Diaphragm Anatomy and Differential Diagnosis

Original Editor - Carin Hunter based on the course by Rina Pandya
Top Contributors - Carin Hunter, Jess Bell, Kim Jackson, Wanda van Niekerk, Lucinda hampton, Merinda Rodseth, Tarina van der Stockt and Ewa Jaraczewska

Anatomy of the diaphragm

  • Fibromuscular dome shaped muscle of inspiration that separates thorax from the abdomen.
  • Forms the floor of thorax and roof of abdomen
  • Left side lower than the right due to presence of the liver on the right.
  • . The left side may also be partially inferiorly located because of the push by the heart. (1,2)


Etiology for elevated diaphragm

An elevated hemidiaphragm may result from direct and indirect causes which include:

  • above the diaphragm 1
    • decreased lung volume
    • atelectasis/collapse
    • prior lobectomy or pneumonectomy
    • pulmonary hypoplasia
  • diaphragm 3-7
    • phrenic nerve palsy
    • diaphragmatic eventration
    • contralateral stroke: usually middle cerebral artery (MCA) distribution
  • below the diaphragm 8
    • abdominal tumor, e.g. liver metastases or primary malignancy
    • subphrenic abscess
    • distended stomach or colon, including Chilaiditi sign/syndrome


Differential Diagnosis

Other situations which may mimic an elevated hemidiaphragm include:


3 Major openings in the Diaphragm:

  1. Caval hiatus: at the level of the T8 vertebra in the central tendon. It allows passage of Inferior vena cava and some branches of the right phrenic nerve.
  2. The esophageal hiatus: at the level of the T10. It allows passage of esophagus, the right and left vagus trunks, the esophageal branches of the left gastric vessels, and the lymph vessels.
  3. The aortic hiatus: anterior to the body of the T12 vertebra between the crura. It allows passage of aorta, thoracic duct, and azygos vein.


Nerve Supply

Phrenic nerve : C3, C4,C5 and sometimes C6 :

  • Motor nerve supply:
  1. left hemidiaphragm with left phrenic nerve
  2. Right hemidiaphragm with right phrenic nerve.
  • Sensory nerve supply:
  • The phrenic nerve innervates the parietal pleura and peritoneum covering the central surfaces of the diaphragm. The lower 6 intercostal nerves supply the periphery of the diaphragm.
  • Large diameter myelinated Phrenic nerve afferents fire with diaphragm contraction. The small diameter continues to fire through out the respiratory cycle
    • Activation of phrenic nerve modulates the sympathetic motor outflow.
    • Phrenic afferents also contribute to somatosensation of the diaphragm and make one aware of the sensation of breathing while awake(3)


Vascular Supply

  • Arterial supply:
  • Inferior phrenic arteries from abdominal aorta
  • The others are superior phrenic, pericardiophrenic, musculophrenic arteries.
  • Venous supply:
  • Same name as the above


Fascial attachments: vertebrae

  • The medial lumbocostal arch is a tendinous arch in fascia covering psoas major. Medially, it attaches to the side of the body of vertebra L1. Laterally, it connects to the front of the transverse process of vertebra L1.
  • The lateral lumbocostal arch is a tendinous arch in fascia covering the upper part of quadratus lumborum. Medially, attach to the front of the transverse process of vertebra L1. Laterally, it connects to the lower border of the 12th rib.


Fascial attachments to muscles

The QL attaches to the inferior portion of the 12th rib, while a portion of the diaphragm attaches to the superior portion of this rib. However, the fascia between these attachments is continuous.

The psoas has a more direct pathway, covering the same basic territory as the QL-iliac muscle to blend with the fascia of the posterior portion of the diaphragm at its proximal end.

