Musculoskeletal strain or sprain: This is often the most common cause of straightening of the normal cervical lordosis, resulting from muscle or ligament injury, usually due to trauma, poor posture, or overuse.

Cervical spondylosis: A condition involving wear and tear on the discs in the neck, which can lead to loss of the normal cervical lordosis.
Herniated cervical disc: A condition where the soft inner gel of the disc leaks out through a tear in the outer layer, potentially causing pain and altering the cervical spine's curvature.
Cervical spine fracture: A break in one of the cervical vertebrae, which can occur due to trauma and may result in the loss of the normal cervical lordosis.

Spinal cord injury or compression: Conditions such as spinal cord compression or injury can lead to serious neurological deficits and require immediate medical attention.
Infection (e.g., osteomyelitis, discitis): Infections of the spine can cause severe pain, fever, and potentially life-threatening complications if not promptly treated.
Tumor (e.g., metastatic disease): Tumors in the cervical spine can cause pain, neurological symptoms, and alterations in spinal curvature, necessitating early diagnosis and treatment.

Rheumatoid arthritis: Although more commonly associated with the hands and feet, rheumatoid arthritis can also affect the cervical spine, leading to instability and loss of lordosis.
Diffuse idiopathic skeletal hyperostosis (DISH): A condition characterized by calcification and thickening of ligaments and tendons, which can affect the cervical spine and alter its curvature.
Scheuermann's disease: A rare condition that affects the spine, leading to kyphosis (forward rounding) of the thoracic spine, but can also affect the cervical region, causing an abnormal curvature.