Muscles/Forearm

Forearm

Humeral head of left flexor carpi ulnaris

HYOO-mer-ul head left FLEK-sor KAR-py ul-NAH-ris

The humeral head of the left flexor carpi ulnaris is the upper arm-origin portion of this forearm muscle on your left side, running from the inner elbow down to your wrist. It flexes and adducts the wrist, stabilizing it during gripping and weight-bearing activities. Strong FCU matters for forearm endurance in sports like tennis or climbing.

Open in 3D Viewer

Common Pain & Injury

Pain often arises from overuse in repetitive wrist flexion, causing medial elbow or wrist ache that worsens with gripping. Strains or tendinopathy can mimic golfer's elbow. See a doctor if pain persists beyond two weeks or includes numbness.

Anatomy & Function

Origin

Medial epicondyle of humerus (inner elbow knob on upper arm bone)

Insertion

Pisiform bone, hook of hamate, and 5th metacarpal (wrist bones and pinky-side hand bone)

Actions

Wrist flexion (bending wrist toward palm)
Wrist adduction (ulnar deviation, tilting wrist toward pinky side)

Innervation

Ulnar nerve (C7-T1)

Muscle Relationships

Antagonists

Extensor carpi ulnarisExtensor carpi radialis

Synergists

Flexor carpi radialisPalmaris longusFlexor digitorum superficialis

Trigger Points

Forms at humeral origin near medial epicondyle; refers pain to medial forearm, wrist, and into 4th/5th fingers, often mimicking ulnar nerve issues.

Stretches

1Wrist extensor stretch with ulnar deviation

2Prayer stretch with pinky-side tilt

3Forearm pronator stretch

Common Conditions

Flexor carpi ulnaris tendinopathyMedial epicondylitisUlnar tunnel syndrome

Anatomical Parts

Humeral head of left flexor carpi ulnaris

FAQ

What does left flexor carpi ulnaris do?

It flexes and adducts the left wrist, aiding grip strength and stability during pushing or racket sports.

Why does my left inner forearm hurt?

Often from FCU overload in repetitive wrist work; trigger points refer pain down to the pinky side.

How to stretch left flexor carpi ulnaris?

Extend your left wrist back with pinky tilt or use a prayer stretch modified for ulnar side.

Flexor carpi ulnaris pain when gripping?

Common in tendinopathy from overuse; rest, ice, and eccentric wrist exercises help recovery.

