Diaphragm: Definition, Location, Anatomy, Function, Diagram (2022)

What is the Diaphragm: Definition

The thoracic diaphragm is a large, flat muscle that plays a vital role in the respiratory system, and is located just beneath the two lungs, dividing the chest cavity from the abdominal cavity [1]. With its characteristic dome shape, it is the primary respiratory muscle, also supporting the lungs and heart [2].


Is the Diaphragm an Organ

It is a skeletal muscle [3], and like many other important muscles, the diaphragm is an organ, one of the most important respiratory organs that humans cannot live without [4].

Where is the Diaphragm Located

The diaphragm is located between the thoracic and abdominal cavities [3], with important organs like the lungs and heart located superior to it, and the liver (proximal position), kidney and stomach being inferior to it. The curved muscle is inserted into the lower part of the rib cage.

(Video) Diaphragm - Definition, Function, Muscle & Anatomy | Kenhub

Diaphragm Muscle Location Picture

Diaphragm Anatomy

Parts of the Main Structure

The Peripheral Muscle

There are three parts of the peripheral muscle, sternal, costal, and lumbar, depending on the location of the peripheral attachment.

Sternal part: Originates from the xiphoid process (extending from the sternum) as two thick, fleshy bands that can be referred to as the left and right strips [5].

Costal part: Originates from the inner side of the 6 costal cartilages of the 7th to 12th ribs on both sides [3, 6]

Lumbar part (Crura): Originates as two tendinous bands from the lumbar vertebrae and the arcuate ligaments (medial and lateral) [3, 5]. These are known as the left and right crura [3] (singular: crus) depending on the point of their origin.

  • Right Crus: Broader and longer than the left one [7], it arises from the anterior surfaces of the first, second and third lumbar vertebrae [5].
  • Left Crus: Arises from the first and second lumbar vertebrae only [8].

Central Tendon

An aponeurosis, (interlacing white, fibrous tissues with a wide area of attachment, taking the place of tendons in flat muscles), the central tendon forms the central upper surface of the diaphragm [9]. It fuses with the pericardium (the outer membrane of the heart) located just above it and helps the heart to stay in place [10].

The radial muscle fibers forming the peripheral muscle all converge and connect to the central tendon [1].

Diaphragm Openings

Since it is located between the abdominal and chest cavities, any structure that needs to pass into the abdominal cavity from above has to go through the diaphragm [3]. The three primary openings are:

(Video) Diaphragm (anatomy)

Caval opening (vena caval hiatus) at the 8th vertebral level: Allows the inferior vena cava [9] and the right phrenic nerve branches [11] to pass through.

Esophageal opening (esophageal hiatus) at the 10th vertebra level: Transmits the esophagus, vagus nerves, and the small esophageal arteries [12].

Aortic opening (aortic hiatus) at the 12th vertebral level: Transmits the aorta, azygos, and hemiazygos veins [13], as well as the thoracic duct [14].

There are a few minor openings or apertures as well, including one on each of the two crura, one transmitting the greater splanchnic nerve, while the other lets the lesser splanchnic nerve pass through. Additionally, there are some small openings in the central tendon for certain veins [5].

What Nerves Innervate the Diaphragm

The phrenic nerve, originating at the C3-C5 vertebral level, provides motor supply to the diaphragm [2], and controls its movement [15]. The medullary inspiratory neuron (responsible for regulating breathing) sends information to the diaphragm via this nerve, enabling us to breathe in. The left side of the diaphragm is innervated by the left phrenic nerve and the right side by the right phrenic nerve [3]. Due to this reason, the two halves are capable of working independently [16]. Both the phrenic nerves provide innervation to the right crus [5].

The outer or peripheral regions of the diaphragm are innervated by the lower 6 to 7 intercostal nerves [7, 16].

