architecture( Glisson's triad) indicating vascular inflow, outflow, and biliary drainag [9; 10)1. Because of this division into self-contained units, each can be resected (alone or in groups) without damaging those remaining as the vascular inflow, outflow and biliary drainage is preserved. Depending on the 3D volume orientation of the liver (longitudinal or oblique orientated) interpretation of Couinaud classification unfortunately finds some inconsistency in literature. While the portal vein plane has often been described as transverse, it may be oblique since the left branch runs superiorly and the right branch runs inferiorly. In addition to forming an oblique transverse plane between segments, the left and right portal veins branch superiorly and inferiorly to project into the centre of each segment Ultrasound Examination technique Patient Preparation It is recommended that a patient undergo a period of fasting prior to upper abdominal imaging to maximise the distension of the gall bladder and to reduce food residue and gas in the upper GI tract which may reduce image quality or precluded liver imaging This is essential for full imaging of the liver and related biliary tree but may not be required in an acute situation such as trauma where imaging of the gall bladder is not immediately essential. a patient may take small amounts of still water by mouth prior to scan, particularly for taking any medications. There is some evidence that smoking can reduce image quality when scanning upper abdominal structures and it is good practice to encourage a patient not to smoke for 6-8 hours prior to US scan. Smoking increases gas intake into upper GI tract and may reduce image quality. Also, some chemicals in tobacco are known to cause contraction of the smooth muscle of the gi tract and this can cause contraction of the gall bladder, even when fasting has occurred, and the gall bladder cannot be scanned E The liver is a large, pyramidal shaped organ and liver sectional anatomy may be best described imaged and defined using by real time ultrasound imaging. Conventional eal time ultrasound produces images of thin slices of the liver on the screen, and so it is essential that the operator scans the entire organ systematically/ritually, in at least two anatomical planes, to be entirely convinced that the entire volume of the liver tissue and structures has been imaged. The operator must then synthesise this 2 dimensional information in their brain to develop a 3 dimensional map of the individual patients liver anatomy and pathology. This requires good hand-eye-brain coordination For orientation, three levels of the central portion of the liver can be differentiated Level of the Confluences of the liver veins [Figure 1] Level of the Pars umbilicalis of the(left) portal vein branch [Figure 2] Level of the gall bladder Figure 3 Figure 1 Confluences of the liver veins. This "junction" level is the first one in ultrasound examination of the right liver lobe by subcostal scanning sections steeply looking"upwards, preferably in deep inspiration [video]. VCI: inferior vena cava. LLV: Left liver vein. MLV. Middle liver vein. C: Confluens of the llv and MLV RLV: Right liver vein. The rlv often separately joins the inferiorarchitecture (Glisson`s triad) indicating vascular inflow, outflow, and biliary drainage [(9;10)]. Because of this division into self-contained units, each can be resected (alone or in groups) without damaging those remaining as the vascular inflow, outflow and biliary drainage is preserved. Depending on the 3D volume orientation of the liver (longitudinal or oblique orientated) interpretation of Couinaud classification unfortunately finds some inconsistency in literature. While the portal vein plane has often been described as transverse, it may be oblique since the left branch runs superiorly and the right branch runs inferiorly. In addition to forming an oblique transverse plane between segments, the left and right portal veins branch superiorly and inferiorly to project into the centre of each segment. Ultrasound Examination technique Patient Preparation It is recommended that a patient undergo a period of fasting prior to upper abdominal imaging to maximise the distension of the gall bladder and to reduce food residue and gas in the upper GI tract which may reduce image quality or precluded liver imaging. This is essential for full imaging of the liver and related biliary tree but may not be required in an acute situation such as trauma where imaging of the gall bladder is not immediately essential. A patient may take small amounts of still water by mouth prior to scan, particularly for taking any medications. There is some evidence that smoking can reduce image quality when scanning upper abdominal structures and it is good practice to encourage a patient not to smoke for 6-8 hours prior to US scan. Smoking increases gas intake into upper GI tract and may reduce image quality. Also, some chemicals in tobacco are known to cause contraction of the smooth muscle of the GI tract and this can cause contraction of the gall bladder, even when fasting has occurred, and the gall bladder cannot be scanned. Examination The liver is a large, pyramidal shaped organ and liver sectional anatomy may be best described imaged and defined using by real time ultrasound imaging. Conventional real time ultrasound produces images of thin slices of the liver on the screen, and so it is essential that the operator scans the entire organ systematically/ritually, in at least two anatomical planes, to be entirely convinced that the entire volume of the liver tissue and structures has been imaged. The operator must then synthesise this 2 dimensional information in their brain to develop a 3 dimensional map of the individual patient`s liver anatomy and pathology. This requires good hand-eye-brain coordination. For orientation, three levels of the central portion of the liver can be differentiated: • Level of the Confluences of the liver veins [Figure 1]. • Level of the Pars umbilicalis of the (left) portal vein branch [Figure 2]. • Level of the gall bladder [Figure 3]. Figure 1 Confluences of the liver veins. This “junction” level is the first one in ultrasound examination of the right liver lobe by subcostal scanning sections steeply “looking” upwards, preferably in deep inspiration [video]. VCI: inferior vena cava. LLV: Left liver vein. MLV: Middle liver vein. C: Confluens of the LLV and MLV. RLV: Right liver vein. The RLV often separately joins the inferior