Arm Bruise with Finger Tingling: Ulnar Nerve Injury Assessment

Tingling in the ring and little fingers after an arm bruise suggests ulnar nerve compression or contusion at the elbow (cubital tunnel) or wrist (Guyon's canal).

Anatomic Basis

• Ulnar nerve (C8–T1) supplies sensation to medial 1.5 digits (little finger, ulnar half of ring finger) and ulnar palm.
• At the elbow, it runs in the cubital tunnel behind the medial epicondyle—superficial, minimally protected.
• A direct blow or hematoma here causes neurapraxia (conduction block) or axonotmesis (axonal disruption).

Red Flags for Urgent Evaluation

• Progressive numbness/weakness
• Thenar wasting (median nerve) or hypothenar wasting (ulnar nerve)
• Inability to cross fingers (ulnar) or make OK sign (median)
• Expanding hematoma, pulsatile mass (brachial artery injury)
• Forearm pain with passive finger extension (compartment syndrome)

Initial Management

1. Protect: Avoid elbow flexion >90°; use elbow pad or towel wrap at night.
2. Ice: 15 min q4–6h for 48h (not directly on skin).
3. NSAIDs for pain/inflammation if no contraindications.
4. Neural glides: Gentle ulnar nerve flossing once acute pain subsides.

When to See a Clinician

Within 24–48 hours if tingling persists, worsens, or weakness develops. Electrodiagnostic studies (NCS/EMG) at 3–4 weeks if not resolving; guides surgical vs. conservative management.

Differential includes C8/T1 radiculopathy, medial cord brachial plexopathy, thoracic outlet syndrome—clinical exam distinguishes.