Is it correct that the Left diaphragm is more responsible to pull the air to Right chest and Right diaphragm is more responsible to pull the air to Left chest? I was looking for the mechanism of this from PRI textbook and other resources, but could not find the one that makes this clear for me. I would really appreciate if you could explain the mechanism and/or give me some resource to explain that.

There is really no ‘one’ excellent resource to go to that will talk about hemi-diaphragm activity influence on the chest wall uniformly or non-uniformly.  There is no discussion how tidal volume or residual  volume of the lung is influenced by thoracic rotation or hyperinflation more so on one side of the chest wall than the other, even when you review the Scoliosis literature.  However, there is a great deal of information on how ribs are influenced by spinal coupling and directional rotation.  The costal aspect of the diaphragm is responsible for rib external rotation upon diaphragm contraction, while the crural fiber is primarily responsible for dome descension and thoracic lumbar spinal extension.  We have two sets of these muscles and when one rotates to the left with the rib cage or thorax, the ribs on the left are externally rotated with respect to the ribs on the right and the extension of the back at the thoracic lumbar vertebral wall is more extended on the left when compared to the right (Left AIC pattern).  Therefore, the costal and crural fiber on the left is at concentric end range and any respiration that occurs in this pattern will primarily occur with the hemi-diaphragm on the left because of the lengthened state of the crural and costal fiber on the right compared to the left.  Reciprocal breathing in this pattern will more than likely compliment reciprocal thoracic wall expansion on the right, because the costal fiber can pull the ribs up on this side, and the recoil upon exhalation is preserved because of the position the thoracic mediastinums.   Most researchers in pulmonary medicine or in functional performance do not measure tidal volume with individuals in this extreme state of torsion or rotation, either because they do not understand how posture can actually be challenged by these concepts or because it is a very untraditional method that would have a very difficult time being accepted by research reviewers and readers, since they probably would not appreciate the significance of thoracic mechanical expansion or lack of, when considering pulmonary function.  PRI is the only resource you will probably find that postulates these concepts that are scientifically sound because of what already exists in evidenced based research to date on rib mechanics, thoracic function and pulmonary studies.  Patterns of respiration such as the Left AIC or Right BC have not been ever considered to my knowledge.   

Asymmetrical ventilation and perfusion between the right and left lungs occurs in more than half of the children with severe congenital and infantile thoracic scoliosis.  However, the severity of lung function asymmetry does not relate to Cobb angle measurements.  Asymmetry in lung function is influenced by deformity of the chest wall in multiple dimensions, and cannot be ascertained by chest radiographs alone (Redding G. Song K. et al Lung function asymmetry in children with congenital and infantile scoliosis. The Spine Journal, 2008, vol 8,(4) 639-644.).  The last sentence describes it all.  It is very difficult to measure lung or perfusion function unilaterally with an x-ray, or any other pulmonary study method only because of the inability to separate flow from one side of the thorax upon normal non-compensatory postural positions versus compensatory postural positions that become neurologically habitual patterns of the “way” we breathe. 

–Ron Hruska

How does the left low trap and serratus “secure the spine” (as mentioned for management of superior T4 following treatment of it)?

The left lower trapezius muscle rotates the mid thoracic spine to the right as it assists with internal rotation of the left ribs that are attached to the thoracic spine, and movement of the same ribs posteriorly. An individual with a superior T4 syndrome is experiencing difficulty in moving the right first and second ribs into internal rotation and the first and second ribs on the left, concomitantly, into external rotation upon left trunk rotation. During right trunk rotation, all the ribs on the left rib cage need to simultaneously rotate into internal rotation and likewise all the ribs on the right rib cage need to rotate into external rotation. After performing a right subclavius manual technique to increase the length of the right subclavius muscle, spinal rotation to the left is needed to take advantage of implementing internal rotation of all the ribs on the right, since now, ribs one and two on the right can internally rotate and ribs one and two on the left can externally rotate.

