Lecture 6: Scalp and Superficial Face Flashcards
What are the 5 layers of the scalp?
S - Skin
C - Close, subcutaneous tissue layer
A - Aponeurotic layer
L - Loose subaponeurotic layer
P - Periosteum of the cranium
The close, subcutaneous tissue layer of scalp is divided how and how do lacerations play a role here?
- A fatty, avascular, superficial portion
- Highly vascular, deep portion
- Lacerations involving the deep portion tend to bleed profusely; tension on this layer causes the wounds to separate, thereby making hemostasis difficult
What is the clinical significance of infections to the loose subaponeurotic layer of the scalp?
- May readily spread, via emissary veins, to the venous sinuses surrounding the brain
- Danger area of the scalp
What are the osteogenic (regenerative) properties of the periosteum of the cranium like?
Very poor osteogenic (regenerative) properties and relatively insensitive to pain
What 3 arteries arise from the External Carotid artery and supply the scalp (which regions)?
1) Occipital artery: supplies the occipital region
2) Posterior Auricular artery: region behind the ear
3) Superficial Temporal artery: temporal region
What are the 2 branches of the internal carotid artery supplying the scalp via the opthalmic artery?
1) Supraorbital artery supplying lateral forehad and scalp
2) Supratrochlear artery supplied the medial forhead and scalp
What is the companion arteries for the greater occipital, lesser occipital, auriculotemporal, supraorbital and supratrochlear nerves?
Where do scalp veins drain?
Indirectly into the dural venous sinuses via eminssary veins
*Important route for the spread of the superficial scalp infections to the brain
What is the subcutaneous musculo-aponeurotic system (SMAS) and why is it clinically relevant?
- Layer of tissue deep to the subcutaneous tissue of the face and neck
- Fused w/ parotid tissue, but can be surgically elevated to perform lower face lifts
What is found embedded in the parenchyma of the Parotid Gland?
- Facial nerve
- Retromandibular vein
- External carotid artery
Explain the sympathetic innervation of the parotid glands, where the fibers originate from and travel.
- Arise from the superior cervical ganglion
- Postganglionic fibers to the parotid gland travel through the internal carotid plexus, carotico-tympanic nerve, tympanic plexus, lesser petrosal nerve, otic ganglion (no synapse), and auriculotemporal nerve before finally termininating in the parenchyma of the gland
Explain the parasympathetic innervation of the Parotid gland (where the fibers originate and travel)?
Preganglionic parasympathetic fibers originate in the inferior salivatory nucleus, course in the glossopharyngeal nerve (CN IX), tympanic nerve, tympanic plexus, and lesser petrosal nerve before synapsing in the otic ganglion
- Postganglionic fibers reach the gland via the auriculotemporal nerve (Posterior Auricular N.)
Describe the size, location, relationships and course of the parotid duct?
- Is 5.0 cm long and 0.5 cm in diameter
- Travels about 1.0 cm below the zygoma, before piercing the buccinator muscle, and entering the mouth
- Close relationship w/ buccal branches of the facial nerve
When is the parotid gland grossly inflammed and hypertrophied?
- Grossly inflammed in cases of epidemic parotitis (mumps)
- Hypertrophied in pt’s w/ chronic bulimia
What nerve branches are found immediately above or below the parotid duct and why is this clinically signigicant to mumps?
- Buccal branches of VII (facial nerve)
- Facial nerve is embedded in the parotid gland
- People with mumps have a great deal of pain when moving the mandible of the jaw
What motor nucleus and nerve provides innervation of facial expression, stylohyoid, posterior digastric, and stapedius
Motor nucleus of VII (SVE)
Which brainstem nuclei associated w/ the facial nerve receive SVA taste impulses from taste buds on the anterior 2/3’s of the tongue?
Solitary nucleus
What is the muscle for raising the eyebrows and facial nerve branch innervation; what would be the clinical sign of dysfunction?
- Frontalis muscle
- Temporal branch of Facial nerve
- Clinical sign would be inability to raise eyebrows
What muscle is responsible for blinking or winking the eyelids, what branch of facial nerve provides innervation; what is the clinical sign of dysfunction?
- Orbicularis Oculi
- Temporal and Zygomatic branches of Facial nerve
- Clinical sign would be drooping of the lower lid, spilling of tears, or corneal drying
What muscle is responsible for smiling and what branch of the facial nerve is responsible for the innervation?
- Zygomatic major
- Zygomatic branch of Facial nerve
What muscle is responsibe for puckering the lips and what branch of the facial nerve; what would be the clinical sign of dysfunction?
- Orbicularis Oris
- Buccal branch of the Facial nerve
- Inability to elevate and retract the angle of the mouth
What are the signs and symptoms of Bell’s or Facial Palsy?
- Ectropion: drooping of the lower lid
- Epiphora: spilling of tears from the eye
- Drying of cornea
- Inability to wink or raise eyebrows
- Unequal smile
- Drooling from the corner of the mouth
What are the 3 subdivisions of the Orbicularis oculi muscle and the main function of each?
1) Orbital portion: protective closing of the lids ad winking
2) Palpebral portion: gentle closing of the lids
3) Lacrimal portion: holds the lids against the eyeball, helping to spread lacrimal secretion across the surface
*Innervated by the temporal and zygomatic branches of CN VII
Paralysis of the Orbicularis Oculi leads to what?
- Drooping of the lower lid (extropion)
- Spilling of tears (epiphora)
- Corneal drying
