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9.08: Zone C6 – Inferior Medial Region

YOUR ASSIGNMENT FOR THIS LESSON

✅ Step #1: Review all content below.

✅ Step #2: Image the C6 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 C6

Note: Clip is sped up.

STANDARD C6 ORIENTATION:
TRANSVERSE

The intersection of the vertical line from medial canthus to the horizontal line from the inferior alar groove is the location of C6.

EXAMPLE OF TRANSVERSE IMAGE ACQUIRED AT C6

Standard image acquired at C6. (Transverse | Left side is patient's midline). See key below for lables.*
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  • In most patients, you will need to increase your depth of penetration here to about 2cm. Make sure you can visualize to the maxillary bone.
  • It can be very difficult to distinguish the LLS and LLSAN muscles from the deep medial cheek fat. Having the patient smile and visualizing contraction can help distinguish muscles from surrounding tissue.
  • You need to fill the alar grove with gel! Otherwise, the air in this space will compromise your ability to obtain good images in this area. Like all zones involving the nose, more gel is better!
  • Three important muscles are stacked here, from superficial to deep; you will see the LLSAN, LLS, and then the alar portion of the nasalis above the maxillary bone.

ANATOMICAL LEGEND FOR C6 LOCATION IN TRANSVERSE

*Standard image acquired at C6 labeled with key anatomical structures.
Superficial Fat Compartments
Deep Fat Compartments

KEY VESSELS IN THE REGION

Note: There is sig. variability in the depth of the angular artery at C6. Between 5-10% of patients will have the angular artery deep to the LLSAN muscle, at times it can be nearly at the level of the bone!

DOPPLER IMAGES ACQUIRED AT C6 OF KEY VESSELS

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  • In C6, it is critical to identify the angular artery if you are performing injections into the piriform fossa. This is because of significant variability in its depth. Between 5% and 10% of patients have this artery deep rather than superficial at the level of the LLSAN.
  • If you glide superiorly towards C3, you often can detect a branch medial to the angular artery moving towards the alar aspect of the nose, the lateral nasal artery. 
  • If you glide lateral from C6, you will often detect the angular vein. 
  • If you are struggling to detect these vessels, try more gel and a lighter touch with the probe.

DO IT YOURSELF CHECKLIST

Structures to Identify on Ultrasound for C6

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