FAQ: Thoracic Outlet Syndrome
Molly Clark 02/02/26Injury – Thoracic Outlet Syndrome (TOS)
Thoracic outlet syndrome (TOS) is a condition that involves compression of neurovascular structures as they pass through the thoracic outlet space. The thoracic outlet space is made up of the anterior scalene muscle, the middle scalene muscle, and the first rib, and can be felt in this location. Within the thoracic outlet space, neurovascular structures pass through, including the brachial plexus, subclavian artery, and subclavian vein.
Where will I feel pain?
The TOS clinical presentation is often varied in symptoms and depends on the affected structures. Symptoms tend to develop gradually and are often intermittent. Symptoms can include sensory changes such as pain, numbness and tingling in the upper limb. This can occur in the neck, shoulder, arm, and hand. A sensation of heaviness, fatigue, or weakness may also be present. Symptoms tend to be worse with specific postures such as arm elevation or sustained overhead activity. In rare cases, limb swelling, temperature changes, or skin discolouration may occur and should be treated immediately.
What movements will I struggle to perform if I have injured this tissue/region?
TOS can bring about a sense of heaviness in the upper arm, and symptoms can be worse with overhead activity, arm abduction, and internal rotation of the shoulder, as this causes more compression on the thoracic outlet space. This can make activities like hair washing, sustained cleaning, throwing, and lifting more difficult.
Will I feel pain in any other regions of my body?
As the thoracic outlet affects a broad base of areas, it is common to feel symptoms such as numbness, tingling, heaviness, and pain in the neck, shoulder, arm, forearm, hand, and wrist due to the distribution of the nerves.
How does it happen?
TOS develops when the thoracic outlet space becomes narrowed or irritated due to:
• Hypertrophy or tightness of the scalene and pectoralis minor
• Repetitive overhead use (e.g. gym, manual labour)
• Postural factors (forward head and rounded shoulders, which can close off the thoracic outlet space and increase tension in this area)
• Carrying heavy loads on the shoulder
• Congenital reasons (e.g. presence of a cervical rib, widened C7 transverse processes)
• Trauma (such as whiplash, which can cause sensitisation around the scalene tissues)
• Strength imbalances around the shoulder girdle
What things should I try initially once I’ve hurt myself?
As thoracic outlet syndrome can be difficult to diagnose and can mimic a myriad of other pathologies, it is important to get a thorough assessment by a trained therapist in order to determine if it is TOS or something else. However, managing load is always a good initial step. For example, if there has been a recent increase in upper body gym work, consider de-loading training. In general, incorporating movement through the shoulder and opening up the mid and upper back can be helpful.
What things should I try to avoid in the initial stages of injury?
Depending on the severity and duration of symptoms, capacity for load will vary. Initially, avoid activities that make symptoms more prominent or worse. This may include:
• Heavy overhead lifting
• Carrying bags over one shoulder
• Prolonged positions of shoulder or arm elevation
• High-load pushing or pulling movements
• Sleeping positions that compress the affected side
What type of exercises or movements do I need to learn, control, or be stronger at to rehab the injury?
Rehabilitation should generally focus on restoring space, strength, and control around the thoracic outlet. General rehab guidelines may include:
• Postural control exercises such as scapular retraction, seated rows, thoracic extension, and mobility exercises like foam roller extensions and open-book stretches
• Exercises that focus on opening the thoracic outlet space, such as banded external rotation of the shoulder, pectoralis minor stretching, scalene stretching, and weighted thoracic extension
• Strengthening exercises including seated rhomboid rows, mid and upper trapezius strengthening, and deep cervical neck flexor training (e.g. chin tucks)
• Other exercises such as rib cage expansion and addressing breathing mechanics can be beneficial, as well as neurodynamic exercises like graded nerve glides to help desensitise the tissues
What other considerations contribute to the injury?
• Poor workplace ergonomics and sustained desk postures can contribute to TOS manifestation and symptom aggravation. These factors should be addressed to tailor a supportive setup, and an osteopath can help with this.
• Poor breathing mechanics and rib position can affect the thoracic outlet space and contribute to overloading certain muscles and underloading others.
• Cervical spine, shoulder, and thoracic mobility will affect overall upper body mobility, control, and positioning, which can influence TOS presentation.
What treatments can help relieve pain or fast-track rehabilitation?
• Manual therapy to the neck, upper back, ribs, and surrounding muscles
• Exercise-based rehabilitation
• Addressing postural and ergonomic considerations
• Load and activity modification
• Breathing mechanics
What are the expected timeframes of rehabilitation?
Expected timeframes vary depending on severity, type, and multiple other factors that influence tissue healing, recovery, and overall pain experienced. Typically, some positive changes can be expected within the first 2–6 weeks, assuming optimal recovery strategies are in place. However, symptoms can persist for months, particularly if there is a structural cause or repeated tissue aggravation. Recovery can be supported by seeing an osteopath, building a solid management plan, reducing aggravating factors, loading tissues appropriately, and addressing lifestyle factors such as sleep, workplace ergonomics, and stress levels. The most effective recovery strategy is one that is tailored to the individual and their specific presentation.