Layers of the SCALP

• SCALP refers to the skin and subcutaneous tissue covering the calvaria
• SCALP is located between the superior nuchal lines and supraorbital margins.

Layers of the SCALP

• There are five layers of the SCALP, which can be remembered using the mnemonic SCALP
• Skin is the first layer
• Connective Tissue forms the second layer
• Aponeurosis, or the Galea Aponeurotica, forms the third layer
• Loose Areolar Tissue forms the fourth layer
• Pericranium forms the fifth and final layer

Skin of the SCALP

• Consists of thick hairy skin
• Contains sweat and sebaceous glands.
• Features a rich supply of arteries, veins, and lymphatic vessels.

Connective Tissue of the SCALP

• The connective tissue layer includes thick, dense connective tissue
• This layer includes sensory nerves
• This layer has a rich vascular supply

Aponeurosis of the SCALP

• This layer is a dense tendinous structure.
• The epicranius muscle attaches to this layer

Layers of the SCALP Attachment and Separation

• The first three layers (Skin, Connective Tissue, and Aponeurosis) of the SCALP are firmly attached
• These three layers of the SCALP are separated during head injuries or surgical openings of the cranium
• The layers are collectively referred to as the "scalp proper"

Loose Areolar Tissue

• This layer has a spongy structure.
• Contains a few arteries and emissary veins.
• Emissary veins extend between the superficial veins of the scalp and the diploic veins of the skull bones.

Pericranium

• This layer forms the periosteum of the skull bones.
• It is comprised of dense connective tissue

Arteries of the SCALP Supplying Blood from External Carotid Artery

• The occipital artery branches off of the external carotid artery within the scalp.
• The posterior auricular artery branches off of the external carotid artery within the scalp.
• The superficial temporal artery branches off of the external carotid artery within the scalp.

Arteries of the SCALP Supplying Blood from Ophthalmic Artery

• The supratrochlear artery is a branch of the ophthalmic artery within the scalp.
• The supraorbital artery is a branch of the ophthalmic artery that goes to the scalp.

Veins of the SCALP

• These veins follow the arteries
• The veins drain into the occipital, posterior auricular, superficial temporal, supratrochlear, and supraorbital veins.

Sensory Nerves Anterior to the Auricle on the SCALP

• The three branches of the trigeminal nerve (CN V) are responsible for sensory innervation
• The ophthalmic, maxillary, and mandibular nerves provide sensory information to the SCALP anterior segment

Sensory Nerves to Posterior Segment of the SCALP

• The dorsal rami of the cervical spinal nerves (C2 and C3) provide sensory innervation
• The greater and lesser occipital nerves are the source of feeling

Lymphatic Drainage

• Lymphatic vessels drain into the submental, submandibular, parotid, mastoid, retroauricular, and occipital lymph nodes.
• The aforementioned lymph nodes primarily drain into the deep cervical lymph nodes.

Face

• Unlike other parts of the head, There is no deep fascia
• In certain regions, superficial fascia is thicker

Face Muscles

• These muscles are located in the subcutaneous tissue
• The muscles extend from bone, or facia, to skin.
• The flexibility of the underlying muscles allows the face to express a variety of emotions through moving the facial skin

Innervation of the Face and Expression

• The facial nerve, also called CN VII, innervates muscles related to expression
• Nerve fibers that innervate facial muscles are classified as SVE (special visceral efferent).

Epicranius Muscle

• Muscles in the SCALP have two parts: the frontalis and occipitalis
• Frontal part elevates the eyebrows when surprised
• Occipital part pulls forehead skin backwards when stretching

Orbicularis Oris Muscle

• This muscle surrounds the mouth and is involved in behaviors such as whistling, where it narrows the mouth.

Depressor Labii Inferioris Muscle

• This muscle pulls the lower lip in an inferior motion

Depressor Anguli Oris Muscle

• This muscle depresses the angle of the mouth

Mentalis Muscle

• This muscle Raises the skin above the chin

Levator Labii Superioris Muscle

• This muscle is responsible for elevating elevation of the upper lip.

Levator Anguli Oris Muscle

• This muscle is responsible for elevating the angle of the mouth

Zygomaticus Major Muscle

• This muscle is responsible for elevating the angle of the mouth, acting superolaterally

Zygomaticus Minor Muscle

• This muscle elevates the angle of the mouth

Levator Labii Superioris Alaeque Nasi Muscle

• This muscle Elevates the upper lip.

Risorius Muscle

• This muscle Pulls the corner of the mouth laterally

Buccinator Muscle

• This muscle functions in blowing, whistling and sucking
• It presses the cheek against the tooth and helps in chewing

Orbicularis Oculi Muscle

• The Palpebral part Gently closes the eyelid
• The Orbital part Strongly closes the eyelid
• Lacrimal part Help to drain the lacrimal punctum (contains lacrimal fluid)

Depressor Supercilii Muscle

• This muscle Approximates the eyebrows

Corrugator Supercilii Muscle

• This muscle Wrinkles the forehead vertically.

Nasalis Muscle

• The Transvers part (inf.) Compresses the opening of the nostrils
• The Alar part (sup.) Widens them

Procerus Muscle

• This muscle Draws the eyebrows inferiorly, and produce transverse wrinkles over the bridge of the nose

Depressor Septi Muscle

• This muscle Widens the nostrils.

