Elbow Weakness

True weakness vs pain-limited weakness

Doctors separate two situations:

• True weakness: the muscle cannot generate force, even when you try your hardest and it does not hurt. This points to a torn tendon, a nerve problem or a brain or spinal cord cause.
• Pain-limited weakness: the muscle works but pain stops you, as in tennis elbow or arthritis. Strength returns when the pain is numbed or settles.

Which movement is weak also helps: bending the elbow (flexion), straightening it (extension), turning the palm up (supination), or gripping.

Causes of elbow weakness

Distal biceps tendon tear

The biceps tendon attaches to the forearm just below the elbow crease. It can tear when a heavy weight forces a bent elbow straight, as in catching a falling object or lifting furniture. Most cases are in men aged 30 to 60.

Signs:

• a sudden pop and sharp pain at the front of the elbow
• bruising in the elbow crease and forearm
• weakness bending the elbow and, even more, turning the palm up (opening a jar or using a screwdriver)
• a visible change: the biceps muscle bunches up toward the shoulder, creating a "reverse Popeye" bulge. This is the elbow "disfigurement" many people notice

Complete tears are best repaired surgically within 2 to 3 weeks. Without repair, people lose about 30 to 40 percent of their turning strength and some bending strength.

Triceps tendon tear

Rare, but it causes weakness straightening the elbow after a fall on an outstretched hand or a heavy push.

Tennis elbow and golfer's elbow

Tennis elbow causes pain on the outer elbow and a weak grip, especially when lifting a cup or kettle with the palm down. Golfer's elbow causes the same on the inner side. The weakness is mostly from pain.

Pinched nerve in the neck

Cervical radiculopathy happens when a disc or arthritis presses on a nerve root in the neck. Each root controls certain muscles:

Neck pain and pain shooting down the arm are common, but not always present.

Nerve compression at the elbow

• Cubital tunnel syndrome: pressure on the ulnar nerve ("funny bone" nerve) causes numbness of the ring and little fingers, a weak grip, clumsiness and, later, wasting of hand muscles. Leaning on the elbow and sleeping with it bent make it worse.
• Radial nerve injury: after a fracture of the upper arm, or pressure during deep sleep with the arm over a chair ("Saturday night palsy"). It causes wrist drop and weak forearm extension.

Injury and arthritis

Fractures, an elbow dislocation and ligament injuries cause pain, swelling and weakness. Elbow arthritis causes stiffness, locking and weakness from pain and lost movement.

Brain, spinal cord and muscle diseases

• Stroke: sudden weakness of the arm, often with face or leg weakness and speech problems.
• Multiple sclerosis and spinal cord compression in the neck.
• Brachial neuritis: severe shoulder pain followed days later by weakness in the shoulder and arm.
• ALS, myasthenia gravis, myositis and muscular dystrophy: gradually increasing weakness, usually in both arms, sometimes with twitching or fatigue.

When to worry about elbow weakness

Get medical care promptly if weakness:

• appears suddenly
• follows a pop or injury
• keeps getting worse
• comes with numbness, muscle wasting or twitching
• affects both arms or other parts of the body

How elbow weakness is diagnosed

A doctor tests each movement against resistance, checks sensation and reflexes, examines the neck, and looks for the biceps "hook" test (hooking a finger under the biceps tendon in the elbow crease, which is absent in a complete tear).

Tests may include:

• X-ray for fractures, dislocation and arthritis
• Ultrasound or MRI for tendon tears
• Nerve conduction studies and EMG to locate a nerve problem and measure its severity
• MRI of the neck for suspected radiculopathy or cord compression
• Brain imaging urgently if a stroke is possible

Treatment for a weak elbow

Treatment depends on the cause:

• Tendon tears: surgical reattachment for complete distal biceps tears in active people. Partial tears and tears in less active people may be treated with rest and physical therapy.
• Tennis and golfer's elbow: activity changes, a counterforce brace, eccentric strengthening exercises and time. Most settle within 6 to 12 months.
• Nerve compression: avoiding leaning on the elbow, a night splint holding the elbow fairly straight, and surgery to release or move the ulnar nerve if weakness or wasting develops.
• Cervical radiculopathy: most improve over 6 to 12 weeks with physical therapy and pain relief. Surgery is considered for progressive weakness.
• Pain relief: acetaminophen (paracetamol), or ibuprofen or a topical NSAID gel at the label dose, avoiding NSAIDs if you have kidney disease, stomach ulcers or take blood thinners.
• Strengthening: once pain allows, a physical therapist builds biceps, triceps, forearm and grip strength gradually.

Frequently asked questions

What causes weak elbow flexion?

Weakness bending the elbow is most often from a distal biceps tendon tear, a pinched C5 or C6 nerve root in the neck, or injury to the musculocutaneous nerve. A tear usually follows a sudden pop when lifting. A nerve cause often comes with neck pain and tingling in the arm.

Why does my elbow look deformed and feel weak?

A bulge in the upper arm with weakness after a pop at the elbow suggests a complete distal biceps tendon tear, where the muscle recoils upward. An elbow that looks out of place after a fall may be dislocated or fractured. Both need prompt assessment.

Can a pinched nerve cause elbow weakness?

Yes. A pinched nerve root in the neck can weaken the biceps or triceps, and compression of the ulnar or radial nerve around the elbow weakens the forearm and hand. Numbness or tingling in a specific part of the arm or hand usually comes with it.

How is elbow weakness treated?

It depends on the cause. Tendinitis improves with activity changes, bracing and exercises. Nerve compression is treated with position changes, splints and sometimes surgery. Complete biceps tendon tears are usually repaired surgically within a few weeks. A physical therapist helps rebuild strength in all cases.