All except one is true regarding carotid sheath
Sympathetic chain runs behind the carotid sheath.
Carotid sheath contains internal carotid artery, internal jugular vein, and vagus nerve
It is formed by investing layer of deep cervical fascia, pretracheal and prevertebral fascia
Sympathetic chain runs vertically through the carotid sheath
9,11, and 12th cranial nerves pierce the upper part of carotid sheath