11.08: Zone P6 – Pogonion of Chin
YOUR ASSIGNMENT FOR THIS LESSON
✅ Step #1: Review all content below.
✅ Step #2: Image the P6 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 P6
STANDARD P6 ORIENTATION:
TRANSVERSE
Pogonion (most anterior projecting part of chin) along midline of face is the location of P6
- Identify the hyperechoic mandible deep in the P6. It will often have an arced appearance here on the midline. Adjust your depth of penetration to position this structure at the bottom of your screen.
- The mentalis is highly variable in its anatomy, over 50% of people will have anatomical variations of this muscle. See diagram below.
- Under standing these variation will allow you to better plan your neuromodular injections of this muscle.
- The mentalis muscle will be hypoechoic and be best visible deep to the subcutaneous layer. Often it will have a wispy appearance, especially if it is a Type B variant.
- Type B variants may be difficult to distinguish from the subcutaneous layer under ultrasound.
EXAMPLE OF TRANSVERSE IMAGE ACQUIRED AT P6
ANATOMICAL LEGEND FOR P6 LOCATION IN TRANSVERSE
DOPPLER IMAGES ACQUIRED AT P6 OF KEY VESSELS
- It can be very challenging to detect vessels in this region which are generally branches of the inferior labial and submental vessels. They are small with slow flow. In many cases identifying these vessels will not be possible at P6.
- Using power doppler can be useful here due to slower blood flow associated with these small vessels.
- Use lots of gel, it is easy to compress these vessels with the transducer which makes them harder to detect. The gel acts as a buffer alleviating pressure placed on these tissues.
- The branches will be superficial to the mentalis in the subcutaneous layer.