In today’s blog post our Oakville physiotherapist at our Oakville physiotherapy clinic will be discussing the topic of Thoracic Outlet Syndrome. First we will
define the injury, explain the clinically relevant anatomy of the impairment, the
three main types of compression in the thoracic outlet region, the etiology and
differential diagnosis, signs and symptoms and management of the condition.
The injury thoracic outlet syndrome simply describes the compression of either
neural or vascular structures as they pass through the ‘thoracic outlet’ of the body.
50-95% of patients diagnosed with thoracic outlet syndrome respond well to
conservative management with their physiotherapist. Usually it is an insidious onset
that brings on the condition, which becomes progressively worse over time. Females
are more susceptible to the injury then men at a 4 to 1 ratio, specifically middle-
aged females as seen in the present literature. The injury may be caused by
repetitive activities, trauma, and congenital anomalies or may occur idiopathically,
meaning its origin is unknown. Also, you should be aware that there are many
synonymous terms for thoracic outlet syndrome. Therefore if you hear any of the
following terms, be aware that it is simply the same injury stated in a different form
and not multiple injuries. These terms are, but not limited to cervical rib syndrome,
scalenus anticus syndrome, costoclavicular syndrome, hyperabduction syndrome,
pectoralis minor syndrome, brachiocephalic syndrome, thoracic inlet syndrome,
nocturnal paresthetic brachialgia, effort vein thrombosis, compression neuropathy
of the brachial plexus and vasculopathy of the brachial plexus.
Anatomy of TOS
Now that we’ve confused you with what seems like a completely different language
in regards to the synonymous terms, it’s time to understand the anatomy of thoracic
outlet syndrome. Think of the injury as a triangle. The base of the triangle is the first
rib, the right side of the triangle is anterior scalene muscle and the left boarder of
the triangle is the middle scalene muscle. The contents within this triangle are the
brachial plexus, the subclavian artery. Therefore, compression of one of or multiple
components of these three structures is what is known as thoracic outlet syndrome.
Recognize that the brachial plexus is a series of different nerves exiting from the
neck, and both the subclavian vein and artery is blood supply. Therefore thoracic
outlet syndrome is a neurovascular injury in nature. However, the majority of
clinically relevant thoracic outlet injuries are neurological in nature and account for
roughly 90% of all cases of thoracic outlet syndrome.
Types of Compression in the Thoracic Outlet
Scalene Triangle Compression
The most common area of compression is in the ‘scalene triangle’, which we
described above. Due to tight scalenes, muscle spasm, muscle hypertrophy,
anomalous fibromuscular bands or the presence of a cervical rib may cause this type
of compression. The ‘cervical rib’ is seen in very few individuals and is an additional
rib, which lies on top of the first rib. Therefore, if you were born with an additional
rib, the space of your ‘triangle’ has shrunk in nature, as your base would be
heightened, therefore increasing the likelihood of compression to the brachial plexus or subclavian artery. Also, the dimensions of the triangle may be reduced if
you extend your neck backwards or rotate your neck to the side of compression.
These postural positions or positions which may occur from trauma may magnify
this type of thoracic outlet injury.
First Rib Compression
The second type of compression is best understood as a sandwich. Imagine that the
top piece of bread is the clavicle, your collarbone, and the bottom piece of bread is
your first rib. Most often carrying a heavier load over your shoulders, such as a
heavy backpack, causes this type of thoracic outlet syndrome. This type of
compression may be reduced in sized by depression of the clavicle, retraction of the
shoulders or extended your neck backwards. The contents of this ‘sandwich’ are
your subclavian artery and subclavian vein, therefore making this type of
compression vascular in nature. At Glen Abbey physiotherapy we rarely see this
type of compression, as the majority of all thoracic outlets are neural in nature.
The third type of compression is called infraclavicular, meaning underneath the clavicle.
On the front part of your shoulder there is a bone called your coracoid process, it
almost looks like a bent finger, a muscle called pectoralis minor attaches onto it and
acts like a sling that moves down and compresses the trunk of the brachial plexus
against one of the ribs underneath it. Therefore this type of compression is neural in
nature and can be made worse by compression of your arm when it is fully raised
away from your side in abduction and with slight lateral rotation.
