The dizziness began as you abruptly turned your head. It has happened several times and you are concerned. Your doctor wants to order some lab and radiographic tests. He is not certain as to what is causing your symptoms. What is the Craniocervical Junction? What is a Craniocervical Junction Disorder? What causes Craniocervical Junction Disorders? What is Jugular Vein Compression? Why is the C1/2 Joint the problematic child? What are the symptoms of Jugular Vein Compression? What is Eagle’s Syndrome? Meet Jane. What are the treatment options for Jugular Vein Compression? Let’s dig in.
What Is the Craniocervical Junction?
The Craniocervical Junction is the area between the Skull and the Cervical spine. It consists of the bone that forms the base of the Skull, the first two bones in the spine, and the neural structures that pass from the brain down into the Cervical Spine.
What Is in the Craniocervical Junction?
The base of the Skull also known as the Occiput has a large opening at its base called the Foramen Magnum. Foramen meanings opening. Magnum means large. So the Foramen Magnum is a large boney opening at the base of the Skull that allows important structures to pass through. Important structures that pass through the Foramen Magnum include:
The Spinal Cord consists of neural tissue that starts at the base of the brain and extends down into the low back. It is a cylindrical bundle of nerve fibers that control our voluntary and involuntary bodily functions. It carries signals between the brain and the rest of the body. As the Spinal Cord descends from the skull and through the neck and rest of the body it is protected on all sides by spinal bones. These bones provide boney armor to protect against injury. The Spinal Cord has an additional layer of protection afforded by the spinal fluid. The spinal fluid is also known as Cerebral Spinal fluid. It surrounds the Spinal Cord and extends the entire length of the spine. The image to the right is a side view of the Spinal Cord as it exits the brain. The Spinal Cord is black in color. The white that surrounds the Spinal Cord is the spinal fluid.
As the Spinal cord descends through the Foramen Magnum and spine, important nerves branch off traveling to different parts of the body. There are a large number of nerves. These include the 12 Cranial nerves some of which control muscles whereas others are connected to internal organs such as the heart and lungs.
Arteries and Veins
Arteries and veins provide blood flow to and from important structures in the head, neck, and body. Without blood flow, the body can not function.
Ligaments are the human duct tape that keeps everything in alignment and stable.
What Is a Craniocervical Junction Disorder?
Craniocervical Junction Disorders are abnormalities of the bones and other structures that join the head and neck. This includes the spinal cord, exiting nerves, spinal fluid, veins, arteries, and ligaments.
Causes of Craniocervical Junction Disorders
Craniocervical Junction Disorders may be present at birth or result from injuries or disorders that occur later. Craniocervical Instability (CCI) is a common Craniocervical Junction Disorder that occurs when one or more of the supporting ligaments becomes injured or loose. Ligaments are thick pieces of connective tissue that connect bone to bone. They provide important stability. To better understand Craniocervical Instability please click on the video below.
Jugular Vein Compression: A Consequence of Craniocervical Instability
Craniocervical Instability can cause a large number of symptoms and limitations. One of these is Compression of the Jugular Vein. What is the Jugular Vein?
The Jugular is a large vein in the neck/head region. It is an important structure as it collects blood from the brain, face, and neck and delivers it to the heart. We all have two Jugular Veins: an external and an internal Jugular Vein. The is one on the right and one on the left. The internal Jugular Vein is the focus of today’s discussion and can be affected by Craniocervical Instability. When the Jugular Vein is compressed the blood is not able to drain into the heart and backs up in the brain. Ouch!
As shown above, the internal Jugular Vein exits the skull and travels down immediately in front of the C1 and C2 neck bones.
Jugular Vein Compression
The most common site of Jugular Vein Compression is in the upper neck. The Jugular Vein lies immediately in front of the C1 and C2 bones. In Craniocervical Instability (CCI) the upper neck bones can move or shift due to loose or damaged ligaments. This instability can lead to compression of the Jugular Vein. Simple movements such as rotation or bending the neck forward or backwards can result in compression of the vein. This is depicted below. The yellow arrow identifies the C2 vertebral body. If there is abnormal bone movement due to ligament instability, the C2 body can move forward thereby compressing the Jugular Vein which is identified in blue in color.
C1/2 Joint: The Problematic Child
Most joints in the body have a ball joint configuration. The ball fits snugly into the socket creating a stable joint. The ball has a convex shape (the curve bends outward). The socket on the other hand is concave ( the curve bends inward). The convex curve fits snuggly into the concave socket.
Unfortunately, the C1/2 joint is NOT a ball socket joint. Its shape is unique in that both surfaces on convex. Yep, they both curve outward. Think of two marbles being held together. Hence this is an inherently unstable joint that requires both stable ligaments and muscles to stay in alignment.
If the ligaments that hold the head onto the neck are loose, one joint surface will slide down on the other as shown above. When this occurs Jugular Vein Compression can occur.
Symptoms of Jugular Vein Compression
Jugular Vein Compression can cause several symptoms. The most common include (3) :
- Noises heard in the head
- Ringing in the ears
- Hearing Difficulties
- Neck discomfort
- Double or blurred vision
- Transient Amnesia
Unfortunately, some of the symptoms of Jugular Vein Compression overlap with those with Craniocervical Instability. This can be challenging in determining the actual source of a given patient’s problems.
Eagle’s Syndrome and Jugular Vein Compression
Eagle’s Syndrome is a rare clinical condition where the styloid process grows in length or its associated ligaments become calcified. The Styloid Process is a thin, slender bone just below the ear. It serves as an anchor for muscles associated with the tongue. Calcification of the ligaments or elongation of the Styloid bone can also cause compression of the Jugular Vein (4). In our experience, given that an elongated Styloid Process is common in patients without any problems at all, and many of the patients diagnosed with Eagle’s Syndrome also have CCI, it makes diagnosing the issue causing the symptoms even more challenging.
