The supine position (pron.: //) is a position of the body: lying down with the face up, as opposed to the prone position, which is face down, sometimes with the hands behind the head or neck. When used in surgical procedures, it allows access to the peritoneal, thoracic and pericardial regions; as well as the head, neck and extremities.
Using terms defined in the anatomical position, the dorsal side is down, and the ventral side is up.
In scientific literature "semi-supine" commonly refers to positions where the upper body is tilted (at 45° or variations) and not horizontal. In the Alexander technique semi-supine position, the knees are raised bent upward while the soles of the feet and the upper body remain in contact with the horizontal surface.
See also 
- Rothrock, J. C. (2007) Alexander's Care of the Patient in Surgery 13th Ed. Mobsy Elsevier: St Louis, Missouri. p. 148.
- Petropoulou, E; Lancellotti, P; Piérard, LA. (2006) "Quantitative analysis of semi-supine exercise echocardiography--influence of age on myocardial Doppler imaging indices." Acta Cardiol. 2006 Jun;61(3):271-7