Although we usually think and talk about muscles as being weak or strong, closer to the truth is that muscles are usually inhibited or facilitated, respectively. Inhibition is when neural input (from our nervous system) to the muscle has been down-regulated. Facilitation is the opposite, when neural input to a muscle is excessive or up-regulated. Facilitated muscles are often those muscles compensating for the loss of input into a movement pattern that should come from the muscle that is inhibited. Inhibition often results from poor posture, pain, injury, micro or macro trauma, overuse, fatigue or some other handicap to the muscle. Muscles that cover more than one joint tend more towards inhibition. You can liken this to someone who has multiple tasks to do. Chances are their energy will be dissipated and they will not be able to focus maximum energy on one single task. Conversely, uni-articular muscles, that cross only one joint, tend more towards facilitation.
Inhibited muscles are not necessarily weak. When we talk about muscles working in pairs and the antagonist having to release when the agonist muscle is in action, i.e. being reciprocally inhibited, the antagonist muscle is not weak but instead is switched off by the nervous system. However, in a muscular imbalance this inhibition will not automatically switch back on until we restore a balanced working relationship between the muscles involved.
A forward head carriage (colloquially known as a ‘computer head’) has become the standard ubiquitous posture in our western, computer-dominated society. Every 2-3cms that your head is forward of your shoulders doubles the weight of your head on your neck and shoulders! And an adult head weighs about 4.5-5 kg! This causes a huge handicap to the extensor group of muscles on the back of our neck. These muscles become facilitated as they attempt to hold our head upright against the force of gravity. This includes the cervical portions of the erector spinae group, the deeper semispinalis, the levator scapula, splenius, suboccipitals, upper trapezius and the sternocleidomastoid (SCM), which extends our head on our neck.
In our neck our spine naturally forms a forward or lordotic curve – the same as that which exists in our low back. We developed this curve as an infant as we leaned to move and find stability in harmony with the all-pervasive gravitational pull of our Mother Earth. Our uprightness is one thing that characterizes us as human beings. We even use this term to mean goodness, rectitude or being honourable. Our neck muscles not only move our neck and head but also provide us with the stability of our head in relation to the rest of our body, especially in relation to our environment where gravity rules.
As a musculoskeletal therapist I mainly see a biased proportion of the population – those with pain. Having studied the x-rays of many patients I found that approximately 95% of these people have a straight neck, i.e. they have lost their natural lordotic curve. Another 3% had irregular curves, swan necks, etc and only about 2% of my patients had retained if not exaggerated lordotic curves. This 2 % were 70 plus year olds, fortunately non-adapted to a computerised society.
A loss of cervical spine lordosis comes from an imbalance of our neck musculature with the superficial neck flexors dominating the action of the deep neck flexors and often the neck extensor muscles compensating for their lack. Our natural curves soften the physical impact on the multiplicity of joints along our spine and also soften the multi-channeled stimuli delivered via our sensory nerves to our brain. This new straight direct route to and from our central nervous system may be a modern adaptation to our fast-paced, information-overloaded society! However, it also does perpetuate a state of over-stimulation, restlessness and a lack of contentment.
When it comes to movement patterning, the head rules and the body follows. This means that any imbalance in the position of our head will affect how we move and even how we breathe! In Part 1 we looked at saving our neck by creating space when practicing various asana, in Part 2 we looked at the optimal movement patterning for our neck when taking our head back into extension. As we have lost our natural developmental neck structure and posture in an upright position let’s now look at how we can correct this both on and off the mat to bring equilibrium and harmony to our neck and nervous system. The first step is to examine in some detail the muscles involved.
The Muscles Involved
Postural muscles always have some tone as they are always on duty to maintain our posture. Their cellular makeup determines their ability to do this so that they have enough energy and oxygen to be able to maintain muscle tone and not fatigue. They are usually deep muscles close to the spine and thereby have a stabilising role. The deep neck flexor muscles, (longus colli and capitus) lie behind our windpipe or trachea and play the role of stabilising one vertebra in relation to the other. The various portions span from the occiput of the cranium to the third thoracic vertebra. Together these muscles not only flex the head and neck but also stabilise the cervical vertebra in the front and in rotation. Spanning many joints, they tend towards inhibition and are nearly always inhibited in those who have a history of neck pain or injury, such as whiplash or in a forward head carriage.
