T4 Syndrome

Be the first to edit this page and have your name permanently included as the original editor, see the editing pages tutorial for help.

Original Editor - Your name will be added here if you created the original content for this page. Lead Editors - Your name will be added here if you are a lead editor on this page.  Read more.

Clinically Relevant Anatomy

In1997 Evans described the basic science behind the origins of T4 syndrome¹. Vasomotor nerve fibers descend in the spinal cord and emerge in the ventral horns and roots. These fibers pass the dorsal root ganglia as it sits in the invertebral foramen. Next they emerge as part of a spinal segmental nerve. Sympathetic fibers leave the segmental nerve and join the sympathetic chain. The sympathetic chain travels down the necks of the ribs with variable areas of ganglia (Greek word “ganglion” meaning “lump”). Branches from the sympathetic chain pass over the costovertebral joints to supply the heart, esophagus, and abdominal viscera. It is not uncommon for these branches to become stretched or affected by neighboring osteophytes. The sympathetic chain fibers ascend or descend a variable number of segments, synapse in a ganglion, and leave the chain to join a peripheral nerve. 

Sympathetic fibers can pass distally leaving the peripheral nerve to join an artery in the neurovascular bundle. Here they assist with the control of blood pressure via vasoconstriction. Sympathetic fibers are motor but do contain afferent filaments which synapse in the dorsal root ganglion and enter the spinal cord with somatic afferents.

It is thought that the head and neck are provided with sympathetic outflow from T1 to T4. The upper trunk and extremities are thought to be supplied by T2 to T5. Symptoms in the neck, head, and upper extremities are believed to be due to any of the following
- Entrapment of segmental spinal nerves which carry sympathetic afferents
- Entrapment or ischemia of sympathetic nerves over rib necks or osteohpytes
- Referred pain from the heart, esophagus, or abdominal viscera
- Referred pain from a thoracic spinal structure
- Referred pain in the neck from a dorsal spinal structure
- Referred pain from any structure in the upper quarter

Mechanism of Injury / Pathological Process

The exact mechanism of T4 syndrome is unclear but it is hypothesized that sustained or extreme postures can lead to relative ischemia within multiple tissues contributing to symptoms of sympathetic origin1. Symptoms originating from the sympathetic nervous system are distinctly different from somatic referred symptoms. The sympathetic nervous system provides pathways for referral of symptoms from the thoracic spine to the head and upper extremities. Symptoms may not be derived solely from the fourth thoracic vertebra, but also other upper thoracic vertebra1,2. Hence “T4 syndrome” may also be referred to as “upper thoracic syndrome”.

Clinical Presentation

add text here relating to the clinical presentation of the condition

Diagnostic Procedures

add text here relating to diagnostic tests for the condition

Outcome Measures

add links to outcome measures here (see Outcome Measures Database)

Management / Interventions

add text here relating to management approaches to the condition

Differential Diagnosis

add text here relating to the differential diagnosis of this condition

Key Evidence

add text here relating to key evidence with regards to any of the above headings

Resources

add appropriate resources here

Case Studies

add links to case studies here (case studies should be added on new pages using the case study template)

References

References will automatically be added here, see adding references tutorial.