Transverse Abdominis

Human Movement Science & Functional Anatomy of the: Transverse Abdominis

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by Brent Brookbush MS, PES, CES, CSCS, ACSM H/FS

Transverse Abdominis via Grey's Anatomy: 20th Edition - http://upload.wikimedia.org/wikipedia/commons/thumb/d/d5/Transversus_abdominis.png/396px-Transversus_abdominis.png

Transverse Abdominis (TVA):

• Lateral Attachment: The lateral raphe of the thoracolumbar fascia between the iliac crest and 12th rib, extending superiorly to the internal aspects of the lower six costal cartilages (interdigitating with the diaphragm),and inferiorly along the anterior two-thirds of the inner lip to the lateral third of the inguinal ligament (13).
• Medial Attachment: "…is a complex and variable bilaminar aponeurosis (13)." The lower fibers extend inferiorly blending with the internal obliques to form the conjoint tendon which attaches to the pubic crest behind the superficial inguinal ring, the remaining fibers below the umbilicus blend with the abdominal fascia, passing in front of the the rectus abdominis to invest in the linea alba. Above the level of the umbilicus the abdominal fascia is bilaminar passing both anterior and posterior to the rectus abdominis (enveloping the rectus abdominis) - the fibers of the TVA invest in the posterior fascia and linea alba via two separate layers of muscle with distinct fiber directions running oblique inferior and oblique superior. The inferiorly turned fibers run continuous with the superiorly turned fibers on the contralateral side and visa-versa (13).
  • The transverse abdominis lays between the internal obliques superficially and the parietal peritoneum inferiorly (abutting the visceral peritoneum and internal organs) (15). It is not likely possible to differentiate the fibers of the internal obliques and transverse abdominis during palpation - adding to the difficulty of this palpation is the thicker, striated fibers of the external obliques lying superficially.
• Nerve: Intercostal nerves via nerve roots T7 through T12, iliohypogastric and ilioinguinal nerves via nerve root L1.
• Action:
  • .Stabilization of lumbar spine, sacroiliac joint and potentially the pubic symphysis by 3 mechanisms (3, 13):
    • Increased intra-abdominal pressure in conjunction with the diaphragm and pelvic floor muscles.
    • Increase tension of the throracolumbar fascia (and potentially a small extensor moment)
    • Compression of the sacroiliac joint working in conjunction with the stiff dorsal sacroiliac ligaments
  • There is some evidence to suggest that this muscle my contribute to extension via the thoracolumbar fascia and an extension moment created by increased intra-abdominal pressure when the spine is flexed (13).
  • This muscle is active during rotation, however it is unlikely that this muscle can generate a rotational force (13).
  • Stabilization of the linea alba, pubic symphysis and inguinal ligament, and thoracolumbar fascia improves the efficiency of other muscles attached to these structures including the rectus abdominis , external obliques , internal obliques , erector spinae , and latissimus dorsi (3)
    • In summary - the transverse abdominis is an important stabilizer; however, it plays little, if any role in movement.

Differentiation between fascial layers of the medial attachment, above and below the umbilicus - http://classconnection.s3.amazonaws.com/223/flashcards/1190223/jpg/rectusabdominis1330649127357.jpg

Integrated Function:

• Stabilization: See above under "Action"
• Eccentrically Decelerates: Inter-segmental motion of the lumbar vertebrae, specifically anterior translation - this may be the most important function of the TVA. Most muscles of the trunk increase anterior translation and shear forces, but only an increase in intra-abdominal pressure and segmental stabilization by the lumbar multifidus can counter the force.
• Synergists:
  • The TVA cannot increase intra-abdominal pressure (IAP) without a co-contraction from the pelvic floor muscles (levator ani, and coccygeus), and a synchronous increase in tone from the diaphragm (consider that inspiration and expiration require rhythmic increases and decreases in activity of the diaphragm, when the need for segmental stabilization increases the activity during the entire breathing cycle increases (13).
  • The TVA via increased intra-abdominal pressure and increased tension of the thoracolumbar fascia, act synergistically with the lumbar multifidus to reduce anterior shear and maintain the alignment of the lumbar vertebrae (segmental stabilization).
    • Note: The synergistic relationship of the TVA with diaphragm, pelvic floor and multifidus muscles for the function of segmental stabilization is known as the Intrinsic Stabilization Subsystem .
  • Some studies show that TVA activation is often paired with an increase in internal oblique activity (13, 16). This is not surprising as the fiber arrangement is very similar, the most lateral aspects of the internal obliques may invest in the lateral raphe of the thoracolumbar fascia just superior to the TVA, and the most inferior/anterior fibers of the internal obliques blend with the TVA to create the conjoint tendon. Although most often I believe this muscle to function with the anterior abdominal muscles as a spinal flexor, rotator and lateral flexor or the spine, there is little doubt that the internal oblique plays dual roles.
  • The TVA may also act synergistically with the lumbar extensors (multifidus and erector spinae ), piriformis , and coccygeus to compress and stabilize the sacroiliac joint.

