1 - Zill - Skull Flashcards
Why is the risk of hematomas so high in the skull?
There is no room inside cranial cavity, cavity molded to brain like glove
Skull Sutures
Fibrous connective tissue joints
Progressively fuse with age
Calvarium
Skull Cap
Bones of Skull Cap
Frontal
Parietal (2)
Occipital
Temporal (2)
Sphenoid
Junction of Temporal Sphenoid, Parietal, and Frontal Bones?
Clinical Relevance?
Pterion (“tear-ee-on”)
Skull fractures easily here, clinically important for epidural hematoma
Fontanelles
Membranes that link bones at birth, aka soft spots
Anterior @ Bregma
Posterior @ Lambda
Lateral @ Pterion
What can be used to access the Superior Sagittal venous sinus in neonates?
Anterior Fontanelle
Three Layers of Skull bone?
1 & 3: Inner/Outer - Hard Cortical Bone
2: Middle - Soft spongy bones, Diploe
Diploic Veins
Clinical Importance?
Course in diploe, connect cranial cavity and surface of skull
- - -
Can transmit infection from scalp to brain via emissary veins
Emissary Veins
Connect:
Scalp to Diploe
Scalp to Sinus
Diploe to Sinus
Connect Outside to Venous Sinus; can transmit infections this way
Bridging Vein
How are these different from Emissary Veins?
Connect surface of brain (cerebral vein)** to **venous sinus
“Inside to venous sinus”
- - -
Remember, emissary veins connect “Outside to venous sinus”
Blood Supply to Calvarium
Outer and Inner?
Clinical?
Outer: Arteries to Scalp
Inner: Meningeal Arteries
Clinical: Skull fracture @ pterion can cause bleeding of Meningeal arteries, and lead to epidural hematoma
Layers of the Scalp (5)
Mnemonic is SCALP!
- S: Skin - Hair, sweat, sebaceous glands
- C: Connective Tissue - Surround vessels, em. veins
- A: Epicranial Aponeurosis - Moveable tendinous sheet
- L: Loose Areolar Tissue - Connect apon. and perio, emissary veins cross
- P: Periosteum - CT layer on outer side of calvarium
Spreading of Infections Through Scalp
Clinical?
“Scalping” - What layers?
Clinical: Infections can spread through loose areolar layer, deep to epicranial aponeurosis (layers 3 and 4)
- - -
Scalping someone is removal of area between the same two layers, 3 and 4
Epicranial Aponeurosis / Loose Areolar Tissue
Nerves of Scalp:
Branches of What?
Additional Innervation?
Branches of Trigeminal (V)
V1: Supraorbital N., Supratrochlear N.
V2: Zygomatico-Temporal N.
V3: Auriculo Temporal N.
Lesser Occipital N. - C2 Ventral Ramus
Greater Occipital N. - C2 Dorsal Ramus
Arteries of Scalp:
Mainly branches of what major vessel?
Why can these bleed excessively?
Major named branches?
Internal and External Carotid A. (some Ophthalmic A.)
Can bleed profusely due to high anastomoses
-
Opthalmic Branches:
- Supraorbital A.
- Supratrochlear A.
-
External Carotid Branches:
- Superficial Temporal A.
- Posterior Auricular A.
- Occipital A.
Temporal Bones Parts (4)?
- Mastoid Process: Hard, palpable behind ear
- Squamous Part: Flat, above ear
- Tympanic Part: Anterior to External Auditroy Meatus
- Petrous Part: Inside skull
Clinical Fractures of Lateral Skull?
Clinical relevance of Temporo-Mandibular Joint?
- Zygomatic Bone (cheek)
- Maxillary Bone-Zygomatic Process
- Temporal Bone-Zygomatic Process
- - -
“TMJ” Disorders
What bone serves as the “core” of the skull?
Sphenoid
Turkish Saddle
Major Landmarks of Sphenoid Bones
Lesser Wing - above Superior Orbital FIssure
Greater Wing - Below Superior Orbital Fissure (extends laterally)
Sella Turcica - “Turkish Saddle” - Depression and Location of Pituitary Gland
Posterior Portion of Sella Turcica?
Clinical Relevance?
Clivus
Meningioma at Clivus
Complex symtoms, many can be present (blurry vision, nauseu, eating, balance)
