[en] This case report describes a periarticular abscess and a suppurative arthritis of the atlanto-occipital joint in an adult horse. The horse showed a painful swelling localized on the atlanto-occipital region and ataxia in all four limbs. During his hospitalization the horse developed recumbency, dysphagia, facial paralysis and seizures. With the use of ultrasonography of the atlanto-occipital region a tentative diagnosis was made which was later confirmed by autopsy. Culture of the abscess revealed a Staphylococcus aureus. However, the horse had a history of recurrent fever, hypertrophy and abcessation of the submandibular lymph nodes, neck pain and dyspnoea for 2 months, suggestive for strangles.