MANUAL MINORS
Nerve injuries to the hand can severely affect both sensation and motor function. The primary nerves affected are usually the median nerve, the ulnar nerve, and the radial nerve, each of which innervates different areas and functions of the hand.
These injuries are often caused by deep cuts, blunt trauma, or severe stretching. The loss of function may be partial or total depending on the extent of the damage, and early diagnosis is essential to prevent permanent sequelae.
Diagnosis
Diagnosis is based on the patient’s medical history, where the type of traumatic injury (cut, crush, etc.) and the symptoms presented are investigated. In the physical examination, sensation and motor function of the hand are evaluated, determining if there are deficits in specific areas:
Median nerve: affects sensation in the thumb, index, middle, and part of the ring finger, and motor function of the thenar muscles.
Ulnar nerve: involves sensation in the little finger and part of the ring finger, and controls the intrinsic muscles of the hand.
Radial nerve: affects the extension of the fingers and the wrist.
Motor tests include thumb opposition (median nerve), abduction of the little finger (ulnar nerve), and wrist extension (radial nerve). In some cases, electrodiagnostic tests (electromyography) or imaging studies may be necessary to determine the degree and exact location of the injury.
Differential Diagnosis
Condition | Main Clinical Characteristics | Key Differentiation |
|---|---|---|
Median Nerve Injury | Loss of sensation in the first three fingers and weakness in thenar muscles | Inability to oppose the thumb and loss of sensation |
Ulnar Nerve Injury | Loss of sensation in the little finger and part of the ring finger, weakness in intrinsic muscles | Claw hand, weakness in little finger abduction |
Radial Nerve Injury | Inability to extend the wrist and fingers | “Wrist drop” (inability to keep the wrist extended) |
Carpal Tunnel Syndrome | Pain and paraesthesia in the fingers innervated by the median nerve | Exacerbated by repetitive wrist movements |
Ulnar Neuropathy | Pain and numbness in ulnar-side fingers | Chronic ulnar nerve entrapment, progressive symptoms |
Emergency Management
In initial management, it is essential to avoid unnecessary mobilisation of the injured hand to prevent worsening of nerve damage. Any open wounds should be irrigated and cleaned, and analgesia administered. If nerve injury is suspected due to penetrating or blunt trauma, the patient should be rapidly referred to a specialist.
Open wounds must be carefully explored to identify and preserve any damaged nerves. Splints may be necessary to immobilise the limb, and antibiotic prophylaxis is applied in cases of contaminated or open wounds.
Definitive Treatment
Definitive treatment generally requires surgical repair of the injured nerve, especially in cases of severance or severe damage. Primary nerve repair may involve direct suturing or, in cases of significant nerve tissue loss, nerve grafts.
After surgery, a rehabilitation programme and occupational therapy are crucial to maximising functional recovery. In less severe injuries, conservative management with immobilisation, physiotherapy, and follow-up may suffice. However, prognosis depends on the extent of nerve damage and the speed of treatment.
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