Facial skeleton, in red. Develops from pharyngeal arches. Nasal, Inferior Nasal Concha, Palatine, Lacrimal, Ethmoid (except cribiform plate), Zygomatic. Mandible, Vomer, Maxilla,Temporal (tympanic portion, including the styloid process),Sphenoid (Pterygoid processes).
Brain skeleton, in white. Develops from paraxial mesoderm. Sphenoid, Temporal, Ethmoid, Parietal, Occipital, Frontal (STEPOF my skull!)
Bones of the Cranium
27 + mandible. Sutures between bones to hold it together, allow for growth. As brain grows, cranial elements around them grow/expand to accommodate. If skull was just one bone, different rates of growth would not be able to be accomodated.
Smallest bone in face. Front medial wall of orbit.
Upper lateral part of face, forms prominence with cheek. Floor of the orbit.
Form the bridge of the nose
Separates nasal cavity from the brain. Located at roof of nose, between two orbits.
Middle Nasal Concha
Medial surface of labryinth of ethmoid ends in middle nasal concha. Directed vertically downward from cribiform plate.
Crest of a rooster. Attachment for dura
Junction for olfactory bulb (CN1), will line either side and innervate nose. Penetrate though holes in cribiform plate to reach nose.
Ethmoid Air Cells
Composed of pockets of air cells, holes in bone
Exist to increase surface area --> more gaseous exchanges/more moisture picked up
Lamina papyracea (layer of paper). Very thin, succeptible to breakage. Forms medial surface of the orbit.
Perpendicular plate (ethmoid bone)
thin lamina of the ethmoid bone, descends from cribiform plate assiting in forming the septum of the nose.
Inferior Nasal Concha
Extends horizontally down lateral wall of nasal cavity
Immediately behind ethmoid.
Greater wing of sphenoid
Lateral. Larger than lesser. Curved upward, laterally, and back. Features: foramen rotundum, foramen ovale, and foramen spinosum.
Lesser wing of sphenoid
Medial. Two thin plates, end in sharp points. Main features are optic canal and superior orbital fissure.
Top foramen of the sphenoid, transmits the maxillary nerve
Middle foramen of the sphenoid, transmits the mandibular nerve, the accessory meningeal artery, and lesser petrosal nerve
Bottom foramen of the sphenoid in the posterior angle near to and in front of the spine; transmits recurrent branch from mandibular nerve
Superior orbital fissure
CN 3,4, Optic 5, and 6 pass through. Part of lesser wing of sphenoid
Superiomedial of sphenoid bone. Lateral of sella turcica
Runs posteromedially through sphenoid bone. Transmits nerve, artery, and vein of pterygoid canal
CN2 (Optic Nerve) passes through. Medial in sphenoid bone
Turkish Cell. Depression in Sphenoid bone, holds pituitary gland. Most medial in sphenoid bone.
Part of sphenoid bone Involved in Mastication. Consist of a medial and lateral bone fused at their upper parts.
Has parts in viscerocranium and neurocranium.
Attachment for muscles. Just below acoustic meatus.
Squamous part of temporal bone
Component of temporal bone. Forms lateral component of neurocranium.
Petrous part of temporal bone
component of temporal bone. wedged in at the base of the skull between the sphenoid and occipital bones
Between medial cranial fossa to posterior cranial fossa in interior.
Has internal/external components. Petrous part of temporal bone + ear canal
Internal acoustic meatus
CN 7/8 pass through
External acoustic meatus
Tympanic part of temporal bone
in front of mastoid process, surrounds acoustic meatus
Arched process connecting temporal with zygomatic bone.
depression in the temporal bone that articulates with the mandibular condyle. Bounded by the articular tubule.
Deep depression in temporal bone posterior to carotid canal. Lodges the bulb of the internal jugular vein.
Carotid passes through temporal here
Transmits facial nerve and stylomastoid artery
Aparatus of Ear
Ossicles: Malleus, Incus, Stapes. Aka middle ear, house the ossicles.
Aka eustachian tube. Links nasopharynx to middle ear. Important for pressure equalization.
form upper jaw/palate of mouth
Vomer + ethmoid separate nasopharynx. Unpaired bone. Located at midsaggital line, forms posterior portion of nasal septum. Thin
Situated at the back of the nasal cavity between maxilla and pterygoid process of sphenoid. Articulates w/ maxilla.
Pockets of air lined with mucous membranes
Passageway from frontal sinuses into ethmoidal area
Largest sinuses. Found in body of maxilla, drain into middle meatus of nose.