Note how the diaphragm moving inferiorly, the pelvic floor moving superiorly, against a drawing-in of the transverse abdominis would significantly reduce intra-abdominal space and increase pressure. When combined with reflexive contraction of the multifidus, a reduction in anterior shear, stabilization, and increased rigidity of the lumbar spine is achieved

Subsystems

• * The transverse abdominis is part of the Intrinsic Stabilization Subsystem (ISS) along with the diaphragm, pelvic floor, and multifidus. As part of this subsystem the TVA contributes to inter-segmental stabilization and rigidity of the lumbar spine, pelvis and sacroiliac joints. You could consider the optimal function of this subsystem essential to efficient function of the other core subsystems . Generally, the ISS is considered relative to the "global stabilizers" of the trunk. The division of core musculature into subsystems is not different, just a further delineation of core muscles based on muscle synergies, their function, and their behavior relative to movement dysfunction.
  • The TVA has a propensity toward under-activity and latent firing. Ideally an increase in segmental stabilization would precede motion of the extremities with sequential addition of global musculature to mitigate forces caused by movement of the extremities. Studies by Richardson et. al. demonstrated activation post extremity motion in individuals with a history of low back pain (13). (See 3 Classic on Core Muscle Recruitment ) With that said, consideration should be given to improving TVA and ISS function in any program aimed at improving core performance.
  • Relative to predictive models of postural dysfunction and movement impairmen t the ISS has propensity toward under-activity. This is most apparent in Lumbo Pelvic Hip Complex Dysfunction (LPHCD) and Sacroiliac Joint Dysfunction (SIJD) , but is also common Upper Body Dysfunction UBD due to the dominance of the Anterior Oblique Subsystem AOS and latissimus dorsi (global stabilizers). Under-activity of the ISS is less common in Lower Leg Dysfunction (LLD) , but still commonly seen when LLD leads to dominance of the Deep Longitudinal Subsystem (DLS) and sacroiliac joint dysfunction.

Arthrokinematics:

• This muscle plays a role in the arthrokinematics of the lumbar spine, sacroiliac joints, and potentially the pubic symphisis.
  • As mentioned above the TVA plays little if any role in motion of the lumbar spine and pelvis. Although some observations have implied a capacity to create an extension moment on the lumbar spine due to the oblique arrangement of the fibers of thoracolumbar fascia and intra-abdominal pressure, most studies have been unable to quantify a force implied by these observations (13,16). The largest impact the TVA has on arthrokinematics is compression of the sacroiliac joint, increased rigidity of the spine by increasing tension of the thoracolumbar fascia, and mitigation of anterior shearing forces by increasing intra-abdominal pressure.

Consider how bilateral contraction of the TVA would increase tension on the thoracolumbar fascia, pulling laterally on both sides simultaneously increasing rigidity. Further, consider how an increase in pressure anterior to the lumbar vertebrae would resist and anterior translation and shear. - http://www.bandhayoga.com/online-courses/online-courses/shaktitest/images/Blog/b38_thoraco-lumbar_section.jpg

Fascial Integration:

My Fascial Hypothesis: Large fascial sheaths not only play a role in the transmission of mechanical force, but may also play a role in dictating the function of muscular synergies. This is likely caused by reducing or increasing tone of invested musculature via reflex arcs formed between mechanoreceptors imbedded in the connective tissue and the attached musculature. In this way my view of fascia differs slightly from noted expert on the subject Tom Myers. I think of these large fascial sheaths (specifically the thoracolumbar fascia, iliotibial band, and abdominal fascial sheath) as natures "mother board." A place for mechanical information to be communicated to the nervous system for more efficient recruitment of the muscular system. Despite having a slightly different philosophy it does not change the fact that fascia plays an important communicative role in the human body and we have Tom Myers to thank for his work.