Blood Supply to the Diaphragm Muscle

Its central part gets arterial supply from the phrenic arteries [3], while the 5 lower intercostal and subcostal arteries provide arterial supply to the costal margins. All these blood vessels connect and open into each other (anastomose) to ensure proper blood supply to the diaphragm [5].

All the arteries are followed by their corresponding veins, with the phrenic veins taking care of the primary drainage of the dome-shaped respiratory muscle. The right phrenic vein drains into the inferior vena cava, and the left phrenic vein empties into the left renal vein, suprarenal vein, or inferior vena cava [5].

(Video) Diaphragm - Anatomy ; Openings and Structures passing

Diaphragm Function – What Does it Do

Despite being a skeletal muscle, the diaphragm is unique as it can work both as a voluntary and involuntary muscle [17]. Humans do have some control over it, as we can increase or decrease the rate of inhalation, or hold our breath [18]. However, it functions on its own most of the time.

How Does the Diaphragm Work in the Respiratory System: Role in Breathing

Forming the floor of the chest cavity, the main function of the diaphragm is to control its volume by means of contracting and relaxing [19]. When the diaphragm contracts and flattens towards the abdominal cavity, dragging the pleura (the serous membrane around the lungs) with it, this reduces the air pressure within the lungs (including in each of the alveoli) [20]. As a result, air from outside rushes in the nasal and oral cavities, traveling down the pharynx, larynx, and trachea into the bronchi to reach the lungs and alveoli. As the diaphragm contracts, it also increases the volume of the thoracic cavity, making room for the inflated lungs [1].

The external intercostal muscles or rib cage muscles (located between the ribs) contract together with the diaphragm, lifting and expanding the rib cage to provide even more space [21].

Diaphragm Function in Breathing

What Happens to it during exhalation: Once the gas exchange takes place within the alveoli, the CO2-rich air fills the alveoli. The diaphragm then relaxes and comes back to its natural dome shape, reducing the space within the chest cavity, thus putting pressure on the lungs so the air can be pushed out [3].

Sudden Diaphragm Contractions and Hiccups

The diaphragm muscle usually moves in a specific rhythm; but sometimes, it gets irritated and contracts too quickly, which makes you draw in excess amounts of air within a short time, which then hits the vocal cords and larynx, causing them to close suddenly, leaving you with a hiccup [22]. A few things that might irritate the muscle include eating too fast, spicy foods or foods that are too hot or too cold, drinking soda or other carbonated drinks, and even stress [1].

(Video) What is the Diaphragm?

What is the Function of Diaphragm in the Digestive System

It is not directly a part of the digestive system but serves the important purpose of keeping the abdominal cavity, and all the organs of the digestive system separated from the respiratory system, so both can function properly. It also allows the esophagus to run through the esophageal hiatus so it can connect the pharynx to the stomach [23].

Associated Conditions

Diaphragm Spasms: Sometimes, the diaphragm spasms causing harmless hiccups may last for days or weeks, indicating some underlying health condition. Sometimes, this abnormally contracted muscle may make it difficult to breathe deeply, leading to other problems [24].

Paralyzed Diaphragm: A trauma to the phrenic nerves, lung or lymph node cancer, injury or surgical trauma to the diaphragm, certain spinal cord conditions and neuropathic diseases may weaken or paralyze the diaphragm (one or both sides). Since the two halves can work on their own, one side being collapsed does not hamper the functioning of the other side. However, it still interferes with the lungs’ ability to take in air, as the muscle cannot contract to its full capacity [25].

Elevated Diaphragm: Sometimes, the sheet muscle may elevate a little higher towards the chest cavity due to some abnormality in the tissues and organs around it. Possible causes include blood clotting or infection within the lungs, pulmonary fibrosis, a collapsed lung [26], and abdominal tumor [27].

Diaphragmatic Hernia: A birth defect, occurring as a fetus is developing in the mother’s womb, it causes the abdominal organs to move up an abnormal hole in the diaphragm [28]. Such cases usually need a diaphragm repair surgery once the baby is born. Tests like ultrasound and x-ray help with the diagnosis.

