Terry-Thomas sign

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD medical weight loss NYC and sleep center NYC

Terry-Thomas sign
Terry-Thomas sign on X-ray
Synonyms	David Letterman sign
Pronounce	N/A
Specialty	Orthopedic surgery, Radiology
Symptoms	Pain in the wrist, instability, decreased grip strength
Complications	Osteoarthritis, chronic wrist pain
Onset	Typically after trauma or injury
Duration	Can be chronic if untreated
Types	N/A
Causes	Scapholunate ligament injury
Risks	Wrist trauma, repetitive strain injury
Diagnosis	X-ray, MRI
Differential diagnosis	Wrist sprain, carpal instability
Prevention	N/A
Treatment	Surgical repair, physical therapy
Medication	N/A
Prognosis	Variable, depends on severity and treatment
Frequency	Common in wrist injuries
Deaths	N/A

Radiographic sign of wrist instability

The Terry-Thomas sign is a radiographic finding indicative of wrist instability, specifically involving the scapholunate ligament. It is named after the British comedian Terry-Thomas, who was known for his distinctive gap between his front teeth, which the sign resembles.

Pathophysiology

The Terry-Thomas sign is associated with a disruption of the scapholunate ligament, which is a critical stabilizer of the carpal bones in the wrist. This ligament connects the scaphoid and lunate bones, and its injury can lead to a gap between these bones, visible on an X-ray.

Radiographic Appearance

On a standard posteroanterior view of the wrist, the Terry-Thomas sign is identified by an increased gap between the scaphoid and lunate bones. Normally, this gap is less than 3 mm, but in the presence of a scapholunate ligament injury, the gap can widen to more than 3 mm, often measuring between 4 to 5 mm or more.

Clinical Significance

The presence of the Terry-Thomas sign is indicative of scapholunate dissociation, which can lead to wrist instability and arthritis if left untreated. Patients may present with wrist pain, weakness, and decreased range of motion. Early diagnosis and management are crucial to prevent long-term complications.

Management

Treatment of scapholunate dissociation may involve conservative measures such as splinting and physical therapy, or surgical intervention to repair or reconstruct the scapholunate ligament. The choice of treatment depends on the severity of the injury and the patient's symptoms.

See also

• Scapholunate ligament injury
• Wrist joint
• Carpal bones
• Arthritis