[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Spine](https://durgical.com/en/anatomy/region/spine/) › Diaphragm [Muscular system](https://durgical.com/en/anatomy/system/muscular-system/) · [Spine](https://durgical.com/en/anatomy/region/spine/) # Diaphragm The diaphragm is the dome-shaped breathing muscle between the chest and [abdomen](https://durgical.com/en/anatomy/region/abdomen/), anchored to L1 to L3; it is the main muscle for breathing in. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=spine&select=diaphragm&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The dome-shaped breathing muscle between the chest and abdomen; its 'crura' attach to the front of L1 to L3. ## What it does The main muscle for breathing in; it also helps raise abdominal pressure to support the [spine](https://durgical.com/en/anatomy/region/spine/). ## Key points - Three main openings: caval at T8 (inferior vena cava, branches of the right [phrenic nerve](https://durgical.com/en/anatomy/phrenic-nerve/)), oesophageal at T10 (oesophagus, vagal trunks), aortic at T12 (aorta, thoracic duct, often the azygos vein) - Its only motor nerve is the phrenic nerve (C3–C5): a complete [spinal cord](https://durgical.com/en/anatomy/spinal-cord/) injury above C3 stops spontaneous breathing - Irritation of its central part refers pain to the shoulder tip (C4 dermatome); its peripheral rim refers pain to the lower [chest](https://durgical.com/en/anatomy/region/chest/) and abdominal wall - The right crus is larger and loops around the oesophageal opening, acting as an external sphincter that helps resist reflux ## Key facts **Origin** Sternal: xiphoid; costal: inner [costal cartilages](https://durgical.com/en/anatomy/costal-cartilage/) 7–12; lumbar: crura (right L1–L3, left L1–L2) and arcuate ligaments **Insertion** Central tendon **Action** Main muscle of inspiration (descends, enlarges thorax); raises intra-abdominal pressure **Nerve** Phrenic nerve (C3–C5), motor and central sensory; peripheral sensory from lower [intercostal nerves](https://durgical.com/en/anatomy/intercostal-nerves/) **Blood supply** Superior and inferior phrenic, pericardiacophrenic, musculophrenic and lower [posterior intercostal arteries](https://durgical.com/en/anatomy/posterior-intercostal-arteries/) ## Relations **Above** [Pleura](https://durgical.com/en/anatomy/pleura/) and the bases of both lungs; the [pericardium](https://durgical.com/en/anatomy/pericardium/) and heart rest on the central tendon **Below** [Liver](https://durgical.com/en/anatomy/liver/) on the right; [stomach](https://durgical.com/en/anatomy/stomach/) and [spleen](https://durgical.com/en/anatomy/spleen/) on the left; the [kidneys](https://durgical.com/en/anatomy/kidney/) and suprarenal glands against its posterior part **Behind** Crura on the bodies of the upper lumbar vertebrae; the medial and lateral arcuate ligaments arch over [psoas major](https://durgical.com/en/anatomy/psoas-major/) and [quadratus lumborum](https://durgical.com/en/anatomy/quadratus-lumborum-muscle/); the [sympathetic trunk](https://durgical.com/en/anatomy/sympathetic-trunk/) passes behind the medial arcuate ligament **Contents** Caval opening (T8): [inferior vena cava](https://durgical.com/en/anatomy/inferior-vena-cava/); oesophageal hiatus (T10): oesophagus, anterior and posterior [vagal trunks](https://durgical.com/en/anatomy/anterior-vagal-trunk/), oesophageal branches of the left gastric vessels; aortic hiatus (T12), behind the median arcuate ligament: aorta, [thoracic duct](https://durgical.com/en/anatomy/thoracic-duct/), [azygos vein](https://durgical.com/en/anatomy/azygos-vein/) ## How to find it It cannot be felt. Its domes are seen on a chest radiograph, the right usually a little higher than the left because of the liver. On ultrasound it is the bright curved line over the liver or spleen that moves down with each breath in; percussing the lower edge of lung resonance in full inspiration and expiration gives a rough measure of its movement. ## Examination - Fluoroscopic sniff test: with a quick sniff a normal dome moves down; a paralysed dome stays still or rises (paradoxical movement), pointing to a phrenic nerve lesion - Diaphragm ultrasound: a dome that neither descends nor thickens during inspiration supports paralysis on that side ## On imaging Chest radiograph: a raised hemidiaphragm suggests phrenic nerve palsy, lung collapse or a process below it; free gas under the domes on an erect film means a perforated hollow organ. CT shows the crura, the hiatuses and hernia contents. ## Clinical notes - Congenital hernias: Bochdalek (posterolateral, usually left, in newborns, with lung hypoplasia) and Morgagni (anterior, retrosternal, usually right, often found later in life) - Hiatal hernia through