Author – Matthew Voigts DO, Atlas Zone Practitioner

INTRODUCTION

This article attempts to explain how, in the author’s opinion, excessive occipital condylar compression during the second stage of labour, caused by a deviation from the evolutionary birthing position, results in incorrect embedding of the superior facets of the atlas. This causes a traumatically rotated position of the atlas bone in relation to the occiput with associated dysfunction of the length/tension relationships of the suboccipital muscles. Due to the intimate relationships between these muscles and the dura mater via myodural ligaments, tensegrity is disturbed and results in asymmetry in the sagittal, frontal and transverse planes. This influences the body in ascending and descending directions. Ascending influences can be observed as cranial/ facial asymmetry, dental midline deviation and forward head posture. Descending influences as functional discrepancy of the upper and lower limbs, scoliosis and a tilted pelvis.

Bilateral Symmetry

Image by Alison Roberts

It appears to be factual that the body plans of most animals have mirror symmetry from head to tail or in the sagittal plane. It is so common that scientists agree that it cannot be coincidence. In fact, symmetry can be regarded as a law of nature and is crucial for understanding science especially physics. Einstein based his Law of Relativity on the fact that the universe was symmetrical. It is not fully understood why symmetry is so widely observed in the natural world and therefore important. It may be gravitational effects or related to the Golden Ratio, phi, Fibonacci sequences or the unsolved equation. Or perhaps they are all linked in some way. This the mathematicians and physicists need to work out. However, I am interested in the fact that evolution has created mammals to be bilaterally symmetrical. I am also particularly interested in why modern humans are showing signs of asymmetry whereas other mammals are not. These signs can be observed as asymmetry of the face and cranium, midline dental deviation, functional short upper and lower extremities and tilted pelvis. However, these asymmetries appear to be biomechanical as if the human body has been twisted through the sagittal plane. Put another way we are bilaterally symmetrical but we have been twisted from head to toe at some juncture.
The observations I make are commonly noticed all the time by various professionals. Ask any dentist how common dental midline deviation is or any manual therapist how often they notice functional short lower extremities and a tilted pelvis, or any cranial osteopath how often he palpates an asymmetrical cranium. And as for facial asymmetry you can even download an app to show you how different each side of your face is!
We accept these facts as normal but in reality they are all signs of biomechanical dysfunction.
I realise some orthodontists and cranial osteopaths may have answers for these observations which may be valid.The Cranio-Cervical Junction – Normal Arthrology and Kinematics
The cranio-cervical junction or upper cervical spine is a complex system of joints which articulate between the occiput and atlas, and atlas and axis. I am particularly interested in the pair of joints between the occiput and atlas known as the atlanto-occipital joints. The atlas has a pair of superior concave facets which face medially and articulate with ellipsoid lateral facing condylar facets of the occiput. The orientation of these joints gives an indication of the movement that is possible, as with any other joint. The atlanto-axial joints consist of two inferior facets of the atlas which are horizontal or parallel to the ground as are the two superior facets of the axis. The angle of these joints shows their intended direction of movement.
Many motion studies have been conducted at these joints which I have referenced below (1,2,3,4,5,6,7). An overview of the results of these studies indicate that between the occiput and atlas i.e. the atlanto-occipital joints, there is very little if no rotation and the small amount of movement that is possible occurs at the end of full rotation of the neck. To quote L Penning ‘ rotational movement between the occiput and atlas, if possible at all, is so small that it is virtually impossible to view radiologically.’ I would like to explain this in more detail as I have read many people’s opinion regarding the movement of the atlas and clarification is important. If a totally symmetrical person had a 3D CAT scan of their cranio-cervical junction in the anatomical position the atlas would be observed in a totally neutral position under the occiput. No rotation or lateral flexion would be observed. The movements allowable at the atlanto-occipital joints are flexion and extension 10 degrees, which involves some translation movement. A couple of degrees of lateral flexion is also possible. So overall the movement at these joints is minimal. Furthermore, if the atlas is observed on 3D CAT or MRI to be rotated in relation to the occiput it is only logical to assume that, due to the fact the morphology of the atlanto-occipital joints do not allow rotation, that this rotation is abnormal and therefore that this condition must be traumatic in origin.
The atlanto-axial joints have a large range of rotation movement allowable due to the angle of the facets. The cranium and atlas move as one unit rotating around the odontoid process.
I believe, due to the laws of nature and symmetry, perhaps as little as 300 years ago the majority of human faces were symmetrical and the atlas was in a neutral or orthogonal position under the occiput. This may also be the case in some cultures living today.

