9.03: Zone C1 – Superior Lateral Region
YOUR ASSIGNMENT FOR THIS LESSON
✅ Step #1: Review all content below.
✅ Step #2: Image the C1 zone on your own with your ultrasond, and using the checklist provided on this page, check off all key structures to be identified in this location.
TRANSDUCER POSITION AT C1
STANDARD C1 ORIENTATION:
TRANSVERSE & LONGITUDINAL
The intersection of the vertical line from lateral canthus to the horizontal line from the superior alar groove is the location of C1.
- First identify the periosteum. Then attempt to identify the layers of tissue to be seen.
- There are muscles and fat to be seen at C1. Below the dermis you will see the superficial medial cheek fat, below this will run the obicularis oculi muscle. Directly under this muscle is the fat of the SOOF.
- A hypoechoic region often in contact with the bone at C1 will be the zygomaticus major muscle.
- If you slightly angulate the probe while in longitudinal, you will be in the same plane as the zygomaticus minor muscle and you will be able to identify more of it.
EXAMPLE OF TRANSVERSE IMAGE ACQUIRED AT C1
ANATOMICAL LEGEND FOR C1 LOCATION IN TRANSVERSE
EXAMPLE OF LONGITUDINAL IMAGE ACQUIRED AT C1
ANATOMICAL LEGEND FOR C1 LOCATION IN LONGITUDINAL
DOPPLER IMAGES ACQUIRED AT C1 OF KEY VESSELS
- There are few vessels in this area relative to most other regions of the face. If you do identify Doppler flow, it is likely a superficial perforator vessel.
- These vessels have slower flow. Power doppler can be useful here, also if using color doppler turn your sensitivity to 2cm/s to detect the slower flow. Just be mindful of motion artifacts.
- These vessels will be superficial and travel in the superficial fat.