Skull and Cranial Cavity

Question 1

Protects the brain, allowing it to expand and develop.
-Creates the Cranial Cavity (pit the brain sits in) and the Skull Cap (Calvaria - the dome)
-Upper 2/3 of orbit and up (except for nasal bone)
-Frontal Bone
-2 Parietal
-2 Temporal
-Occipital Bone

Answer 1

Neurocranium

Question 2

Facial Skeleton
-Lower 1/3 of orbit and down, plus Nasal bones.
-2 Nasal Bones
-Horizontal plate of the Palatine Bone
-2 Lacrimal Bones (right behind nasal bones)
-Ethmoid Bone (perpendicular plate)
-2 Zygomatic Bones (cheekbones)
-Maxilla
-Inf nasal conchae
-Vomer
-Mandible

Answer 2

Viscerocranium

Question 3

Bones are separated by Fibrous sutures that make fibrous joints.
-Start out with very loose and expansive sutures as the brain enlarges in size.
As we grow older, sutures become ossified. When they are completely ossified, say they are synostosis (suture has been replaced with a bony line).

Answer 3

Sutures

Question 4

In infancy, frontal bone is actually 2 bones separated by this. Closes and starts ossifying early in life (3-9 months of age)

Answer 4

Metopic Suture

Question 5

-Soft spots not covered by bone, just covered by meninges (dura mater)
-Unossified gaps between bones
-Generally close within the first year of extrauterine life
-Complete ossification (Synostosis) occurs during the 5th decade of life.

Answer 5

Fontanelles

Question 6

Diamond Shaped.
Between the frontal and parietal bones.

Answer 6

Anterior Fontanelle

Question 7

Triangular Shaped. Between the parietal and the occipital bones.

Answer 7

Posterior Fontanelle

Question 8

Fontanelle between the Parietal bone and greater wing of the Sphenoid.
-Begins to close during the first year of life

Answer 8

Anterolateral Fontanelle

Question 9

Fontanelle between the temporal bone and occipital bone.
-Begins to close during the first year of life

Answer 9

Posterolateral Fontanelle

Question 10

Children are more likely to develop ear infections (Otitis Media) than adults due to this being more horizontal (Adults point forward, down, and medially)

Answer 10

Eustachian tube

Question 11

Bones that lie within the sutures, mainly within Lambdoid Suture.
-Genetic aberration or due to disease (Osteogenesis Imperfecta, Rickets, Vit D deficiency, Cleidocradnial Dysostosis, Down Syndrome)

Answer 11

Wormian Bones

Question 12

Superficial Layer, compact and dense bone

Answer 12

Outer Table

Question 13

Intermediate layer. Cancellous (spongy) bone containing red marrow and venous pathways.

Answer 13

Diploe

Question 14

Deep layer, compact and dense bone that is brittle and breaks easily

Answer 14

Inner Table

Question 15

-Frontal Diploic Vein
-Anterior Temporal Diploic Vein
-Posterior Temporal Diploic Vein
-Occipital Diploic Vein

Drain the scalp, bones of the neurocranium, and terminate in dural venous sinuses to be returned into peripheral circulation

Answer 15

Diploe

Question 16

Draining blood out of the scalp, pierces outer table of the bone, and lies in the intermediate layer (Diploe) layer. Joined by the Diploic vein.

Answer 16

Scalp Vein

Question 17

Where scalp vein and Diploic Vein come together.
-Receives venous drainage from the scalp veins and Diploic Veins.
Pierces the skull and drains into the Superior Sagittal Sinus. Blood goes back into circulation to be recycled.
Valveless - allow for retrograde flow (infection risk)

Answer 17

Emissary vein

Question 18

-Roof: Frontal Bone with 2 orbital plates
-Medial Wall: Lacrimal Bone, Orbital Plate of the Ethmoid Bone, Perpendicular Plate of the Palatine bone (very tiny) and the Crista Galli
-Lateral Wall: Zygomatic Bone
-Floor: Maxilla
Apex: Greater wing of Sphenoid; contains Optic Canal (for CN II) and Ophthalmic Artery.

Answer 18

Orbit

Question 19

Optic Nerve and Ophthalmic Artery pierce the skull via this

Answer 19

Optic Canal

Question 20

Contains the infraorbital vein (drains orbit) and also running with it is Inferior Orbital Nerve (supplies general sensation to the face)

Answer 20

Inferior Orbital Fissure

Question 21

Groove coming out of the Inferior Orbital Fissure that conducts the Infraorbital Nerve (Gen sen to face/viscerocranium)

Answer 21

Infraorbital Groove

Question 22

Contains the Nasolacrimal Duct (terminates in Inf. Nasal Concha)

Answer 22

Nasolacrimal Canal

Question 23

Thinnest area of the skull; start at top of ear and measure out in front about 1.25 in.
-Coming together of squamous portion of temporal bone with greater wing of sphenoid and parietal bone
-Location of Anterior Branch of Middle Meningeal Artery (Supplies blood flow to Meninges)
-Fx here = Epidural Hematoma

