Anatomy of the Scalp

Arterial Supply: 10 arteries (5 on each side)
- In front of the auricle: supratrochlear, supraorbital, and superficial temporal arteries
- Behind the auricle: posterior auricular and occipital arteries
Venous Drainage: veins follow arteries and have the same names

10 nerves on each side (5 in front of the auricle and 5 behind the auricle)
- Sensory nerves: from trigeminal nerve (supratrochlear, supraorbital, zygomaticotemporal, and occipital nerves)
- Motor nerves: from facial nerve (temporal branch)

Skin of the face:
- Very vascular and rich in sebaceous and sweat glands
- Facial skin is oily due to sebaceous glands
Superficial fascia: contains facial muscles, vessels, and nerves of the skin, and fat
Deep fascia: absent from the face except over the parotid gland (parotid fascia)
Facial muscles (Muscles of facial expression):
- Originate from bone and insert into skin
- Bring about different facial expressions
- Examples: orbicularis oculi, procerus, orbicularis oris, and buccinator

Motor nerve supply: all muscles of the face and scalp are supplied by the facial nerve
- Extra cranial part of the facial nerve
  - Leaves the skull through the stylomastoid foramen
  - Divides into 5 terminal branches within the parotid gland
Sensory nerve supply: trigeminal nerve is the chief sensory nerve of the face
- Gives 3 sensory branches: ophthalmic, maxillary, and mandibular nerves

Similar to that of the scalp
Deep connections of the facial vein:
- Communicates with the cavernous sinus through connections with the superior ophthalmic and pterygoid plexus veins

3 main arteries: facial, transverse facial, and arteries accompanying cutaneous nerves
- Facial artery: branches of the external carotid artery
- Transverse facial artery: branch of the superficial temporal artery
- Arteries accompanying cutaneous nerves: infraorbital, mental, buccal, supraorbital, and supratrochlear arteries

Site and type: lies in the space between the external acoustic meatus, sternomastoid muscle, masseter muscle, angle of the mandible, and pharyngeal wall
Parts of the gland:
- Main part
- Deep part (medial narrow edge)
- Post-glenoid part (behind the temporomandibular joint)
- Accessory part (above the parotid duct)
- Parotid duct
Relations:
- Apex: overlaps posterior belly of the digastric, cervical branch of the facial nerve, and the two divisions of the retromandibular vein
- Superior surface: cartilaginous part of the external acoustic meatus, posterior surface of the temporomandibular joint, and superficial temporal vessels
- Superficial surface: skin, superficial fascia, great auricular nerve, and platysma
- Anteromedial surface: masseter muscle, temporomandibular joint, and posterior border of the ramus of the mandible
- Posteromedial surface: mastoid process, sternomastoid, posterior belly of the digastric, and carotid sheath

Site: deep to the ramus of the mandible
Shape and boundaries: has a roof, anterior, posterior, lateral, and medial walls
Communications:
- With the temporal fossa: passage deep to the zygomatic arch
- With the pterygopalatine fossa: through the pterygomaxillary fissure
- With the middle cranial fossa: through the foramina ovale and spinosum
- With the orbit: through the inferior orbital fissure
Contents:
- Muscles: lateral and medial pterygoid muscles
- Nerves: mandibular division of the trigeminal nerve, chorda tympani branch of the facial nerve, and otic parasympathetic ganglion
- Vessels: maxillary artery and the pterygoid venous plexus