Supplies blood to the thoracic limbs, neck and cranial & ventral thorax. It branches extensively, as follows:
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*'''Costocervical trunk''': This is the first branch of the subclavian, it subsequently divides into the '''supreme intercostal artery''' at the level of the neck and around the withers.
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*'''Deep cervical artery''': Supplies the dorsal cervical musculature in the nuchal region.
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*'''Vertebral artery''': Runs in the transverse foramina of the cervical vertebrae and enters the vertebral canal at the level of the atlas. It supplies adjacent cervical musculature.
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*'''Superficial cervical artery''': Supplies the base of the neck.
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*'''Internal thoracic artery''': Runs just above the sternum and divides to form '''intercostal branches'''. It terminates at the level of the diaphragm, becoming the '''musculophrenic artery''' and the '''cranial epigastric artery'''.
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After forming the above branches, the subclavian artery continues around the first rib to enter the thoracic limb as the '''axillary artery'''.