Table 1:

The delineation of the internal jugular and collateral vessels shown for both positions

Volunteer	Supine				Sitting
Volunteer	IJV	EJV	VP	NV	IJV	EJV	VP	NV
1	+	+	–	+	–	+	+	+
2	+	+	–	–	–	+	+	+
3	+	+	+	+	–	–	+	+
4	+	–	+	+	+	+	+	–
5	+	+	+	–	+	–	+	+
6	+	+	–	+	(+)	–	+	+
7	+	–	+	+	+	–	+	+
8	+	+	–	–	+	–	–	+
9	+	+	–	–	(+)	–	+	–
10	+	+	–	+	+	+	+	+
11	+	+	–	+	+	–	–	+
12	+	+	–	–	(+)	–	+	–
13	+	+	+	–	(+)	–	+	+
14	+	+	–	–	(+)	–	+	+
15	+	+	–	–	(+)	–	+	+

Note: + indicates vessel delineated; –, vessel not delineated; in parentheses, delineation of the IJV only on 1 side.