1. The root of the neck
Ehab ZAYYAN, MD, PhD

2. The area of the neck immediately above the inlet into the thorax
The root of the neck
The area of the neck immediately above the inlet into the thorax

3. Scalenus anterior muscle
Origin: transverse process of the 3rd, 4th, 5th and 6th vertebrae.
Insertion: scalene tubercle of the 1st rib and into a ridge on the upper surface of the 1st rib.
Nerve supply: anterior rami of C4, C5, C6
Action: elevation of the 1 st rib, lateral flexion and rotation of the cervical vertebral column

5. Relations of the scalenus anterior muscle
Anteriorly: prevertebral fascia, phrenic nerve, superficial cervical and suprascapular arteries, internal jugular and subclavian veins.

6. Posteriorly: subclavian artery, brachial plexus, cervical dome of the pleura.
Medially: vertebral artery and vein, thyrocervical trunk, sympathetic trunk and thoracic duct (left side).
Laterally: roots of the phrenic nerve, roots of the brachial plexus, and the subclavian artery

14. Scalenus Medius muscle
Origin: transverse processes of the first 6 cervical vertebrae
Insertion: the upper surface of the first rib, behind the brachial plexus and subclavian artery
Nerve supply: same like anterior scalene muscle
Action: like anterior scalene muscle

16. Posterior scalene muscle
Origin: transverse processes of the upper cervical vertebrae
Insertion: outer surface of the second rib

19. Subclavian artery Right: arises from the brachiocephalic artery
Left: arises from the arch of the aorta
Divided into three parts be the anterior scalene muscle.

21. First part of the subclavian artery
From its origin to the medial border of the anterior scalene muscle.
Relations: CCA, vagus, IJV, Sympathetic trunk.
Apex of the lung, right RLN

22. Branches of first part of the subclavian artery
Vertebral artery
Thyrocervical trunk
Internal thoracic artery

23. Vertebral artery
Passes in front of the transverse process of the 7th cervical vertebra and enters the foramen transversarium of the 6th cervical vertebra. Above the atlas it enters the vertebral canal and assends into the skull via the foramen magnum.

24. Thyrocervical trunk It gives three branches: Inferior thyroid artery
Transverse cervical artery (superficial cervical artery)
Suprascapular artery

25. Internal thoracic artery
Arises from the lower border of the subclavian
Descends in the thorax between the 1st costal cartilage and the pleura.
It is crossed by the phrenic nerve

26. Second part of the subclavian artery
Lies behind the anterior scalene muscle
One branch: Costocervical trunk: divides into:
Superior intercostal artery
Deep cervical artery

27. Third part of the subclavian artery
Extends from the lateral border of the anterior scalene muscle to the outer border of the first rib where it becomes the axillary artery.

28. Subclavian vein
Begins at the outer border of the first rib as a continuation of the axillary vein.
At the medial border of the ant scalene it joins the IJV to form the innominate veins.