Fascial Integration of the External Obliques:

• The Thoracolumbar Fascia: This fascial structure may be one of the most complex structures of the human movement system. Studies have verified a rich presence of Pacini corpuscles (quick adapting receptors that respond to pressure and vibration), Paciniform corpuscles (like Pacini corpuscles but smaller), Golgi Tendon Organ (slower adapting receptors that respond to muscular contraction), and Interstitial Receptors (free nerve ending they may respond to tension, pressure, or pain). Check out this article on receptors and fascia, great read - "Innervation Excerpt". As the TVA has the best fiber arrangement for increasing tension in the thoracolumbar fascia it is not absurd to consider this muscle intimately related to the optimal functional of all of the muscles that invest into it. The thoracolumbar is invested by the internal obliques , erector spinae , and latissimus dorsi , gluteus maximus  and biceps femoris via the sacrotuberous ligament (3).
• The Linea Alba: The linea alba serves as a central anchor, and along with the abdominal sheaths may serve as a way of communicating force and muscle activity between the anterior trunk musculature. Any lateral, posterior, or rotational force imparted on the truck will result in an increase in rectus abdominis, external and internal oblique, and transverse abdominis activity (3). This ensures the optimal dissipation of forces and protection of non-contractile tissues and joints. Due to a lack of bony support (i.e. no attachment to ribs) the lumbar spine in particular requires optimal synergistic function of trunk musculature to prevent excessive motion and injury. Applying the same notion considered for the thoracolumbar fascia, the TVA may play a central role in maintaining optimal tension of this structure for the efficient function of the rectus abdominis , internal obliques and external obliques .
• The Conjoint Tendon: The most inferior/anterior fibers of the internal obliques blend with the TVA to create the conjoint tendon. This implies a synergistic relationship between these two muscle that may be the bridge between local and global stabilization.

The Conjoint Tendon - https://www2.aofoundation.org/AOFileServerSurgery/MyPortalFiles?FilePath=/Surgery/en/_img/surgery/04-Approaches/62/Ilioing/62-ilioing-4b2-540.gif

Behavior in Postural Dysfunction:

This muscle may be prone to adaptive lengthening (abdominal distension), over-activity and latent firing.

The transverse abdominis is prone to under-activity and plays a key role in optimal core function. As mentioned above in "Core Subsystems":

This is most apparent in Lumbo Pelvic Hip Complex Dysfunction (LPHCD) and Sacroiliac Joint Dysfunction (SIJD) , but is also common Upper Body Dysfunction UBD due to the dominance of the Anterior Oblique Subsystem AOS and latissimus dorsi (global stabilizers). Under-activity of the ISS is less common in Lower Leg Dysfunction (LLD) , but still commonly seen when LLD leads to dominance of the Deep Longitudinal Subsystem (DLS) and sacroiliac joint dysfunction.

In short, this muscle is addressed in most programs. However, unlike other core musculature this muscle is treated during activation, with reinforcement of TVA activation during all subsequent movement by cuing the "drawing-in" maneuver ("Belly button to spine, draw in the lower abs, pull your belly away from the waistband of your pants, etc."). Note, the drawing-in maneuver should not include motion of the spine or pelvis. Motion of the spine or pelvis implies dominance of the global stabilizers, most often spinal flexion occurs indicating over-activity of the rectus abdominis.

Note the lower abdominal region is "drawn in" during this glute bridge - http://lauralovesfitness.files.wordpress.com/2012/06/dsc_33782.jpg

Clinical Implications:

• Low back pain
• Costovertebral/costotransverse joint pain (pain often felt during breathing)
• Sacroiliac joint pain and dysfunction
• Pelvic floor pain
• Pain at or around the pubis
• Hernia
• Diastasis recti

Signs of Altered Length/Tension and Tone:

• Overhead Squat:
  • Anterior Pelvic Tilt: Long/Under-active
  • Asymmetrical Weight Shift: Long/Under-active
  • Excessive Forward Lean: Long/Under-active
  • Abdominal Distension: Long/Under-active
  • Flexion of the spine during "Hands Down" modification: Long/Under-active
• Goniometric Assessment
• * N/A
• Palpation of the Quadratus Lumborum:
  • N/A

The Fued: Richardson, Hodges & Hides versus McGill"

