FIGURE 1 | Illustration depicting the predominant veins and sinuses involved in the craniocervical venous outflow. Venous narrowing is depicted at locations of interest in chronic cerebrospinal venous insufficiency. http://www.frontiersin.org/Endovascular_and_Interventional_Neurology/10.3389/fneur.2011.00044/full

Illustration depicting the predominant veins and sinuses involved in the craniocervical venous outflow. Venous narrowing is depicted at locations of interest in chronic cerebrospinal venous insufficiency. Lazzaro M.A. et al (2011)

‘Recent reports have emerged suggesting that multiple sclerosis (MS) may be due to abnormal venous outflow from the central nervous system, termed chronic cerebrospinal venous insufficiency (CCSVI).’

Lazzaro M.A. et al (2011)

http://www.frontiersin.org/Endovascular_and_Interventional_Neurology/10.3389/fneur.2011.00044/full

This is a very exciting article on the how venous outflow could be implicated in MS. The diagram above shows the sites the researchers have identified as being restricted.

There is a long tradition in cranial work of supporting drainage from the head by working at the thoracic outlet (or inlet, depending on what term you prefer, both are used for the same area). The first craniosacral therapist I ever saw would always start at the thoracic outlet, maybe he was on to something.

In the thoracic outlet hold the hands are above and below the base of the neck – upper hand spread over  the suprasternal notch, first rib and clavicles, the lower hand underneath the the cervical thoracic junction. I like to try and feel the shape of the hole made by the first rib and orient to the health of all the tubes moving through the region (dural tube, oesophagus, trachea, carotid sheaths). Pulsing arteries softening, spreading of the fascia sheets, easing of the movement of C7 and a shift in the first rib and clavicles all speak of change in this region.

The image above includes drainage routes via ‘spinal column drainage route’, ‘pterygoid plexus’ and ‘vertebral vein’ that are fairly new to me – nice bits of anatomy to appreciate.

Another route for cerebrospinal fluid (CSF) to leave the skull you can consider is shown below. A significant amount of CSF drains as lymphatic outflow from the cranial cavity via the ethmoid (and to a lesser degree perineural spaces of cranial and spinal nerves) and is collected by the lymphatic vessels of the head and neck (Pollay 2010).

This research helped me appreciate the dynamics of the ethmoid and cervical lymphatics as important in fluid draining from the skull. Pollay also indicates that poor outflow of CSF is not good for the health of the nervous system.

A great image from Pollay 2010 showing the dual outflow system for drainage of CSF. Outflow is via both the arachnoid villi into the venous sinuses and the lymphatic outflow (mostly through the ethmoid via CN I)

A great image from Pollay 2010 showing the dual outflow system for drainage of CSF. Outflow is via both the arachnoid villi into the venous sinuses and the lymphatic outflow (mostly through the ethmoid via CNI olfactory nerve sheaths)

‘The lymphatic system has been shown to develop earlier than that of the arachnoid villi and therefore appear to be a dominant CSF outflow route in the late fetal and early neonatal period. There is convincing evidence that the arachnoid villi system loses it efficiency with age, which can influence the total turnover rate of the CSF with possible neurodegenerative consequences.’

Pollay 2010

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2904716

See also this post for more on the venous outflow in cranial work

http://cranialintelligence.com/2012/01/19/working-with-the-venous-sinuses/

References

Lazzaro M.A. et al (2011) Endovascular therapy for chronic cerebrospinal venous insufficiency in multiple sclerosis. Front. Neur., 14 July 2011 | doi: 10.3389/fneur.2011.00044

Pollay, M. (2010) The function and structure of the cerebrospinal fluid outflow system. Cerebrospinal Fluid Res. 2010; 7: 9. Published online 2010 June 21. Accessed 2/10/12 via http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2904716

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