The Philtrum
The anatomical term for the vertical groove on the upper lip just below the nose is the philtrum.
Anatomical Definition
The philtrum is the midline depression that extends from the base of the nose (columella base/nasal spine) down to the upper lip, specifically to Cupid's bow 1. This distinctive facial feature is bounded laterally by two raised ridges known as the philtral columns or philtral ridges 2, 3.
Structural Components
The philtrum consists of three key anatomical elements:
- Philtral dimple (hollow): The central depression itself
- Philtral columns (ridges): The two parallel raised borders on either side of the dimple
- Vascular boundaries: The left and right ascending philtral arteries that branch from the superior labial artery define the lateral borders of the philtrum, coinciding precisely with the location of the philtral columns 2
Underlying Anatomy
The philtrum's characteristic shape results from specific muscular arrangements 4:
- Contralateral deep orbicularis oris muscle fibers cross the philtrum dimple to reach the lateral philtrum ridge
- Superficial reticular muscle fibers from the levator labii superioris, zygomaticus minor, zygomaticus major, and orbicularis oris insert into the medial philtrum ridge
- These intersecting muscle fibers create the distinctive ridges
The philtrum represents a compartmentalized area of superficial fat separated from adjacent lip compartments by membranes and associated vessels 2.
Clinical Significance
The philtrum serves as an important anatomical landmark in facial assessment 1 and is a defining aesthetic feature that governs individual facial characteristics 5. Its proper formation and symmetry are critical considerations in cleft lip repair and other reconstructive procedures 3, 5.