By reaching forward with the right arm to activate the right low trap and right serratus anterior for left spinal rotation and scapular movement on the thorax, you re-align all the ribs by moving the right ribs into internal rotation. Reaching forward with the right arm a little more upon exhalation would help this process even more. Then, reverse and move the left arm forward, upon exhalation, to rotate the spine and rib cage to the right. Every time you inhale, with the left arm reaching forward, expand or move back the left posterior ribs a little more. By moving the left ribs back on inhalation with the left serratus anterior, as the spine is being held or stabilized in right trunk rotation, the diaphragm can assist with air flow into the left posterior chamber of the left lung promoting universal posterior thoracic expansion during right trunk rotation without losing internal rotation provided by the left serratus anterior of the left lower ribs.

From this point on, your right lower trap will now experience more stabilization from the left lower and mid ribs and the left lower trapezius during alternating arm reaching or trunk rotation. In essence, the left lower trap is now serving as an eccentric stabilizing force for left posterior thoracic expansion during left heel strike and left arm reach. Without the left lower trapezius and left serratus anterior functioning upon left arm reach, the spine would not need to rotate to the right with the left lower trapezius because it may already be oriented to the right because of lost left posterior thoracic expansion and inability to open the apical or posterior left lung and chest wall. The left first and second ribs staying in an internal rotated state, limits the ability to expand the upper posterior mediastinum or lung tissue. Therefore, following the right subclavius manual technique used for treatment of a superior T4 syndrome, alternating right lower trapezius and right tricep with left lower trapezius and left serratus anterior is highly recommended for spinal stabilization during alternating trunk rotation or gait.

-Ron Hruska

Why is FA IR that is decreased bilaterally usually considered a patho-compensatory pattern?

Individuals who compensate by externally rotating their bilateral femurs in their anteriorly rotated and inwardly directive acetabulums have a tendency to overstretch their iliofemoral and pubofemoral ligaments by over-contracting their femoral acetabular external rotators. Their posterior capsules usually become restrictive and tight over time secondary to establishing a bilateral AF ER (acetabular femoral external rotation) osseous position. Because of the overstretched anterior soft tissue and restrictive posterior capsule and soft tissue, internal rotation is decreased or limited actively or passively. This is considered a pathologic event because of compensatory activity of the femoral acetabular external rotators to align the femurs on a pelvis that is orienting both femurs inwardly.

–Ron Hruska

Why is humeral glenoid internal rotation (HGIR) often limited on both sides with a superior T4 syndrome?

Without reviewing all the respiratory issues associated with a Superior T4 syndrome, one will usually find limitation with left apical expansion of the upper quadrant on the left side, when a PRI Apical Expansion Test is performed to assess left thoracic expansion as the right ZOA is manually maintained.   If the top left 3 ribs are in a state of internal rotation and cannot externally rotate, more than likely, left upper thoracic expansion will be more limited than the right, because of the corresponding external rotation of the upper 3 ribs on the right. This is commonly seen after a left ZOA is achieved and overall right apical and medial mediastinum expansion has increased.  

The upper spine remains oriented to the right in a Superior T4 state, even if a manual or a non-manual technique improved right apical and lateral chest wall flexibility and expansion. The lower ribs on the left are no longer in a state of external rotation and the lower ribs on the right are not in a state of internal rotation after repositioning. The upper 2 to 3 ribs on the left may remain in a state of obligatory internal rotation, because of the continued effort of the right scalenes, upper trapezius and subclavicular muscle to externally rotate the top right 2 to 3 ribs for assisted expansion on the right upon inhalation. This rib rotation position of the upper right ribs assists with “pulling” air in on the right side, since the middle and lower mediastinum and chest wall cannot expand efficiently, secondary to the chronic compensatory movement of these right upper rib elevators and shortness of the soft tissue that keeps these ribs externally rotated toward the right clavicle. This chronic compensatory state of the upper ribs has occurred on the same chronic compensatory pattern of the leftward thorax rotation provided by the musculature that is rotating the left lower ribs externally and right lower ribs internally. After reestablishing spinal neutrality or a neutral positioned spine below T4, compensatory activity is no longer needed from the aforementioned right upper rib external rotators. Since these overactive accessory muscles of respiration become shortened over time in their compensatory effort to offset this leftward thoracic rotation, reciprocal rotation of these upper ribs is lost, and manual activity to reduce this soft tissue shortness, especially below the clavicle, is required for alternating upper quadrant (apical compression and decompression) function to occur. In summary the upper 3 or 4 vertebral bodies remain oriented or rotated to the right because of the above non-universal hemi-rib directional influences on the spine.  Keep in mind the overall neutrality of the lower vertebral bodies is not capable of offsetting the direction of the spine to the right because of the upper ribs influence on upper spinal orientation from the visual, vestibular or occlusal systems or direct rotation to the right from the upper thoracic mechanical rib direction. Thus, overall the upper spine remains ‘oriented’ to the right in a Superior T4 state.