the oesophageal hiatus: the sliding type (the gastro-oesophageal junction moves up) is by far the most common; in the paraoesophageal type the fundus rises beside a junction that stays in place - Shoulder-tip pain from blood, pus or gas under the diaphragm (ruptured spleen, subphrenic abscess, after laparoscopy) is referred through the phrenic nerve - Hiccups are involuntary contractions of the diaphragm closed off by the glottis; the reflex runs through the phrenic and vagus nerves, so persistent hiccups can come from irritation anywhere along them - Phrenic nerve injury (neck or heart surgery, tumour, interscalene block) paralyses one side; paralysis of both sides causes marked breathlessness lying flat ## Development Built from the septum transversum (central tendon), the pleuroperitoneal membranes, the mesentery of the oesophagus (crura) and body-wall muscle. It forms in the neck region and descends, which is why its nerve comes from C3–C5; a pleuroperitoneal membrane that fails to close leaves a Bochdalek hernia. ## Memory aid C3, 4, 5 keeps the diaphragm alive. Openings: I 8 10 Eggs At 12 (IVC T8, oEsophagus T10, Aorta T12). ## Related conditions - [Pompe disease (glycogen storage disease type II)](https://durgical.com/en/conditions/pompe-disease/) - [Respiratory acidosis](https://durgical.com/en/conditions/respiratory-acidosis/) - [Refeeding syndrome](https://durgical.com/en/conditions/refeeding-syndrome/) - [Organophosphate and carbamate poisoning](https://durgical.com/en/conditions/organophosphate-and-carbamate-poisoning/) - [Coral snake envenomation (Micrurus)](https://durgical.com/en/conditions/coral-snake-envenomation/) - [Oesophageal perforation (Boerhaave syndrome)](https://durgical.com/en/conditions/oesophageal-perforation/) - [Hiatal hernia](https://durgical.com/en/conditions/hiatal-hernia/) - [Trichinellosis](https://durgical.com/en/conditions/trichinellosis/) - [Critical illness polyneuropathy and myopathy (ICU-acquired weakness)](https://durgical.com/en/conditions/critical-illness-polyneuropathy-and-myopathy/) - [Congenital diaphragmatic hernia](https://durgical.com/en/conditions/congenital-diaphragmatic-hernia/) - [Acute respiratory failure (hypoxaemic and hypercapnic)](https://durgical.com/en/conditions/acute-respiratory-failure/) - [Obesity hypoventilation syndrome](https://durgical.com/en/conditions/obesity-hypoventilation-syndrome/) - [Penetrating trauma (stab and gunshot wounds)](https://durgical.com/en/conditions/penetrating-trauma/) - [Traumatic diaphragmatic injury](https://durgical.com/en/conditions/traumatic-diaphragmatic-injury/) - [Gastro-oesophageal reflux disease (GERD)](https://durgical.com/en/conditions/gastro-oesophageal-reflux-disease/) - [Achalasia](https://durgical.com/en/conditions/achalasia/) ## Test yourself Think of the answer, then tap the question to see it. ## What are the levels of the three main openings of the diaphragm? Caval T8 (inferior vena cava), oesophageal T10 (oesophagus, vagal trunks), aortic T12 (aorta, thoracic duct, azygos). ## What is the motor nerve of the diaphragm, and what are its roots? The phrenic nerve, C3–C5 («C3, 4, 5 keeps the diaphragm alive»); a complete cord injury above C3 stops spontaneous breathing. ## Why does irritation under the central diaphragm cause shoulder-tip pain? Its central part is sensed by the phrenic nerve (C3–C5), so pain is referred to the C4 dermatome at the shoulder tip. ## What does the sniff test show in a paralysed hemidiaphragm? The paralysed dome stays still or rises (paradoxical movement) instead of descending, pointing to a phrenic nerve lesion. ## How do Bochdalek and Morgagni hernias of the diaphragm differ? Bochdalek: posterolateral, usually left, in newborns with lung hypoplasia. Morgagni: anterior retrosternal, usually right, often found later. [Add to my cards (5)](https://durgical.app/estudiar/?add=/en/anatomy/diaphragm/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** diaphragma TA2 2327 **Official Spanish (DeCS)** Diafragma DeCS D003964 **English (TA2)** Diaphragm **Also called** thoracic diaphragm · respiratory diaphragm · thoracoabdominal diaphragm ## Related - [Psoas major](https://durgical.com/en/anatomy/psoas-major/) - [Quadratus lumborum](https://durgical.com/en/anatomy/quadratus-lumborum-muscle/) - [L2 vertebra](https://durgical.com/en/anatomy/lumbar-vertebra-spine-and-pelvis/) - [L3 vertebra](https://durgical.com/en/anatomy/lumbar-vertebra-spine-and-pelvis-l3/) - [T11 vertebra](https://durgical.com/en/anatomy/t11/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=22421); [Anatomy, Thorax: Diaphragm](https://www.ncbi.nlm.nih.gov/books/NBK519558/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/diaphragm/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/diaphragm/