A 25-year-old man presented to the Emergency department in a rural South African hospital after a left, submental neck stab with a knife. Examination was deemed unremarkable, and the patient was discharged, but re-attended 2 days later complaining of a painful, swollen neck. Further examination identified Horner's syndrome, and further investigation revealed that the blade of the knife had remained in the patient's neck. This was successfully removed in theatre. This case illustrates the importance of careful history, examination and diagnostic imaging in the management of penetrating neck injuries. Horner's syndrome can be easily missed in a busy Emergency department and may indicate life-threatening pathology in the context of neck trauma. The difficulties in assessing and managing this type of injury are discussed.