Since spinal orientation to the right existed below T12 and above T4, before repositioning effort of the spine and diaphragm, right ‘orientation’ of the spine above T4 may remain after repositioning effort on those with Superior T4 syndrome tendencies. Reestablishment of internal rotation of the upper top ribs on the right will allow the left ribs to all work in unison and into neutral or external rotation. This is necessary for proper thoracic on scapular movement and scapular on thoracic movement to occur on either side of the thorax. If horizontal abduction of the right upper extremity also does not occur, because of pec major and minor, subscapularis, and latissimus dorsum soft tissue restriction, upper right spinal orientation would also continue to directly challenge the right gleno-humeral joint kinematics and indirectly the left gleno-humeral joint kinematics.

These brachial chain limitations are described and outlined on page 42 of the Postural Respiration manual. For the most part the positions of the left and right scapulas remain the same as if they were lying on a non-Superior T4 state. However, in addition to the over action of the latissimus and the pectoralis major on the left, the teres major and the infraspinatus become hyperactive and shortened over time in attempting to externally rotate a humeral bone that lies in glenoid that also has the top 3 ribs internally positioned.  External rotation is more than likely limited on the left side because of latissimus activity as previously stated, but internal rotation could also be limited because of the compensatory activity of the short humeral external rotators, that were also previously mentioned, and the kinematic discord at the gleno-humeral joint because of the unstable scapula state. The left gleno-humeral joint kinematics are altered because of the posterior superior shift of the humeral head in the glenoid. The left humeral head could be impacted by the anterior inferior glenoid, upon internal rotation of the humerus, when there is a posterior superior shift of the humeral head. The anterior capsule is often over stretched or lengthened secondary to the ongoing attempt to horizontally abduct on a scapula that is elevated and adducted upwardly, not downwardly as you would find more typical in the non-Superior T4 state.  These events contribute to the humeral glenoid instability so often seen on the left side of a person with a right Superior T4 Syndrome.

-Ron Hruska

Could someone at PRI explain how a flat plane splint changes neural tone that results in an inhibition of accessory breathing muscles, brachial chain and AIC? I have observed a marked improvement in the ability of person to achieve inhibition of these chains and facilitation for diaphragm breathing with posterior mediastinal expansion when the splint is in place.

Any mouth appliance or oral orthotic will impact or influence sensory input that the brain receives from occlusal references. By reducing or changing familiar contact references from cusps or surfaces of teeth, that are associated with specific neural tension of the musculature of the head and neck, an individual, who is patterning respiratory function around the cervical-cranial neural tension, will have to discover new reference points for respiratory function. If diaphragmatic position is not ideal at both attachment sites on the ribs and thoraco-lumbar spine and sensory reference from the floor, pelvis and hips is unilateral at the time the oral splint or orthotic is applied, demands and tension on the visual system and other sensory organs, tongue, temporal bone for hearing, etc. will more than likely increase. Accessory respiration is a volitional event and should remain this way if thoracic reference and expansion is sensed upon inhalation during tongue up and teeth apart function. A forward, thrusting tongue and above normal static contact are indicators of bruxing, trismic or clenching behavior as a result of dependency on the accessory respiratory system, because of limited sense of thoracic expansion secondary to the neurologic hyperventilatory state that co-exists. By allowing the mandible or neck to shift or move and become ‘unstable’, the referenced “pull” for this accessory respiratory function is now eliminated and the need to establish more moderate level of forward bending position, of the thorax is created. Thus, better relaxation of all accessory muscles of respiration and better mechanical advantage of both the hemi-diaphragms of the thorax also occurs. 

