From the Guidelines
For numbness and pain radiating from the left bicep down to the hand, a thorough evaluation by a healthcare provider is necessary to determine the cause, which may involve nerve compression or irritation, and diagnostic tests such as MRI, EMG, and nerve conduction studies should be considered. The symptoms described suggest possible nerve compression or irritation, which could be caused by various conditions, including cervical radiculopathy, cubital tunnel syndrome, or other nerve entrapment syndromes 1. A neurological examination testing strength, reflexes, and sensation will likely be performed by the doctor.
Diagnostic tests may include:
- Electromyography (EMG) and nerve conduction studies to assess nerve function
- MRI of the cervical spine and/or arm to visualize potential compression sites
- Possibly X-rays to check for bone abnormalities
- Blood tests to rule out conditions like diabetes or vitamin deficiencies
The pattern of numbness in specific fingers can help determine which nerve is affected, with median nerve issues typically affecting the thumb, index, and middle fingers, and ulnar nerve problems affecting the ring and little fingers. According to a recent study, MRI is useful for the diagnosis of biceps tendon injury, with sensitivity and specificity reported at 92.4% and 100%, respectively, in detecting distal biceps tendon ruptures 1. Another study found that US can be considered an alternative to MRI in the evaluation of the distal biceps tendon ruptures, with the medial imaging approach demonstrating substantial interreader agreement 1. However, MRI is still the preferred imaging modality for accurately identifying the type of distal biceps tendon tear, thus enabling the orthopedic surgeon to provide a more precise treatment plan. Don't delay seeking medical attention as early diagnosis and treatment can prevent permanent nerve damage.
From the Research
Numbness and Pain in Left Bicep Radiating to Left Hand
- The symptoms described, such as numbness and pain in the left bicep radiating down to the left hand, may be indicative of neurogenic thoracic outlet syndrome (NTOS) 2, 3, 4, 5, 6.
- NTOS is a condition characterized by compression of the nerves and/or blood vessels that pass through the thoracic outlet, which is the space between the neck and shoulder 2.
Diagnostic Tests
- Electrophysiological evaluations, such as nerve conduction studies (NCS) and electromyography (EMG), are commonly used to diagnose NTOS 3, 4, 5.
- Medial antebrachial cutaneous (MABC) sensory nerve action potential amplitude is often decreased in patients with NTOS 2, 3, 5.
- Abnormalities in the abductor pollicis brevis, first dorsal interosseous, and adductor digiti minimi muscles may be detected through needle EMG examination 3.
- Radiologic studies, such as brachial plexus MRI and computed tomography angiography (CTA), may be used to detect structural abnormalities, including focal stenosis of the subclavian artery 2.
Specific Tests for NTOS
- Nerve conduction assessment, including medial antebrachial cutaneous SNAP, ulnar SNAP, median CMAP, and ulnar CMAP, may provide clues in favor of NTOS 3.
- Needle examination of the abductor pollicis brevis, first dorsal interosseous, and adductor digiti minimi muscles may show abnormalities consistent with NTOS 3, 4, 5.
- The thoracic outlet stress test may be used to reproduce the patient's symptomatology and diagnose NTOS 6.