09-04 Thoracic Outlet Syndrome

Question 1

Definition of TOS

Answer 1

• Impingement/compression on neurovascular bundle (BP and SC Artery Vein or Axillary Artery/Vein)
• C7 rib, or cervical rib coming off C7 (elongated C7 TP) compromises exit space for BP

Question 2

Neurogenic TOS (True TOS)

Answer 2

• Presents with cervical rib or elongated C7 TP
• Paresthesia and pain along medial border of arm
• Muscle weakness
• Atrophy (intrinsic muscles of hand)
• Positive EMG
• Affects less than 1% of population
• Rare

Question 3

Anatomic variations - Cervical Ribs

Answer 3

• Incidence: 0.74%
• Female/Male Ratio - 7:3
• Complete vs. incomplete
• More common on left side (brachiocephalic and subclavian artery)

Question 4

Anatomic variations - Anomalous 1st ribs

Answer 4

• Incidence: 0.78%

- Equal occurrence in men and women

Question 5

Nonspecific neurogenic TOS

Answer 5

• “symptomatic”
• Similar to neurogenic TOS, but no radiological abnormalities
• No muscle atrophy
• No EMG findings
• Most TOS complaints fall into this category

Question 6

Thoracic Outlet

Answer 6

• Brachial Plexus (C5-T1)
• Subclavian artery
• Subclavian vein
• Posture: Scapula - depressed or anterior tilt can impinge

Question 7

Other entrapment areas (nonspecific neurogenic

Answer 7

Scalene