The thoracic region

During its course it gives off numerous branches. In the thoracic region, the following branches arise medial to the scalenus anterior muscle:

Vertebral artery

The first artery is the vertebral artery which ascends until it reaches the vertebral column at the transverse foramen of the sixth or seventh cervical vertebra.

Internal thoracic artery

Second is the internal thoracic artery which runs in the opposite direction to the vertebral artery behind the sternum and costal cage. It branches off into three smaller arteries:

• The superior epigastric artery arises and runs below the costal margin, entering the rectus sheath.
• The pericardiacophrenic artery accompanies the phrenic nerve between the pleura and pericardium and helps supply the fibrous pericardium. It anastomoses with the musculophrenic and superior phrenic arteries.
• The musculophrenic artery supplies the upper musculature of the diaphragm.

Thyrocervical trunk

The third artery is the thyrocervical trunk which gives off four branches as it ascends:

• The inferior thyroid artery ascends, makes a loop behind the common carotid artery and courses towards the backside of the thyroid crossing the recurrent laryngeal nerve. It branches off arteries to the larynx (inferior laryngeal artery), infrahyoid muscles and prevertebral muscles and many more smaller ones to the surrounding structures.
• The ascending cervical artery is next and ascends along the phrenic nerve at the level of the fourth cervical vertebra.
• The transverse cervical artery divides into a superficial and deep branch.
• The superficial branch runs superficially in the lateral cervical region and then under the trapezius muscle (together with the accessory nerve). The deepbranch branches off into two smaller arteries, one of which follows the dorsal scapular nerve along the medial border of the scapula. The suprascapularartery courses above the scapula in front of the anterior scalene muscle and behind the clavicle. It anastomoses with the scapular circumflex and thoracoacromial arteries (via the acromial branches).

The muscular region

The costocervical trunk arises behind the anterior scalene muscle and divides into two main branches:

• The supreme intercostal artery is the highest of all intercostal arteries and supplies the upper two intercostal spaces, the deep neck and back muscles, the skin of the back and the vertebral canal.
• As the trunk descends it gives rise to the deep cervical artery between the first rib and the seventh cervical vertebra which supplies the deep neck musculature.

Subclavian artery branches: Mnemonic

One smart and fun way to remember the correct order and names of the most important branches of the subclavian artery is to learn the mnemonic ‘Very Tired Individuals Sip Strong Coffee Served Daily’.

It covers the following structures:

• Vertebral artery
• Thyrocervical trunk

1. Inferior thyroid artery
2. Superior cervical artery
3. Suprascapular artery

• Costocervical trunk

1. Supreme intercostal artery
2. Deep cervical artery

Takeaway

The branches of the subclavian artery are the following (‘Very Tired Individuals Sip Strong Coffee Served Daily’):

• Vertebral artery
• Thyrocervical trunk

1. Inferior thyroid artery
2. Superior cervical artery
3. Suprascapular artery

• Costocervical trunk

1. Supreme intercostal artery
2. Deep cervical artery