– Ron Hruska

“My question regarding thoracic outlet syndrome is this: when doing the right or left arm reach after having restored rib cage position (all tests negative), should I be instructing them to keep their ribs on the ground even though they are reaching? Since after re-establishing position, the next step is to retrain the ribs to sit on the scaps (TS movement), should I instruct them to always keep the ribs back, and when reaching, only let the scaps and arm slide forward? Or, especially with a right arm reach, do we still want them to rotate the ribs to the left in order to keep ZOA on the left? A secondary question would be, why do we start with a left arm reach in a TOS client? The only resource I am going off is the article on the PRI website here about the football players with bilateral TOS, so I guess I was a little confused when after re-establishing rib cage position, the next exercise prescribed was a left serratus vs right tricep/serratus, as is outlined in the Postural Respiration matrix.”

With regards to your questions, I would encourage you to keep the ribs on the ground when in a supine position as you alternately reach with either arm and hand.  Yes you would want the athlete to reach forward while at the same time move the posterior rib cage posteriorly since you have established neutrality.  You would want to emphasize left posterior mediastinum movement in the earlier process to  engage the serratus anterior to move the ribs back on the scapula and the right arm forward to facilitate the right serratus anterior to move the scapula forward on the thorax.  Again this would be early on in the treatment or strengthening program.  Rotating the rib cage to the left with a right arm reach is fine as long as you do not allow the anterior ribs on the left to “pop” up too much, in the process.  You start with a left arm reach to promote rib external rotation on the right and internal rotation on the left with left abdominal wall engagement.  This facilitates left thoracic abduction and right lateral intercostal and left posterior mediastinal concurrent expansion.  It also promotes LAFIR at the left hip, so that alternating activity with the hips can occur with proper left hip and rib cage integration, otherwise the disintegration will bias the LAIC pattern, and not the RAIC pattern.  The left serratus anterior and left lower trap assists the mid to lower thoracic spine to rotate to the right, as the left serratus stabilizes the thorax during right spinal rotation from the left low trap and IR of the left ribs and assists moving the left ribs back during left rib IR.  The right low trap and tricep retracts and posteriorly tilts the scapula as lower spinal rotation to the left occurs which promotes thoracic flexion and deactivation of the right latissimus.

-Ron Hruska, MPA, PT

“We are doing a pelvic / thoracic study with our players. The primary tester has measured subjects hip ROM prone and I know we do most of ours seated. Could you enlighten me on the differences as there is some debate. I know the capsule is tensioned differently and the tissue compression seated is different than prone but wanted to get your take.”

You obviously can test rotation in either position and will more than likely arrive at the same values if the hip capsule is in a position of true rest or neutrality with respect to all three planes.  When the hip is in an anatomical prone position, ER is accompanied by anterior glide of the femoral head.   Rotation is limited by tension in the anterior capsule and the pubofemoral ligament.  Since most ligaments are more loose in the seated position, I personally like testing in this position.  ER is now accompanied by a superior glide of the femoral head and rotation is limited by the superior capsule and the iliofemoral ligament.  Since I like to look at the ilium position in general , this position is more reflective of iliofemoral restriction and pathology if it exists.  IR is accompanied by a posterior glide of the femoral head when in prone and tension in the posterior capsule and tension of the ischiofemoral ligament limits IR.  IR is accompanied by an inferior glide of the femoral head and is limited by tension in the inferior capsule and the superior ischiofemoral ligament in the seated position, which makes me more likely to look at in this position because of the influence of the inferior capsule, not the posterior capsule seen with the prone position.  The inferior capsule restriction indicates that the individual I am testing may need more level 4 or 5 squatting to get the IR needed if indeed the restriction is an inferior versus a posterior capsule limitation.  If IR is more restricted when in the prone position, than I would implement a posterior capsule stretch type of program to compliment concurrent active IR.

