Anatomy study note · Thorax

Diaphragm

A dome-shaped sheet of muscle and tendon separating the thoracic and abdominal cavities. It is the most important muscle of inspiration.

Key points

• Main muscle of inspiration; phrenic nerve C3, 4, 5.
• Openings: IVC T8, oesophagus T10, aorta T12.
• Right dome higher (liver): upper border of rib 5.
• Right crus L1–3; left crus L1–2.
• Paralysed half rises. Central irritation → shoulder-tip pain.
• From septum transversum, pleuroperitoneal membranes, dorsal mesentery.
• Posterolateral hernia: pleuroperitoneal canal stays open.
• Crura: posterior abdominal wall mesoderm.
• Skeletal muscle: multinucleated, peripheral nuclei, striated.
• Epimysium → perimysium → endomysium.

The full note in the atlas also covers

Features · Origin · Insertion · Action · Nerve supply · Histology · Development · Clinical notes

Sign in free to see it on the 3D model, read the full note and practise questions on it.

Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 4, PDF pp. 494, 496–503; ch. 3, PDF p. 342
• Inderbir Singh’s Human Embryology, ch. 14, PDF pp. 221–224
• BRS Cell Biology & Histology, 7th ed., ch. 8, PDF pp. 135–144

More from the thorax

• Esophagus
• First rib
• Heart
• Intercostal arteries
• Intercostal muscles
• Intercostal nerves
• Internal thoracic artery
• Internal thoracic vein
• Interventricular septum
• Joints of the ribs
• Left atrium
• Left coronary artery

Privacy policy · Designed by DATXOC LLC.