Contained in body of sphenoid.
Form lower jaw.
Head and neck of mandible. Point where it articulates with the articular disc of the temporomandibular joint.
Ramus of Mandible
Lateral surface of dorsal mandible
Anteroposterior ridge of mandible
Alveolus of Mandible
Anterior to teeth, tooth socket
opening on the internal surface of the ramus. Allows mandibular nerve and vessels to pass
Groove along interior of mandible, lodges mylohyoid vessel/nerves.
attachments to temporalis and masseter muscles
responsible for structure of chin
allows passage of mental nerve and vessels
Plate-like bones surrounding the brain. "Skull-cap". Unique plate-like bones composed of inner and outer tables, with cancellous diploë in between
Layer consists of bone containing red bone marrow
Bones of the Orbit
Bones of orbit: Sphenoid, frontal, lacrimal, ethmoid, palatine, maxilla, zygomatic
Bones of Nasal Cavity/Nasalpharynx
Vomer, ethmoid, Nasal, Lacrimal, Ethmoid, Sphenoid, palatine, inferior nasal concha, maxilla
Only moving joint of the cranium. Head of mandible rides on Articular Tubercle, not against the Mandibular Fossa
Suture between Frontal and parietal
Suture between Sphenoid and parietal. Found at position of pterion.
Suture between squamous and parietal
Cranial suture from parietal to occipital
Occipital to mastoid (petrous part of temporal)
Destroyed with age, sutures together sagitally the frontal bone
Between two parietal bones in skull
Soft membranous gaps in infants' head between incomplete sutures in the cranium. Colloquially refered to as "soft spots"
Seen in skulls when undergoing rapid growth, bony elements along sutures. Also refered to as Incan/Wormian bone
Le Fort Classification
Maxillary bones (and their neighbors) tend to fracture in set patterns; bilaterally and either horizontally, pyramidally, or transverly.
Large opening in occipital bone of cranium, spinal cord exits. Medulla oblongata, vertebral arteries, and accessory nerve (CNXI)
Premature fusion of one side of crania, either coronal or lambdoidal sutures ( flattening of one side of the skull). Flat head syndrome, increased because of SIDS training --> babies being put on their back.
Deformities resulting from premature closure of cranial sutures. Type of deformity depends on which sutures fuse prematurely. 5-8% of newborns
Long narrow head resulted from premature fusion of sagittal suture (40-60%)
Premature fusion of coronal suture (20-30%). Another form of "flat head" syndrome. [Note not from lecture: This is frequently a characteristic of Down Syndrome]
Premature fusion of metopic suture (<10%). Results in triangle shaped forehead as visible from top.
Premature fusion of coronal, lambdoidal, and sagittal. Extremely rare. Skull appears clover shaped, usually a significant reduction in IQ.
Severe reduction in brain size
abnormal buildup of CSF in the ventricles of the brain --> increase of cranial pressure --> mental disability/death
Coronal suture and sagittal suture intersection
Point where eyebrows come together. Right above naison
Intersection of frontal bone and nasal bones
intersection of the frontal, temporal, sphenoid, and parietal bones, generally along the sphenoparietal suture
The point at the intersection of the sagittal and lambdoidal sutures
Anterior Cranial Fossa
depression in the floor of the cranial vault which houses the frontal lobes. Formed by frontal bones, cribiform plate of ethmoid, and sphenoid
Middle Cranial Fossa
Houses temporal lobe of brain.
Posterior cranial fossa
Houses cerebellum, pons, and medulla
Nasopalatine Nerve (from CN V2) and Sphenopalatine Vessels
Greater and Lesser Foramen
Greater and Lesser Palatine Nerve (from CN V2) and Vessels
Mandibular Nerve (CN V3) and Accessory Meningeal Artery
Foramen Spinosum (Base of Cranium)
Middle Meningeal Artery and Meningeal Branch of Mandibular Nerve (CN V3)
Internal Carotid (Carotid Canal passes through horizontally)
Carotid Canal (Base of Cranium)
Internal Carotid Artery
External Acoustic Meatus (Base of Cranium)
Stylomastoid Foramen (Base of skull)
Facial Nerve (CNVII)
Inferior Petrosal Sinus becomes Internal Jugular Vein, Glossopharyngeal Nerve (CN IX), Vagus Nerve (CN X), Accessory Nerve (CN XI), and Posterior Meningeal Artery
Located below Condyle. Hypoglossal Nerve passes through