Clinical Relevance: Paralysis of the Diaphragm

  • Diaphragmatic paralysis is due to an interruption in its nervous supply. This can occur in the phrenic nerve, cervical spinal cord, or the brainstem. It is most often due to a lesion of the phrenic nerve:
  • Mechanical trauma: ligation or damage to the nerve during surgery.
  • Compression: due to a tumor within the chest cavity.
  • Myopathies: such as myasthenia gravis.
  • Neuropathies: such diabetic neuropathy.
  • Inflammatory: Many systemic diseases can lead to inflammation of the phrenic nerve or diaphragm leading to diaphragmatic palsy. Viral infections like HIV, West Nile virus and poliomyelitis virus, bacterial infections like Lyme disease, and noninfectious causes like sarcoidosis and amyloidosis have been linked to diaphragmatic weakness.
  • Myopathies: such as myasthenia gravis.
  • Neuropathies: such diabetic neuropathy, inclusion body myositis, dermatomyositis, multiple sclerosis, anterior horn cell disease, chronic demyelinating disease, and neuralgic myopathy.(Ricoy, 2019)

Idiopathic: In nearly 20% cases, no obvious cause if detected after extensive investigations and are referred as idiopathic

Differential Diagnosis(30)

  • Alveolar hypoventilation
  • Anterior horn cell or neuromuscular junction disease
  • Cerebral haemorrhage
  • Cervical fracture
  • Decreased pulmonary compliance
  • Guillain-Barre syndrome
  • Myasthenia gravis
  • Peripheral neuropathies
  • Pleural adhesions

Symptoms of diaphragmatic weakness

  • Unilateral : asymptomatic and detected incidentally.They show limitation in exercise capacity, lower O2 Saturation levels.
  • ⅓ of the patients: exertional breathlessness
  • Dyspnea at rest with comorbidities such as cardiopulmonary conditions.
  • Bilateral weakness: dyspnea at mild exertion to dyspnea at rest.
  • Further compromise→ orthopnea.
  • Progressive hypoventilation → hypercapnia and right heart failure. Worse during sleep.

Paradoxical Breathing

Paralysis of the diaphragm produces a paradoxical movement. The affected side of the diaphragm moves upwards during inspiration, and downwards during expiration. A unilateral diaphragmatic paralysis is usually asymptomatic and is most often an incidental finding on x-ray. If both sides are paralysed, the patient may experience poor exercise tolerance, orthopnoea and fatigue. Lung function tests will show a restrictive deficit. (4)

https://youtu.be/8TnrNrrEjuE

Effects of diaphragmatic breathing(6)

1. Detoxifies and Releases Toxins: Our body is designed to release 70% of its toxins through breathing. At least 3x times per day for 39 seconds

2. Anti-stress: Brain releases cortisol, the “stress hormone” under stress and anxiety. By taking deep breaths, heart rate slows, more oxygen enters the blood stream and ultimately communicates with the brain to relax. Deep breathing also ups the endorphins.

3. Relaxation and mood elevation: Diaphragmatic breathing stimulates vagus nerve which is parasympathetic, thus inducing relaxation.

4. Deep Breathing Relieves Pain:

Breathing into pain will increase circulation to that specific area, relieves tension and increase oxygenation. This triggers the release of endorphins, thus effecting pain relief.

5. Deep Breathing Enhances the Immune System:

Deep breathing enhances the body’s ability to metabolize nutrients and vitamins. Deep breathing aids in digestion which helps strengthen the immunity.

6. Lowers blood pressure. With relaxation blood vessels dialate, which improves circulation and lowers blood pressure. Deep breathing also slows and regulates the heart rate, which also helps with lowering BP.

7. Deep Breathing Improves Cellular Regeneration: With deep breathing the body is better oxygenated and has better circulation which enhances the body’s efforts of cellular regeneration.

8.Helps support correct posture. Inspiration lengthens the spine, facilitates lumbopelvic movements, activates core muscles.