Platysma muscle

• The muscle extending to the neck

Motor Nerve Face Innervation

• Motor Function is from Facial Nerve
• Sensory information is from the Trigeminal Nerve

Facial Nerve CN VII

• SVE fibers are in all muscles of facial expression
• SVA fibers receive taste sensation from the anterior 2/3 of the tongue
• GVE fibers supply parasympathetic motor fibers going to the submandibular and sublingual glands, in addition to salivary and lacrimal glands
• GSA fibers respond to sensation near the external acoustic meatus

Facial Nerve Path

• Leaves the CNS and enters the temporal bone through the internal acoustic meatus
• The nerve then follows an "S" shape inside the temporal bone (in the facial canal)
• it leaves the skull through the stylomastoid foramen and gives its posterior auricular nerve
• The nerve then Enters into the tissue of parotid gland, where it splits, branching into five terminal nerve groups: Temporal, Zygomatic, Buccal, Marginal mandibular, as well as Cervical

Greater Petrosal Nerve Branch

• Arises as it enters the facial canal at the level of the geniculate ganglion, which is the sensory ganglion of the facial nerve
• Carries presynaptic parasympathetic fibers to the pterygopalatine ganglion
• Extends forward and enters into the pterygoid canal and terminates at the pterygopalatine ganglion
• Termed as the nerve of the pterygoid canal" within said canal
• Postsynaptic parasympathetic nerves arise from the pterygopalatine ganglion and innervate the lacrimal gland

Nerve to Stapedius Muscle Branch

• Supplies nerves to the stapedius muscle
• Said muscle is one of two inside the middle ear

Chorda Tympani Branch

• It is the last branch of the facial nerve within the facial canal
• Enters the middle ear cavity (tympanic cavity) and runs close to the tympanic membrane
• Leaves the skull passing through petrotymanic fissure, joining with the lingual nerve toward the tongue
• Carries presynaptic sympathetic axons going to the submandibular ganglion
• As the postsynaptic parasympathetic axons arise from ganglionic neurons within the submandibular ganglion, it innervates nearby submanibular and sublingual glands
• The chorda tympani carries the axons conveying taste sensation from the anterior 2/3 of the tongue

Branches as it Leaves the Stylomastoid Foramen

• Posterior auricular nerve, by Supplying the motor innervation of the rudimented muscles of the auricle and the occipital part of the occipitofrontal muscle.
• This nerve also Receives feedback from sensory information in the skin surrounding the auricle.
• A Motor branch, to the stylohyoid muscle andthe posterior belly, are also nearby
• And of course Temporal
• Zygomatic
• Buccal
• Marginal mandibular, as well as the previously mentioned Cervical
• These branch to create Muscles for facial expression

Trigeminal Nerve, CN V

• GSA fibers transmit sensory information for the face
• SVE fibers support motor innervation for muscles of mastication like some others
• CN V splits into Ophtalmic Nerve, Maxillary Nerve, and Mandibular Nerve

Ophthalmic Nerve: (V1)

• Sends sensory information as its sole role
• Enters orbit through the superior orbital fissure
• Branches supply the superior portion of the nasal cavity, as well as the eueball
• Leaves at orbit to go into related components surrounding the face

As the Ophthalmic Nerve Enters Orbit It Releases

• Frontal (a branch)
• Lacrimal (another branch)
• The Nasociliary Division: (A nerve part that also branches)
• Frontal, and from it 2 final connections, which are both inside orbit
• As part, Supraorbital supplies the mucosa with feedback about frontal sinus pressure levels, with a feedback function that also has access for skin of forehead use
• The Supratrochlear has control via nearby Supraorbital use by its own individual nerve to middle of nearby skin sections surrounding

Maxillary Nerve (V2)

• Transfers Sensory feedback with no motor information running through it
• Exits bone cavities while passing the foramen
• Leads out to pterygopalatine space
• All maxillary-related connections reach out until entering up some inferior opening from within a facial
• Travels last bit by a part called
• infraorbital

Maxillary Nerve, Branch Components:

• Zygomatic division – This gives off a pair by means of going along thru structures nearby together as they bring messages about both sides or over that same stretch

• Nasopalatine Nerve: Which leads into those openings while bringing a transmission. – The Pterygopalatine parts link this into those channels; there's still signals to have some response – Supply keyareas, like those by where they connect/make for these various responses, before moving on into this type zone by using certain types. --- The branches help enable signals with in nasal walls or parts nearby ---------- The connections make feedback on both the top half, such at top tooth edges

The Key Mandibular Section:

• (V3)This connection sends out both reactions that need it and info received from contact to area within with its muscles which do chewing
• Travel through bone by passing from ovale to send some through below at temple area when going down in distance
• ** These three divisions of cranial area has something nearby the path from which it goes, as every path in those area's as sensory component.

CN V1 Ophthalmic is the one that the nerve with skin area has 2 pieces

  ### CN43, The Muscle Connector has a special pathway

There are two components, both has the parts we need to create some effects

(We require specific action) That comes away via sides down over place to then move

Branch of Posterior

A set that help for each kind's action

A : With Spinous support will have signal so has function of knowing if damage for the dura. Medial Pterygoid helps have its messages work , as with helping know amount of energy its had for what it will

(More notes relating to the facial arterties were ommitted here)

Vessels in Region (Veins - More notes were ommitted here)

• Veins will run that match vessels for these nerves above
• They create those pathways on which body signals, messages etc. runs
• It lets bodies make up its action pathways
• Exterior route: it creates action on those under side with
• Those inside routes help take messages toward top It is what allows face do facial motions or sense pain etc. all those together as just parts and types etc : (Facial vessel, sensory messages)
• This was not everything, but should cover some bases*