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11.09: Zone Lips – Upper & Lower

YOUR ASSIGNMENT FOR THIS LESSON

✅ Step #1: Review all content below.

✅ Step #2: Image the upper and lower lip 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 FOR THE LIPS

Note: Clip has been sped up

STANDARD LIP ORIENTATION:
TRANSVERSE & LONGITUDINAL

Scan along entire vermillion portion of the lips, including vermillion border running from both commissures through the midline. When scanning transverse, scan the upper and lower lips separately.

The P Zones and Relevant Landmarks
QUICK TIP
  • Because of the irregular contour of the lips, it is recommended to use a generous amount of ultrasound gel when imaging this location.
    • Instruct the patient to keep their lips closed without pressing them together with force. The mouth should be closed in a natural manner. Inform the patient in advance that they may get some ultrasound gel in their mouth; however, if this occurs, reassure them that the gel will not harm them.
  • When imaging the lips, you will notice three separate layers.
    • Most superficially, you will observe the dermal layer with its subcutaneous tissue. This layer often has a somewhat isoechoic appearance.
    • Deep to this layer, you will notice a hypoechoic linear structure. Depending on the angle of your probe and its position on the lips, you may see a single hypoechoic linear structure or two matching hypoechoic lines. If you see multiple structures, note that this is still a single muscle—the orbicularis oris muscle.
      • As this muscle moves through the lips, it curls in on itself towards the wet-dry border of the lip. The portion located at the wet-dry border is known as the pars marginalis, whereas the remainder of the muscle you will image in the lips is known as the pars peripherals. (SEE ANATOMY DIAGRAM BELOW)
    • Deep to the orbicularis oris muscle, there will be another, often more hyperechoic, layer of tissue associated with the oral mucosa.
      • Within this layer, you may see some small hypoechoic, circular structures, which are glands associated with the mucosa of the lips. Beaware, that on occasion, these glands can be misconstrued as dermal filler. 
    • Deep to the oral mucosa, you will see linear, highly hyperechoic structures that have an appearance similar to bone. These are the teeth inside the mouth.

EXAMPLE OF TRANSVERSE IMAGE ACQUIRED OF UPPER LIP

Standard image acquired of upper lip at midline. (Transverse| Left side is patient's left lateral). See key below for lables.*

ANATOMICAL LEGEND UPPER LIP IN TRANSVERSE

*Standard image acquired of upper lip labeled with key anatomical structures.

EXAMPLE OF TRANSVERSE IMAGE ACQUIRED OF LOWER LIP

Standard image acquired of lower lip at midline. (Transverse| Left side is patient's left lateral). See key below for lables.*

ANATOMICAL LEGEND LOWER LIP IN TRANSVERSE

*Standard image acquired of lower lip labeled with key anatomical structures.

EXAMPLE OF LONGITUDINAL IMAGE ACQUIRED OF UPPER & LOWER LIPS

Standard image acquired upper and lower lips at midline. (Longitudinal | Left side is deep). See key below for lables.*

ANATOMICAL LEGEND FOR UPPER & LOWER LIPS IN LONGITUDINAL

*Standard image acquired of upper and lower lips labeled with key anatomical structures.
Lips in longitudinal cossection. Note the two parts of the ob.oris muscle.

DOPPLER IMAGES ACQUIRED AT LIPS OF KEY VESSELS

There is a lot of anatomical variation in the position of the superior and inferior labial arteries. Traditionally in textbooks they are found deep to the ob. oris. muscle. However, in a large minority you will see the artery run between the pars of the muscle or even superfical to the pars marginalis. This diagram shows the probality of the artery existing in these three locations.

UPPER LIP (TRANSVERSE VIEW)

LOWER LIP (TRANSVERSE VIEW)

UPPER & LOWER LIP (LONGITUDINAL VIEW)

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  • Generally, the superior and inferior labial arteries are not challenging to visualize. However, in patients with thinner and smaller lips, they can occasionally be more difficult to see than anticipated. 
  • The labial artery has a tortuous course. Because of this, you will not often be able to visualize large segments of the artery in a single ultrasound image. You will need to angle the probe as you move and scan over the lips in order to appreciate all the various tortuous segments of this artery. 
    • As the labial arteries course through the lips they often penetrate the ob. oris muscle before plunging again more deeply below the muscle.
  • There is a significant degree of anatomical variation in the course of the labial arteries. This is important to know and is one of the major utilities of scanning the lips prior to performing any dermal filler injections in this region. By doing this, you will be able to identify the anatomical variants and better appreciate the risks posed by this vascular structure in your particular patient.
    • In approximately 70% of patients, the labial arteries will course primarily deep to the orbicularis oris muscle.
    • However, this means that in approximately 30% of patients, the artery will be located primarily in a different location! This runs contrary to the traditional teaching often provided to injectors when learning how to inject this region.
    •  The labial artery is more likely to be more superficial in the lower lip than in the upper lip. In approximately 30% of patients, the artery will primarily run between the pars marginalis and pars peripherals of the orbicularis oris muscle in the lower lip.
    • See this diagram for more details.

DO IT YOURSELF CHECKLIST

Structures to Identify on Ultrasound for Upper & Lower Lips

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