Depressed Fracture Characteristics

Depressed Fracture

• Refers to fractures resulting from a heavy blunt instrument and small surface area impact.
• Impact at high velocity with a small surface area can result in a depressed fracture.
• The area of depression is fragmented by radial fracture lines that extend outward from the point of impact.
• Depressed fracture occurs in the outer table of the skull; the inner table remains intact if the force of impact is insufficient to fracture both tables.
• Flat bones of the skull are composed of two layers of compact bones and cancellous bone in between.
• Applied force leads to compression of the outer table at the point of force and traction on both sides of the force.
• With the inner table there is traction at the point of the force and compression on both sides of the force.
• Fracture occurs on the inner table at the point of force and in the outer table on both sides of the force because there is little support for fractured bones.
• The depressed area takes the shape of the causative object, so it is like a signature fracture.
• Depression is maximal at the point of impact.
• A portion of fractured bone becomes driven inwards below the normal anatomical level.
• Depressed bone can potentially injure the blood vessels of the brain.
• Injury is more likely in the inner table as it is not as supported.

Comminuted Fracture

• This is a fracture where the bone is broken, splintered, or crushed into multiple pieces.

Depressed Comminuted Fracture

• A depressed comminuted fracture is commonly caused by heavy blunt objects with a wide surface area and high momentum.
• Car accidents and falling from a height are common causes.
• A mosaic fracture (spider's web) is a comminuted depressed fracture with radiating fissures.

Complications of Depressed Fracture

• Cerebral laceration may occur due to the depressed bony fragment.
• Intracranial hemorrhage.
• Cerebral compression can occur due to depressed fragments and hemorrhage.
• Intracranial infection.
• Decompression operation may result in a bony gap (permanent infirmity).

Basal Skull Fractures

• Almost any diffuse impact to the vertex of the skull will produce basilar fractures.
• It is more commonly associated with blows to the back of the head and can run either antero-posteriorly or pester-anteriorly.
• Basilar fractures resulting from blow on the lateral aspect or the vertex of the skull generally traverse the base of the skull from side to side (hinge fractures).

Skull Fractures with Sharp Instrument (light and heavy)

• Skull fractures due to sharp instruments are as follows:

Sharp and light instrument

• Example: Knife
• Cut Fracture

Chipped Fracture

• Light and sharp instrument which pass tangentially causing removal of the outer table

Sharp and heavy instruments

• Injuries produced by an ax.
• If the blade of an ax result a cut fracture
• The blade may pass tangentially to the outer table making it a chipped fracture
• The cut may be triangular if the striking is done with an angle.
• Striking with the head of the ax results in localized depressed fractures,.
• The handle of the ax can cause fissure fractures.