Prezygomatic space: anatomy of the midface
- Nerve
- Highlighted area
Quick facts
- Definition
- A triangular gliding space over the body of the zygomatic bone, beneath the orbicularis oculi muscle.
- Upper boundary
- Orbicularis retaining ligament, at the level of the lower orbital rim.
- Lower boundary
- Zygomatic (zygomatico-cutaneous) ligaments, in the lower part of the cheekbone area.
- Contents
- Practically no important structures inside; nerves and vessels lie at the borders.
- Relevance in HOF
- Linked to malar bags (festoon and malar mound) and to persistent malar edema.
The prezygomatic space is a triangular gliding space located over the body of the zygomatic bone, beneath the orbital portion of the orbicularis oculi muscle. It is bounded above by the orbicularis retaining ligament and below by the zygomatic ligaments. This space lets the orbicularis glide over the bone when blinking and smiling, and it is where malar bags, also called festoons, form.
Where is it and what are its boundaries?
| Boundary | Structure | What to look for |
|---|---|---|
| Superior | Orbicularis retaining ligament | Usually coincides with the palpebromalar groove |
| Inferior | Zygomatic (zygomatico-cutaneous) ligaments | Base of the malar bag; barrier to fluid drainage |
| Roof | Orbicularis oculi muscle, orbital portion | Becomes looser with age |
| Floor | Pre-periosteal fat and periosteum of the zygoma, with the origin of the lip elevator muscles | Plane next to the bone |
The SOOF, the fat beneath the orbicularis, sits next to the roof of the space, just below the orbicularis retaining ligament. The zygomatic branches of the facial nerve and the zygomaticofacial vessels pass along the borders and the floor, not through the interior of the space.
What are a festoon and a malar mound?
With aging, the roof of the space (orbicularis and skin) loses firmness and the ligaments that bound it become more evident. Two findings then appear:
- Malar mound (malar bag): a rise in the upper cheek, above the zygomatic ligaments, usually with an edema component.
- Festoon: a hanging fold of lax skin and muscle over the same area, which can have several "steps".
Both get worse with fluid retention, salt, allergies, poor sleep and chronic sun exposure. The assessment is in malar bags: assessment.
Why does it matter in HOF?
- Persistent edema: fluid that builds up in this space tends to get trapped above the zygomatic ligaments, which explains malar swelling that is slow to resolve. The topic is covered in swelling.
- Planning the cheekbone and the tear trough: in someone who already has a malar bag or festoon, volume in the area is usually considered more cautiously, because it can accentuate the bag or the edema.
- Differential for the tear trough: separating depression (lack of volume) from excess (bag, festoon, eyelid fat) changes the whole indication.
How does it show up in the assessment?
- Light from above and an oblique view: show the bag and the step at the ligaments.
- Variation through the day: a bag that is worse in the morning suggests an edema component.
- Smile test: the festoon usually rises and folds when smiling.
Also called: prezygomatic space, malar mound space.
Frequently asked questions
What is a festoon?
It is the name given to a hanging bag or fold in the upper cheek, below the lower eyelid, linked to laxity of the orbicularis oculi and of the tissues over the prezygomatic space. Unlike a tear trough caused by depression, it is an excess that worsens with swelling.
Why does malar edema take so long to go away?
Edema in the region of the prezygomatic space tends to get trapped above the zygomatic ligaments, which act as a barrier to drainage. That is why malar swelling can persist longer than in other areas of the face.