The root of the neck Ehab ZAYYAN, MD, PhD

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

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

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

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

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

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

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.

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

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

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.

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

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

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

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.

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.