Section 01 of 20
Introduction
Flexor carpi ulnaris (FCU) is the most medial of the superficial forearm flexors. It has two heads, one from the medial epicondyle and one from the olecranon and posterior ulna, joined by a tendinous arch.
The ulnar nerve enters the forearm by passing between these two heads (the cubital tunnel), which makes FCU an important landmark for both palpation and nerve safety.
Section 02 of 20
Origin
| Origin | Humeral head: common flexor tendon from the medial epicondyle. Ulnar head: medial olecranon and the upper two-thirds of the posterior border of the ulna through an aponeurosis. |
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Section 03 of 20
Insertion
| Insertion | Pisiform, then the hook of the hamate and the base of the fifth metacarpal through the pisohamate and pisometacarpal ligaments. |
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Section 04 of 20
Actions
| Primary action | Wrist flexion. |
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| Secondary actions | Ulnar deviation of the wrist (toward the little finger); stabilizes the pisiform and the ulnar side of the wrist. |
| Movement at the joint | Wrist (radiocarpal and midcarpal) joints. |
| Heads / fiber groups | Two heads: humeral (medial epicondyle) and ulnar (olecranon and posterior ulna), with the ulnar nerve passing between them. |
| Functional examples | Gripping; hammering; golf and racquet swings; pushing up from a chair. |
Wrist flexion
Flexes the hand at the wrist, together with the other wrist flexors.
Ulnar deviation
Draws the hand toward the little-finger side, working with extensor carpi ulnaris.
Pisiform stability
Stabilizes the pisiform and the ulnar side of the wrist during gripping and pushing.
Section 05 of 20
Nerve Innervation
| Nerve | Ulnar nerve, C7–C8 (T1 in some descriptions). |
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The ulnar nerve passes between the two heads at the elbow. Tingling in the ring and little fingers, or weak grip, may reflect ulnar nerve compression rather than muscle tightness.
Section 06 of 20
Blood Supply
| Blood | Ulnar artery and its posterior ulnar recurrent branch, with contributions from the ulnar collateral vessels. |
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Section 07 of 20
Pictures and Visual Anatomy
Section 08 of 20
Functional Movement
FCU is active in gripping, hammering, throwing, golf and racquet swings, and pushing up from a chair. It works with extensor carpi ulnaris to keep the wrist stable on the ulnar side during forceful grip.
Section 09 of 20
Synergists and Antagonists
Synergists: flexor carpi radialis and palmaris longus in wrist flexion; extensor carpi ulnaris in ulnar deviation. Antagonists: the wrist extensors oppose flexion; extensor carpi radialis longus and brevis and the radial deviators oppose ulnar deviation.
Section 10 of 20
Palpation and Location
Client position and technique
Position the client with the forearm supported, palm up. Ask for wrist flexion with slight ulnar deviation against light resistance. The tendon stands out on the ulnar side of the wrist proximal to the pisiform. Follow it up the medial forearm to the belly along the ulna.
Protect nearby structures
Avoid pressure in the groove behind the medial epicondyle, where the ulnar nerve is superficial (the funny bone), and over the pisiform and the ulnar side of the wrist, where the ulnar artery and nerve pass. Stop if tingling spreads into the ring and little fingers.
Section 11 of 20
Massage Therapy Relevance
FCU is commonly overloaded in people who grip or type intensively and in golfers and racquet players. Because the ulnar nerve passes between its heads, ulnar-side symptoms need careful screening.
Section 12 of 20
Dysfunction: What Happens When Movement Goes Wrong
Changes in how a muscle works can change how a joint moves. The points below describe possibilities that may be associated with altered muscle function; they are not diagnoses, and one muscle is never assumed to be the sole cause of a problem.
When the muscle is weak
Weakness may reduce wrist flexion, ulnar deviation, and grip strength and may be associated with ulnar nerve problems.
When it is tight or shortened
Tightness may be associated with limited wrist extension and radial deviation and may add tension near the medial elbow.
When it is overused
Repetitive gripping and swinging may load the muscle and may contribute to medial elbow and ulnar wrist ache.
When it is strained
A strain may cause pain along the ulnar side of the forearm and wrist with resisted flexion; wrist injuries and nerve problems can look similar.
When it is inhibited or others compensate
Reduced activation may be associated with a weaker grip and compensation from other wrist muscles.
