Face, Scalp and Skull Flashcards
What is the portion of the skull making up the face?
Viscerocranium
What is the viscerocranium derived from?
Pharyngeal arches which come from neural crest cells
The portion of the skull that contains the brain and brainstem (meninges as well) would be what?
Neurocranium
What are the parts of the neurocranium?
- Cranial Base (basicranium): underlying the brain
- Cranial Vault (calvaria): covers the brain
- Sensory Capsules: bones encapsulating sensory organs
What is Endochondral Ossification? Give an example(s)
Hyaline cartilage that is replaced by bone (Cranial Base = chondrocranium)
What is Intramembranous Ossification? Give an example(s)
Bone tissue that directly replaces mesenchyme. (Calvaria, maxilla, mandible, zygomatic, squamous portion of temporal bone)
What is Pharyngeal Arch Derivatives (in relation to ossification)? Give example(s)
Neural crest cells that migrate into arches and from bone. (Malleus, incus, stapes, styloid process of temporal bone, hyoid bone)
Pharyngeal Arch 1 becomes what bones?
Arch 1: Maxilla, mandible, zygomatic bone, malleus, and incus
Pharyngeal Arch 2 becomes what bones?
Arch 2: Stapes, styloid process, lesser horn of hyoid, and superior portion of the hyoid
Pharyngeal Arch 3 becomes what bones?
Arch 3: Greater horn of hyoid and inferior portion of hyoid
All of the cranial base is ossified except for what?
Nasal Septum and Spheno-occipital synchondrosis (SOS)
What are the three modes of pistnatal growth?
Endochondral, Sutural, and Remodeling
What is Endochondral growth?
Occurring at synchondroses, it is similar to epiphyses of long bones where hyaline cartilage is replaced by bone
What is Sutural growth?
Creation of bones in sutures
What is remodeling growth?
Complex scouring and addition of bone to create a new surface
Facial bones develop from what?
mesenchyme of pharyngeal arches
What are the sinus of the skull
Sphenoid, ethmoid, maxillary, and frontal
When do sinuses develop?
Birth: not present
1 year: Growth center present
2 years: Definitive sinuses
When do the fontanelles close?
3 months: Posterior and anterolateral fontanelles
2 years: Anterior and posterolateral fontanelles
What are the types of Craniosynostoses?
Sagittal (Scaphocephaly): Premature closure of sagittal suture
Coronal: premature closure of one (anterior plagiocephaly) or both (brachycephaly) coronal sutures
Metopic (trigonocephaly): premature fusion of metopic suture
Lambdoid (posterior plagiocephaly): premature closure of lambdoid suture
What is the treatment for craniosynostosis?
Helmet that acts like the skull
What structures make up and are found in the Anterior Cranial Fossa?
Bones: Frontal, Ethmoid, Sphenoid
Brain: Frontal Lobe
Nerve: Olfactory Nerves
Structures: Orbit of the eyes just inferior
What structures make up and are found in the Middle Cranial Fossa?
Bones: Sphenoid and Temporal
Brain: Temporal Lobe
Arteries: Middle Meningeal Artery
Nerve: CN II, CN III, IV, V, VI
Structures: Cavernous Sinus, Pituitary Gland, and Hypothalamus
What structures make up and are found in the Posterior Cranial Fossa?
Bones: Temporal and Occipital
Brain: Cerebellum
Nerve: CN VII, VIII, IX, X, XI, XII
Structures: Brainstem (pons and medulla)
What are the muscles of facial expression?
Frontalis
Orbicularis oculi
Procerus
Nasalis
Levator labii superioris
Zygomaticus
Levator anguli oris
orbicularis oris
Risorius
Mentalis
Depressor Anguli oris
Platysma
Buccinator
Levator labii superioris alaeque nasi
What nerve innervates muscles of facial expression?
CN VII (Facial)
What is the pathway in which the facial nerve innervates the muscles of facial expression?
- Brainstem
- CN VII
- Internal Acoustic Meatus
- Geniculate Ganglion
- Facial Canal
- Stylomastoid Foramen
- Muscles
What is the pathway in which the facial nerve innervates glands and tongue?
- Brainstem
- CN VII
- Internal Acoustic Meatus
- Middle Ear (chorda tympani)
- Petrotympanic fissure
- Lingual N (CN V)
- Submandibular Ganglion
- Taste of anterior 2/3 tongue and submandibular and sublingual glands
The Facial Nerve (CN VII) gives off what branches?
Posteriorly: Posterior Auricular Nerve
Anteriorly: Temporal, Zygomatic, Buccal, Mandibular, Cervical
Name the branches of the external carotid artery.
Superior thyroid artery
Ascending pharyngeal artery
Lingual artery
Facial artery
Occipital artery
Posterior auricular artery
Maxillary artery
Superficial temporal artery
The facial artery branches into what arteries?
Superior and inferior labial artery
Angular Artery
What are the layers of the Scalp?
Skin
Connective Tissue
Aponeurosis (epicranial)
Loose (areolar) connective tissue
Periosteum (pericranium)
What veins drain into the external jugular vein?
Posterior auricular + Superficial temporal and auriculotemporal vein
The supraorbital and infraorbital veins drain deeply to the what?
Cavernous sinus (and the pterygoid plexus)
What is clinical relevant to the cavernous sinus?
Active site for infections to travel (meningitis)
What is the pathway of veinous drainage of the superficial scalp?
Scalp veins -> emissary veins -> dural venous sinus
Describe the cutaneous innervation of the face/scalp
V1 (ophthalmic n): Tip of nose and frontal bone
V2 (Maxillary n): Lateral nose and cheek
V3 (mandibular n): Mandible and anterior ear
C2 (greater and lesser occipital): Greater posterior scalp and lesser is right behind ear
What are the branches of V1 that innervate the skin?
- Supra-orbital
- Supratrochlear
- Lacrimal
- Infratrochlear
- External nasal
What are the branches of V2 that innervate the skin?
- Infra-orbital
- Zygomaticofacial
- Zygomaticotemporal
What are the branches of V3 that innervate the skin?
- Buccal
- Mental
- Auriculotemporal
Define Bell’s Palsy
Paralysis of muscles of facial expression due to lesion or inflammation around facial nerve
- might not have anterior 2/3 taste on tongue
- might not have decreases secretion from glands
- Will have loss of efferent limb of corneal reflux
What is the most common cause of Bell’s Palsy?
Inflammation of nerve at the stylomastoid foramen
What is Herpes Zoster Oticus?
Ramsay Hunt Syndrome where the varicella zoster virus in the geniculate ganglion becomes active
Symptoms: Otalgia (ear pain), auricular vesicles, peripheral facial paralysis
What is Trigeminal Neuralgia?
Mild to severe pain along the branch of the trigeminal nerve due to compression of nerve, sclerosis, tumors, ect…
The Herpes Zoster Virus (found in the dorsal root ganglion) can affect the trigeminal nerve. Which branch is most commonly affected?
V1