Evidence Based Practice :

Allison et al reported that during lumbo-pelvic motion control tests, diaphragmatic activity increases in healthy subjects(7)  O’Sullivan concluded in their case studies that lumbopelvic movements decreases in patients with diaphragmatic injuries. (8)

Moreover, patients with chronic lower back pain have often been reported to have defects in posture and motor control (9) (10)

Effect of mechanical ventilation on diaphragm

  • VIDD: Ventilator-induced diaphragmatic dysfunction: defined as loss of diaphragmatic force- generating capacity as a consequence to use of mechanical ventilation due to suppressed inspiratory effort.
  • Mechanical ventilatory assistance contributes to  diaphragm muscle inactivity and unloading thus leading to diaphragmatic  atrophy and fatigue(11)
  • Diaphragm weakness is a leading cause of difficult weaning from mechanical ventilation (12) and Loss of thickness of diaphragm muscle, however, if there is insufficient ventilatory support and diaphragm is not unloaded adequately leading to load-induced inflammation and injury. (13)
  • Diaphragm atrophy developing during mechanical ventilation strongly impacts clinical outcomes. Targeting an inspiratory effort level similar to that of healthy subjects at rest might accelerate liberation from ventilation.(29)


1,2 : Oliver KA, Ashurst JV. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Dec 9, 2018. Anatomy, Thorax, Phrenic Nerves.

Bordoni B, Purgol S, Bizzarri A, Modica M, Morabito B. The Influence of Breathing on the Central Nervous System. Cureus. 2018 Jun 01;10(6):e2724

3. Fayssoil A, Behin A, Ogna A, Mompoint D, Amthor H, Clair B, Laforet P, Mansart A, Prigent H, Orlikowski D, Stojkovic T, Vinit S, Carlier R, Eymard B, Lofaso F, Annane D. Diaphragm: Pathophysiology and Ultrasound Imaging in Neuromuscular Disorders. J Neuromuscul Dis. 2018;5(1):1-10

4. The Diaphragm - Actions - Innervation - TeachMeAnatomy. Teachmeanatomy.info. https://teachmeanatomy.info/thorax/muscles/diaphragm/. Accessed July 30, 2020.

5. McCool FD, Manzoor K, Minami T. Disorders of the Diaphragm. Clin. Chest Med. 2018 Jun;39(2):345-360

6.Diaphragm Deep Breathing. https://www.eugeneor.gov/DocumentCenter/View/14142/Diaphagmatic_breathing?bidId=.

7. Allison GT, Kendle K, Roll S, Schupelius J, Scott Q, Panizza J. Aust J Physiother. 1998; 44(2):95-102

8. Changes in pelvic floor and diaphragm kinematics and respiratory patterns in subjects with sacroiliac joint pain following a motor learning intervention: a case series.O'Sullivan PB, Beales DJ, Man Ther. 2007 Aug; 12(3):209-18

9. Pain and motor control of the lumbopelvic region: effect and possible mechanisms. Hodges PW, Moseley GL. J Electromyogr Kinesiol. 2003 Aug; 13(4):361-70.

10. Diagnosis and classification of chronic low back pain disorders: maladaptive movement and motor control impairments as underlying mechanism. O'Sullivan P. Man Ther. 2005 Nov; 10(4):242-55)

11. Vassilakopoulos T, Petrof BJ. Ventilator-induced diaphragmatic dysfunction. Am J Respir Crit Care Med. 2004;169(3):336-341.

12. Dres M, Dubé B-P, Mayaux J, Delemazure J, Reuter D, Brochard L,et al. Coexistence and impact of limb muscle and diaphragm weakness at time of liberation from mechanical ventilation in medical intensive care unit patients. Am J Respir Crit Care Med 2017;195:57–66

13. Orozco-Levi M, Lloreta J, Minguella J, Serrano S, Broquetas JM, Gea J. Injury of the human diaphragm associated with exertion and chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2001;164:1734–1739

29.  Goligher E, Dres M, Fan E, Rubenfeld G. Mechanical Ventilation–induced Diaphragm Atrophy Strongly Impacts Clinical Outcomes | American Journal of Respiratory and Critical Care Medicine. Atsjournals.org. https://www.atsjournals.org/doi/10.1164/rccm.201703-0536OC. Published 2017.

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