Where Does TOS Come From?
So now that we have an understanding of the three types of compression that may
be seen with thoracic outlet syndrome, its time to understand the why. The different
etiologies of the injury are the cervical rib, an elevated first rib, a larger first thoracic
rib, hypertrophic scalene musculature, malunion of previously fractures clavicle, a
pancoast tumor in the apex of the lung, an enlarged transverse process of the
seventh cervical vertebrae, poor posture, trauma, exostosis and dislocation of the
humeral head under the acromion. There are a fair number of differential diagnosis’
seen in thoracic outlet syndrome, meaning that although you may have signs and
symptoms of the injury these injuries may be the true root cause: ulnar nerve
compression, median nerve compression, cervical spondylosis, progressive
muscular atrophy, myofascial trigger points, double crush syndrome and visceral
Symptoms of TOS
There are numerous different symptoms that patients complain of at Glen Abbey
Physiotherapy when working with their physiotherapist and team. Patients usually
state that there is a radiating pain from the neck into the shoulder and down the
arm, which is made worse by elevating their upper limbs. You may notice
paraesthesia radiating down the arm, meaning numbness, tingling, burning pain.
Pins and needles early in the morning beginning into the hand or forearm and move
centrally up the arm and toward the neck as the day goes on is another symptom
commonly seen in neural thoracic outlet syndromes. Your upper limb may feel
heavy or weak in nature and tire easily as there would be a lower neural supply to
the muscles innervated by your brachial plexus. Common vascular symptoms of
patients with compression to their subclavian vein or artery are rapid fatigue and numbness of the arm in prolonged arm above head movements, lower temperature
in arm, lacking pulse in the affected hand, cold swollen, glossy, discolored
appearance of hand after exercising and there may be tenderness over the
anatomical course of the subclavian artery or vein.
Signs of Thoracic Outlet Syndrome
When conducting a detail assessment of the patient at Glen Abbey Physiotherapy,
we recognize pertinent signs, which help us diagnose a thoracic outlet syndrome.
We may find tight scalene or pectoralis minor musculature, an alternation in your
respiratory pattern, restricted accessory movements in your neck and cervical
thoracic region of your spine, myotomal weakness with compression of the brachial
plexus, positive orthopedic tests, muscle atrophy, signs of sympathetic involvement,
the presence of a cervical rib seen on x-ray, positive nerve conduction studies,
Doppler studies to reveal vascular involvement and a difference in blood pressure
from the left and right arms. Any combination of these findings may lead us to
believe a thoracic outlet syndrome may be the root cause of your injury or
Treatment for Thoracic Outlet Syndrome
Once a correct diagnosis is achieved, your physiotherapist and team will work with
you to help correct, manage and prevent the injury from progressing and affecting
your activities of daily living, sports, hobbies, work and everyday motions. We will
prescribe the necessary exercises to decrease the amount of compression, utilize
manual techniques to help facilitate joint movements, muscle releases and neural
flow. Ice, heat, taping techniques, IFC, shockwave, ultrasound or acupuncture may
all be additional modalities that your physiotherapist may utilize to help manage the
present condition. Most of all your team at Glen Abbey Physiotherapy will help
educate you about the condition and what you can do during your every day
conduct to help reduce compressive forces to help alleviate your signs and
symptoms, including at home stretches and exercises.
Acupuncture Treatment For Thoracic Outlet Syndrome
As discussed above, Thoracic Outlet Syndrome can originate from a number of sources. Acupuncture is an excellent option in treating thoracic outlet originating from tight muscles in the neck and causing nerve symptoms down the arm. Acupuncture is designed to affect the nerves, and can help calm down nerve-related symptoms. Dr. Jenn would target points in the neck, shoulder, elbow and hand to alleviate symptoms release muscle tension. Acupuncture is pain-free, effective and long-lasting.
If you or anyone you know may be suffering from thoracic outlet syndrome or you
believe thoracic outlet syndrome may be the root cause to your signs and
symptoms, please visit us at Glen Abbey Physiotherapy and our physiotherapist and
team would be happy to help you on your road to recovery.