The Cranio-Cervical Junction of modern humans
Asymmetry at the cranio-cervical junction has been observed and studied.
William G Blair DC took measurements from cadaveric bone specimens of the cranio-cervical junction. These were his findings
79% of individuals have one occipital condyle asymmetrically anterior to the contralateral condyle.
77% have the foramen magnum apex turned off center
77% have a short occipital condyle compared to the contralateral side when compared to the orbital floor
64% have a short condyle when compared to the baseline of the skull
66% have a short condyle when compared with a vertical median line
I list further references below which highlight the asymmetry that is so common of the atlas and occipital condyles (8,9,10,11,12).

In my opinion, this information indicates osseous adaptation to some traumatic event and this region of the spine is not obeying the natural law of symmetry. Furthermore, the fact that asymmetry of the atlas and occipital condyles has been observed brings into question the value of palpation in this region which manual therapists are so ready to inform patients of their findings regarding the position of the atlas. Palpation can realistically and accurately only give feedback on the overall symmetry of this region.
If it can be agreed that atlas rotation is abnormal and represents a traumatic event that is common to modern populations, it is logical to presume that the aetiology must be an event that every modern human experiences. The only event that could involve a trauma that is common to everybody is birth. To understand how this may happen knowledge of the normal birth process is required.

Suboccipital Muscles and Fascia

There are four pairs of sub-occipital muscles – rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis superior and obliquus capitis inferior. According to Grays Anatomy 20th Edition none of these muscles have an action which will independently rotate the atlas on the occiput or vice versa. It clearly states that the occiput and atlas rotate together as a unit around the odontoid peg. A quantitative study of muscle spindles in suboccipital muscles of human foetuses was conducted in 2001 (13). The results of this study are very insightful and suggest that the suboccipital muscles do not play a role in movement at the craniocervical junction due to the absence of Golgi Tendon Organs but their role is proprioceptive, that is they sense joint position and movement changes, due to the extremely high density of muscle spindles compared to other muscles.

Myodural Bridge

Anatomical research concerning the fascial connections or myodural communications bridging the posterior epidural spaces between rectus capitis posterior major, rectus capitis posterior minor and obliquus capitis inferior and the dura mater is well documented (14-21). Furthermore, research suggests that via this communication the suboccipital muscles act as a dural anchor and as an active stabiliser of the spinal cord (17,19,22). The importance of this cannot be over-emphasised. If the atlas is traumatically rotated the consequential alteration of the length tension relationships of the suboccipital musculature will in turn result in asymmetrical dural tension in both an ascending direction acting on the intracranial dural connections and a descending direction acting on the dural spinal connections especially at the sacrum. This dural torque that emanates from the cranio-cervical junction will create cranial distortion and sacral imbalance with all the subsequent effects.

Normal Birth Process with particular reference to biomechanical stresses at the atlanto-occipital vicinity

70% of normal labours present with the cranium in the Left Occiput Anterior (LOA) position. Blair’s observations of cranio-cervical asymmetry were in the 70% range and 70% of people have a functional short right lower extremity. The baby’s cranium particularly at the level of the cranio-cervical junction is subject to considerable compressive forces during the second stage of labour which is well described by various cranial osteopathic authors (23,24). However, it is rotation under compression that must underline the aetiology of traumatic atlas rotation. As the baby’s cranium descends into the pelvis uterine contractions evenly compress the baby’s body onto its cranium which is resisted by the mother’s pelvic soft tissues. The baby’s cranium is required to traverse the narrowest part of the mother’s pelvis at the level of the ischial spines. For this to occur the cranium needs to rotate 90 degrees so the baby’s face is posterior. This rotation under compression is normal. However, if the mother’s pelvis is restricted in some way the pressure exerted on the occipital condyles by the superior facets of the atlas becomes excessive. It is by this situation that traumatic atlas rotation may occur.

