71. Antescalenus, interscalenus, and scalenovertebral spaces.

Overview

The scalene muscles, together with the first rib, define three spaces at the root of the neck: the antescalene, interscalene and scalenovertebral spaces. They are the passages for the subclavian vessels, the brachial plexus and the structures that run between the neck and the thorax.

Scalene spaces and their contents

Compression of the subclavian artery or of the lower trunk of the brachial plexus in the interscalene space (thoracic outlet syndrome) causes pain, numbness and vascular signs in the arm.

Lateral cervical region

• anterior – posterior border of sternocleidomastoid muscle
• posterior – anterior border of trapezius
• inferior – clavicle

Subdivided by the omohyoid m. into:

1. Omoclavicular triangle
2. Omotrapezoid triangle

Omoclavicular triangle

Omoclavicular triangle:

Boundaries

1. Cranially: omohyoid – inferior belly
2. Caudally: clavicle
3. Ventrally: sternocleidomastoid – posterior margin

Content

1. Subclavian artery and vein
2. Brachial plexus
3. Phrenic nerve
4. Supraclavicular nerves
5. Ascending cervical artery and anterior vertebral vein
6. Transverse cervical artery and veins
7. Suprascapular artery
8. External jugular vein
9. Venous angle
10. 9.1 Opening of the thoracic duct on the left side
11. 9.2 Opening of the right lymphatic duct on the right side
12. Supraclavicular lymph nodes