Sulcus ulnaris syndrome (cubital tunnel syndrome)

Anatomy: Where does the ulnar nerve run on the elbow?

The ulnar nerve is an important arm nerve for feeling and fine motor skills on the ulnar side of the hand. It runs behind the inner elbow bone (medial epicondyle) in a bony groove, the ulnar sulcus - colloquially known as the "musician's bone". A band of soft tissue roof (cubital tunnel) stretches over it. When you bend your elbow, the nerve is stretched and the tunnel becomes narrower, which can increase pressure and friction.

• Sensation supply area: little finger and ulnar half of the ring finger
• Motor skills: fine hand muscles (interossei), thumb adduction, parts of the flexion force
• Constrictions: Ulnar sulcus, cubital tunnel, rarely higher constriction points along the upper arm

What is Ulnar Sulcus Syndrome?

The ulnar sulcus syndrome – also known as cubital tunnel syndrome or ulnar neuropathy at the elbow – refers to irritation or compression of the ulnar nerve in the elbow groove. This initially causes sensitive symptoms such as tingling, pins and needles or the fingers falling asleep. If left untreated, muscle weakness and, in the late stages, visible hand muscle loss can occur. The aim of therapy is to reduce pressure and tension-related stress on the nerve and improve its ability to glide.

Typical symptoms

• Tingling, numbness or “electric” feeling in the little finger and ulnar ring finger
• Increase in discomfort when bending the elbow, at night or when using the telephone
• Pain or tenderness on the inside of the elbow (musical bone)
• Weakness when spreading/closing fingers, unsteady grip with tweezers
• Fine motor skills problems (buttoning, typing), occasionally reduced grip strength
• In advanced cases: visible thinning of the palm muscles

Not all symptoms have to occur at the same time. Early sensory complaints are usually easier to resolve than long-standing muscular failures.

Causes and risk factors

There is usually repeated mechanical irritation: pressure on the nerve or stretching from prolonged bending. Sometimes there are anatomical peculiarities in which the nerve jumps unstable over the bone (subluxation). Swelling or bony changes can also narrow the tunnel.

• Permanent elbow support (desk, car armrest, cycling)
• Prolonged bending (phone calls, sleeping position, gaming, reading in bed)
• Professional manual work, vibration, workbench work
• After trauma, fracture healing, osteoarthritis or cysts in the elbow area
• Nerve instability in the ulnar sulcus (snapping/jumping)
• Concomitant diseases: diabetes, thyroid disorders; nicotine
• Rare: space-occupying lesions (ganglion, lipoma) or pronounced deformities

Diagnosis: This is how we proceed

Diagnosis is based on complaints, clinical examination and, if necessary, technical procedures. It is important to distinguish it from other nerve constrictions or causes in the cervical spine.

• Anamnesis: temporal course, occupational/sports stress, nighttime complaints
• Clinic: pressure pain on the sulcus, tingling when tapped (tinel), elbow flexion test
• Function: testing finger abduction, thumb adduction, tweezer grip
• Assessment of nerve gliding and possible subluxation
• High-resolution sonography: representation of the nerve diameter, sliding behavior, space-occupying areas
• X-ray if bony causes are suspected; MRI individually
• Nerve conduction velocity/EMG to objectify conduction block or axonal damage

A combination of clinical testing and imaging is often sufficient. Neurophysiological measurements are particularly helpful in cases of unclear or advanced findings and before a planned operation.

Differential diagnoses: What do you have to differentiate between?

• Ulnar compression in Guyon's box on the wrist
• Carpal tunnel syndrome (median nerve) with the hand falling asleep at night
• Radial compression syndrome with forearm/back of hand symptoms
• Cervical spine-related nerve root irritation (C8/T1)
• Polyneuropathies (e.g. in diabetes) with bilateral, symmetrical symptoms

Conservative therapy: First address the cause in everyday life

In the majority of mild to moderate cases, improvement can be achieved through consistent, everyday measures. It is important to have low-pressure and low-tension postures as well as ergonomics that are gentle on the nerves.

