Curious case of the bilaterally absent omohyoid muscle

We planned a left composite resection with modified radical neck dissection (Type 1) and reconstruction for a 63-year-old woman with squamous cell carcinoma of the left retromolar trigone (cT4a N2b M0, Stage IVA). We looked for the intermediate tendon of the left omohyoid (because it is a landmark for the internal jugular vein in its lower third), but found that the entire muscle was missing (Fig. 1).

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