The Diaphragm in Pediatric Therapy: An Essential Focus for Effective Treatment

Dawn Sandalcidi will be a keynote speaker at HWConnect 2025 on March 28-30, 2025. You can also join her in upcoming courses: Pediatric Pelvic Floor, Diaphragm, and Postural Development: Intro to Core Function and Continence in Children on September 29th, Pediatrics Level 1 -Treatment of Bowel and Bladder Disorders on October 26-27, or Pediatrics Level 2 - Advanced Pediatric Bowel and Bladder Disorders on November 2-3.

As physical and occupational therapists, we aim to provide the best possible care for our young patients by understanding and addressing the underlying mechanisms affecting their health. The diaphragm is one of the most important yet often overlooked structures. This muscle plays critical roles in both respiratory and postural functions and has far-reaching implications for the stability and health of children.

In this blog, we’ll explore the anatomy, function, and clinical relevance of the diaphragm, its connections to the pelvic floor muscles, and the broader implications for pediatric therapy.

Anatomy Of The Diaphragm

In order to appreciate the functions that the diaphragm plays in breathing and movement, you must first understand the anatomy. The diaphragm is the thin, dome-shaped muscle that separates the thoracic and abdominal cavities. Its structure is divided into two primary components:

1. The Crural (Vertebral) Portion: The crural portion, or muscular “legs” of the diaphragm, originates from vertebrae of the lumbar spine, providing stability and anchoring the diaphragm in place.
2. The Costal Portion: The costal portion originates from the xiphoid process of the sternum and the upper margins of the lower rib pairs.

At the center of the diaphragm lies the “central tendon”, the non-muscular aponeurosis at which the muscular fibers converge. This tendon acts as a pivotal point during the contraction of the diaphragm.

When the diaphragm contracts during inspiration, the dome of the diaphragm descends, shortening the muscle fibers and increasing the volume of the thoracic cavity. This action decreases intrapleural pressure, allowing the lungs to expand and fill with air. At the same time, abdominal pressure increases as the diaphragm displaces the rib cage and moves downward.

The relationship between the diaphragm and the rib cage is vital for effective breathing and functional movement. Keep this in mind when working with kids who have low tone or poor strength. Breathing mechanics and diaphragm optimization are essential to assess. Proper contraction of the diaphragm not only facilitates lung expansion but also ensures that the core and extremities are stabilized, leading to efficient and stable movement patterns.

Let’s take a closer look at these functional connections.

The Diaphragm’s Connections To Posture And Pelvic Floor

A critical concept in understanding the diaphragm’s function is the Zone of Apposition (ZOA). The ZOA is the vertical area of the diaphragm that extends from the inside of the lower ribs to the top of the diaphragm. This zone maintains the diaphragm's dome shape, which is important for effective breathing.

When the ZOA is well-maintained, the diaphragm can contract efficiently without the need for accessory muscle recruitment. This efficiency prevents compensatory breathing patterns that can lead to respiratory and postural issues.

Conversely, a decreased ZOA can result in poor diaphragm contraction, leading to inefficient breathing and overuse of accessory muscles. Musculoskeletal effects on posture can include issues such as:

• Anterior rib flare
• Lung hyperinflation
• Hyperlordosis
• Protruding abdomen
• Weakness of the anterior core muscles with poor pressure system management

The diaphragm works in close coordination with the pelvic floor muscles (PFM) and the abdominal muscles. This interaction is vital for managing intra-abdominal pressure (IAP) and maintaining stability in both the thoracic and abdominal cavities when breathing.

1. During inspiration, the diaphragm descends, causing an eccentric lengthening of the abdominals and the PFM, which stabilizes the core.
2. During exhalation, the diaphragm relaxes and ascends, while the abdominals and PFM contract concentrically.

This basic overview of the diaphragm's connections is expanded upon in my live online course, Pediatric Pelvic Floor Diaphragm and Postural Development, where I delve deeper into how these relationships impact children with pelvic floor issues like constipation, diastasis rectus, and even cystic fibrosis.

The diaphragm, in coordination with the abdominal muscles and the PFM, helps to stabilize the spine and pelvis during movement. This stabilization is essential for maintaining balance and posture when learning developmental motor skills.

This coordination also ensures that pressure within the thoracic and abdominal cavities is managed effectively, influencing respiratory capacity and lymphatic drainage.

Furthermore, the fascial connections from the diaphragm establish healthy function of many organ systems. Let’s take a look at this in more detail, so you can understand how this directly affects your practice as a pediatric therapist.