When it does not coordinate well with synergists and antagonists
Poor coordination with extensor carpi ulnaris and flexor carpi radialis may alter ulnar-side wrist stability.
Section 13 of 20
Conditions, Pathologies, and Pain Relationships
Medial epicondylalgia (golfer's elbow)
Overload of the common flexor tendon causes medial elbow pain with gripping. Avoid aggressive pressure at the epicondyle.
Cubital tunnel syndrome
Ulnar nerve compression at the elbow can cause numbness in the ring and little fingers and weak grip and needs referral.
FCU tendinopathy and pisotriquetral pain
Ulnar-sided wrist pain with resisted flexion or ulnar deviation may involve the FCU tendon or pisiform region.
Differential considerations
Ulnar-side wrist injury (TFCC, hook of hamate fracture), cervical radiculopathy, and Guyon canal entrapment can all cause ulnar-side pain.
Section 14 of 20
Example Clinical Relationship
A golfer reports medial elbow pain and tingling in the ring and little fingers after a round. Flexor carpi ulnaris may be overloaded, and because the ulnar nerve passes between its heads, the tingling may be associated with cubital tunnel irritation. Golfer's elbow, neck problems, and ulnar-side wrist injury can look similar; progressive weakness, clawing, or wasting needs referral.
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Massage and Treatment Approaches
For healthy, non-acute tissue, support the forearm palm up and begin with broad effleurage along the medial forearm. Progress to comfortable kneading and longitudinal strokes along the belly toward the wrist, avoiding the medial elbow groove and pisiform.
| Movement | Use gentle, pain-free active wrist movements within comfort. |
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| Regional work | Consider the other flexors, pronator teres, triceps, and neck and shoulder posture when history supports it. |
| Avoid | Deep pressure in the ulnar groove at the elbow, over the pisiform, or on an acutely inflamed tendon. |
Section 16 of 20
Precautions and Contraindications
Precautions and contraindications
- Acute injury, suspected fracture, or recent surgery at the elbow, wrist, or hand.
- Use caution with ulnar or median nerve symptoms, inflammatory arthritis, or reduced sensation.
- Avoid open wounds, infection, and marked swelling.
- Ask about anticoagulant use and easy bruising.
Section 17 of 20
Red Flags and When to Refer
Red flags and referral
- Progressive weakness, clawing of the ring and little fingers, or wasting between the thumb and index finger.
- Sudden loss of wrist flexion after a pop, or hand pain after a fall onto the wrist.
- Hot, red, swollen elbow or wrist with fever.
- Neck pain with spreading arm weakness, or chest pain and shortness of breath.
Section 18 of 20
Study Summary
Attachments
Origin: medial epicondyle and olecranon/posterior ulna. Insertion: pisiform, then hamate and fifth metacarpal by ligaments.
Actions
Wrist flexion and ulnar deviation.
Supply
Ulnar nerve (C7–C8); ulnar artery.
Section 19 of 20
Instructor Narration
Open narration transcript
Flexor carpi ulnaris is the most medial of the superficial forearm flexors, running along the ulnar side of the forearm to the wrist.
It has two heads. One arises from the medial epicondyle through the common flexor tendon, and the other from the olecranon and posterior ulna. Its tendon inserts on the pisiform, then continues to the hook of the hamate and the base of the fifth metacarpal by ligaments. The ulnar nerve passes between the two heads at the elbow.
It flexes the wrist and deviates the hand toward the little-finger side. Flexor carpi radialis and palmaris longus help with flexion, and extensor carpi ulnaris works with it for ulnar deviation.
The ulnar nerve, roots C7 to C8, supplies it, and blood comes from the ulnar artery.
To palpate, ask for wrist flexion with slight ulnar deviation and find the tendon proximal to the pisiform. Avoid the ulnar groove behind the medial epicondyle and the ulnar side of the wrist, and stop if tingling spreads into the ring and little fingers.
Golfer's elbow, cubital tunnel syndrome, FCU tendinopathy, and ulnar-side wrist injuries can overlap. Refer progressive weakness, clawing, a hot swollen joint, hand pain after a fall, or neck pain with arm weakness.
Remember: medial epicondyle and ulna to the pisiform, wrist flexion with ulnar deviation, and the ulnar nerve.
Section 20 of 20