In my last blog post, I touched upon how we get stuck in a Left AIC/Right BC pattern. To briefly summarise my last post, the Left AIC/Right BC pattern arises from human asymmetries. There are two important bodily asymmetries to remember. Firstly there are the physical asymmetries of the diaphragm (right vs left) which create functional asymmetries (i.e. left diaphragm works a postural stabilizer while right diaphragm works a respiratory coordinator). Secondly there are the functional asymmetries of the brain (right vs left) which create physical assymetires in the body (i.e. overactive left brain creates postive feedback loop for right side dominance). But what exactly does this pattern constitute in of itself ?
Left AIC is an abbreviation for Left Anterior Interior Chain. This chain describes the left swing, right stance phase of gait (walking), which
means that our right leg is grounded while our left leg is in the air ‘swinging’. This is not inherently a bad thing as it is supposedly to occur in the gait cycle, your pelvis being stuck in Left AIC and not being able to leave is. This causes certain muscles to become
overactive (that need to be inhibited/turned off), specifically the right hemisphere of the diaphragm, the right bicep femoris, the left illiacus, the left psoas major, the left vastus lateralis, and the left tensor fascia latate. These muscles become overactive because the hips (pelvis) as a whole are chronically oriented to the right via the sacrum (low part of spine connected to the pelvis). This causes the left side of your pelvis to open out and forward (Externally Rotate, Abduct and Flex), while the right side of your pelvis closes in and backward (Internally Rotate, Adduct and Extend). The attached image is what a pelvis stuck in the Left AIC pattern looks like. This pattern can also heavily contribute to knee pain (which I will discuss in future content).
Right BC is an abbreviation for Right Brachial Chain. This chain describes how the torso (trunk) rotates to the left, in response to the hips (pelvis) rotating to the right during Left AIC. Just like Left AIC, Right BC is not inherently a bad thing as it naturally occurs during the gait cycle. However just as it is with Left AIC being stuck with your ribcage in this position is problematic. This causes certain muscles become overactive
(that need to be inhibited/turned off). Specifically, the right hemisphere of the diaphragm, the right deltoid/pec major, the right
pec minor, the right intercostals, the right scalenes, and the right sternocleidomastoid. This is because the torso (trunk) is positioned to
the left due to compensatory thoracic spine rotation from the Left AIC pattern below it. This makes it so the left hemi rib cage opens up/expands (Externally Rotates) while the right hemi rib cage closes in/compresses (Internally Rotates). This rib cage compensation causes the left scapula to move down and in (Externally Rotate and Protract) while the right scapula moves up and out (Internally Rotate
and Retract). The attached image is what a ribcage stuck in the Right BC pattern looks like. This pattern can also heavily contribute to shoulder pain (which I will discuss in future content).
Neither Left AIC or Right BC is inherently bad, it is being chronically stuck in either of them (although it's very common that someone is stuck in both patterns) that contributes to your chronic pain symptomology. And hopefully based on this information you can start to further understand how your chronic pain might arise from breathing and walking. But how do you know if you're in the pattern or not ? Well I'll discuss this more in my next blog post.