– Ron Hruska, MPA, PT

I was just teaching someone the left SL version of the Scissor Slide non-manual technique and got confused with the breathing. I was thinking that no matter which side someone is lying on, the left adductor push down (or up) would be with the exhale and the left AF IR would be on the inhale. This is not the case, though. Why so?

This is a very good question and provides an opportunity to expand on an email response that was posted on Sept 25, 2008. Our human neuromuscular tendency is to establish more of an infinity for left pelvis descension, even when we transfer our weight over to the left side, and right pelvis ascension, again without respect for which leg we transfer our weight to, upon inhalation. This pelvis diaphragm activity upon inhalation reflects our general urge to stand and position ourselves on our right foot and hip.  This overuse of musculature that neurologically establishes ease for R AFIR and R pelvic outlet IsP ER (Ischio pubo external rotation)and R SI IR (Sacral ilio internal rotation); and L AFER and L pelvic inlet IP ER (Ilio pubo external rotation) and L IS IR (Ilio sacral internal rotation) during inhalation and exhalation phases of thoracic diaphragm respiration can be addressed by learning how to breathe when the pelvis floor is placed more into a state of ascension. Therefore activity that implements more left pelvis inlet extension, internal rotation, and inlet adduction, as well as more right pelvic outlet extension, external rotation and outlet adduction upon inhalation would be desirable to reduce this asymmetrical neuro behavior pattern associated with R AFIR, L AF ER and pelvis descension on the left.

When we place someone on their right side and have them inhale upon pulling their left leg back, we will essentially activate the left ischiocondylar adductor  and iliacus to extend, internally rotate and adduct the left ilium or establish left inlet IP IR, as the left pelvic outlet is flexed, externally rotated and abducted (IsP ER) by the left pubococygeus, obturator internus, and iliococcygeus muscles as the pelvis diaphragm ascends. Inhaling during this maneuver enables the posterior mediastinum and posterior pelvis/hip capsule region to “open” up.  Exhaling as you maintain the above postion reinforces respiration with more overall pelvis ascension. When you place someone on their left side and have them exhale as they move or push their right leg forward you are essentially asking them to move their pelvis, into a right pelvic outlet ischio pubo internal rotation state or a R AF ER state, through activation of the right piriformis, coccygeus, and gluteus maximus musculature.  You would ask the patient to inhale to help maintain more of a right pelvis descension state during inhalation, to help offset the neuro positional pattern of this pelvic diaphragm, that overall is acting more in an ascension state, regardless of which leg one stands on. Slightly lifting your bottom leg or knee during inhalation will engage your left ischiocondylar adductor and compliment the pulling action of this muscle on the pube for right femoral and acetabular advancement, as right pelvis descension and left pelvis ascension positions are maintained, during thoracic diaphragmatic respiration. – Ron Hruska, MPA, PT

Ok, If we’re super in love with the right triceps for sagittal Right BC inhibition, aren’t we also loving the left biceps (long head) for the same reason?

Let’s consider not the long head of the biceps alone but the short head as well.

The scapula on the R is positioned in a state such that the inferior angle is moving posteriorly away from the ribcage and the superior edge is moving anteriorly toward the ribcage.  This is facilitated by pec minor activation and subsequent triceps inhibition.  Also, though perhaps to a lesser degree, the R biceps may act, via the long head, but also and possibly more importantly so, the short head (due to its attachment to the coracoid) synergistically with the pec minor.    And the end result can be biceps tendinitis.  One mechanism for reduction of the biceps activity is via triceps activation.  On an interesting side note I had a pt with right biceps pain and the first line of attack was to activate right subscapularis.  This was suggested because I already had him on a triceps program and he was neutral.  By engaging subscapularis I facilitated IR of the humerus which was now positioned in ER as a result of neutrality, which yielded prolonged inhibition of the subscapularis.  Subscapularis activation created internal rotation and internal rotation alone is sufficient to inhibit biceps, because it is a lack of internal rotation (as a compensatory strategy to manage system extension) that results in the alliance of biceps with anterior deltoid and upper trapezius on that R side.  This polyarticular chain of muscle which becomes a respiratory accessory muscle chain at this point can become so dominant that injury is an inevitable outcome if no intervention takes place.

