Updated: Jul 5
Type of Trauma: None
Sign and Symptoms: Dizziness, Headache, Neck Pain, Syncope (Fainting)
Imaging findings: Agenesis of the C1 Posterior arch.
Outcome: Patient was referred for further investigation.
Mid 40s male visited Silverdale Chiropractic for his dizziness, neck pain and drop attacks (Cardiovascular syncope). Patient was already nearly fainting by just doing a normal cervical rotation by reaching the end range of the motion. There is a condition called a Bow Hunter Syndrome. When the hunter uses the bow to shoot the arrow they turn their head. There are occasions where the hunters find themselves on the ground and realized they passed out. Bow hunter's syndrome (BHS), also known as rotational vertebral artery (VA) syndrome, refers to symptomatic vertebrobasilar insufficiency (VBI) caused by mechanical occlusion or compression of the VA at the atlantoaxial or subaxial level during neck and head rotation.
During the physical examination, the patient's dizziness certainly was reproduced with the cervical rotation and continuing of the rotated position gave him the sensation of passing out.
CBCT revealed an agenesis of the posterior arch of C1, resulting in a forward transition of the C1 TVP which could choke the internal jugular veins between the elongated styloid processes and forward transition of the C1 TVP will displace the transverse foramen forwardly as well, thus affecting the vertebral arteries and veins as well.
Agenesis of the C1 posterior arch
Vertebrobasilar insufficiency syndrome (Bow-hunter syndrome) due to the possible bilaterally disrupted internal jugular veins and vertebral arteries and veins
Patient was absolutely unaware of all these in despite when he was hospitalized for a month in the past to find out what was making his heart rate slow (Bradycardia) and in result of a syncope. Further assessment such as MRI to ensure the sound integrity and function of the spinal cord and the structures at the CCJ therefore he was referred to his GP.