11.03: Zone P1 – Superior Anterior Cheek
YOUR ASSIGNMENT FOR THIS LESSON
✅ Step #1: Review all content below.
✅ Step #2: Image the P1 zone on your own with your ultrasound, and using the checklist provided on this page, check off all key structures to be identified in this location.
TRANSDUCER POSITION AT P1
STANDARD P1 ORIENTATION:
TRANSVERSE
Intersection of Horizontal line from P5 to midpupillary vertical line is the location of P1.
- First identify the periosteum of the maxillary bone. Adjust your depth of penetration accordingly.
- Superficial to the hyperechoic bone you will see a highly hypoechoic linear region. This is actually the oral cavity (between the oral mucosa inside the mouth and the gums.
- Medially you will see a hypoechoic muscle, this is the superior-lateral edge of the orbicularis oris muscle. Lateral to this is another hypoechoic linear muscle which is often the LLS muscle with the zygomaticus minor muscle superimposed on top of it superficially.
EXAMPLE OF TRANSVERSE IMAGE ACQUIRED AT P1
ANATOMICAL LEGEND FOR P1 LOCATION IN TRANSVERSE
EXAMPLE OF TRANSVERSE IMAGE ACQUIRED AT P2
DOPPLER IMAGES ACQUIRED AT P1 OF KEY VESSELS
- The facial artery can often, but not always be found in this position (70% of patients approx.). It will often run reasonably superficial within the superficial nasolabial fat. However, anatomic variants are not uncommon.
- If you are struggling to find the artery identify it at C6 then follow it's course back inferior-laterally to P1.
- If you cannot find the artery look medial to P1 towards P5. In Asians the facial artery is often more medial from P1.