Summary of Head Trauma: Fractures and Imaging

## Introduction This StudyFi material summarizes key information on skull fractures and temporal bone fractures, focusing on classifications, complications, diagnostic features, and practical scenarios. This material is intended for self-study and does not cover details on "Temporal Bone Fractures" or "Head Trauma Imaging," which are discussed elsewhere. > Definition: A skull fracture is a disruption of the continuity of the calvarium or skull base due to mechanical injury; a temporal bone fracture involves the bones in the temporal region and can affect ear structures and nerve pathways. ## Basic Classification of Skull Fractures ### Linear (Nondisplaced) Fractures - Most common type of calvarial fracture - May be difficult to detect on CT scans, especially if parallel to the imaging plane - Isolated linear fractures typically do not require treatment ### Depressed and Comminuted Fractures - Depressed: bone fragment is driven inward, often with contusion of the underlying cerebellum or brain - Comminuted: multiple fragments - Surgical intervention is often indicated for depressed and compound (open) fractures > Definition: A depressed fracture is a type of fracture where a bone fragment is pushed inward towards the brain tissue; a compound fracture involves a break in the skin's integrity with communication to the fracture site. ### Skull Base Fractures (General) - Critical locations: skull base region, orbits, facial bones - For assessing the degree of comminution and depression, thin slices with a bone algorithm and multiplanar reconstructions are recommended. ## Temporal Bone Fractures — Key Types and Consequences Note: This section does not provide a detailed overview of "Temporal Bone Fractures"; instead, it focuses on general classifications related to their functional consequences. ### Longitudinal vs. Transverse Fractures - Longitudinal: run parallel to the long axis of the petrous bone; often associated with middle ear dysfunction and ossicular dislocation - Transverse: run perpendicular to the long axis of the petrous bone; more frequently lead to inner ear damage, sensorineural hearing loss, significant vertigo, and perilymphatic leak > Definition: A transverse temporal bone fracture is a fracture perpendicular to the long axis of the petrous bone and is often the result of an impact to the occipital or frontal region. Practical Example: A patient reports intense vertigo and sudden hearing loss in one ear after a fall from a height — consider a transverse temporal bone fracture with possible inner ear injury. ### Otic capsule–sparing vs. otic capsule–violating - Otic-sparing: the fracture runs anterolateral to the otic capsule, typically following a localized impact to the temporoparietal region - Otic-violating: the fracture involves the otic capsule (cochlea, semicircular canals) Comparison of Consequences (Table): | Feature | Otic-sparing | Otic-violating | |---|---:|---:| | Risk of Facial Nerve Injury | Lower | 2–5x Higher | | Risk of CSF Leak | Lower | 4–8x Higher | | Risk of Hearing Loss | Lower | 7–25x Higher | | Risk of Intracranial Complications | Lower | Higher (epidural hematoma, subarachnoid hemorrhage) | Practical Implications: Otic-violating fractures require more intensive monitoring for CSF leak, hearing preservation, and assessment of facial nerve function. ### Complications Associated with Temporal Bone Fractures - Sensorineural hearing loss - Severe vertigo and nystagmus - Perilymphatic fistula (CSF or perilymphatic fluid leak into the middle ear) - Facial nerve palsy (30–50%, often complete) - Vascular injury (carotid artery, jugular vein), especially with transverse fractures Did you know that a perilymphatic fistula can cause a combination of fluid leakage, hearing reduction, and significant vestibular symptoms, including rotatory vertigo? ## Soft Tissue and Scalp Examination - When evaluating CT/MRI scans for head trauma, begin by examining extracerebral structures. - Scalp sw