• Relief: Stop resting your elbows on hard edges and use pads
• Night positioning: keep elbows approximately extended; soft night splint/bandage
• Telephone/PC: Headset instead of cell phone on your ear; Forearm rests, keyboard/mouse ergonomic
• Load control: frequent short breaks, changing positions, stretching without pain
• Physiotherapy: nerve-sparing mobilization of the ulnar nerve, sliding exercises, posture training
• Pain management: short-term anti-inflammatory medication after medical consultation; Cooling/heating pulses individually
• Tape/cushion: soft protective padding on the elbow for leaning activities

A structured conservative approach over 6 to 12 weeks is common. Consistent implementation in everyday life and good instructions are crucial.

Physiotherapy and ergonomics in detail

• Nerve mobilization: gentle, painless gliding exercises in a low dose, individually adapted
• Movement skills: Training elbow and shoulder mechanics, avoiding extreme flexion under load
• Strengthening: gradual training of the shoulder blade and forearm muscles to relieve pressure
• Workplace: Optimize table height, chair height, armrests, keyboard and mouse position
• Sport: when cycling, handlebar pads/grips, vary grip position; Adjust breaks and technique

Infiltrations and regenerative procedures: When does it make sense?

Nerve injections are not standard for ulnar sulcus syndrome because of the risk of nerve irritation and the evidence is limited. In selected situations, ultrasound-targeted perineural injection or hydrodissection may be considered – with careful risk-benefit assessment and informed consent. Regenerative procedures such as PRP have no proven evidence for elbow nerve congestion and are not routinely recommended.

Surgical therapy: Clear indication, differentiated approach

Surgery is considered if relevant symptoms persist despite adequate conservative therapy, if a clear conduction disorder can be identified or if motor deficits or muscle breakdown are already present. Intervention can also make sense if there is evidence of a mass or severe nerve instability.

• In-situ decompression: opening of the cubital tunnel to relieve pressure
• Anterior transposition of the nerve (subcutaneous, intramuscular, submuscular) for subluxation/instability or stretch problems
• Medial epicondylectomy in special constellations
• Accompanying corrections for bony spurs, cysts or scar strands

The aim is to reduce pressure and friction and restore lubrication. As with any procedure, there are risks such as bruising, infection, persistent or changed sensations, scarring problems or incomplete improvement of symptoms. An individual benefit-risk comparison is crucial; Expectations of healing should be realistic.

Follow-up treatment and prognosis

• Early mobilization: after a short period of rest, regular, pain-free movements
• Nerve and soft tissue gliding: early functional exercises according to instructions
• Stress build-up: depending on the activity, return within 2 to 6 weeks, varies from person to person
• Monitoring: progress checks, adjustment of ergonomics and exercises

Cases detected early have a good chance of improvement. Sensory disorders often regenerate more quickly than motor deficits. Muscle weaknesses that have existed for a long time can sometimes persist. Comorbidities such as diabetes can slow recovery.

Prevention and self-help in everyday life

• Elbow pads at work, soft edges or forearm rests
• Make phone calls with a headset and don't use a laptop on a narrow sofa with your elbows strongly bent
• Regular micro-breaks during office and manual work
• Sleep hygiene: lying on your side with a pillow as a “stopper”, light night bandage
• Gentle nerve mobilizations according to instructions, no aggressive stretches
• Quit smoking and promote metabolic health

When should you seek medical advice?

• Increasing numbness or pain despite relief over several weeks
• New onset muscle weakness, clumsiness, dropping objects
• Visible muscle loss in the hand
• Complaints after elbow trauma or with significant joint deformation
• Bilateral, progressive or atypical symptoms

The earlier stressful factors are identified and reduced, the better the chances of conservative improvement.

Your supply in Hamburg

We combine a careful clinical examination with high-resolution sonography of the nerve. Our focus is on conservative treatment with individual instructions on ergonomics and nerve mobilization. If necessary, we coordinate further diagnostics (e.g. nerve conduction velocities) and discuss surgical options without time pressure and with realistic expectations. Location: Dorotheenstraße 48, 22301 Hamburg.