On the L side the position of the scapula is opposite the R in many cases and subsequent activation of the L biceps may be necessary as a result of its positional disadvantage.  Likewise, inhibition of subscap may be necessary if it has been acting as a compensatory IR muscle to counter ER positioning.  To that end, we should also see a need for activation of teres minor and infraspinatus (following repositioning) on the L side as well.  Doing so can improve compensatory demands of internal rotation of the humerus when in the R BC pattern.   Compensatory internal rotation of the humerus could then possibly increase L pec major activity as it acts synergistically with subscap during compensatory L TR in the R BC pattern.  The end result of this patterning could easily create the need for L pec inhibition as a mechanism for L biceps activation!  Thus the mechanism for increasing biceps activity (as opposed to triceps on the R side) would be to improve rotation via reduction of the “alliance” of pec major and subscapularis.

One must understand that not everyone develops biceps tendinitis as a result of L AIC, R BC patterning however if it becomes the case then the above scenario are likely. –Michael Cantrell MPT, PRC

One of my colleagues has started the Myokinematic Restoration home study course and we were discussing some of the testing. One question that came up was: Why are we putting the patient in the start position with the bottom leg in hip and knee flexion for the Adduction Drop Test?

The ADT is a modified version of an Ober’s test.  The original test was described in 1935 (Dr. Frank Ober) as a means to correlate back pain and hip mobility. The Ober Test is taught differently now in PT curricula as a test for IT band tightness, but that is an erroneous interpretation of the intent of the test.

Putting the patient in a flexed position to start satisfies a couple of purposes.  First, it helps the patient feel stable (balanced) and therefore they aren’t actively working to hold themselves steady while you are trying to move them (better able to rest when at rest). More importanty, it clears the bottom leg out of the way to test true adduction. From a PRI perspective, the ADT is a key test for determining an AIC pattern. A Left AIC pattern is a position of right stance / left swing or right hip straight / left hip flexed and is caused by an overactive chain of muscles on the front of the left side of the lower body (from the diaphragm down).  A Left AIC patterned individual will have difficulty with proper left stance and right swing and when you test the left side you are placing their FAs into the L stance/R swing positions.  If the Left AIC musculature will not let go (cannot be inhibited), then the patient will not be able to passively adduct their leg (as a result of bony limitation (reference Myokinematic Restoration manual)). – Josh Olinick, DPT, MS, PRC

In the description under the Anterior Interior Chain (AIC) in the Postural Respiration manual, descriptor #6 mentions that “As a result of ilium anterior rotation, the femur is biomechanically oriented inward and torsional demands on the psoas as an ineffective femoral external rotator and the vastus lateralis and biceps femoris as antagonistic hip stabilizers, increases. I am having difficulty understanding how the vastus lateralis is involved with hip stabilization. Could you please clarify?

Great Question!

The vastus lateralis and biceps femoris act on the femur (hip) as antagonistic muscles to each other. One externally rotates the femur (the biceps femoris) and one internally rotates the femur (the vastus lateralis) when the foot is planted on the ground. When the VL contracts, the proximal attachment of the vastus lateralis pulls or rotates the femur inwardly therefore producing internal rotational movement that is countered by external rotational movement from the biceps femoris with the foot planted. Therefore, these two muscles act on and under the femur antagonistically to each.

When the innominate (ilium) anteriorly rotates, these two muscles become challenged because of poor position to counteract on each other, for femoral stabilization. Their effectiveness in keeping the pelvis or acetabulum positioned correctly on heel strike is lost, because the psoas has to work harder as an external rotator to keep the femur lined up with the foot at mid-stance. Internal rotation need from the vastus lateralis, anterior glute med/min, and medial hamstrings is now not necessary – since the femur is already directed inwardly by the forward anteriorly oriented innominate and acetabulum. The psoas (ER) and tensor fascia latae (IR) now become your primary femoral and hip stabilizers through anterior innominate rotation. Effective femoral stabilization at mid-stance occurs only when the innominate can move posterior at or upon the “heel off” phase of push off. Without posterior innominate rotation, effective femoral stability from the vastus lateralis and biceps femoris is lost.