Cervical Spondylosis without Cord Compression: This condition involves wear and tear on the discs in the neck, which can cause pain and weakness in the upper limbs without necessarily compressing the spinal cord. The absence of cord compression on MRI supports this diagnosis, as the symptoms can be due to foraminal stenosis or other non-compressive mechanisms.

Peripheral Nerve Entrapment (e.g., Carpal Tunnel Syndrome, Cubital Tunnel Syndrome): Conditions that affect the nerves outside the spinal cord can cause limb weakness and pain. These are common and can coexist with or mimic cervical spine issues.
Musculoskeletal Conditions (e.g., Tendinitis, Bursitis): Inflammation or injury to the muscles, tendons, or bursae around the shoulder or neck can cause pain and weakness in the upper limbs.
Thoracic Outlet Syndrome: Compression of the nerves or blood vessels that pass into the thoracic outlet (the space between your collarbone and first rib) can cause pain and weakness in the upper limbs.

Multiple Sclerosis: An autoimmune disease that affects the brain and spinal cord, leading to a wide range of neurological symptoms, including weakness. Although less common, missing this diagnosis could have significant implications for treatment and prognosis.
Spinal Cord Infarction or Arteriovenous Malformation: Although the MRI did not show cord compression, it's crucial to consider vascular causes of spinal cord dysfunction, as these can be catastrophic if not promptly addressed.
Infections (e.g., Osteomyelitis, Discitis): Infections of the spine can cause pain and neurological symptoms, including weakness, and require urgent treatment to prevent serious complications.

Amyotrophic Lateral Sclerosis (ALS): A progressive neurological disease that affects nerve cells in the brain and the spinal cord, causing loss of muscle control. ALS is rare but should be considered in the differential diagnosis of progressive limb weakness.
Neoplastic Conditions (e.g., Schwannoma, Neurofibroma): Tumors of the nerve roots or spinal cord can cause localized pain and neurological deficits, including weakness. These are less common but important to rule out, especially with persistent or worsening symptoms.
Plexopathies (e.g., Brachial Plexitis): Inflammation of the brachial plexus can cause severe pain and weakness in the upper limb. This condition is relatively rare but should be considered in the appropriate clinical context.