Diaphragmatic Eventration: Another congenital malformation, it causes the diaphragmatic muscles to partially be replaced with some thin membranous fibroelastic tissues [29].

Other Conditions that Might Affect the Diaphragm: Abdominal bloating may put pressure on the diaphragm, preventing it from contracting properly, leading to a feeling of tightness, irritation, pain when breathing in, and shortness of breath [30]. An accidental injury to the abdomen or chest may rupture the sheet muscle, leading to a number of complications.


    1. http://www.innerbody.com/image/musc06.html
    2. http://www.medicinenet.com/script/main/art.asp?articlekey=2983
    3. http://teachmeanatomy.info/thorax/muscles/diaphragm/
    4. https://www.ncbi.nlm.nih.gov/pubmed/20217342
    5. https://www.kenhub.com/en/start/c/diaphragm
    6. https://www.drugs.com/dict/costal-part-of-diaphragm.html
    7. https://radiopaedia.org/articles/diaphragm
    8. http://pubs.rsna.org/doi/full/10.1148/rg.285075187
    9. http://anatomyzone.com/anatomy-feed/central-tendon-diaphragm/
    10. https://radiopaedia.org/articles/central-tendon-of-diaphragm
    11. https://radiopaedia.org/articles/vena-caval-foramen
    12. https://radiopaedia.org/articles/oesophageal-hiatus
    13. https://radiopaedia.org/articles/aortic-hiatus
    14. https://www.gpnotebook.co.uk/simplepage.cfm?ID=1422917689
    15. http://www.averybiomedical.com/phrenic-nerve-damage-causes-treatments/
    16. https://www.dartmouth.edu/~humananatomy/part_4/chapter_20.html
    17. http://www.madsci.org/posts/archives/1996-05/829835620.Me.r.html
    18. http://www.yorku.ca/earmstro/res/qanda.html
    19. http://study.com/academy/lesson/diaphragm-definition-function.html
    20. http://www.healthline.com/human-body-maps/diaphragm
    21. http://www.innerbody.com/image_chest1/chest01.html
    22. http://kidshealth.org/en/kids/hiccup.html
    23. https://www.kenhub.com/en/library/anatomy/esophagus
    24. https://www.ncbi.nlm.nih.gov/pubmed/8018554
    25. https://www.cedars-sinai.edu/Patients/Health-Conditions/Paralyzed-Diaphragm.aspx
    26. https://www.axappphealthcare.co.uk/health-information/expert-help/what-is-a-raised-diaphragm/
    27. https://radiopaedia.org/articles/elevated-hemidiaphragm
    28. http://www.stanfordchildrens.org/en/topic/default?id=diaphragmatic-hernia-90-P02357
    29. https://www.uptodate.com/contents/eventration-of-the-diaphragm-in-infants
    30. http://www.healthline.com/health/abdominal-bloating-and-shortness-of-breath#overview1
(Video) Diaphragm Anatomy - Definition, Origin, Insertion, Openings, Functions | Dr Aiman


What is the function and location of the diaphragm? ›

The diaphragm, located below the lungs, is the major muscle of respiration. It is a large, dome-shaped muscle that contracts rhythmically and continually, and most of the time, involuntarily. Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges.

Where is the diaphragm location anatomy? ›

The diaphragm is a thin skeletal muscle that sits at the base of the chest and separates the abdomen from the chest. It contracts and flattens when you inhale. This creates a vacuum effect that pulls air into the lungs.

What is the function of diaphragm diagram? ›

diaphragm, dome-shaped, muscular and membranous structure that separates the thoracic (chest) and abdominal cavities in mammals; it is the principal muscle of respiration.

Where is the diaphragm located quizlet? ›

What is the diaphragm and where is it located? A double-domed (right and left dome) sheet of skeletal muscle, located at the inferior most aspect of the rib cage.

