Definition: the parotid gland is the largest of the salivary
glands. It lies wedged between the mandible and the sternocleidomastoid.
Structure: it is made of serious acini covered by a tough
capsule, the parotid sheath derived from the investing layer of the deep
cervical fascia.
Structures that transverse the gland superficial to deep.
1.      
Fascia nerve
2.      
Retrommandibular vein
3.      
External carotid artery.
Blood supply: branches from the external carotid artery
supply the gland. Venous return is to the retromandibular vein.
Lymph drainage: lymph drains to the nodes within the parotid
sheath and then to the superior group of the deep cervical nodes.
Nerve supply: the gland receives sensory fibres from the
auriculotemporal nerve. Secremotor fibres arise from cell bodies in the otic
ganglion.
Clinical correlates: a malignant tumour of the parotid
gland  may involve the fascial nerve and
produce fascial palsy.