Answer 23

Pterion

Question 24

Positioned between the Dura Mater and the Inner table of the bones of the periosteum (epidural space).
Injuries can cause hematoma - compresses brain and pushes it over to one side

Answer 24

Middle Meningeal Artery

Question 25

-Forms the orbital plates -Forms the forehead -Contains the Frontal Lobes and Cerebral Cortex -Shallow depression in the front is where the frontal lobe sits (Anterior Fossa)

Answer 25

Frontal Bone

Question 26

-Posterior portion of the skull and cranial cavity -Deep well to contain the cerebellum and the brainstem -Foramen Magnum: Large opening in the center. Allows the brainstem to transition to the spinal cord

Answer 26

Occipital Bone

Question 27

-Singular bone with 2 greater wings and 2 lesser wings with 2 Anterior Clinoid Processes -Body contains Hypophyseal fossa (pituitary gland sits here) -Dorsum Sellae contains Posterior Clinoid Processes -Tuberculum Sellae -Lateral and Medial Pterygoid Plates (with Hamulus of Medial)

Answer 27

Sphenoid Bone

Question 28

-Hypophyseal Fossa -Posterior Clinoid Processes -Dorsum Sellae -Tuberculum Sellae

Answer 28

Sella Turcica

Question 29

Squamous: Flat portion Zygomatic: Helps form cheek External Auditory (Acoustic) Meatus: Hole Mastoid Process: behind ear Styloid Process: needle-like structure Petrous Portion: Rock cliff

Answer 29

Temporal Bone

Question 30

Basilar part Occipital condyles (where the skull articulates with the 1st cervical vertebrae) Foramen magnum External Occipital Protuberance Superior Nuchal Line Inferior Nuchal Line Clivus Internal Occipital Protuberance

Answer 30

Occipital Bone

Question 31

Space medial to mandible. -In between lateral pterygoid plate -above greater wing of the sphenoid -below it is skin -Depression underneath mandible

Answer 31

Infratemporal Fossa

Question 32

-Runs diagonally, very hard bone -Contains the inner ear (Cochlea - hearing, Vestibule - static positioning, and 3 Semicircular Canals - balance and equilibrium) -Run in different planes so we can keep our balance and equilibrium. Contain receptors within each. Internal Acoustic Meatus: -Runs with Vestibulocochlear Nerve (CN VIII). Balance, equilibrium, and hearing. -Facial Nerve also runs through internal acoustic meatus

Answer 32

Petrous Portion of Temporal Bone

Question 33

Anterior: very shallow, frontal lobe/cerebral cortex Middle: deeper than anterior, contains temporal lobes of the cerebral cortex Posterior: Deepest. Contains cerebellum and brainstem.

Answer 33

Cranial Fossae

Question 34

Occipital bone Parietal bone Petrous portion of the temporal bone

Answer 34

Posterior Cranial Fossa

Question 35

Greater wing & Body of the sphenoid bone Petrous and squamous part of the temporal bone

Answer 35

Middle Cranial Fossa

Question 36

2 Lesser wings of the sphenoid bone (with anterior clinoid processes) Frontal Bone & 2 Orbital plates 2 Cribriform plates of the ethmoid bone Crista galli of the ethmoid bone

Answer 36

Anterior Cranial Fossa

Question 37

Forms the lower jaw. Articulates with the Temporal Bone at the TMJ (Temporomandibular Joint) -Can get arthritis in this joint, pain, etc.

Answer 37

Mandible

Question 38

Composed of a mandibular condyle and the mandibular fossa (in the temporal bone). -can open/close jaw and lateral movement (grind), protraction/retraction.

Answer 38

TMJ

Question 39

-Elevation (closes): Temporalis, masseter, and medial pterygoid -Depression (opens): Digastric, geniohyoid, mylohyoid, and Lateral Pterygoid Muscle

Answer 39

Movement of the Mandible

Question 40

The Mandibular Foramen transmits this nerve. -Branch of Trigeminal n. -Runs into jaw, penetrates mandibular foramen, continues down into lower jaw and gives sensation to lower teeth. Emerges on either side of the chin via the mental foramen and then it becomes the mental nerve.

Answer 40

Inferior Alveolar Nerve

Question 41

Supplies general sensation to the lower teeth, lower lip, and chin; lies right behind the Lingual Nerve

Answer 41

Mental Nerve

Question 42

SCALP: -Skin -Connective Tissue (bleeding occurs if cut happens here) -Aponeurosis (thin muscle that connects frontalis m. with occipitalis m.) -Loose Connective Tissue: Allows you to wiggle skin around on your scalp (infection risk!!!! no resistance to keep it from spreading) -Pericranium (periosteum): Connective tissue (stiff) surrounding the bone

Answer 42

Layers of the Scalp

Question 43

Also called the Galea Aponeurotica -3rd Layer of the Scalp -Attachment of the Frontalis m. and the Occipitalis m.

Answer 43

Scalp Aponeurosis