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# Quadratus plantae

The quadratus plantae is a flat muscle in the sole that pulls on the long toe-flexor tendon to straighten its pull on the toes.

Official name: Quadratus plantae muscle

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## What it is

A flat, square muscle of the sole, from the heel bone to the long toe-flexor tendon.

## What it does

Pulls on the flexor digitorum longus tendon so the toes curl straight instead of at an angle.

## Key points

- Second layer of the sole, with the flexor digitorum longus tendons and the lumbricals; supplied by the lateral plantar nerve
- The lateral plantar nerve and artery cross the sole obliquely between it and flexor digitorum brevis
- Baxter's nerve (first branch of the lateral plantar nerve) passes between its medial head and abductor hallucis, a site of entrapment in heel pain

## Key facts

**Origin**
Medial surface and lateral margin of plantar calcaneus (two heads)

**Insertion**
Posterolateral margin of flexor digitorum longus tendon

**Action**
Assists flexor digitorum longus in flexing toes 2–5; straightens its oblique pull

**Nerve**
Lateral plantar nerve (S2–S3)

**Blood supply**
Medial and lateral [plantar arteries](https://durgical.com/en/anatomy/medial-plantar-artery/)

## Relations

**Superficial**
[Flexor digitorum brevis](https://durgical.com/en/anatomy/flexor-digitorum-brevis/), with the [lateral plantar nerve](https://durgical.com/en/anatomy/lateral-plantar-nerve/) and vessels running between them

**Deep**
Plantar surface of the [calcaneus](https://durgical.com/en/anatomy/calcaneus/) and the [long plantar ligament](https://durgical.com/en/anatomy/long-plantar-ligament/)

**Medial**
[Abductor hallucis](https://durgical.com/en/anatomy/abductor-hallucis/); the plantar nerves and vessels enter the sole along its medial edge

**In front**
The [flexor digitorum longus](https://durgical.com/en/anatomy/flexor-digitorum-longus/) tendon where it divides, with the lumbricals arising just beyond

## How to find it

It cannot be felt. In dissection it appears under flexor digitorum brevis; on MRI it lies on the underside of the calcaneus and joins the flexor digitorum longus tendon in the midfoot.

## On imaging

Not seen on radiographs. MRI or ultrasound shows it in the second layer of the sole, running from the calcaneus to the flexor digitorum longus tendon. It is a landmark for Baxter's nerve, which passes between it and abductor hallucis; in suspected entrapment, MRI looks for oedema or fatty atrophy of abductor digiti minimi.

## Common problems

- Like the other small muscles of the foot, it can weaken with age, nerve problems or tight shoes, which can let the arch drop or the toes change shape.

## Clinical notes

- Baxter's nerve entrapment: chronic medial heel pain that mimics plantar fasciitis, sometimes with wasting of abductor digiti minimi
- In medial approaches to the heel, the lateral plantar neurovascular bundle lies on its superficial surface

## Anatomical variants

- Its lateral head is small or absent in some people

## Test yourself

Think of the answer, then tap the question to see it.

## What are the origin, insertion and nerve supply of the quadratus plantae?

Two heads from the plantar calcaneus, to the posterolateral margin of the flexor digitorum longus tendon; lateral plantar nerve.

## What is the action of the quadratus plantae?

It assists the flexor digitorum longus in flexing toes 2–5 and straightens its oblique pull, so the toes curl straight.

## Which nerve runs between the quadratus plantae and the flexor digitorum brevis?

The lateral plantar nerve, with the lateral plantar artery, crossing the sole obliquely.

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Educational information, not medical advice. For any symptom, see a health professional.

## Its names

**Official Latin (TA2)**
musculus quadratus plantae TA2 2684

**Official Spanish (DeCS)**
Músculo cuadrado plantar

**English (TA2)**
Quadratus plantae muscle

**Also called**
flexor accessorius muscle · musculus flexor accessorius

## Related

- [Lateral plantar nerve](https://durgical.com/en/anatomy/lateral-plantar-nerve/)
- [Toe flexor tendon](https://durgical.com/en/anatomy/tendon-of-flexor-digitorum-longus/)
- [Flexor digitorum brevis](https://durgical.com/en/anatomy/flexor-digitorum-brevis/)
- [Plantar arteries](https://durgical.com/en/anatomy/medial-plantar-artery/)
- [Calcaneus](https://durgical.com/en/anatomy/calcaneus/)

Sources: Terminologia Anatomica (TA2); [Anatomy, Bony Pelvis and Lower Limb, Foot Muscles](https://www.ncbi.nlm.nih.gov/books/NBK539705/).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/anatomy/quadratus-plantae-muscle/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/quadratus-plantae-muscle/