From the Guidelines
Subclavian area syndrome, also known as thoracic outlet syndrome (TOS), is primarily caused by compression of the brachial plexus, subclavian artery, and/or subclavian vein at the superior thoracic outlet, which can be due to anatomical abnormalities, trauma, or repetitive stress. The compression can occur in three distinct spaces: the costoclavicular triangle, the interscalene triangle, and the pectoralis minor space 1.
Causes of Compression
- Anatomical variants such as a cervical rib, anomalous first rib, or C7 transverse process can cause narrowing of the scalene triangle 1.
- Trauma from accidents, especially those resulting in clavicular or rib fractures, can lead to post-traumatic changes that compress the neurovascular structures 1.
- Repetitive stress from activities that require repetitive upper-extremity movement, such as swimming or throwing, can lead to symptoms of TOS 1.
- The subclavius muscle may hypertrophy, further narrowing the costoclavicular space, and repetitive stress can lead to thickening and fibrosis in the subclavian vein wall 1.
Clinical Implications
The compression of neurovascular structures can result in various symptoms, including venous symptoms (venous TOS), neurological dominant symptoms (neurogenic TOS), or arterial dominant symptoms (arterial TOS) 1. Understanding the causes of compression and the resulting neurovascular changes is crucial for choosing and interpreting radiological imaging and planning intervention 1.
Management
Treatment of TOS typically involves addressing the underlying cause of compression, which may include physical therapy to improve posture and strengthen supporting muscles, avoiding aggravating activities, and in severe cases, surgical decompression to remove the structures causing compression 1.
From the Research
Causes of Subclavian Area Syndrome
The subclavian area syndrome, also known as thoracic outlet syndrome (TOS), is a condition that arises from compression of the subclavian vessels and/or brachial plexus as they travel from the thoracic outlet to the axilla 2. The causes of TOS vary and can include:
- Anatomical anomalies in the thoracic outlet, such as variations in the insertion of the anterior scalene muscle or the presence of a cervical rib or fibrous and muscular bands 2, 3
- Compression of the subclavian artery or vein, or thrombus formation in the venous vasculature 2
- Abrupt movements, hypertrophy of the neck musculature, and anatomical variations in which the brachial plexus roots pass through the musculature 3
- Edema, pregnancy, repeated overhead motions, blockage of an artery or vein, or abnormal posture 3
- A prominent first rib, which can cause subclavian artery stenosis 4
- Congenitally abnormal first ribs, which can produce vascular compromise 5
Common Anatomical Anomalies
Common anatomical anomalies that can predispose a patient to TOS include: