Skull trauma anatomy

Question 1

What are the complications of skull fractures?

Answer 1

Possible brain damage, intrusion of bone fragments
Epilepsy
Infection

Question 2

Discuss a high-velocity impact on the skull.

Answer 2

produces penetrating
depressed fractures localized, impacts,intrusion of bone
radiating fissures (spider’s web)
may injure underlying brain

Question 3

Discuss flat impact.

Answer 3

Produce linear, non-displaced fractures
- straight or curved lines
- tend to follow lines of force
- course modified by suture lines and convolutions of skull

Question 4

Discuss ring impact.

Answer 4

Circular (around foramen magnum)
- falls onto feet from a height

Question 5

Discuss open head injury.

Answer 5

Occurs when the skull is penetrated by a sharp instrument (such as a knife) or an
explosive missile (such as a bullet or shell fragments)
In penetrating head injuries, tissue damage will be found at the point of
penetration and surrounding the path of the intruding object

Question 6

What are the consequences of open head injury?

Answer 6

– swelling,
– lacerations from skull fragments,
– and vulnerability to infection and further injury

Question 7

Discuss a close head injury.

Answer 7

Is primarily caused by a blunt impact or
blow to the head without penetrating the
skull
The most common form of brain damage
is caused by a closed head injury

Question 8

What are the complications of a closed head injury?

Answer 8

– swelling,
– increased intracranial pressure,
– and tissue compression

Question 9

Discuss the pathogenesis of specific head injuries.

Answer 9

Sudden impact to the head causing change in momentum or movement of the brain
The sudden change in movement may over stretch blood vessels in the brain and cranial
nerves

Question 10

Explain contusions.

Answer 10

that are both at the site of the impact and on the complete opposite side of the primary impact
A contusion is a visible bruise (bleeding) on the brain

• Anteroinferior frontal
• Anterior Temporal
• Occipital Regions

Petechial hemorrhages- coalesce- intracerebral hematomas later on

Question 11

Discuss diffuse axonal injury.

Answer 11

Diffuse Axonal Injury is caused by strong rotational forces of the head, such as with a car accident
* The unmoving brain lags behind the movement of the skull, causing brain structures to tear
* There is extensive tearing of nerve tissue throughout the brain which can disrupt the brain’s regular communication and chemical processes

Question 12

What type of hematoma is associated with cerebral contusions?

Answer 12

Subdural haematoma

Question 13

Which region of the cranium is often affected by epidural hematoma?

Answer 13

Squamous portion of temporal bone- usually a minor head injury.

Question 14

Compare subdural hematoma in adults and infants.

Answer 14

A: Cerebral convexities over frontal/temporal regions
C/I:Occipital + Parietal cortex
Parafalcine (post falx cerebri), supratentorial
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Question 15

Compare bones in the skull that covered by muscle and those that are not covered by muscle.

Answer 15

composed of cancellous bone (diploë)
sandwiched between 2 tablets. The diploë is
absent where the skull is covered with
muscles, leaving the vault thin and prone to
fracture

Question 16

List the anatomic sites of the skull that are prone to fracture

Answer 16

Squamous temporal
parietal bones (over temples)
sphenoid sinus, wings
foramen magnum
petrous temporal ridge
middle cranium weakest- multiple foramen and thin bones
cribriform plate and the roof of orbits and the areas between the mastoid and dural
sinuses in the posterior cranial fossa

Question 17

Olfactory nerve.

Answer 17

Fractures of CP- tear nerve filaments,
Direct frontal or occipital blows
Edema or hematoma can compress the olfactory bulb and the tracts in their location directly below the frontal lobes

Question 18

Optic nerve.

Answer 18

Blow to the brow region
acute downward displacement of orbit wall
with nerve except part attach to intracanalicular region, stretch

Severe frontal impact can also cause fracture in the region of sella and clinoids, resulting in chiasmal injury

Question 19

Oculomotor nerve

Answer 19

compressed at the tentorial hiatus by uncus in transtentorial herniation
Avulsion or stretching of the nerve at mesencephalo-pontine junction can result in isolated oculomotor palsy

Question 20

Which nerve is usually damage by a shake?

Answer 20

Trochlear
sudden change in linear acceleration
brainstem against the tentorium

Question 21

Trigeminal nerve and ganglion.

Answer 21

severe maxillofacial and skull base injury
Orbital s and i, forehead, orbit and maxilla
mandible, inferior dental branch and mandibular division

Question 22

Fractures in which areas will lead to damage in the Abducens nerve?

Answer 22

Pretroclinoid ligament and cavernous sinus
Hyperextension of cervical spine

Question 23

Discuss facial nerve injury.

Answer 23

deceleration head injury: greater superficial petrosal nerve
shearing force results in intraneural contusion, edema and hemorrhage.
meatal foramen due to its narrow size in the
labyrinthine segment is another site of compression
Fracture of the otic capsule indicates severe
trauma, and the facial nerve damage is
generally complete in such cases

Question 24

Which nerves does a fracture to the jugular foramen damage?

Answer 24

Glossopharyngeal (CN IX), Vagus (CN
X) and Accessory nerve (CN XI)

Extracranial: gunshot

Question 25

Where should a fracture occur to damage the hypoglossal nerve?

Answer 25

occipital condyle: passes medially