Where it is
Inside the trunk, between the thorax and the abdomen; in the drawing, the dotted line bulging forward.
- Layer
- Muscles
- System
- Muscles
- Region
- Breathing
What it is and what it does
A large, flat, dome-shaped muscle that completely separates the thoracic cavity from the abdominal cavity. It arises from the lumbar vertebrae (the crura of the diaphragm), from the ribs, the costal cartilages and the xiphoid process, and inserts on the central tendon. It is the main muscle of inspiration; the muscles of the thoracic wall help, especially during exertion.
The cupola, the highest part of the dome, is asymmetrical in the dog: on the left it reaches the level of the sixth rib, on the right one intercostal space further back; the esophageal hiatus lies ventral to thoracic vertebra 12, and the costal part attaches to the cartilage of the ninth rib, to cartilages 10-11 slightly below the junction with the rib, to rib 12 at its ventral end and to the last rib below its middle (Sisson, 1914).
Worth remembering
It is the main muscle of inspiration; the chest muscles help, especially during exertion.
Names
- Latin term: diaphragma.
- In Romanian: Diafragma (Romanian page).
In the atlas lessons
Muscles: what moves what (5 min):
Breathing: the diaphragm, the dome between the thorax and the abdomen, is the main muscle of inspiration; the external abdominal oblique compresses the abdomen and assists expiration.
Questions from the atlas
"Find it on the drawing" questions whose answer is this structure; in the atlas you will find them in the question bank and in the lessons.
- Show the diaphragm on the drawing. (level 2)