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Diafragma

Musculus diaphragma

The principal muscle of respiration, the diaphragm is a musculotendinous dome that separates the thoracic and abdominal cavities. When it contracts, the dome flattens, increasing thoracic volume and generating the negative pressure that draws air into the lungs during inspiration. Sternal, costal, and lumbar origins converge on its central tendon, and three major openings transmit the inferior vena cava at the level of T8, the esophagus at T10, and the aorta at T12. A diaphragmatic hernia allows abdominal organs to pass into the thoracic cavity, and paralysis of the phrenic nerve causes the muscle to rise abnormally within the thorax. Involuntary spasms of the diaphragm produce hiccups.

Un tabique musculotendinoso en forma de cúpula que separa las cavidades torácica y abdominal. Tiene orígenes esternal, costal y lumbar que convergen en el centro tendinoso. Tres aberturas principales dan paso a la aorta (T12), el esófago (T10) y la vena cava inferior (T8).

On this page
Tipo Muscle
Sistema corporal Muscular
Región corporal Tórax
Estructura principal thoracic segment muscle
Nombre latino Musculus diaphragma
FMA ID 13295

Función

El músculo principal de la respiración. Su contracción aplana la cúpula muscular, aumentando el volumen torácico y generando presión negativa para introducir aire en los pulmones durante la inspiración.

Significado clínico

Las hernias diafragmáticas permiten que los órganos abdominales entren en la cavidad torácica. La parálisis del nervio frénico causa elevación diafragmática. El hipo resulta de espasmos diafragmáticos involuntarios.

Frequently Asked Questions

How does the diaphragm produce breathing?

During inhalation, the diaphragm contracts and flattens its dome-shaped resting configuration, descending toward the abdomen. This increases the vertical dimension of the thoracic cavity, reducing intrathoracic pressure below atmospheric pressure and causing air to rush into the lungs. During exhalation at rest, the diaphragm relaxes and passively returns to its dome shape, reducing thoracic volume and expelling air.

What nerve controls the diaphragm and where does it originate?

The diaphragm is controlled almost entirely by the phrenic nerve, which originates from cervical spinal cord levels C3, C4, and C5—remembered by the mnemonic 'C3, 4, and 5 keep the diaphragm alive.' Each hemidiaphragm receives its own phrenic nerve, one from each side. This is why a high cervical spinal cord injury (above C3) results in loss of spontaneous breathing.

What is a diaphragmatic hernia?

A diaphragmatic hernia occurs when abdominal organs—such as the stomach, intestines, or spleen—herniate through a defect in the diaphragm into the thoracic cavity. Congenital diaphragmatic hernias are a serious neonatal emergency causing lung compression and respiratory failure. Acquired hernias can occur through the esophageal hiatus (hiatal hernia) or from traumatic rupture.

What causes hiccups, and are they related to the diaphragm?

Hiccups result from involuntary, repetitive spasms of the diaphragm. Each spasm causes a sudden inhalation that is abruptly stopped by closure of the vocal cords, producing the characteristic 'hic' sound. Common triggers include rapid eating, carbonated drinks, alcohol, and gastric distension. Persistent hiccups lasting more than 48 hours may indicate an underlying medical condition.

What three major structures pass through the diaphragm, and at what vertebral levels?

Three major structures pass through openings in the diaphragm: the inferior vena cava passes through at the T8 level (caval opening), the esophagus passes through at T10 (esophageal hiatus), and the aorta passes through at T12 (aortic hiatus). A common mnemonic is 'I ate (8) ten (10) eggs (esophagus) at (aorta) twelve (12).'

References

  1. Foundational Model of Anatomy — FMA:13295 Reference anatomy ontology (University of Washington)
  2. UBERON — UBERON:0001103 Cross-species anatomy ontology (EMBL-EBI Ontology Lookup Service)

Aviso médico

Este contenido es solo para fines educativos e informativos. No pretende ser un sustituto del consejo médico profesional, diagnóstico o tratamiento. Siempre busque el consejo de su médico u otro proveedor de salud calificado ante cualquier pregunta que pueda tener sobre una condición médica. Nunca ignore el consejo médico profesional ni demore en buscarlo debido a algo que haya leído en este sitio web.

Educational Disclaimer

This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical decisions.

Data sources: Terminologia Anatomica, Foundational Model of Anatomy, Wikidata.