Table 1. Classification of dysbaric osteonecrosis lesions (after the United Kingdon Medical Research Council). * = classification of the present case .

Lesion	Subtype	Comments
A type lesions Juxta-articular:	A1 Dense area with intact articular cortex	Prevalence of A lesions:
	A2 Spherical opacities
	A3 Linear opacities	Tunnellers and saturation divers
	A4 Structural failures	Femur > Humerus
	- Translucent subcortical bands
	- Collapse of articular cortex
	- Sequestration of cortex*	Other divers
	A5 Secondary degenerative osteoarthritis	Humerus > Femur
B type lesions Shaft	B1 Dense areas
	B2 Irregular calcified areas	n/a
	B3 Translucent and cystic areas