01.02 / NERVE COMPRESSION
Other Nerve
Entrapments
A nerve can come under pressure at more than one point along the arm. Where it is affected helps explain the pain, altered sensation or loss of strength — and guides the next step in care.
01 / ELBOW / WRISTUlnar nerve
Ulnar Nerve
Compression
What it is
The ulnar nerve supplies sensation to the little-finger side of the hand and powers many muscles used for precise finger movements. Compression can interrupt either function. At the wrist, the nerve passes through a small channel called Guyon’s canal; pressure here is also called ulnar tunnel syndrome.
1Sensation, strength and dexterity
You may notice pins and needles, reduced feeling or an awkward grip. Turning a key, opening a packet or keeping hold of small objects can become harder. More advanced compression may cause visible loss of muscle between the hand bones.
- Tingling or numbness on the little-finger side of the hand.
- Difficulty spreading the fingers or pinching firmly.
- Weakness can matter even when there is little pain.
Finding the point of pressure
At the wrist, a ganglion cyst, a nearby injury or repeated pressure through the heel of the palm can narrow the space around the nerve. Cycling handlebars and some tools can load this area. The cause may be local and treatable, so the exact site matters.
1The same nerve, different sites
The elbow is another common compression site. Cubital tunnel syndrome is the name for ulnar compression there; it is not a different nerve disorder. Previous injury, arthritis or repeated pressure can contribute. This chapter considers the wider pathway, including wrist entrapment.
4Positions that may bring symptoms on
Leaning on the inner elbow or keeping it deeply bent can aggravate compression at the elbow. Sustained pressure on the palm may aggravate a wrist problem. Notice the positions that trigger symptoms, but avoid repeatedly provoking them to test the nerve yourself.
3Understanding the problem.
Choosing the next step.
Examine the whole pathway
Assessment maps the affected fingers and checks grip, pinch, small-muscle strength and muscle bulk. The wrist and elbow are examined for tenderness, a lump or a moving nerve. Neck symptoms and other possible causes of a numb or weak hand also help guide the examination.
2Tests that help locate the problem
Nerve conduction studies and EMG can help identify where signals are impaired and whether muscles are affected. Ultrasound or MRI may show a cyst or another compressing structure; bone imaging is selected when an injury or joint problem is suspected. Tests answer a clinical question, rather than replacing the examination.
3Take pressure off the nerve
For suitable mild cases, care may start with changing aggravating tasks, padding pressure points and a carefully fitted splint or positioning aid. The plan depends on whether the elbow or wrist is involved. A therapist can help make changes practical without adding new pressure.
Pain relief may ease discomfort, but ongoing numbness or loss of strength still needs review. Agree a follow-up point so the response is checked.
3Release at the right site
Persistent symptoms, weakness or evidence of nerve damage may make surgery appropriate. At the wrist, decompression opens the tight channel and addresses an identified cause such as a ganglion. Elbow surgery follows a different plan; selected cases require moving the nerve as well as releasing it.
41Healing skin is only the beginning
Wound healing and nerve recovery happen at different speeds. Sensation and strength may improve over months, and severe, long-standing damage may not fully recover. Return to gripping, work or sport is tailored to the operation and hand function; hand therapy may support that progression.
1When review should not wait
Arrange assessment for persistent tingling or symptoms that disturb sleep or everyday tasks. Increasing weakness, difficulty separating the fingers or visible hand-muscle wasting deserve prompt review. Waiting for severe pain can miss an important change in nerve function.
402 / FOREARM / WRISTRadial nerve
Radial Nerve
Compression
Three patterns worth separating
- Radial tunnel syndrome: a deep ache on the outer upper forearm, often provoked by lifting or rotation; usually no cutaneous numbness or true muscle paralysis.
- Posterior interosseous nerve (PIN) palsy: difficulty straightening the fingers or thumb, usually without skin numbness.
- Superficial radial nerve irritation: burning, tingling or numbness towards the thumb side of the back of the hand, without motor weakness.
Where compression develops
Load, repetition and local pressure
Symptoms may occur with repetitive forearm rotation or forceful use, but a particular job does not establish the diagnosis. Previous trauma and local tissue changes also matter. The history should include equipment, straps, recent procedures and any injury, alongside how symptoms affect everyday activities.
6When extension changes
With PIN palsy, the wrist may still lift even when the fingers and thumb do not straighten normally; sometimes it lifts towards the thumb side. A wider radial nerve injury can affect more movements. New loss of extension should be assessed promptly rather than labelled as ordinary forearm strain.
7A CLINICAL DISTINCTION
The pattern points towards the pathway.
| Ulnar nerve | Radial nerve | |
|---|---|---|
| Movement clues | Pinch, grip and finger coordination | Straightening fingers and thumb; sometimes wrist extension |
| Sensory clues | Little finger and adjacent ring finger | Thumb side of the back of the hand, if the superficial branch is involved |
| Important distinction | Compression can occur at the elbow or wrist | Pain-only radial tunnel syndrome differs from motor nerve palsy |
These are orientation clues. The site and branch involved determine the symptoms, and overlapping problems need an examination.
Understanding the problem.
Choosing the next step.
Pain location and muscle testing
The clinician checks where the forearm is tender and tests individual movements against resistance. Pain-limited effort must be distinguished from loss of nerve-driven strength. Tendon problems around the elbow and other nerve disorders can resemble radial tunnel symptoms, so no single tender spot proves the diagnosis.
5Why a normal test is not always the end
Nerve conduction studies and EMG can help locate a motor nerve injury and distinguish it from other causes of weakness. Ultrasound or MRI may be useful for a suspected mass or structural problem.
In pain-only radial tunnel syndrome, electrical studies can be normal. Their results must be interpreted with the history and examination, rather than used alone to confirm or dismiss the symptoms.
105Reduce irritation, preserve movement
Selected cases improve with activity changes, avoiding sustained pressure, short-term splinting and clinician-guided pain relief. Rehabilitation is tailored to the affected branch and your symptoms. A tight external item should be addressed; a medical cast needs professional review rather than adjustment at home.
Treatment is reviewed if symptoms persist or strength changes. Exercises should not repeatedly reproduce nerve pain.
98A decision based on the nerve involved
Surgery may release a confirmed area of compression when suitable non-surgical care has not helped. A compressing lesion or progressive motor deficit can change the urgency and choice of treatment. Different radial nerve problems require different procedures; an operation for pain alone is not automatically the answer.
97Progress depends on the type of problem
Relieving irritation and restoring muscle power are different goals. Pain may improve gradually; a damaged motor nerve can take much longer to recover, and recovery may be incomplete. After a release or reconstruction, protection and hand therapy are tailored to the procedure. There is no single timetable for return to heavy use.
67When specialist review is needed
Seek review for continuing forearm pain or sensory changes despite reducing pressure. New or progressive difficulty lifting the fingers, thumb or wrist needs prompt assessment, especially after an injury. Tell the clinician whether the movement is impossible or mainly limited by pain; that difference helps guide the next step.
10THE NEXT CHAPTER / YOUR CARE
Which nerve needs attention?
A specialist assessment connects the location of your symptoms with changes in sensation, movement and strength, helping you understand the cause and the care available.
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