There are 4 big arteries that take blood to the brain: right & left carotid arteries in the front of the neck, & the 2 vertebral arteries toward the back. In rare cases, their artery walls can tear, with layers splitting apart from each other (“dissection”). This can occur from minor trauma, including physical exertion (likely due to abrupt neck movements). Cases have been caused by exercising vigorously (like swimming the crawl, & various sports), roller coaster rides, yoga, childbirth, sex, even sneezing or coughing.
The main symptom is neck pain or headache, almost always on just one side, which usually comes on gradually, but may occur abruptly. Patients may have vertigo, double vision, slurred speech hoarseness, trouble swallowing, but many have no such symptoms.
We’d especially suspect this if a patient with new neck pain or headache has abnormalities on neurological exam, in particular a droopy eyelid & small pupil on one side of the face, or can’t stick their tongue out straight. Diagnosis is made by CT scan or MRI. This should be done in an E.R., since dissections can cause strokes, although most get better on their own.