Thoracic Outlet Syndrome (TOS) is a group of related symptoms that indicate a restriction in the neurovascular bundle that supplies the upper extremity. TOS is not a clear diagnosis. Like other syndromes, such as Chronic Fatigue Syndrome or Piriformis Syndrome, it is a collection of related symptoms.
The term “thoracic outlet syndrome” implies that the dysfunction has occurred where the nerves and vascular structures pass over the first rib. In spite of that, the name “Thoracic Outlet Syndrome” usually refers to structural problems impacting the neurovascular bundle from the first rib to the axilla. These problems may include restrictions in the brachial plexus, subclavian artery, subclavian vein, and subclavian lymph trunk.
The first section of this document reviews the boney structures that are most directly involved. The remaining sections examine the other involved structures, building from posterior to anterior.
Casually, people use “Thoracic Outlet Syndrome” when talking about pain and dysfunction in the upper extremity. This document focuses on the structures that create restriction and dysfunction in the neurovascular structures of the thoracic outlet.
Interestingly, the muscles discussed here also have trigger point patterns that refer to the arm. In addition, several other muscles, not in the thoracic outlet structure, refer from the torso into the arm. Look at the post on “Torso into Arm” for those muscles and their trigger point patterns.
Anatomy – Throacic Outlet
The anatomy of these structures is important to understand the syndrome. This post walks through the structures one at a time.
Trigger Points and Anomalies Make This More Complicated
The thoracic outlet structures are complex. To make it more complicated, muscles like scalenes, pec minor, and levator scapula have statistically significant variations. Scalenes are quite variable in size, attachments, and, even, number of muscles. The pectoralis minor is variable in its attachment on ribs. Levator scapula sometimes attaches to a rib. Also, posture, activity, and weight all add to how this area works.
Many muscles that in the neck, upper back, and chest refer to the upper torso, shoulder, and down the arm. These patterns look like thoracic outlet problems. infraspinatus, pectoralis major, and serratus posterior superior create these kinds of patterns.
Posts Related to Thoracic Outlet Syndrome
These posts are directly related to the anatomy, pain patterns, self-care, and treatment of Thoracic Outlet Syndrome.
Trigger Point Patterns That Refer Into
the Torso, Shoulder and Down the Arm
These patterns look like TOS because they refer into the torso, shoulder, and down the arm. Some of these patterns come from TOS muscles and others do not.
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Tony Preston has a practice in Atlanta, Georgia, where he sees clients. He has written and taught about anatomy, trigger points, and cranial therapies since the mid-90s.
*This site is undergoing significant changes. We are reformatting and expanding the posts to make them easier to read. The result will also be more accessible and will include more patterns with better self-care. In the meanwhile, there may be inconsistencies in formatting, content presentation, and readability. Until we get older posts updated, please excuse our mess.