Fracture of the Right Cervical Rib

Trauma. What is the diagnosis? • Xray of the Week

Figure 1. What is the diagnosis?

Figure 2: Coronal CT Images display a fracture through the right cervical rib (red arrows).

Figure 3: Axial and Coronal CT Images display edema in the soft tissues adjacent to the fracture (yellow arrows).

Fracture of the Right Cervical Rib

Overview and Rarity

Cervical ribs are true supernumerary ribs arising from the C7 transverse process and are a common congenital variant on cross-sectional imaging; on large CT series they are present in roughly 2.0% of adults and are under-reported unless actively sought. [1] A fracture of a cervical rib is an exceedingly uncommon event described only in isolated case reports and small case series; reported mechanisms include direct trauma, falls, and repetitive occupational load (eg, heavy backpack use). [2,3]

Clinical Findings

Patients typically present with focal supraclavicular or neck pain, a palpable tender mass at the thoracic inlet, or delayed symptoms of thoracic outlet syndrome (TOS) — most often neurogenic (paresthesia/weakness in the ulnar distribution) and occasionally vascular (upper-extremity ischemia, digital emboli). Many reported fractures initially present as atraumatic swelling or delayed neurogenic symptoms after a remote injury. [2,3]

Imaging — Modality Selection & Technique

Thin-section multidetector CT (bone kernel, ≤1.0-mm collimation) with multiplanar reformats is the modality of choice for identifying cervical ribs and confirming fracture (cortical discontinuity, step-off, displacement, callus or sclerosis in healing) because plain radiographs frequently miss fractures at the cervicothoracic junction due to overlap and suboptimal projection. [4]

Post-processing strategies that improve detection and reporting accuracy include coronal/oblique reformats through the rib axis, curved planar or “unfolded” rib reconstructions, and single-in-plane rib-cage reformations — all of which increase sensitivity for osseous injury and streamline preoperative planning. [5]

When neurovascular compromise is suspected clinically or when the fracture lies close to the subclavian vessels/brachial plexus, CT angiography (CTA) with neutral and provocative/postural maneuvers (abduction or elevation of the ipsilateral arm) can demonstrate dynamic arterial or venous compression, stenosis, aneurysm, thrombosis, or abnormal vessel course related to the fractured cervical rib. Helical CTA protocols and multiplanar 3-D reformations are particularly helpful for surgical planning. [6,7]

Imaging Findings — What to look for

• Cervical rib identification: a continuous osseous structure originating from the C7 transverse process that may articulate (partially or fully) with the first rib or clavicle. [1]

• Acute fracture features: sharp cortical break or lucent fracture line with surrounding soft-tissue swelling, displaced fragments, and occasionally small adjacent hematoma. [4]

• Subacute/chronic healing: sclerotic margins, callus formation or pseudoarthrosis at an articulation site that can mimic chronic nonunion; correlation with clinical history is essential. [2,3]

• Relationship to neurovascular structures: focal narrowing or indentation of the subclavian artery/vein, abnormal vessel angulation/arching, or proximity to the lower brachial plexus should be documented; dynamic imaging may demonstrate postural exacerbation. [6,7]

• Associated findings: first-rib abnormalities, anomalous fibrous bands, or concurrent first-rib or clavicular fractures — include these in the report because they alter management. [7]

Differential considerations (imaging)

Differentiate true acute fracture from: unfused ossification centers or congenital pseudoarthrosis, chronic nonunion/pseudarthrosis of a cervical rib, an anomalous elongated C7 transverse process, or osseous lesions (eg, osteophyte, benign bone tumor). Cortical irregularity plus focal bone marrow/soft-tissue edema on MRI (if obtained) or clear cortical disruption on bone-window CT favor acute fracture. [5]

Treatment & Prognosis

Initial management of isolated, uncomplicated cervical-rib fractures is generally conservative: activity modification, short-term immobilization/analgesia, and physiotherapy. Surgical referral is indicated when there is persistent pain, symptomatic nonunion/callus mass, or objective neurovascular compromise (TOS) attributable to the fractured rib. Surgical options include supraclavicular or transaxillary resection of the cervical rib (with ± scalenectomy and addressing fibrous bands), and preoperative vascular imaging is recommended when arterial or venous involvement is suspected. Outcomes are generally favorable after appropriate decompression; durable symptom relief is reported in series where resection was indicated. [8,9]

References

1. Viertel VG, Intrapiromkul J, Maluf F, Patel NV, Zheng W, Alluwaimi F, Walden MJ, Belzberg A, Yousem DM. Cervical ribs: a common variant overlooked in CT imaging. AJNR Am J Neuroradiol. 2012;33(11):2191-2194. doi: https://doi.org/10.3174/ajnr.A3143. PubMed

2. Kamath GS, Borkar S, Chauhan A, Chidanand B, Kashyap N, Warrier R. Isolated cervical rib fracture. Ann Thorac Surg. 2010;89(6):e41-e42. doi: https://doi.org/10.1016/j.athoracsur.2010.02.035. PubMed

3. Dar RA, Wani SH, Mushtaque M. Isolated cervical rib fracture: a rare etiology of thoracic outlet syndrome. Case Rep Surg. 2011;2011:163792. doi: https://doi.org/10.1155/2011/163792. PubMed

4. Jelly LM, Evans DR, Easty MJ, Coats TJ, Chan O. Radiography versus spiral CT in the evaluation of cervicothoracic junction injuries in polytrauma patients who have undergone intubation. Radiographics. 2000;20(Spec No):S251-S259. doi: https://doi.org/10.1148/radiographics.20.suppl_1.g00oc20s251. PubMed

5. Dankerl P, Seuss H, Ellmann S, Cavallaro A, Uder M, Hammon M. Evaluation of rib fractures on a single-in-plane image reformation of the rib cage in CT examinations. Acad Radiol. 2017;24(2):153-159. doi: https://doi.org/10.1016/j.acra.2016.09.022. PubMed

6. Remy-Jardin M, Remy J, Masson P, Bonnel F, Debatselier P, Vinckier L, Duhamel A. Helical CT angiography of thoracic outlet syndrome: functional anatomy. AJR Am J Roentgenol. 2000;174(6):1667-1674. doi: https://doi.org/10.2214/ajr.174.6.1741667. PubMed

7. Raptis CA, Sridhar S, Thompson RW, Fowler KJ, Bhalla S. Imaging of the patient with thoracic outlet syndrome. RadioGraphics. 2016;36(4):984-1000. doi: https://doi.org/10.1148/rg.2016150221. PubMed

8. Sanders RJ, Hammond SL. Management of cervical ribs and anomalous first ribs causing neurogenic thoracic outlet syndrome. J Vasc Surg. 2002;36(1):51-56. doi: https://doi.org/10.1067/mva.2002.123750. PubMed

9. Moridzadeh RS, Gelabert MC, Rigberg DA, Gelabert HA. A novel technique for transaxillary resection of fully formed cervical ribs with long-term clinical outcomes. J Vasc Surg. 2021;73(2):572-580. doi: https://doi.org/10.1016/j.jvs.2020.07.064. PubMed

Kevin M. Rice, MD is the president of Global Radiology CME and is a radiologist with Cape Radiology Group. He has held several leadership positions including Board Member and Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015, Dr. Rice and Natalie Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" Award for the Most Effective Radiology Educator. He was once again a semifinalist for a "Minnie" for 2021's Most Effective Radiology Educator by AuntMinnie.com. He has continued to teach by mentoring medical students interested in radiology. Everyone who he has mentored has been accepted into top programs across the country including Harvard, UC San Diego, Northwestern, Vanderbilt, and Thomas Jefferson.

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