After reading the texts by these amazing professionals (listed in the bibliography 13 & 16), I am now more convinced than ever that this is a completely fabricated feud by professionals who have not read either book from cover to cover. These professionals have different approaches to rehabilitation, but both refer to each others studies extensively to support their approaches. If you think that these two worlds cannot co-exist I suggest you:

1. Read their books from cover to cover
2. Read my article "The Search for Congruence ."

In summary, neuromuscular reeducation of the intrinsic stabilization subsystem should be addressed first, followed by reeducation and conditioning of the global musculature (core subsystems ), and finally integration into functional activities. All steps are necessary for a complete recovery from low back pain or attaining optimal performance. "Drawing in" should be sufficient for stabilization of the lumbar spine and pelvis during most daily activity - activity without an added external load, or significant increase in velocity. "Bracing" is necessary during an individuals higher intensity activity - this could range from reaching over-head in an older individual, to loaded activities like carrying groceries in the middle aged and healthy, to weight lifting and sport in the athletic population. Cue the "drawing-in" maneuver during all activities, and "bracing" when appropriate.

Exercises for Activation of the Transverse Abdominis:

Transverse Abdominis Activation:

Transverse Abdominis and Gluteus Maximus Activation Progression:

Reactive Integration for the Core (Crunch and Catch):

Additional Core Activation/Reactive Integration:

Ball Bridge:

Static Ball Bridge with Trunk Rotation:

Dynamic Ball Bridge with Trunk Rotation:

Bibliography:

1. Phillip Page, Clare Frank , Robert Lardner , Assessment and Treatment of Muscle Imbalance: The Janda Approach © 2010 Benchmark Physical Therapy, Inc., Clare C. Frank, and Robert Lardner
2. Dr. Mike Clark & Scott Lucette, “NASM Essentials of Corrective Exercise Training” © 2011 Lippincott Williams & Wilkins
3. Donald A. Neumann, “Kinesiology of the Musculoskeletal System: Foundations of Rehabilitation – 2nd Edition” © 2012 Mosby, Inc.
4. Michael A. Clark, Scott C. Lucett, NASM Essentials of Personal Training: 4th Edition, © 2011 Lippincott Williams and Wilkins
5. Leon Chaitow, Muscle Energy Techniques: Third Edition, © Elsevier 2007
6. Tom Myers, Anatomy Trains: Second Edition. © Elsevier Limited 2009
7. Shirley A Sahrmann, Diagnoses and Treatment of Movement Impairment Syndromes, © 2002 Mosby Inc.
8. David G. Simons, Janet Travell, Lois S. Simons, Travell & Simmons’ Myofascial Pain and Dysfunction, The Trigger Point Manual, Volume 1. Upper Half of Body: Second Edition,© 1999 Williams and Wilkens
9. Cynthia C. Norkin, D. Joyce White, Measurement of Joint Motion: A Guide to Goniometry – Third Edition. © 2003 by F.A. Davis Company
10. Cynthia C. Norkin, Pamela K. Levangie, Joint Structure and Function: A Comprehensive Analysis: Fifth Edition © 2011 F.A. Davis Company
11. Florence Peterson Kendall, Elizabeth Kendall McCreary, Patricia Geise Provance, Mary McIntyre Rodgers, William Anthony Romani, Muscles: Testing and Function with Posture and Pain: Fifth Edition © 2005 Lippincott Williams & Wilkins
12. Brent Brookbush, Fitness or Fiction: The Truth About Diet and Exercise © 2011 Brent Brookbush - http://www.amazon.com/Fitness-Fiction-Truth-About-Exercise/dp/0615503012
13. Carolyn Richardson, Paul Hodges, Julie Hides. Therapeutic Exercise for Lumbo Pelvic Stabilization - A Motor Control Approach for the Treatment and Prevention of Low Back Pain: 2nd Edition (c) 2004 Elsevier Limited
14. Andrew Biel, Trail Guide to the Human Body: 4th Edition, © 2010
15. Robert Schliep, Thomas W. Findley, Leon Chaitow, Peter A Huijing. Fascia: The Tensional Network of the Human Body. (c) 2012 Elsevier Limited
16. Stuart McGill. Low Back Disorders: Evidence Based Prevention and Rehabilization - Second Edition. (c) 2007 Stuart McGill, published by Human Kinetics

© 2013 Brent Brookbush

Questions, comments, and criticisms are welcome and encouraged.