Table 6.

Summary table of the risk factors mentioned in the text.

Congenital Risk Factors	Acquired Risk Factors	Trauma-Related Risk Factors
Cervical rib [22] Pseudoarthrosis of the clavicle [38] First rib variation (increased width, congenital malformation) [30] Ectopic insertion of pectoralis minor [62] Morphological variations of scalene muscles (AS, MS, SMM) [45,50] Subclavius posticous muscle presence [58] Brachial plexus variation (piercing AS and/or MS) [67] Superior pleural sinus presence [26] Congenital ligaments and bands [69] Elongated transverse process of C7 [27]	Hypertrophy of the AS, MS, and subclavius muscle [1,72,76] Repetitive overhead shoulder movements [82] Sports associated with risk of TOS (baseball, swimming, water polo, judo, climbing) [82,83] Lower position of the shoulder girdle [91] Hypermobility of the shoulder joint [92] Occupations with overhead movements or sedentary work patterns (e.g., computer users or musicians) [98,99,100]	Whiplash injury car/motorcycle accident [115] Arthritis of the first costovertebral joint and hydrocortisone injection into the costovertebral joint [126] Neuritis of the brachial plexus [127]