Pierre-Robin Sequence

pierre-robin-sequence

Pierre-Robin Sequence is not a syndrome, it’s a sequence. While it is a collection of features, one happens because of the one that came before.

The features are:

  • Retrognathia/micrognathia (posterior mandible or very small mandible)
  • Glossoptosis (downwards/posterior displacement of the tongue due to the small mandible
  • Airway obstruction (because the tongue is in the way)

Pierre-Robin Sequence is associated with cleft palate (50% of children with the sequence have cleft palate). There are two proposed theories:

  1. The first is that the tongue simply gets in the way of the palate from fusing
  2. The second is that the tongue prevents the newly fused palate from staying fused (this is currently the more popular theory)

PRS, though not a syndrome itself, is associated with multiple syndromes including Stickler Syndrome, velocardiofacial syndrome, fetal alcohol syndrome and Treacher Collins Syndrome.

Teeth (and how to number and name them)

Teeth are pesky things, there are a bunch of them and they all seem to have a bunch of different names. Technically speaking, a full set of adult teeth is 32. However many people end up getting their wisdom teeth taken out, bringing them down to only 28 teeth in total.

There are 4 “types” of teeth

  1. Incisors – 8 in total
  2. Cuspids aka Canines – 4 in total
  3. Bicuspids aka Premolars – 8 in total
  4. Molars – 12 in total (counting the wisdom teeth)

Of course, to say “the 2nd incisor on the top right” is just far too many words to say and write down, so different coding systems were developed to make things snappier. The most commonly used system in North America and the one that’s used by the World Health Organization is the FDI World Dental Federation notation.

The FDI system numbers the 4 quadrants of the mouth, starting at the top-right and going clockwise:

  • 1 = top right
  • 2 = top left
  • 3 = bottom left
  • 4 = bottom right

Each tooth is then numbered starting at the middle and working back:

  • 1 = first incisor
  • 2 = second incisor
  • 3 = cuspid/canine
  • 4 = first bicuspid/premolar
  • 5 = second bicuspid/premolar
  • 6 = first molar
  • 7 = second molar
  • 8 = third molar (wisdom tooth)

Anatomy of the ear

Who knew that the ear could have so many parts to it? This is getting into some detailed anatomy, but you will be able to impress your staff person with your incredible knowledge.

As a side note, you may also be able to impress your local piercer, as most of the more unusual ear piercings are simply named after the bit of ear the hole is going through.

Lip Anatomy

Lip lacerations are kind of a big deal when it comes to facial injuries. It’s because whether we admit it or not, they’re a very important part of the overall cosmetic appearance of the face.

The tricky thing is the vermillion border, which is a fancy term for where the red of the lips meets the rest of the face. The lip is then further divided into the dry vermillion (the part that you put lip stick on, because it’s the part that you can see with the mouth closed) and the wet vermillion (the part that you don’t put lipstick on unless you want it on your teeth).

So when you’re repairing lips, you need to make sure that everything lines up juuuust right. The other important considerations are that unlike fingers, you can’t just pump the lips full of local anesthetic because it will distort the anatomy, this means that a nerve block is preferred. The upper lip receives innervation from the infraorbital nerve (a branch of CNV2) and the lower lip receives innervation from the inferior alveolar nerve (more specifically the mental nerve, which originate from CNV3).

Blood supply comes from the superior and inferior labial arteries (guess which one goes to which lip), which are branches off the facial artery.

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