Exercises for Humeral head of left flexor carpi ulnaris

20

Bottoms-Up Clean From The Hang Position position 1

Bottoms-Up Clean From The Hang Position position 2

Bottoms-Up Clean From The Hang Position

intermediate·kettlebells

Cable Wrist Curl position 1

Cable Wrist Curl position 2

Cable Wrist Curl

beginner·cable

Dumbbell Lying Pronation position 1

Dumbbell Lying Pronation position 2

Dumbbell Lying Pronation

intermediate·dumbbell

Dumbbell Lying Supination position 1

Dumbbell Lying Supination position 2

Dumbbell Lying Supination

intermediate·dumbbell

Farmer's Walk position 1

Farmer's Walk position 2

Farmer's Walk

intermediate·other

Finger Curls position 1

Finger Curls position 2

Finger Curls

beginner·barbell

Kneeling Forearm Stretch position 1

Kneeling Forearm Stretch position 2

Kneeling Forearm Stretch

Palms-Down Dumbbell Wrist Curl Over A Bench position 1

Palms-Down Dumbbell Wrist Curl Over A Bench position 2

Palms-Down Dumbbell Wrist Curl Over A Bench

beginner·dumbbell

Palms-Down Wrist Curl Over A Bench position 1

Palms-Down Wrist Curl Over A Bench position 2

Palms-Down Wrist Curl Over A Bench

beginner·barbell

Palms-Up Barbell Wrist Curl Over A Bench position 1

Palms-Up Barbell Wrist Curl Over A Bench position 2

Palms-Up Barbell Wrist Curl Over A Bench

beginner·barbell

Palms-Up Dumbbell Wrist Curl Over A Bench position 1

Palms-Up Dumbbell Wrist Curl Over A Bench position 2

Palms-Up Dumbbell Wrist Curl Over A Bench

beginner·dumbbell

Plate Pinch position 1

Plate Pinch position 2

Plate Pinch

intermediate·other

Rickshaw Carry position 1

Rickshaw Carry position 2

Rickshaw Carry

intermediate·other

Seated Dumbbell Palms-Down Wrist Curl position 1

Seated Dumbbell Palms-Down Wrist Curl position 2

Seated Dumbbell Palms-Down Wrist Curl

beginner·dumbbell

Seated Dumbbell Palms-Up Wrist Curl position 1

Seated Dumbbell Palms-Up Wrist Curl position 2

Seated Dumbbell Palms-Up Wrist Curl

beginner·dumbbell

Seated One-Arm Dumbbell Palms-Down Wrist Curl position 1

Seated One-Arm Dumbbell Palms-Down Wrist Curl position 2

Seated One-Arm Dumbbell Palms-Down Wrist Curl

intermediate·dumbbell

Seated One-Arm Dumbbell Palms-Up Wrist Curl position 1

Seated One-Arm Dumbbell Palms-Up Wrist Curl position 2

Seated One-Arm Dumbbell Palms-Up Wrist Curl

beginner·dumbbell

Seated Palm-Up Barbell Wrist Curl position 1

Seated Palm-Up Barbell Wrist Curl position 2

Seated Palm-Up Barbell Wrist Curl

beginner·barbell

Seated Palms-Down Barbell Wrist Curl position 1

Seated Palms-Down Barbell Wrist Curl position 2

Seated Palms-Down Barbell Wrist Curl

beginner·barbell

Seated Two-Arm Palms-Up Low-Pulley Wrist Curl position 1

Seated Two-Arm Palms-Up Low-Pulley Wrist Curl position 2

Seated Two-Arm Palms-Up Low-Pulley Wrist Curl

beginner·cable

Also Works Humeral head of left flexor carpi ulnaris

10

Alternate Hammer Curl position 1

Alternate Hammer Curl position 2

Alternate Hammer Curl

beginner·dumbbell

Alternate Incline Dumbbell Curl position 1

Alternate Incline Dumbbell Curl position 2

Alternate Incline Dumbbell Curl

beginner·dumbbell

Alternating Hang Clean position 1

Alternating Hang Clean position 2

Alternating Hang Clean

intermediate·kettlebells

Atlas Stone Trainer position 1

Atlas Stone Trainer position 2

Atlas Stone Trainer

intermediate·other

Atlas Stones position 1

Atlas Stones position 2

Atlas Stones

Axle Deadlift position 1

Axle Deadlift position 2

Axle Deadlift

intermediate·other

Backward Drag position 1

Backward Drag position 2

Backward Drag

beginner·other

Band Assisted Pull-Up position 1

Band Assisted Pull-Up position 2

Band Assisted Pull-Up

beginner·other

Barbell Curl position 1

Barbell Curl position 2

Barbell Curl

beginner·barbell

Barbell Deadlift position 1

Barbell Deadlift position 2

Barbell Deadlift

intermediate·barbell

Related Forearm Muscles

abductor pollicis longus

This forearm muscle runs to the thumb base, abducting and extending it for radial deviation. Vital for wrist stability in lifts like deadlifts. Forearm specialists train it for grip resilience.

Tiny elbow extensor at back upper forearm, stabilizes during pressing and gripping. Aids triceps in extensions. Powerlifters note its elbow lockout role.

brachioradialis

The brachioradialis is the thick forearm muscle on the radial (thumb) side, visible in hammer curls. It flexes the elbow in neutral grip, stabilizing during pulls and carries. Builds Popeye forearms for grip strength.

extensor carpi radialis brevis

The ECRB is a forearm extensor on the radial side, extending and abducting the wrist. Mid-forearm location builds wrist stability for racquets and grips.

extensor carpi radialis longus

The ECRL is the longer radial wrist extensor, more proximal in forearm for powerful extension and abduction. Stabilizes in heavy pulls.

extensor carpi ulnaris

The ECU is the ulnar (pinky) wrist extensor in posterior forearm, balancing extension with deviation. Key for stability in sports.

extensor digiti minimi

The EDM is a thin forearm muscle specifically extending the pinky finger at knuckles and wrist. Lies ulnar to EDM, aids fine grip control.

extensor digitorum

The extensor digitorum is the central posterior forearm muscle, extending fingers 2-5 at knuckles and wrist. Fan-like tendons create dorsal hand ridges for grip extension.

Forearm Pain Guide

Common causes and relief

Activities & Sports

See which activities use Humeral head of left flexor carpi ulnaris