Pinpoint
Muscles/Foot

Foot

flexor accessorius

FLEK-sor ak-seh-SOR-ee-us

Flexor accessorius (quadratus plantae) is a flat muscle in the sole of the foot that assists flexing the lateral toes. It aligns toe flexors for even toe curl in gripping surfaces. Useful for climbers and martial artists needing foot grip.

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Common Pain & Injury

Deep heel or midfoot ache, cramping with push-off. Rare strain. See doc for plantar pain radiation.

Anatomy & Function

Origin

Medial and lateral plantar surfaces of calcaneus (heel bone).

Insertion

Tendons of flexor digitorum longus (lateral toe flexors).

Actions

  • Flexion of lateral toes (toe curl)
  • Assists long flexor alignment

Innervation

Lateral plantar nerve (S1-S2).

Muscle Relationships

Antagonists

Extensor digitorum longus

Synergists

Flexor digitorum brevisLumbricals

Trigger Points

Under arch; refers to heel and toes.

Stretches

1Plantar fascia roll
2Deep toe flexor stretch

Common Conditions

Quadratus plantae strainPlantar fasciitis mimic

Anatomical Parts

Left flexor accessoriusRight flexor accessorius

FAQ

Flexor accessorius foot?

Helps curl toes straight for powerful foot grip.

Quadratus plantae pain?

Deep sole pain; massage and arch support.

Exercises for flexor accessorius

20
Ankle Circles position 1
Ankle Circles position 2

Ankle Circles

beginner
Anterior Tibialis-SMR position 1
Anterior Tibialis-SMR position 2

Anterior Tibialis-SMR

intermediate·other
Balance Board position 1
Balance Board position 2

Balance Board

beginner·other
Barbell Seated Calf Raise position 1
Barbell Seated Calf Raise position 2

Barbell Seated Calf Raise

beginner·barbell
Calf Press position 1
Calf Press position 2

Calf Press

beginner·machine
Calf Press On The Leg Press Machine position 1
Calf Press On The Leg Press Machine position 2

Calf Press On The Leg Press Machine

beginner·machine
Calf Raise On A Dumbbell position 1
Calf Raise On A Dumbbell position 2

Calf Raise On A Dumbbell

intermediate·dumbbell
Calf Raises - With Bands position 1
Calf Raises - With Bands position 2

Calf Raises - With Bands

beginner·bands
Calf Stretch Elbows Against Wall position 1
Calf Stretch Elbows Against Wall position 2

Calf Stretch Elbows Against Wall

beginner
Calf Stretch Hands Against Wall position 1
Calf Stretch Hands Against Wall position 2

Calf Stretch Hands Against Wall

beginner
Calves-SMR position 1
Calves-SMR position 2

Calves-SMR

intermediate·foam roll
Donkey Calf Raises position 1
Donkey Calf Raises position 2

Donkey Calf Raises

intermediate·other
Dumbbell Seated One-Leg Calf Raise position 1
Dumbbell Seated One-Leg Calf Raise position 2

Dumbbell Seated One-Leg Calf Raise

beginner·dumbbell
Foot-SMR position 1
Foot-SMR position 2

Foot-SMR

intermediate·other
Knee Circles position 1
Knee Circles position 2

Knee Circles

beginner·Bodyweight
Peroneals-SMR position 1
Peroneals-SMR position 2

Peroneals-SMR

intermediate·foam roll
Peroneals Stretch position 1
Peroneals Stretch position 2

Peroneals Stretch

intermediate·other
Posterior Tibialis Stretch position 1
Posterior Tibialis Stretch position 2

Posterior Tibialis Stretch

intermediate·other
Rocking Standing Calf Raise position 1
Rocking Standing Calf Raise position 2

Rocking Standing Calf Raise

beginner·barbell
Seated Calf Raise position 1
Seated Calf Raise position 2

Seated Calf Raise

beginner·machine

Also Works flexor accessorius

10
90/90 Hamstring position 1
90/90 Hamstring position 2

90/90 Hamstring

beginner·Bodyweight
Alternate Leg Diagonal Bound position 1
Alternate Leg Diagonal Bound position 2

Alternate Leg Diagonal Bound

beginner
Alternating Hang Clean position 1
Alternating Hang Clean position 2

Alternating Hang Clean

intermediate·kettlebells
Atlas Stones position 1
Atlas Stones position 2

Atlas Stones

expert·other
Backward Drag position 1
Backward Drag position 2

Backward Drag

beginner·other
Ball Leg Curl position 1
Ball Leg Curl position 2

Ball Leg Curl

beginner·exercise ball
Barbell Deadlift position 1
Barbell Deadlift position 2

Barbell Deadlift

intermediate·barbell
Barbell Full Squat position 1
Barbell Full Squat position 2

Barbell Full Squat

intermediate·barbell
Barbell Glute Bridge position 1
Barbell Glute Bridge position 2

Barbell Glute Bridge

intermediate·barbell
Barbell Hack Squat position 1
Barbell Hack Squat position 2

Barbell Hack Squat

intermediate·barbell

Related Foot Muscles

Abductor digiti minimi of left foot
This small muscle on the outer edge of the left foot spreads the little toe away from the others, aiding balance and push-off in gait. It's vital for foot arch stability during running or lateral movements. Runners and athletes appreciate its role in preventing foot pronation issues.
Abductor digiti minimi of right foot
This muscle runs along the outer arch of the right foot, abducting the little toe to support lateral stability and toe-off in walking. Essential for preventing supination injuries in trail running. It matters for overall foot mechanics in dynamic sports.
abductor hallucis
This medial foot muscle abducts and flexes the big toe, supporting the arch and propulsion in walking or sprinting. Key for preventing flat feet and plantar fasciitis. Runners target it for injury prevention and efficiency.
adductor hallucis
Inner foot muscle adducts the big toe, stabilizing the transverse arch during toe-off. Prevents hallux valgus and aids propulsion. Important for barefoot training enthusiasts.
extensor hallucis brevis
The extensor hallucis brevis is a small muscle on the top of the foot that specifically extends the big toe (hallux). It works alongside other extensors to lift the toes during walking or running, preventing toes from dragging. For fitness enthusiasts, it's key for foot stability in activities like sprinting or plyometrics.
First lumbrical of left foot
The first lumbrical of the left foot is a small worm-like muscle that flexes the big toe's base and extends its tip, stabilizing during gait. It fine-tunes toe position for balance in yoga or barefoot training. Key for foot intrinsic strength.
First lumbrical of right foot
The first lumbrical of the right foot flexes the big toe's proximal joint and extends the distal one for precise foot control. Essential for push-off in unilateral sports like kicking. Builds foot dexterity for minimalist shoe training.
Flexor digiti minimi brevis of left foot
This small muscle in the left foot's sole flexes the pinky toe at its base. It aids toe grip for balance on uneven terrain. Relevant for barefoot runners enhancing foot intrinsics.

Foot Pain Guide

Common causes and relief

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Activities & Sports

See which activities use flexor accessorius

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Pinpoint·Interactive 3D Anatomy & Exercise Guide