Clinical Example: Meet Jane
Jane is a 50 yr old patient with headaches, neck discomfort, and double vision who was evaluated at the Centeno-Schultz Clinic. Conservative treatment with a large number of clinics and providers had failed. Her imaging was quite telling and is shown below.
The image above is a top-down cross-section view of the C1 bone. It is a CT scan. The black ring-like structure in the middle of the picture is the C1 bone. The small oval structure that is in the upper portion of the ring-like structure is the Dens. The Dens is a boney projection of the C2 bone. It looks like the Washington Monument.
The lines represent the front-back angle of each bone. The red line is for the C1 bone whereas the green is for the C2 bone (Dens). The angles should be the same for the C1 and C1 bones. Unfortunately for Jane, the two lines are off meaning that the bones are misaligned ( AKA rotated). The red line marked C1 is almost straight (pointing slightly off to the left) and the line through the Dens shows that C2 is rotated to the right. They shouldn’t be positioned like this as strong ligaments usually prevent this from happening, so this is reasonable evidence that the ligaments that hold the head on are too loose (CCI).
In the image above we have an actual CT image of the Jugular Vein filled with radiographic contrast. The C2 bone is identified by the yellow arrow, which is a dark oblong-shaped structure. The yellow arrow is pointed to it. In the image of the left, the C2 bone has rotated forward placing pressure on the Jugular Vein. Note that the Jugular Vein is much smaller in size as it passes this bone. In the image on the right, the vein is normal size. this is because the bone has not rotated forward on this side. Hence the image on the left shows Jugular Vein Compression
Treatment Options for Jugular Vein Compression Due to Craniocervical Instability
Treatment options will depend upon the severity of one’s symptoms and degree of Jugular Vein Compression. When appropriate the first-line treatment should be conservative care like upper cervical chiropractic care ( NUCCA or AO).
When conservative care fails, the next step is precise injections of PRP or Bone Marrow Concentrate into the upper cervical facets and ligaments. If this fails to provide significant benefit, Bone Marrow Concentrate can be injected directly into the Alar and Transverse ligaments. This procedure is a technically challenging procedure and is only performed in Broomfield, Colorado. How can tightening ligaments help? Realize that instability is a dynamic concept. Meaning that the vein gets compressed with head movement because the C1 and C2 bones move too much in the wrong directions (rotation against each other). Hence, tightening the ligaments that are supposed to prevent this motion can help avoid compressing the vein. To learn more about this procedure please click on the video below.
When symptoms fail to respond to conservative and interventional treatment, surgery is recommended. Most commonly hardware is placed across the C1/2 joints to provide stability. Fusion is major surgery and is associated with significant complications including bleeding, infection, failure, persistent pain, and Adjacent Segment Disease.
- The Craniocervical Junction is the area between the skull and the Cervical Spine.
- The Craniocervical Junction consists of the Spinal Cord, the Cranial nerves, arteries, and vein and ligaments.
- Craniocervical Junction Disorders are abnormalities of the bones and other structures that join the head and neck.
- Craniocervical Junction Disorders may be present at birth or result from injuries or disorders that occur later.
- Craniocervical Instability (CCI) is a common Craniocervical Junction Disorder that occurs when one or more of the supporting ligaments becomes injured or loose.
- Jugular Vein Compression can occur as a result of Craniocervical Instability.
- The most common site of Jugular Vein Compression is in the upper neck.
- In Craniocervical Instability (CCI) the upper neck bones can move or shift due to loose or damaged ligaments. This instability can lead to compression of the Jugular Vein.
- The C1/2 joint is inherently unstable due to its convex/convex structure. Most joints are concave/convex in design.
- Symptoms of Jugular Vein Compression include headaches, ringing in the ears, neck discomfort, double vision, and dizziness.
- Eagle’s Syndrome is a rare clinical condition where the styloid bone grows or its ligaments become calcified that can cause compression of the Jugular Vein.
- Treatment options for Jugular Vein Compression depend upon the symptoms and the severity of the compression. Options include conservative care, injections, and surgical fusion.
If you or a loved one has sustained an injury with ongoing headaches, neck pain, and dizziness that has not responded to conservative care please schedule a telephone candidacy discussion with a board-certified, fellowship-trained physician. From the comfort of your home or office learn what treatment options are available for you. Call today and stop the pain, misery, and suffering.
1.Offiah CE, Day E. The craniocervical junction: embryology, anatomy, biomechanics and imaging in blunt trauma. Insights Imaging. 2017;8(1):29-47. doi:10.1007/s13244-016-0530-5
2.Zdilla MJ, Russell ML, Bliss KN, Mangus KR, Koons AW. The size and shape of the foramen magnum in man. J Craniovertebr Junction Spine. 2017;8(3):205-221. doi:10.4103/jcvjs.JCVJS_62_17
3..Li M, Su C, Fan C, Chan CC, Bai C, Meng R. Internal jugular vein stenosis induced by tortuous internal carotid artery compression: two case reports and literature review. J Int Med Res. 2019;47(8):3926-3933. doi:10.1177/0300060519860678.
4.Zamboni P, Scerrati A, Menegatti E, Galeotti R, Lapparelli M, Traina L, Tessari M, Ciorba A, De Bonis P, Pelucchi S. The eagle jugular syndrome. BMC Neurol. 2019 Dec 21;19(1):333. doi: 10.1186/s12883-019-1572-3. PMID: 31864313; PMCID: PMC6925502.