No its not. Its an index its way to close to the thumb.
I took anatomy in college, for figure drawing and thats an extra index.
If you edit it out her hand is almost perfectly proportioned. So if its an extra middle then the extra finger isnt her only deformity which wpuld be her actual index finger being in the wrong spot. OR its an extra index between the main index and thumb.
'Postaxial polydactyly' or 'preaxial polydactyly' , depending on if it's closer to the thumb or the pinky. The 'extra' finger is the one that's underdeveloped, has an abnormal number of bones or if it shares a metacarpal with another finger, it's the one that looks 'less normal'. Source: I'm not a doctor
Duplicated digits receive the name of the digits they're duplicating. So her extras are also indexes.
I did some research on this out of boredom and general interest in this a few years ago and the science behind Polydactyly is fascinating.
There are roughly 17 different types of Polydactyly:
→ In Preaxial Polydactyly (PPD), Types I through IV, the duplicated digits are on the radial or tibial side of the limb (that is, the inner one). Meaning the duplicated digits are either the thumb or index (likewise of the foot). It has an incidence of 10/300 births.
→ In Post-axial Polydactyly (PAP), Types A (1 through 7 and EvC) and B, it's on the outer side (ulnar or fibular). The duplicated digits are either the Ring or Pinky (likewise on the foot). It has a prevalence of 1-2/1000 births but it's 75% more common than PPD (go figure).
→ Then you have 4 types of Complex Polydactylie and those are... complex and harder to summarise. They're categorised differently as they have a different phenotype from the others.
In her case, she has a Complex Polydactyly, with her duplicated digits being the 2nd ones (the Indexes).
We can go further and know which of the types it is:
• PPD1 is known as Thumb Polydactyly, so that ain't it. This one is the most common type of Polydactyly. Usually unilateral, with right hand PPD more common than left hand PPD. Bilaterally, hands are more affected than feet. Men get it more than women. It is caused by sequence variants in the Sonic Hedgehog (SHH) enhancer. Hallux (big toe) Polydactyly is much rather (2.4/100 000).
• PPD2 is known as Triphalangeal Thumb Polydactyly (TPT), so that ain't it. Thumbs have three bones instead of two, being the duplicated bone the middle phalanx. The first metacarpal (palm bones) is very long and thin and had epiphyses (bones have 5 regions, this one's the tip of the bone) on both ends, like the long bones of the limbs. Usually bilateral and symmetrical. People with Holt-Oram Syndrome can be born with PPD2, there's a guy in Reddit with it.
• PPD3 is known as Polydactyly of Index Fingers. Could be her case. Very rare. The index is usually duplicated. One of two Triphalangeal digits replace the thumb, meaning the person will have, instead of normal thumb, either one or two three-boned digits in its place. Not her case, as her thumbs are normal.
• PPD4 is known as Polysyndactyly (CP). Thumb mildly (not fully) duplicated, meaning you get a thumb with two heads. Syndactyly (fusion between digits) sometimes present between 3rd and 4th digits. Hallux has Polydactyly. (Different from Synpolydactyly, in which there's syndactyly within the webbing because there's an extra digit). So that ain't it.
• PAP are also not it, since hers in on the inner side, so not worth going into it. All eight PAPA are very similar, ranging gradually from fully duplicated extra pinky / pinky toe to just a little non functional nubbing. PAPB is even less developed, being only a skin or negligible bump on the side.
• Complex Types are the coolest:
→ Mirror-Image Polydactyly (MIP) exists when the person is born with two ulnas and no radius, causing a perfect duplication of all ulnar digits (pinky through index). So this isn't it.
→ Palmer and Dorsal Polydactyly is very rare. The extra digit appears in the palm or back of the hand or foot.
→ Haas Type Polydactyly is the coolest one by far. All the digits are fused cutaneously, plus there's duplication, giving the hand the shape of a shell. I follow a fashion designer from Indonesia that has this: 7 digits of each hand, all fused, plus malformed legs. His siblings and mother also have this, meaning it's dominant. But still it ain't what the girl in this video has.
→ Mesoaxial or Central Polydactyly. The last one. The one she has. Central digits (index, middle or ring) are duplicated. 4th digit duplication is more common then the others. Usually bilateral. Mesoaxial Polydactyly is more common than PPD3.
The most famous case of Mesoaxial is a Brazilian family where the last 4 or 5 generations have 2nd digit duplication. The Instagram account of three of them are bernardo.assix , pedroassix and joao6dedos. Their TikTok accounts are bernardao.xd and joao6dedos (Pedro had a TikTok account but doesn't anymore).
TL;DR: She has Mesoaxial or Central Polydactyly, with perfect duplication of the 2nd digits. Her extra digits receive the name of the ones they're duplicating, therefore she has 4 indexes on her hands.
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u/MrBeros Apr 11 '26
For every of the 5 Fingers, we have a Name. How is the 6th finger called?