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5.07: Zone F5 – Medial Canthal Line

YOUR ASSIGNMENT FOR THIS LESSON

✅ Step #1: Review all content below.

✅ Step #2: Image the F5 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 F5

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STANDARD F5 ORIENTATION:
TRANSVERSE

Locate this zone by drawing a vertical line from the medial canthus which ends 1-3 cm superior to the bone of the orbital rim, at this point is F5.

QUICK TIP
  • Similar to other zones in the forehead, make sure you decrease your depth of penetration here, as the tissues examined are shallow.
  • Examination of this zone often involves carefully scanning superiorly and inferiorly 1-2 cm. As you move inferiorly, you may notice another superficial hypoechoic region above the frontalis, which is the orbicularis oculi m.

EXAMPLE OF IMAGE ACQUIRED AT F5

Standard image acquired at F5. See key below for lables.*

ANATOMICAL LEGEND FOR F5 LOCATION

*Standard image acquired at F5 labeled with key anatomical structures.

KEY VESSELS IMAGED AT F5

Key vascular anatomy at F5 is the supratrochlear a. and its transition from deep to superfical relative to the frontalis m.

DOPPLER IMAGE ACQUIRED AT F5 OF KEY VESSELS

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QUICK TIP
  • As you scan inferior from F5, you should look deep for the supratrochlear a. If you find it deep to the frontalis m., follow it until you note it is transitioning the frontalis m. to run superficial as it courses more superiorly. This transition point is an important landmark for any forehead injectable treatments!
  • It can still be very hard and sometimes simply impossible to image vessels at F5. If you do see vessels here, then it is helpful clinical information. It does not preclude their presence in the imaged region if you do not see them.
  • I suggest increasing your doppler sensitivity to 1.8-2.5 cm/s. Just be aware that this will increase the chance of motion artifacts.
    • Alternatively, this is a good location to use power Doppler.

DO IT YOURSELF CHECKLIST

Structures to Identify on Ultrasound for F5

Once you have completed this checklist, mark this part of the lesson as complete.