Caesarian
Babies born by caesarian section are born with negative condylar compression i.e. traction. The forces involved in extracting a baby by this method are far greater than the normal birth process. The traction forces required cause rebound reactive tension and symmetry disturbances particularly in the neck region (24).

EVOLUTIONARY BIRTHING POSITION

In May 1987 a paper was published in the American Journal of Public Health by L Dundes, titled ‘the evolution of maternal birthing position’. This paper describes how a reclining birth position gradually disseminated across the developing countries beginning in France possibly under some influence from Louis XIV (1638-1715). A supine birthing position gradually became the mandatory position for birth in the developed world mainly as the result of the medical fraternity influencing people that pregnancy and birth should be viewed as an illness rather than natural. Until only recently expectant mothers are being given more choices regarding giving birth. Pre-Louis XIV, i.e. 300 hundred years ago, there is very little evidence of women giving birth in a horizontal position. Women squatted, sat, knelt or were on all fours. All these positions involve gravity but most importantly these positions, particularly the deep squat position with the feet parallel, the pelvic outlet is 30% larger. At the narrowest level of the pelvis, the ischial spines, a decrease in the lateral diameter of 30% one must presume would have a major impact on condylar compression. In addition, the restriction on the sacrum in the supine position will also further compromise the baby’s cranium. The other point to consider is most pregnant modern woman will have been born by mothers who gave birth to them in the supine position. If a pregnant modern woman has a traumatically rotated atlas they will have a tilted pelvis due to an unbalanced sacrum. This asymmetry of the pelvis will cause further complications for the unborn baby’s journey.

TMJ, Occlusion and the Upper Cervical Spine

Temporo-Mandibular joint dysfunction is a very common problem. A growing number of dentists are beginning to understand and treat this condition using oral appliances aimed at reducing the TMJ discal disorder. Specialist dentists have known for a long time of a relationship between the upper cervical spine and occlusion. In fact in 1955 Casey Guzay determined that the muscle controlled pivotal axis of the mandible occurs at the dens between the atlas and axis vertebra. These findings were put into sophisticated series of drawings entitled The Quadrant Theorem (25,26). The occlusal plane is level with the inferior border of the atlas and this is a very important fact as it enables an explanation of how spinal alignment affects occlusion and vice versa. However, it is important to emphasise that compensations occur below C1.
An important fact arises that is being overlooked by many. Traumatic atlanto-occipital dysfunction pre-exists an established occlusion and TMD. In fact, traumatic atlas rotation must be an important predisposing factor for TMD due to the fact, that this condition disturbs the whole tensegrity of the cranium via dural torque and causes many postural compensations. In my opinion, the first step in any protocol to treat TMD should be to correct the myofascial components related to traumatic atlanto-occipital dysfunction. In this way, the postural corrections that ensue may sometimes be enough to avoid additional treatment altogether.

CONCLUSION

This short article covers many topics which could be elaborated on in much more detail. Clearly many mothers will continue to give birth to babies in a supine position and it is inevitable that sometimes this is an only option for the health of the baby and mother. After a baby is born crying and suckling have a beneficial effect on reducing molding and a certain amount of fascial unwinding occurs as the human body always attempts to reach homeostasis. However, the consequences of excessive condylar compression disturb the tensegrity of the infant’s body by too larger a degree to recover and the effects will be maintained and compensations for this disorder will remain. These may be subtle in most until compensations are broken down by additional traumas throughout life.
Correcting the myofascial components related to atlanto-occipital dysfunction can provide an extremely powerful healing catalyst and can result in the alleviation of many painful conditions. However sometimes the results are limited by the biomechanical compensations for this disorder that have failed over time with their subsequent degenerative effects.
Once the permanent teeth have erupted, occlusion is established and full ossification of the cranial region has occurred, compensations for this dysfunction become more difficult to treat in the cranial region. Additional methods such as oral orthotics, which can provide powerful orthopaedic forces, will sometimes be required.
When a baby is ‘out of the valley of the shadow of birth’ it is important that a clear strategy is adopted to address this condition and other effects of birth trauma but also an alternative strategy which would include eliminating other bio-mechanical disorders that develop in infancy such as mouth breathing and dysfunctional tongue posture before the permanent teeth erupt.

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