The diagnosis of thoracic outlet syndrome is challenging since in the vast majority of cases there is no universal test reliably demonstrating the presence of the disease. Big part of the diagnosis comes from awareness of TOS as a potential cause of patient symptoms. Even experienced physicians may fail to recognize signs and symptoms of TOS. One study from USA demostrated that on average patients visited 4 different doctors before the correnct diagnosis was made . However, once the thoracic outlet syndrome is suspected there is high chance that the diagnosis is correct. A study from large refferal center in the USA demostrated that the percentage of the correct diagnosis from doctors' referal was 91% and from patients self-referral was 97% . This study shows that patients are almost (or maybe even better) as good as doctors in suspecting TOS.
Although suspecting TOS is very important significant work needs to be done to confirm the diagnosis. There is no single reliable test used to detect TOS. Therefore, the diagnosis is made by combination of clinical and radiological findings. Making diagnosis of TOS is like putting pieces of a puzzle. A highly experienced doctor is required to perform clinical examination, interpret imaging and make differential diagnosis with other, similar diseases. Dr. Aghayev has been working with TOS patients for most of his career and is considered as internationally recognized expert in this area.
Careful history and physical examination are essential keys to suspect the thoracic outlet syndrome. TOS is a chronic disease and patents report long-lasting symptoms. Particular attentions should be given to TOS specific symptoms like exercise induced pain or inability to perform overhead tasks. These "red flags" can point to the presence of TOS from the very beginnig of evaluation. After countless conversations with TOS patients I noticed that there is certain "TOS pattern". Recognizing this pattern is both conscious and intuitive.
Poor posture carries a risk for TOS development and I always check postural abnormalities. Kyphois, scoliosis, shoulder and collar bone asymmetry are frequently encountered in TOS patients. They are usually subtle and barely visible to untrained eye and therefore frequently missed. Pain and tenderness at the junction of the neck and shoulder area is very typical but not specific to TOS. Tapping of the thoracic outlet area from behind usually illicits pain and is my preferable test since it highly sensitive to TOS and is not seen in other diseases.
Neurological examination should focus on muscle weakness and sensory deficits in the arm and hand. The correct examination requires deep knowledge of anatomy of brachial plexus, its branches and their skin/muscle distributions. Unfortunately, most physicians do not have such knowledge and experience and even most obvious deficits are frequently missed. Even if neurological examination is performed the findings are eiter missed or misinterpreted.
The presence of atrophy (muscle wasting) is particularly important since it is an indicator of disease severity. Atrophy is usually prominent on thenar side of the hand. I check the atrophy by comparing two hands side by side. This way the presence of even subtle muscle wasting can be noted. All hand muscles are innervated by the lower pherart of brachial plexus – specifically by C8 and T1 nerve roots. These nerve roots are not usually affected by other diseases and therefore presence of C8 and T1 radicular symptoms is strong indication of TOS. Usually all hand muscles weak on testing. This clinical finding can be used to distinguish from other peripheral nerve entrapment neuropathies such as carpal tunnel syndrome and cubital tunnel syndrome. In carpal tunnel syndrome the median nerve is entraped in the wrist area under transverse carpal ligament. Clinically, some (but not all) thenar muscles are affected. These muscles are commonly recognized as LOAF muscles – L: lateral two lumbricals, O: opponens pollicis, A: abductor pollicis brevis, F: flexor pollicis brevis. In cubital canal syndrome all other hand muscles are affected. Significant number of TOS patients get wrong diagnosis of carpal or cubital tunnel syndrome and even undergo surgery. Wrong diagnosis and failed surgery may be avoided by knowing muscle groups affected by these syndromes and distinguishing them from thoracic outlet syndrome.
Neurogenic TOS causes variety of sensory disturbances. They include pain, paresthesia (pins and needlles), numbness in the affected area. Only numbness can be examined by clinician. Thorough sensory examination of entire arm and hand for all sensory modalities (touch, pain, temperature, vibration) is time consuming and usually not performed by doctors. Rather limited areas are superficially examined. Also there is significant confusion among doctors about sensory disturbances in TOS. Another problem arises from complexity of sensory innervation. Below is a picture of skin areas innervated by various nerves.
It is well known that the lower part of brachial plexus which comprises C8, T1 roots and inferior truncus (which forms by merge of C8 and T1 roots) is most frequently affected by TOS. This part of the brachial plexus innervates the inner (ulnar) side of the arm, forearm and hand. Therefore, presence of hypoesthesia in aforementioned area is quite typical for TOS. Yet, most clinicians fail to recognize hypoesthetic area as symptom of TOS. In fact, usually the hypoesthesia on the ulnar side is considered as sign of ulnar nerve entrapment in the cubital canal. However, ulnar nerve doesn't provide sensory innervation to arm and forearm. Only inner (ulnar) side of the hand including last two fingers are innervated by the ulnar nerve. In other words sensory area affected by TOS is much larger than ulnar nerve's skin area. The medial side of the arm and forearm are innervated by other nerves - intercostobrachialis and medial cutaneous antebrachial nerves. Neurogenic TOS affects mostly C8/T1/inferior trunk and all its braches - ulnar, medial cutaneus antebrachial, intercostobrachial. Medial cutaneous antebrachial nerve has highest diagnostic value and its involvement is almost encountered exclusively in TOS. Alas, doctors almost never pay attention to this nerve.