The scalene muscles on the lateral side of the neck are portioned into anterior, middle and posterior fibres. They extend from the transverse processes of the second to seventh cervical vertebrae down to the first and second ribs. The scalene muscles both flex and laterally flex the neck. The plexus of nerves that supply our arm and hand, the brachial plexus, passes between the anterior and middle portion of the scalenes and can be the cause of forearm, wrist and hand pain or dysaesthesia, sometimes misdiagnosed as Carpal Tunnel Syndrome. Additionally, the long thoracic nerve also runs through the scalene muscles to supply the serratus anterior, the most important stabilising muscle of the shoulder.
The scalenes are anatomically tight. Their fine muscular slips are very sensitive, always online and ready to lift our ribcage should we need take the slightest increase in inspiration. Their prime position to lift the ribcage makes the scalenes accessory muscles of respiration. In this role they are often over-utilised because of inadequate diaphragm muscle engagement. They are only used in passive breathing if our head is well balanced on our shoulders, which means that with a forward head posture these muscles are usually facilitated. Assess your breathing pattern: vertical movement of the ribcage versus lateral movement of the ribs is indicative of faulty ‘chest breathing’ and inevitably over-facilitated scalene and SCM muscles.
The superficial SCM muscles tend towards compensation and thereby facilitation. The two heads both attach to the mastoid process of the temporal bone as well as the occiput of the cranium. One head then reaches forward to the sternum, the other to the medial part of the clavicle. It is these attachments onto the chest that enable SCM to elevate the ribcage. The obliquity of the SCM makes it a complex muscle as it can moves on three planes. On the sagittal plane it flexes the neck and extends the upper cervical vertebrae. On the coronal plane the SCM laterally flexes the neck and on the transverse plane it acts as a short range (clavicular head) and a long-range (sternal head) rotator. In this way it is responsible for equilibrium of the position of our head in all of these three planes atop the rest of our body.
When you turn you head to the left the muscle that pops up on the right side of your neck is your SCM. The upper cervical extension performed by the SCM muscle translates to jutting the chin. Whilst leading with your chin is a good way to initiate extension of your neck, as when doing back bending postures, as a habitual posture it means that your SCM will be hyperactive. Try to catch yourself in your habitual head/neck posture, eg at your computer, driving your car, a short person talking to taller people, etc. Now place your hand on your SCM and feel its level of engagement. Drop you chin and feel the SCM release.
How to Have a Happy Neck
Adjusting our posture requires gentle, consistent practice in our activities of daily living and when we practice our yoga asana and techniques. Here is a simple and effective correction to get the curve back in your neck. Take note of the ease, spaciousness and grace this brings to your posture and breathing.
Gently tuck your chin and imagine drawing a large smile under your chin where it meets your throat and from ear to ear. You will automatically feel a lengthening of the neck as the SCM releases and the deep neck flexors are activated. You can exaggerate the sense of lengthening your neck by elevating the crown of your head toward the ceiling being careful to not lose the softness in the front of the throat and a sense of ease.
To strengthen the deep neck flexor muscles lie on your belly and come up onto your elbows in a sphinx posture. Now adopt the above posture or ‘smiling neck technique’. From here gently lift the back of your head and neck toward the ceiling. Check that you maintain a balanced shoulder position and that you are not elevating or rounding the shoulders in this position.
Neutral Cervical Spine
We often talk about the importance of a neutral low back in order to keep our lumbar spine happy. In the area of our cervical spine the majority of us are way off neutral with our straight modern necks. Neutral implies a place of ease where there is neither dominance, compensation nor inhibition. If you have facilitated SCM muscles it will pull your head forward and harden and straighten the benevolent curve in your neck. When we release the SCM the deep neck flexor muscles can engage. This enables a balanced position of ease with the muscle guywires of the neck in harmony and in the place of least resistance against gravity.
Always with you on the mat