The Deep Front Line (DFL, from Thomas Meyers Anatomy Trains) is one of our most fundamental tracks of soft tissue. It is the soft tissue equivalent and partner of our skeleton (especially the axial) and is what most fundamentally holds the core of our structure together when it comes to musculature and soft tissue. To explain its role to my patients I tell them to think of a bridge. The concrete or steel of the bridge is your skeleton/spine (primarily axial) while the tissues of the deep front line are like the tension cables. Together their compression and tension hold together as the foundation of our structure with excellent integrity, if everything is doing its job. As long as there is no break or other structural problem with the skeleton (that concrete/steel part of the bridge) then we don’t have to worry about that. The majority of the problem comes in when there is problems in regulating tension in the soft tissues of the deep front line. All of you reading this know it’s not a matter of isolated or simple chronic tightness or ‘over use’ that causes tension disparities, nor is it because the muscles are ‘weak’ so we won’t even cover that aspect here (it seems half my articles are just explaining the premise of neuromuscular control theory).

Deep Front Line Fascia

So what problems do happen with the DFL tension? Simply stated one length of the deep front line either gets too tight or too loose for the overall DFL to hold the tension it needs for dynamic structural integrity. When one length tightens too much…another has to slacken. When one slackens, another has to tighten. Any of you who do neuromuscular work and are familiar with anatomy trains can probably without hesitation tell me what 75% of someone’s deep front is up to (facilitation or inhibition) without even looking; and you probably have some notion for what’s causing what. This is because while individual circumstances and variables will change exactly what’s going on, the overall approach that the MCC takes to keep the structure safe is generally the same: compress and limit range of motion (there are some joints and injuries where this is not the case, such as ankle injuries). Anything that can compress is usually used for this function, and anything that will decompress is usually at least down-regulated if not inhibited.

This video discusses the Deep Front Line, the core muscular/fascial chain that fails in OP patients. Fixing OP is about strengthening this chain. Each of the first four sessions focuses on the front, back, lateral and spiral lines, undoing any pulls, strain or restrictions within them. The middle four sessions. The middle four sessions are dedicated to releasing myofascial restrictions in the deep front line which is the core line running from your feet to your head.

The overall effect commonly looks like an undulation of facilitated, inhibited, facilitated, inhibited, etc. though not always. For example I most typically find the toe flexors and or post tib working for most if not all of the adductors. The pelvic floor is either facilitated for itself (commonly posterior to anterior but it can be all or nothing as well, especially after pregnancy/genital surgeries; episiotomies are common culprits) or for part of the core above. The iliacus is commonly facilitated for the psoas, though honestly I don’t tend to consider the psoas and iliacus as part of the deep line structure in this way, but I’ll leave that opinion for another article. The TVA, RA and multifidus is typically inhibited, with the TVA having the hardest job working (95% of the time or more it doesn’t; if you find one functioning, DON’T BELIEVE IT. Mess with things until it fails. If they’re on your table with a complaint, I don’t believe their TVA. An eccentrically loaded diaphragm is probably making it look like a pass.) followed by the RA and then the multifidi closely behind. The pelvic floor may be working for one of the aforementioned 3 primary core muscles, though the next step in the chain is the diaphragm which because it is attached to a balloon it’s an amazing central hub of facilitation. Commonly it will hold tension, even if only eccentrically (check my article on eccentric contractions causing false positives) to give the MCC enough sense of tension to allow things to function, including the TVA. Deep Front Line Fascia

The deep front line continues up along the spine and throughout the thoracic cage including wrapping around the lungs and other organs. If your patient has pleurisy, see if clearing the deep front line helps as the condition is generally considered idiopathic but my money is on some form of severe deep front line dysfunction. As we go proximal we get into the deep neck flexors, which are commonly inhibited by a whole mess of things (extensors, especially suboccipitals, 1-2 of the scalenes, and or a levator), then into the floor of the mouth, the tongue, the masseter, and the temporalis. Unsurprisingly, this last group of structures tend to be highly facilitated. With the jaws wide range of motion and extreme strength, let alone common use, it is a shoe in for holding tension at the top of the chain so is very typically facilitated for large stretches of the core in the DFL as well as the neck, causing TMJ ‘syndrome’ frequently (even if they aren’t aware, see how evenly their jaw opens at the TMJ) and occasionally with attached tinnitus, let alone tension headaches around the temporalis.
So to recap and add a bit: we often see the deep posterior calve compartment working for the adductors, as well as the psoas, sometimes more (I’ve seen iliacus, TVA, RA, etc.). The pelvic floor, diaphragm and jaw commonly are facilitated for any of the three main core muscles; the TVA, RA, and multifidi/erectors (sometimes one to one, sometimes one to all). The neck flexors can be do the jaw or something else in the deep front line but usually I find that a local relationship to the neck/cervical vertebrae as part of a cervical compression strategy (more in my article on c2 displacement concerning cervical/axial compression strategies).
The thing to remember is that this is not a facilitation/inhibition relationship of ACTION, but one of tension. While one adductor may inhibit another via reciprocal inhibition as a functional antagonist, and a gastroc head may cause plantar flexon when there is no extension of the hip for ambulation, this set of relationships is most purely one of creating adequate structural tension around a strategy of compression. This means that while the pelvic floor, diaphragm and TMJ musculature are facilitated, releasing them does not necessarily fix the problem. Typically these structures tighten because something else fails and tension is required. As I tell my patients; if you take a week off sick and come back to find your co-worker has been doing your job, is that their fault? The work needed to be done, so they did it, don’t blame them. But if you can’t get your work done because of a mugger? Yeah, that’s the guy to take care of.
As always I urge people to find the actual culprit; releasing a facilitated diaphragm is no better than our previous paradigm of stretching a muscle because it’s tight. You must ask and find out why! I do not release these muscles very frequently because they are victims being forced to work too hard in most instances. Sometimes a local trauma will change the situation but most of the time it is simply a global stability strategy and you need to find the source. I may treat some symptomatically (but never the diaphragm) at these levels, but you aren’t treating the source unless you have reason to know it’s the source.
This brings us to finding the original cause, which generally goes out of the scope of this article but we’ll give you a direction. 90%+ of what I treat is scars, concussions, broken bones and joint injuries, or they are being referred out to deal with limbic trauma (see my article on limbic/MCC function and their interplay in rehab work). There are of course other injuries, but these cover the main sources of ‘original causes’ which are driving the body to create a global compensation strategy in the first place, which again is marked by axial compression and is likely the cause of your deep front line dysfunction.
So let’s take an example: Patient A presents with chronic headaches, neck tightness, and low back pain. Upon initial testing you find the flexor hallucis longus working for the majority of the adductors and the psoas, the masseter working for the neck flexors and diaphragm working for the TVA. A pretty typical pattern, but when we get into the history we find that this patient had a vaginal tear (or episiotomy) during birthing and that she has also had urine urgency and poor sense of bladder fullness (when she has to go, she has to go i