Vertebral artery

Origin – it is the first branch of the first part of vertebral artery it is the largest branch
of subclavian artery  it is one of the two principal arteries of the brain, in addition, it also
supplies spinal cord meanings, surrounding muscles & bones

Branches & distribution - it is divided into four parts

First part:- First part is cervical & is horizontal it extends from the origin to entry into
foramen transversarium. it doesn’t give any important branches
Second part:- Second part is vertebral & is vertical it extends from 6th cervical vertebra
to 2nd cervical vertebra through foramen transversarium it gives spinal &
muscular branches
Third part:- Third part is suboccipital & horizontal it present in Suboccipital triangle it
gives only muscular branches
Fourth part:-  Fourth part is cranial & is vertical it extends from the posterior
atlantooccipital membrane to the lower border of Pons it gives

Branches

1. Meningeal branches supply meninges of posterior cranial fossa 
2. Branches to spinal cord & brain 

• Posterior spinal artery gives two branches which run on anterior & posterior to the dorsal root of the spinal nerve 
• Anterior spinal artery – it arises from the terminal part of vertebral artery it supplies medial part of medulla including pyramid & hypoglossal nuclei 
• Posterior inferior cerebral artery – it is the most tortuous artery in the body it is the largest branch of vertebral artery it supplies 
• Lateral part of the medulla  
• Fourth ventricle by forming choroid plexus 
• Inferior vermis inferolateral surface of the cerebellar hemisphere 

Relations
a) The sympathetic plexus of vertebral artery runs around the artery
b) Middle cervical ganglion lies anteromedially
c) Inferior cervical ganglion lies posteromedially

Applied anatomy    

1. Medial medullary syndrome – the lesion of the anterior spinal artery is manifested by impairment of volitional (desired ) movement on the contralateral side due to the involvement of the corticospinal tract 
2. Ipsilateral loss of movement of the tongue, wasting of tongue muscles due to the involvement of hypoglossal nerve nuclei 
3. Lateral medullary syndrome -  Wallenberg syndrome it is due to the lesion of posterior inferior cerebellar artery this is manifested by loss of pain & thermal sensibility of the same side of the face & opposite half of the body paralysis of the vocal cord soft palate & pharyngeal muscles of the ipsilateral side 
4. Subclavian steal syndrome -  it takes place in obstruction of the subclavian artery proximal to the origin of the vertebral artery . some amount of blood is stolen from the brain through the vertebral artery of the opposite side to maintain the collateral circulation 

Other Diagrams