The Diaphragm’s Fascial Connections To Organ Systems
Beyond its muscular and respiratory functions, the diaphragm is also deeply interconnected with the body’s fascial system. Fascia surrounds every structure in the body, providing support and facilitating movement. Fascia has contractile properties, so a problem with the diaphragm or its related structures can cause dysfunction along the entire fascial chain.

The diaphragm has direct fascial connections to several key organs, including:

• Heart
• Lungs
• Liver and Colon
• Esophagus

These fascial connections highlight the diaphragm’s role in managing information between the chest and abdomen, as well as its influence on organ function. When kids have dysfunction in their diaphragm or its associated fascial structures, this can lead to a range of issues, such as digestive, breathing, and swallowing problems.

The diaphragm also influences postural stability through its relationship with the glottis, which controls airflow through the vocal cords. Engagement of the glottis during upright perturbations or stability tasks enhances thoracic stability. The proper function of the glottis needs to be considered when working with kids on breathing mechanics, trunk stability, or pelvic floor engagement.

You must also look at neurological connections to the diaphragm, such as those involving the phrenic, vagus, trigeminal, and hypoglossal nerves. What many therapists often see as classic mechanical issues or classic digestive issues, can actually have distal neurological origins. This includes mechanical conditions such as headaches and thoracic outlet syndrome, and autonomic digestive conditions such as gastroesophageal reflux, aerophagia, and functional gastrointestinal disorders.

Get good at connecting the pieces and understanding the root causes of dysfunction, rather than simply treating the kids’ symptoms.

Clinical Implications For Pediatric Therapy
For pediatric therapists, understanding the diaphragm’s role in respiration, postural stability, and its broader connections within the body is essential for effective treatment. Children with conditions such as cerebral palsy (CP), respiratory issues, constipation, and musculoskeletal pain can benefit significantly from interventions that target the diaphragm and its associated structures.

For example, in children with CP, research has shown that kids with better diaphragmatic function exhibit greater ambulatory mobility, abdominal expansion, and respiratory function compared to kids with impaired diaphragmatic function. You should prioritize treatment of the diaphragm for children with CP, especially those who are non-ambulatory. [1]

Similarly, addressing diaphragmatic function can play a critical role in managing pediatric patients with respiratory conditions, such as asthma. Ensuring that the diaphragm maintains its dome shape and ZOA can improve the child’s breathing efficiency, reduce the reliance on accessory muscles, and enhance overall respiratory function.

Lastly, the diaphragm’s role in maintaining intra-abdominal pressure and coordinating with the pelvic floor muscles is crucial for managing conditions like constipation and urinary incontinence. By optimizing diaphragmatic function, you can support children’s pelvic floor function and help improve their bowel motility and urinary continence.

There are many widespread health implications that you have the power to influence as a pediatric therapist! If you are looking to deepen your understanding of the diaphragm and its role in pediatric health, join me virtually for my live Pediatric Pelvic Floor Diaphragm and Postural Development course on September 29, 2024.

This course will provide you with the knowledge and tools you need to enhance your practice and improve outcomes for your young patients. Don't miss this opportunity to expand your skill set and make a meaningful difference in the lives of the children you treat.

Reference:

1. Bennett S, Siritaratiwat W, Tanrangka N, Bennett MJ, Kanpittaya J. Diaphragmatic mobility in children with spastic cerebral palsy and differing motor performance levels. Respir Physiol Neurobiol. 2019 Aug;266:163-170. doi: 10.1016/j.resp.2019.05.010. Epub 2019 May 21. PMID: 31125702.

AUTHOR BIO

Dawn Sandalcidi PT, RCMT, BCB-PMD

Dawn Sandalcidi is a trailblazer and leading expert in the field of pediatric pelvic floor disorders. She graduated from SUNY Upstate Medical Center in 1982 and is actively seeing patients in her clinic Physical Therapy Specialists, Centennial CO.

Dawn is a national and international speaker in the field, and she has gained so much from sharing experiences with her colleagues around the globe. In addition to lecturing internationally on pediatric bowel and bladder disorders, Dawn is also a faculty instructor at the Herman & Wallace Pelvic Rehab Institute. Additionally, she runs an online teaching and mentoring platform for parents and professionals.

In 2017, Dawn was invited to speak at the World Physical Therapy Conference in South Africa about pediatric pelvic floor dysfunction and incontinence. Dawn is also Board-Certified Biofeedback in Pelvic Muscle Dysfunction (BCB-PMD). She has also been published in the Journals of Urologic Nursing and Section of Women’s Health.

In 2018, Dawn was awarded the Elizabeth Noble Award by the American Physical Therapy Association Section on Women's Health for providing Extraordinary and Exemplary Service to the Field of Physical Therapy for Children.