Scalp, face and parotid Flashcards
What are the five layers of the scalp?
S kin C onnective tissue (dense) A poneurotic layer L oose connective tissue P ericranium
Where are the neurovascular structure found in the scalp?
Dense connective tissue
Which layer of the scalp does infection localise to?
Loose connective tissue
What is the nerve supply to the posterior scalp?
Greater occipital nerve and third occipital nerve from the posterior rami (C2 and C3)
What is the nerve supply to the frontal scalp?
Supratrochlear and supraorbital nerves
What is the nerve supply to the parietal side of the scalp?
Greater auricular nerve
Lesser occipital nerve
Auriculotemporal nerve
What is the blood supply to the scalp?
Branches of external carotid (no branches in neck but branches at scalp eg superficial temporal artery and vein)
Branches from ophthalmic artery (which is a branch of internal carotid)
What is the lymphatic drainage of the scalp?
Posterior-mastoid and occipital nodes then deep cervical nodes
Anterior- Preauricular and parotid nodes
Key muscles of facial expression
nerve
Platysma Occipitofrontalis Auricularis Orbicularis occuli Buccinator All innervated by facial nerve
Two parts of orbicularis occuli loss?
Orbital- can’t squeeze eyes shut
Palpebral- can’t gently shut eyes
Loss of innervation to lower lip muscles (marginal mandibular nerve)
Presents with initial droop of bottom of mouth but then upper lip compensates so present with snarl
Sensation of face
Forehead: Ophthalmic V1 via orbital fissure
Cheek: Maxillary V2 via foramen rotundum
Chin: Mandibular V3 via foramen ovale
Where is parotid gland
Superficial part sits on ramus of mandible
Posterior part wraps around behind mandible
Opens into tooth cavity near second upper molar tooth
Parotid duct location
On top of masseter muscle then pierces buccinator muscle
Surface: line between tragus and junction of lips, middle third, 1.5cm above and below forming rectangle where it sits
which layer is the first layer you see surrounding the parotid gland
Investing fascia which surrounds sub lingual and parotid gland (C2)
Innervation of parotid gland
Sensory: auricotemporal nerve (V3)
Sympathetic: Superior cervical ganglion
Parasympathetic: V3 and CN9
Facial nerve path and branches
Exits skull via stylomastoid foramen
1st branch = posterior auricular nerve
2nd branch = supplies posterior belly of digastric and stylohyoid muscles
3rd branch = temperozygomatic
4th branch = cervicofacial
Penetrates parotid gland and comes out as
temporal, zygomatic, buccal, marginal mandibular and cervical branches
Muscles supplied by terminal facial nerve branches
Temporal- orbicularis occuli and occipitofrontalis
Zygomatic- orbicularis occuli, frontalis and lower eye muscles (loss means can’t close eye)
Buccal- Buccinator and muscles of upper lip
Marginal mandibular- lower lip muscles
Cervical- platysma muscle
What does the parotid gland surround?
Masseter muscle External carotid artery Retromandibular vein Facial nerve (if you see bleeding you have already cut the nerve)
Two pathologies associated with parotid duct
Salivary duct stone
Cheek laceration
What is the surface anatomy of the frontotemporal branch of the facial nerve?
A line 12mm anterior to the porion along the supraorbitalmeatal line and infraorbitalmeatal line
and a line joining the zygomaticotemporal and frontozygomatic sutures “comprehensively captures the distribution of the nerve”