Typical skin areas affected in TOS vs cubital canal syndrome
Provocative testing is an essential part of clinical examination. The purpose of these tests is to elicit TOS symptoms using specific clinical maneuvers in order to establish diagnosis.
Radiographic examination plays an important role in diagnosing TOS. X-ray, CT scan, MRI, and Doppler USG are commonly used radiological tools.
3D CT angiographic reconstruction from a patient with TOS. Note that the subclavian artery narrows as it passes over the accessory rib. The accessory rib makes an abnormal joint with the first rib (white circle).
Nerve conduction studies like EMG and ENG may be helpful, but in the majority of cases, they do not provide a definitive diagnosis. Thus, the diagnosis is mainly made by careful clinical examination.
1. Landry GJ, Moneta GL, Taylor LM, Jr., Edwards JM, Porter JM. Long-term functional outcome of neurogenic thoracic outlet syndrome in surgically and conservatively treated patients. J Vasc Surg. 2001;33(2):312-317; discussion 317-319. https://doi.org/10.1067/mva.2001.112950
2. Likes K, Rochlin DH, Salditch Q, et al. Diagnostic accuracy of physician and self-referred patients for thoracic outlet syndrome is excellent. Ann Vasc Surg. 2014;28(5):1100-1105. https://doi.org/10.1016/j.avsg.2013.12.011
Common symptoms of a brain tumor can vary greatly and depend on the tumor's location, size, and growth rate. They may include headaches, seizures, changes in personality or behavior, memory problems, and difficulty with balance, speech, hearing, or vision. Learn more on this topic in our Brain Tumors section.Learn More
Treatment options for a pituitary adenoma include observation, medication, surgery, and radiation therapy. The best treatment option depends on the size and type of the tumor, the patient's overall health, and personal preferences. Learn more about Pituitary Adenoma treatment in the corresponding section.Learn More
Scoliosis treatment depends on the degree of the curve and the patient's age. Non-surgical treatments include physical therapy, brace use, and pain relievers. In severe cases, surgery may be required to correct the curve. Learn more about scoliosis is treated in our Scoliosis Treatment section.Learn More
The diagnosis of TOS is made in conjunction with the patient's history, symptoms, physical examination, imaging tests, and neurophysiological tests. Treatment can include physical therapy, pain management, and surgery in severe cases. Learn more about treatment options in our Thoracic Outlet Syndrome Treatment section.Learn More
Warning signs of a brain aneurysm can encompass sudden and severe headaches, blurred or double vision, neck pain, fainting or dizziness, and sensitivity to light. However, many aneurysms may not show symptoms until they leak or rupture. Learn more about this in our Brain Aneurysms section.Learn More
The need for surgery typically depends on the size, location, and growth rate of the aneurysm. Generally, aneurysms larger than 7mm, those located at certain parts of the brain, or those showing signs of growth on consecutive scans may require surgical intervention. To understand the specifics, it's best to consult with a neurosurgeon. More on this topic in our Brain Aneurysms section.Learn More
Currently, there's no standard blood test that can definitively diagnose brain cancer. While certain markers or changes may suggest a tumor's presence, imaging tests like MRI or CT scans remain primary diagnostic tools. Learn more about the diagnostic processes for brain cancer in our Brain Tumors section.Learn More
The growth rate of brain tumors can vary based on the type and grade of the tumor. Some tumors grow slowly and might not cause symptoms for years, while others can grow rapidly and present symptoms within weeks or months. The onset of symptoms also depends on the tumor's location and size. Learn more about the progression of brain tumors in our Brain Cancer section.Learn More
After brain surgery, patients might experience fatigue, mood fluctuations, or cognitive changes. Recovery time varies, and regular follow-ups are essential to monitor healing and detect any complications. Learn more about the recovery process for different disorders in our Brain Diseases Treatment section.Learn More
As we age, the spine undergoes natural degenerative changes. Discs may lose hydration and elasticity, vertebral bones might thin, and there can be a gradual narrowing of the spinal canal, which might lead to spinal stenosis or other conditions. Learn more about spine disorders in our Spine Diseases section.Learn More
Most patients start feeling better within 48 hours of kyphoplasty, with full recovery in a few weeks.Learn More
Recovery from vertebroplasty is typically quick, with most patients resuming normal activities within a few days.Learn More
Both procedures involve stabilizing fractured vertebrae, but kyphoplasty includes the inflation of a balloon to create space before cement is injected, whereas vertebroplasty injects cement directly without balloon inflation.Learn More
Patients with certain types of fractures, severe osteoporosis, or those with an active infection might not be suitable candidates for kyphoplasty. Always consult with a spinal specialist.Learn More
The three primary types of scoliosis are idiopathic (cause unknown, most common in adolescents), congenital (due to bone abnormalities present at birth), and neuromuscular (stemming from nerve or muscle disorders). Learn more about the differences between these types and the nature of this condition in the dedicated Scoliosis section.Learn More
Hunchback, or kyphosis, can be caused by poor posture, spinal trauma, congenital issues, osteoporosis, disc degeneration, or certain diseases like tuberculosis.Learn More
Tailbone pain, or coccydynia, without evident injury can arise from prolonged sitting, childbirth, tumors, infections, or can sometimes have an idiopathic (unknown) origin.Learn More