What is the origin of the diaphragm? ›

Thoracic diaphragm
OriginSeptum transversum, pleuroperitoneal folds, body wall
ArteryPericardiacophrenic artery, musculophrenic artery, inferior phrenic arteries
VeinSuperior phrenic vein, inferior phrenic vein
NervePhrenic and lower intercostal nerves
10 more rows

What is the diaphragm made of? ›

The diaphragm is primarily composed of muscle and fibrous tissue. The central tendon is a large part of the diaphragm that anchors the diaphragm to the ribs.

What are the 3 diaphragms? ›

The 3 diaphragms include our respiratory, pelvic, and laryngeal diaphragms, which have intimate connections to systemic functioning which affects our overall health, as well as how successfully we are to interact with the world around us.

What is the definition of diaphragm in biology? ›

(DY-uh-fram) The thin muscle below the lungs and heart that separates the chest from the abdomen.

What color is the diaphragm? ›

The diaphragm (in yellow oval) is visible as a sheet of skeletal muscle, which separates the thoracic and abdominal cavities. To get air into the lungs (inspiration), the rib cage expands and the diaphragm contracts to enlarge the thoracic cavity, generating a negative pressure within the lungs, causing air to flow in.

What is the function of diaphragm Class 7? ›

The diaphragm helps in the inspiration and expiration of air in and out of the lungs. At the time of inspiration, the diaphragm contracts, increasing the pulmonary volume thereby reducing the intrapulmonary pressure to less than the atmospheric pressure and air moves into the lungs.

Where is your diaphragm and stomach? ›

The diaphragm is a large muscle that lies between your abdomen and chest. You use this muscle to help you breathe. Normally, your stomach is below the diaphragm, but in people with a hiatal hernia, a portion of the stomach pushes up through the muscle. The opening it moves through is called a hiatus.

What is the meaning of diaphragm Class 7? ›

The diaphragm is the muscle that separates the chest (thoracic) cavity from the abdomen. The diaphragm is the main muscle of respiration. Contraction of the diaphragm muscle expands the lungs during inspiration when one is breathing air in.

How does a diaphragm work quizlet? ›

How does the diaphragm work? Diaphragm blocks the opening of uterus, spermicide stops sperm from moving - goes onto cap - both sdes. Sicilone can develop cracks holes, becomes thi, develop weak spots and wrinkle.

How does the diaphragm help you breathe quizlet? ›

When you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. This increases the space in your chest cavity, into which your lungs expand. The intercostal muscles between your ribs also help enlarge the chest cavity. They contract to pull your rib cage both upward and outward when you inhale.

What nerves control the diaphragm? ›

The phrenic nerve is among the most important nerves in the body due to its role in respiration. The phrenic nerve provides the primary motor supply to the diaphragm, the major respiratory muscle. Phrenic nerve injury, such as may occur from cardiothoracic surgery, can lead to diaphragmatic paralysis or dysfunction.

How thick is the diaphragm? ›

The average thickness of the diaphragm is 0.22–0.28 cm in healthy volunteers37 and 0.13–0.19 cm in a paralyzed diaphragm. A diaphragm thickness less than 0.2 cm, measured at the end of expiration, has been proposed as the cut-off to define diaphragm atrophy.

Do we have 2 diaphragms? ›

The mammalian diaphragm has traditionally been studied as a respiratory muscle. However, there is mounting evidence that suggests that it should more correctly be characterized as two separate muscles, the crural diaphragm and the costal diaphragm (De Troyer et al. 1981; Mittal, 1993).

How many diaphragms do we have? ›

The five diaphragms (tentorium cerebelli, tongue, thoracic outlet, thoracic diaphragm and pelvic floor) represent an important tool for the osteopath to evaluate and find a treatment strategy with the ultimate goal of patient well-being.

How big is the diaphragm? ›

Diaphragm Size

Small-diaphragms are typically classified as being 1/2″ (12.7 mm) or less in diameter, while large-diaphragms generally have diameters of 1″ (25.4 mm) or more.

