Cervical Rib Syndrome
Extra rib at C7 compressing neurovascular structures of the thoracic outlet
ICD-10: Q76.5 · cervical condition
A cervical rib is a supernumerary (extra) rib arising from the seventh cervical vertebra rather than the thoracic spine. Present in about 0.5–1% of the population, it is bilateral in roughly 50% of cases and more common in women. Most cervical ribs are asymptomatic and discovered incidentally on chest or neck imaging. However, when the rib — or a fibrous band extending from an incomplete cervical rib — compresses the lower trunk of the brachial plexus or the subclavian artery, it produces the clinical syndrome of thoracic outlet syndrome. Neurogenic cervical rib syndrome manifests as pain, paresthesias, and weakness in an ulnar nerve distribution (ring and little fingers, medial forearm), reflecting lower brachial plexus involvement. Vascular compression produces subclavian artery stenosis or aneurysm, with arm claudication, Raynaud phenomenon, or, in severe cases, distal emboli causing digit ischemia. The combination of a bony cervical rib with a constricted thoracic outlet from hypertrophied scalene muscles produces the most symptomatic presentations. First-line treatment is conservative: physical therapy targeting scalene and pectoralis minor stretching combined with postural correction relieves symptoms in many patients. Surgical cervical rib resection, typically combined with first rib resection and scalenectomy, is reserved for cases failing conservative care or presenting with vascular complications.
Anatomy & Pathology
The scalene triangle (thoracic outlet) is formed by the anterior scalene muscle anteriorly, the middle scalene posteriorly, and the first rib inferiorly. The brachial plexus and subclavian artery pass through this triangle; the subclavian vein passes anterior to the anterior scalene. A cervical rib narrows this triangle from below, reducing the space available for these neurovascular structures. Even an incomplete cervical rib consisting of only a fibrous band extending from the C7 transverse process to the first rib can produce the same compression effect as a complete bony rib.
Symptoms
- Pain and paresthesias in the ulnar forearm and hand (ring and little fingers)
- Hand and intrinsic muscle weakness (lower brachial plexus involvement)
- Arm pain worsened by overhead activity or carrying objects
- Raynaud phenomenon or hand coldness (vascular involvement)
- Palpable mass in the supraclavicular fossa
- Subclavian bruit on auscultation
- Finger discoloration or embolic events in severe vascular cases
Causes & Risk Factors
- Congenital cervical rib (complete or incomplete) arising from C7 transverse process
- Fibrous band extending from a rudimentary cervical rib to the first thoracic rib
- Hypertrophied anterior scalene muscle narrowing the scalene triangle
- Poor posture with shoulder drooping (stretches neurovascular bundle over the rib)
- Trauma causing callus formation or scalene scarring around a cervical rib
Imaging Findings
Imaging studies are commonly used to identify findings associated with this condition. Results vary by individual; a qualified spine specialist interprets findings in the context of a full clinical evaluation.
MRI
- Brachial plexus MRI neurography: compression of the lower trunk (C8-T1) between the scalene muscles or by the cervical rib
- Subclavian artery or vein compression on dynamic MRI in provocative arm position (EAST maneuver)
- Cervical rib visible as an extra bony structure arising from C7 on coronal sequences
- Note: Normal MRI does not rule out neurogenic TOS — clinical and electrodiagnostic findings are equally important
CT Scan
- CT angiography/venography in vascular TOS: subclavian artery aneurysm, stenosis, or subclavian vein thrombosis
- Best modality to visualize the cervical rib anatomy and its relationship to the scalene triangle
- Dynamic CT angiography with arm elevated demonstrates vascular compression during provocation
X-Ray
- AP cervical spine X-ray: cervical rib visible as an extra horizontal process from C7 (present in ~0.5–1% of the population)
- Bilateral involvement is common — assess both sides
- Chest X-ray: apical lung mass (Pancoast tumor) must be excluded as it mimics neurogenic TOS
Who Is Commonly Affected
The following patterns are commonly associated with this condition based on published population studies. Individual presentation varies; these figures are informational only.
Peak Age Range
20–45 years for neurogenic TOS; vascular TOS can present at any adult age
Gender Distribution
Neurogenic TOS: female predominance (approximately 3:1); vascular TOS: male predominance for arterial type
Estimated Prevalence
Cervical ribs in ~0.5–1% of the population; only a minority become symptomatic; neurogenic TOS accounts for approximately 95% of all TOS cases
Treatment Options
Conservative
- Physical therapy: scalene and pectoralis minor stretching, postural correction, shoulder girdle strengthening
- Activity modification and ergonomic adjustments to reduce provocative positions
- NSAIDs and neuropathic agents (gabapentin) for pain management
Surgical
- Cervical rib resection via supraclavicular approach — removes the offending rib and fibrous bands
- First rib resection via transaxillary or supraclavicular approach to widen the thoracic outlet
- Scalenectomy (anterior and/or middle scalene resection) to decompress the brachial plexus
When to see a spine specialist
See a vascular surgeon or thoracic surgeon urgently if you develop sudden arm pain with color change, digit ulceration, or loss of radial pulse — these suggest subclavian artery thrombosis or embolism requiring emergency intervention. Neurological symptoms (hand weakness, persistent paresthesias) warrant evaluation by a specialist experienced in thoracic outlet syndrome.
Specialists Who Treat Cervical Rib Syndrome
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Questions to Ask Your Doctor
Bring these questions to your next appointment about cervical rib syndrome.
- 1
Is my thoracic outlet syndrome neurogenic (nerve-related) or vascular — and how does that affect urgency and treatment?
- 2
What provocative tests confirmed my diagnosis, and have I had electrodiagnostic studies (EMG/nerve conduction) to evaluate the brachial plexus?
- 3
What does physical therapy focus on for TOS — posture, scalene stretching, or something else — and how long before I'd expect results?
- 4
If I need surgery, what is the difference between cervical rib resection and first rib resection, and which would apply to me?
- 5
What are the risks of the "Paget-Schroetter" vascular crisis if I continue conservative management of vascular TOS?
Research Evidence
No studies reviewed yet for this condition. Check back soon — our evidence pipeline runs nightly.
Clinical Evidence
Frequently Asked Questions
Is a cervical rib always removed if found on imaging?
No. The majority of cervical ribs are asymptomatic and require no treatment. Resection is reserved for patients with documented neurogenic or vascular thoracic outlet syndrome that has failed at least 3–6 months of dedicated physical therapy, or for patients with acute vascular complications such as subclavian artery aneurysm, thrombosis, or distal emboli.
How is cervical rib syndrome different from cervical radiculopathy?
Cervical radiculopathy compresses a nerve root at the foramen in the neck, producing dermatomal pain in a specific pattern corresponding to that level. Cervical rib syndrome compresses the lower trunk of the brachial plexus below the spine, producing an ulnar distribution pattern with positive vascular provocative tests (Adson, hyperabduction). MRI of the cervical spine is typically normal in cervical rib syndrome.
What is the success rate of surgery for cervical rib syndrome?
Surgical outcomes depend on the predominant symptom type. Vascular TOS from cervical rib has excellent surgical outcomes, with over 90% resolution of vascular symptoms after rib resection. Neurogenic TOS is more variable; 70–80% of properly selected patients report significant improvement. Early surgical intervention before muscle wasting or irreversible nerve injury leads to better outcomes.