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What is Foramen magnum transmits all except: and explain in detail?
Structures passing through foramen magnum are:

Through anterior part 
Apical ligament of dens
Membrana tectoria
Through subarachnoid space 
Spinal accessory nerve
Vertebral arteries
Anterior and posterior spinal arteries
Through posterior part 
Lower part of medulla
Tonsils of cerebellum
Meninges