What are the main parts of diaphragm? ›

The diaphragm is a musculotendinous sheet. It has three muscular parts (sternal, costal, and lumbar), each have their own origin and all insert into the central tendon of diaphragm. The diaphragm is shaped as two domes, with the right dome positioned slightly higher than the left because of the liver.

Do men have a diaphragm? ›

He noted that “the ordinary breathing in the two sexes differs. In men it is chiefly by the diaphragm; in women chiefly by the ribs” [44].

What are the 7 diaphragms of the body? ›

The crown chakra, third eye, throat, heart, solar plexus, sacral and root chakra. Each of the diaphragms is created by some of the thickest fascia in the body which from a sense of energy as well as fluid flow is not a coincidence.

Is the diaphragm a core muscle? ›

Working in close relationship with the deep abdominals, the pelvic floor, and the multifidus muscles in the lower back, the diaphragm is part of your intrinsic core.

What is the function of diaphragm in microscope? ›

The field diaphragm controls how much light enters the substage condenser and, consequently, the rest of the microscope.

Is the diaphragm a skeletal muscle? ›

The mammalian diaphragm muscle is essential for respiration, and thus is one of the most critical skeletal muscles in the human body.

What muscle attaches to the diaphragm? ›

The fascia involving the diaphragm posteriorly, ie, at the retroperitoneal level, is separated in four parts. It joins the aortic system, inferior vena cava, liver, psoas muscles, quadratus lumborum, cardiac area, phrenic-esophageal ligaments and, finally, the kidneys.

Is diaphragm on left or right? ›

It is dome shaped, slightly higher on the right side and it curves up toward the centre. The diaphragm features a boomerang shaped central tendon which is connected all around by muscular fibers which originate on the lumbar spine,the bottom edge of the ribcase and sternum.

How do you read your diaphragm? ›

How to Pronounce Diaphragm? (CORRECTLY) - YouTube

What is the function of ribs and diaphragm in breathing? ›

When the lungs inhale, the diaphragm contracts and pulls downward. At the same time, the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside. As a result, air rushes in and fills the lungs.

What is the function of ribs? ›

The ribs are the bony framework of the thoracic cavity. The ribs form the main structure of the thoracic cage protecting the thoracic organs, however their main function is to aid respiration.

What is ribs class 7th? ›

A rib is a curved bone in a person's chest. Your ribs protect your internal organs. A rib is also the curved bone in a pig's chest, and some people eat that with barbeque sauce. Ribs are strong and flexible, and they form a kind of protective cage around our soft inside parts.

Can you control your diaphragm? ›

We do have some conscious control over our diaphragm muscle, exemplified by the fact that we can, at will (my emphasis), protrude our bellies (increase the circumference of our abdomens) and hold that posture, as well as consciously regulate how fast we inhale and exhale (as in panting).

How do you remove a diaphragm? ›

After you have sex

After sex, leave your diaphragm in place for at least 6 hours. To remove your diaphragm, hook your finger on the front rim. Gently pull it down and out. Try not to tear a hole in it with your fingernails.

Can you feel your diaphragm? ›

Place one hand on your upper chest and the other just below your rib cage. This will allow you to feel your diaphragm move as you breathe. Breathe in slowly through your nose so that your stomach moves out, causing your hand to rise. The hand on your chest should remain as still as possible.

How do you breathe short answers 7? ›

During inhalation, ribs move up and outwards and diaphragm moves down. This movement increases space in our chest cavity and air rushes into the lungs. The lungs get filled with air. During exhalation, ribs move down and inwards, while diaphragm moves up to its former position.

What is the function of ribs Class 10? ›

The ribs protect the lungs and expand as we inhale to facilitate space for the lungs to expand like the diaphragm. The ribs then contract expelling the air in the lung.

