10.04: Zone M2 – Antegonial Notch
YOUR ASSIGNMENT FOR THIS LESSON
✅ Step #1: Review all content below.
✅ Step #2: Image the M2 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 M2
STANDARD M2 ORIENTATION:
TRANSVERSE
Palpate the antegonial notch anterior to the border of the masseter muscle, this is the location of M2.
- First identify anterior border of the masseter muscle as you did at M1. Then roll the probe just off the anterior border of this muscle. Next, adjust your depth to visualize the mandible with will appear as a deep hyperechoic line below the masseter.
- Alternatively simply palpate the antegonial notch anterior to the masseter and place the probe in this location.
- This is a very important vascular region due to the facial artery and vein entering the face at this location. These are generally large caliber facial vessels in this location and easy to locate on doppler.
EXAMPLE OF TRANSVERSE IMAGE ACQUIRED AT M2
ANATOMICAL LEGEND FOR M2 LOCATION IN TRANSVERSE
KEY VESSELS IN THE REGION
DOPPLER IMAGES ACQUIRED AT M2 OF KEY VESSELS
- If you are injecting at any time along the lateral mandible or cheek we suggest scanning M2 to identify the facial artery and attempting to track its course over the region you will be addressing.
- Recall that the facial vein is posterior to the facial artery
- Both these vessels will run within the buccal fat anterior to the masseter muscle at M2.
- At M2 these are large caliber vessels with higher rates of flow, this makes doppler imaging easy. This is a good location to practice doppler ultrasound.