Key structures that may be visible in the nasal zones:
ZONE
POSSIBLE KEY ANATOMY*
P1 Intersection of horizontal line from P5 to midpupillary vertical line
Orbicularis oris m.
Zygomaticus major m.
Facial a.
P2 Intersection of the vertical line from midpupillary to the horizontal line from the lateral commissure of the lips
Orbicularis oris m.
DAO m.
Buccinator m.
Facial a.
Buccal fat pad
Superior labial a.
P3 Intersection of the vertical line from midpupillary to the horizontal line from the mentolabial crease
Orbicularis oris m.
DAO m.
DLI m.
Platysma m.
Inferior labial a.
P4 Intersection of the vertical line from midpupillary to the horizontal line from the mentolabial crease
Orbicularis oris m.
DAO m.
DLI m.
Inferior labial a.
P5 Midway between sub-nasal septum and upper vermillion border on midline of face
Orbicularis oris m.
Depressor septi nasi m.
Columellar a.
P6 Pogonion (most anterior projecting part of chin) along midline of face
Mentalis m.
Submental a.
Lip Upper & Lip Lower Upper and lower lips from lateral commissure to midline
Orbicularis oris m.
Superior labial a. (upper lip)
Inferior labial a. (lower lip)
*The structures that can be identified in each zone are subject to variation based on probe footprint, resolution and individual anatomical variability.