How do we breathe? ›

Air is pulled into your nose or mouth, and into your windpipe. This divides into airways supplying the left and right lungs. The air passes down the airways, which divide another 15 to 25 times, and finally into thousands of smaller airways until the air reaches the air sacs.

Where is the diaphragm located microscope? ›

Iris Diaphragm controls the amount of light reaching the specimen. It is located above the condenser and below the stage. Most high quality microscopes include an Abbe condenser with an iris diaphragm.

What is the function of the diaphragm on a microscope? ›

The condenser aperture diaphragm is responsible for controlling the angle of the illuminating light cone and, consequently, the numerical aperture of the condenser.

Where is the diaphragm and stomach? ›

Overview. The diaphragm is a thin dome-shaped muscle which separates the thoracic cavity (lungs and heart) from the abdominal cavity (intestines, stomach, liver, etc.).

Where is the diaphragm located in a fetal pig? ›

2. Use your fingers to probe the chest area of the pig. You should be able to feel the hard sternum (breastbone) and the tiny ridges of the ribcage. Keep moving down until you feel the bottom edge of the rib cage; this is where the diaphragm separates the thoracic cavity from the abdominal cavity.

What is diaphragm in human eye? ›

The iris is the diaphragm, the pupil is the aperture. In the human eye, the iris can both constrict and dilate, which varies the size of the pupil.

What is the function of microscope? ›

A microscope is an instrument that is used to magnify small objects. Some microscopes can even be used to observe an object at the cellular level, allowing scientists to see the shape of a cell, its nucleus, mitochondria, and other organelles.

What is the definition of the iris diaphragm? ›

Definition of iris diaphragm

: an adjustable diaphragm of thin opaque plates that can be turned by a ring so as to change the diameter of a central opening usually to regulate the aperture of a lens.

What is the function of the diaphragm and condenser? ›

The purpose of the condenser is to concentrate the light onto the specimen, its diaphragm regulates resolution, contrast and depth of field. Many modern course microscopes are equipped with a condenser and an associated condenser diaphragm.

What is the function of the microscope diaphragm quizlet? ›

what is the function of a diaphragm in a microscope? allows the user to adjust the amount of light that is focused on the specimen being observed.

What is a diaphragm What does it do microscope quizlet? ›

Found on high power microscopes under the stage, the diaphragm is, typically, a five hole-disc with each hole having a different diameter. It is used to vary the light that passes through the stage opening and helps to adjust both the contrast and resolution of a specimen. It is particularly useful at higher powers.

What is the normal position of diaphragm? ›

Normally the right side of the diaphragm is higher than the left.

How thick is the diaphragm? ›

The average thickness of the diaphragm is 0.22–0.28 cm in healthy volunteers37 and 0.13–0.19 cm in a paralyzed diaphragm. A diaphragm thickness less than 0.2 cm, measured at the end of expiration, has been proposed as the cut-off to define diaphragm atrophy.

Is the diaphragm a body cavity? ›

Ventral body cavity

The diaphragm forms the floor of the thoracic cavity and separates it from the more inferior abdominopelvic cavity. The abdominopelvic cavity is the largest cavity in the body occupying the entire lower half of the trunk.

What is the function of diaphragm in fetal pig? ›

The action of breathing is a muscular operation, the muscles involved are: the diaphragm which separates the thoracic from the abdominal cavity, and the intercostal muscles found between the ribs (bone). These muscles, when contracted, increase the thoracic cavity size during inhalation to allow for the air to rush in.

What is the color of the diaphragm? ›

The diaphragm (in yellow oval) is visible as a sheet of skeletal muscle, which separates the thoracic and abdominal cavities. To get air into the lungs (inspiration), the rib cage expands and the diaphragm contracts to enlarge the thoracic cavity, generating a negative pressure within the lungs, causing air to flow in.

What is the function of the stomach in a fetal pig? ›

Stomach. The stomach is a muscular organ responsible for storage, initiating the breakdown of nutrients, and passing the digesta into the small intestine.


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