Cervical Radiculopathy: This condition, often resulting from a herniated disk or bone spur in the cervical spine, compresses or irritates the nerves that branch out from the spine, leading to pain, numbness, or weakness in the arm. It is a common cause of arm nerve pain due to the high prevalence of cervical spine issues.

Carpal Tunnel Syndrome: A condition that occurs when the median nerve, which runs from the forearm into the palm of the hand, becomes pressed or squeezed at the wrist. Symptoms include numbness, tingling, and pain in the hand and arm.
Thoracic Outlet Syndrome: Involves compression, injury, or irritation of the nerves and/or blood vessels (arteries and veins) in the thoracic outlet area, which lies between your collarbone (clavicle) and first rib. This can lead to pain in the shoulders and neck and numbness in the fingers.
Brachial Plexus Injury: An injury to the brachial plexus, a network of nerves that conducts signals from the spinal cord to the shoulder, arm, and hand. This can cause a range of symptoms including pain, numbness, and weakness in the arm.

Acute Compartment Syndrome: A serious condition resulting from increased pressure within a muscle compartment, which can lead to nerve and muscle damage. It requires immediate medical attention.
Spinal Cord Injury or Compression: Conditions such as spinal stenosis, tumors, or abscesses can compress the spinal cord, leading to severe and potentially irreversible neurological deficits if not promptly addressed.
Vascular Conditions (e.g., Arterial Thrombosis or Embolism): Although less common, vascular issues can cause arm pain and must be considered, especially in patients with risk factors for vascular disease.

Peripheral Neuropathy: While more commonly associated with diabetes or other systemic conditions, peripheral neuropathy can cause nerve pain in the arms. It's less common as a primary cause of arm nerve pain but should be considered, especially in patients with underlying conditions.
Tumors (e.g., Neurofibromas, Schwannomas): Benign or malignant tumors affecting the nerves can cause arm nerve pain. These are less common but important to diagnose early for appropriate management.
Inflammatory or Autoimmune Conditions (e.g., Guillain-Barré Syndrome): These conditions can cause widespread nerve damage and should be considered in the differential diagnosis, especially if there are systemic symptoms or rapid progression of symptoms.