THE THORAX
THE DIAPHRAGM (Fig. 4. 5) The diaphragm forms the highly convex floor of the thoracic cage. It arises from vertebral, costal and sternal origins and from the central tendon. The vertebral part arises from the crura and arcuate ligaments. The right crus is attached to the bodies and discs
of L 1 - L 3 vertebrae. The smaller left crus arises from the vertebral body and disc of L1 and L2 vertebrae. The medial arcuate ligament is a thickening of the fascia over the psoas muscle from the body of L2 to the transverse process of L1 lumbar vertebrae. The lateral arcuate ligament is a thickening of the fascia over quadratus lumborum
Fig. 4. 5 Diaphragm: (a) view f r o m below showing origin and openings; (b) crura and arcuate ligaments; (courtesy of Professor J. B. Coakley); (c) crura of the diaphragm as seen on axial and (d) coronal MRI.
1. Right crus of diaphragm
4. Aorta
7. Pedicle
2. Left crus of diaphragm
5. Vertebral body
8. Lamina
3. IVC
6. Spinal cord
9. Psoas muscle
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