Diaphragm
From Ganfyd
| Diaphragm | |
|---|---|
 | |
| System: | Muscle |
| Function: | on contraction central tendon pulled down which increases vertical diameter of thorax inspiration abdominal straining weight-lifting thoraco-abdominal pump |
| Origin: | Sternal Part- small right and left slips arising from posterior surface xiphoid process Costal part - six slips arise from deep surfaces of lower six ribs and their costal cartilages vertebral part - crura:right crus arises from sides of bodies of L1-L3 (some fibres pass to left around oesophagus), left crus arises from sides of bodies of L1,L2 arcuate ligaments: medial thickened upper margin of fascia over psoas muscle from side of body of L2 to tip of transverse process L1,lateral thickened upper margin of fascia over quadratus lumborum from transverse process L1 to lower border 12th rib, median connects medial borders of both crura crosses anterior to aorta |
| Branches: | |
| Insertion: | central tendon whose superior surface is partially fused with fibrous pericardium |
| Arterial supply: | |
| Venous drainage: | |
| Lymphatic drainage: | |
| Innervation: | Phrenic nerve from C3,4,5 some sensory supply to periphery from lower 6 intercostal nerves |
| Vertebral levels: | |
| Search for Diaphragm in Gray's. | |
For the contraceptive diaphragm see Contraception:Barrier methods.
The diaphragm is the musculotendinous division between the pleural and peritoneal cavities. Embryologically it is formed in part by the septum transversum with contributions from the pleuro-peritoneal mesodermal membranes. It plays an important role in the mechanics of respiration.
Openings
- inferior vena cava at T8
- + terminal branches of right phrenic nerve
- oesophagus at T10 (through right crus)
- also with vagus nerves
- oesophageal branches of left gastric vessels
- lymphatics of lower 1/3 of oesophagus
- aorta at T12 (posterior to median arcuate ligament)
- also with azygos vein and thoracic duct
Other openings
- greater, lesser and least splanchnic nerves pierce crura
- sympathetic trunks pass posterior to medial arcuate ligament
- superior epigastric vessels pass between sternal and costal origins
- left phrenic nerve pierces left dome
- neurovascular bundles of 7th to 11th intercostal spaces pass between muscular slips of costal
