Sympathetic innervation of the body (recap)

• Originates from autonomic centres in brain
• Passes down spinal cord
• Exits spinal cord with T1-L2 spinal nerves
• Travel to sympathetic chains running the length of vertebral column
• Pass into all spinal nerves (anterior and posterior rami)
• Pass into splanchnic nerves to eventually supply organs

Sympathetic innervation of the head and neck

• Presynaptic sympathetic axons from CNS exit spinal cord in T1 spinal nerve
• Presynaptic sympathetic axons ascend within sympathetic chain and synapse in superior cervical sympathetic ganglion
• Post-synatic sympathetic axons enter internal and external carotid nerves
• Internal and external carotid nerves are carried to the organs of the head on the surface of the branches of the internal and external carotid arteries
• Opthalmic artery (from internal carotid) carries sympathetic axons into the orbit

Parasympathetic innervation of the body (recap)

• All parasympathetic axons leave the CNS via cranial nerves III, VII, IX and X and via sacral spinal nerves - craniosacral outflow
• Parasympathetic ganglia in head - to eye, lacrimal gland and salivary gland
• Vagus nerve supplies organs of the neck, chest and abdomen as far as the mid-gut
• Sacral spinal nerves 'carry' sympathetic axons to the the hindgut, pelvis and perineum