The subclavian artery arises from the brachiocephalic artery and travels upward and laterally in the thorax before becoming the axillary artery at the outer border of the first rib. It is divided into three parts by the scalenus anterior muscle. The first part gives rise to the vertebral, thyrocervical, and internal thoracic arteries. The second part lies behind the scalenus anterior and gives off the costocervical trunk. The third part extends to the outer border of the first rib before becoming the axillary artery in the axilla.

1. Subclavian artery
Scalenus Anterior muscles divides the artery into 3 parts :
Right subclavian artery Left subclavian artery
Origin : brachiocephalic artery
Course : arches upward and laterally over the pleura
and btw the sclaneus ant and med muscles
At the upper border of the 1st rib it becomes axillary
artery
Origin : arch of aorta in the thorax
Course : ascends to the root of the neck and arches
laterally similar to the right subclavian artery

2. 1st part
Extends fro the origin of the subclavian artery to MEDIAL
border of scal. Anterior muscle
Giving 3 branches
 Vertebral artery
 Thyrocervical trunk
 internal thoracic artery
2nd part
Lies behind the scal. Anterior muscle
Gives following branches
Cost cervical trunk (backward over the dome of the plura
dividing into
 Superior intercostal artery
 Deep cervical artery
3rd part
Extends from the Lateral Border of Scal. Anterior Muscle
Cross the post triangle of the neck to the lateral border of the
1st rib becoming Axillary artery , closely related to the nerves
of brachial plexus
Occasionally giving branches
• Superficial cervical arteries
• Suprascapular arteries

4.  Continuation of subclavian
artery
 Exteds from outer border of
1st rib upto lower border of
Teres major muscle
 Continues as brachial artery
 Closely related to brachial
plexus cords
 Pectoralis minor muscle
divides the artery into 3 parts.

5.  Axial artery pulsastion can be felt against
the lower part of the lateral wall of axilla
In order to check bleeding from the distal part of limb
- The artery can be compressed against the humerus in the
lower part of the lateral wall of axilla