skull fracture (cranial fracture)

Introduction

Also see head trauma.

Classification

• simple fracture: a break in bone without damage to skin
• linear skull fracture: a break in a cranial bone resembling a thin line, without splintering, depression, or distortion of bone
• depressed skull fracture: break in a cranial bone (or 'crushed' portion of skull) with depression of the bone in toward the brain.
• compound fracture: a break in, or loss of, skin & splintering of the bone
• basilar skull fractures involve the base of the skull; includes most skull fractures
• Rene Le Fort, a French surgeon, identified lines of weakness in the facial bones where fractures are most likely to occur
  • type 1 runs across the maxilla, or upper jaw
  • type 2 is pyramidal in shape, breaking the cheekbone below the orbit (eye socket) & running across the bridge of the nose
  • type 3 separates the frontal bone behind the forehead from the zygoma (cheekbone) as well as breaking the nasal bridge (craniofacial separation)

Etiology

• head injury, including falls, automobile accidents, physical assault, & sports injuries

Pathology

• the skull is prone to fracture at certain sites including
  • thin squamous temporal bone & parietal bones over the temples
  • sphenoid sinus
  • foramen magnum
  • petrous temporal ridge
  • inner parts of the sphenoid wings at the skull base
• the middle cranial fossa is the weakest, with thin bones & multiple foramina
• other site prone to fracture include
  • cribriform plate
  • roof of orbits in the anterior cranial fossa
  • areas between the mastoid & dural sinuses in the posterior cranial fossa

Physiology

• 10 times more force is required to fracture a cadaveric skull with overlaying scalp than the one without
• diploe does not form where the skull is covered with muscles leaving the vault thin and prone to fracture

Clinical manifestations

• most patients with linear skull fractures are asymptomatic
• signs suggestive of skull fracture include:
  • bleeding from wound, ears, nose, or around eyes
  • ecchymoses behind the ears (Battle sign) or under the eyes
  • drainage of clear or bloody fluid from ears or nose
• ~25% of patients with depressed skull fracture do not report loss of consciousness, ~25% lose consciousness for < 1 hour
• presentation may vary depending on other associated intracranial injuries
• see head trauma

Radiology

• computed tomography is the imaging modality of choice

Management

• adults with simple linear fractures without neurological deficits do not require any intervention & may be discharged home to return if symptomatic
• children with uncomplicated skull fractures should be discharged home
• role of surgery is limited
  • infants & children with open depressed fractures require surgical intervention
  • consult neurosurgery

More general terms

• bone fracture
• head injury

More specific terms

• Leforte fracture
• maxillary fracture
• nasal fracture
• orbital fracture (blowout fracture)
• zygomatic fracture

Additional terms

• skull (cranium)