start with chest radiography to identify osseous abnormalities including cervical ribs, first rib anomalies, or congenital malformations that could cause compression 1

Definitive Neurogenic TOS Imaging

MRI chest without IV contrast is sufficient and preferred for diagnosing neurogenic TOS, as it demonstrates compression of neurovascular bundles in all three anatomical spaces 1

The MRI protocol must include:

• High-resolution T1-weighted and T2-weighted sequences in sagittal and axial planes to delineate the brachial plexus, muscular attachments, and compression sites 1
• Both neutral and arms-abducted positions to demonstrate dynamic compression and effacement of fat adjacent to brachial plexus roots, trunks, or cords 1
• T1-weighted imaging identifies causative lesions including cervical ribs, congenital fibromuscular anomalies, and muscular hypertrophy 1

Critical Pitfall to Avoid

Do not use CT or ultrasound alone for neurogenic TOS - these modalities lack adequate resolution of neural structures 1

Confirmatory Testing

• Ultrasound-guided diagnostic injection into the pectoralis minor space can confirm the diagnosis when combined with thorough history and physical examination 2, 3
• Dynamic arterial and venous Doppler ultrasound can display compression during provocative maneuvers 3

Rule Out Competing Diagnoses

You must exclude:

• Cervical radiculopathy - cervical spine pathology may mimic or exacerbate TOS symptoms 1
• Primary ulnar neuropathy at the elbow - compression at the cubital tunnel or retro-epicondylar groove 4, 5
• Peripheral neuropathies, vascular disorders, and space-occupying lesions 2

Management Strategy

First-Line Conservative Treatment (3-6 months trial)

Conservative management succeeds in the majority of patients and must be attempted before surgical consideration 1, 2

Specific interventions include:

• Pectoralis minor stretching exercises 2
• Periscapular and postural retraining to address scapular dyskinesia 2
• Physical therapy focused on the thoracic outlet 6
• Adequate pain management 6
• Patient education to eliminate repetitive overhead activities and positions that provoke compression 2

Surgical Intervention Criteria

Surgery should only be considered when conservative management fails after an adequate 3-6 month trial, OR when there is true neurogenic TOS with progressive symptoms, significant functional compromise, or in high-risk occupations where recurrence prevention is critical 1

Surgical options include:

• Pectoralis minor release (open or arthroscopic approach) for isolated pectoralis minor syndrome 2
• When indicated by preoperative workup, combine with suprascapular nerve release and brachial plexus neurolysis for complete infraclavicular thoracic outlet decompression 2
• First rib resection with scalenectomy if compression involves the costoclavicular or interscalene spaces 1, 7

Key Clinical Pearls

• Compression in the pectoralis minor space is rare but documented - most nTOS compression occurs in the costoclavicular space, making thorough evaluation essential 1
• The symptoms are diverse and the path to correct diagnosis is often prolonged, requiring treatment in specialized departments 6
• In young patients without other risk factors, consider TOS when embolic events occur in upper extremities 6
• Venous compression during arm abduction is commonly seen in both asymptomatic and symptomatic individuals - clinical correlation is essential and imaging findings alone are insufficient for diagnosis 1