A medical illustration depicting the pathophysiology of nerve injury and central sensitization. The diagram shows a sagittal section of the human brain and a cross-section of the mandible. In the mandible, the inferior alveolar nerve is shown within the mandibular canal; a callout labeled 'Injured site' highlights a mechanical disruption (neurotmesis or axonotmesis) of the nerve fibers, while an adjacent vessel remains intact. A neural pathway is traced from this peripheral injury site, ascending through the trigeminal ganglion toward the central nervous system. Within the brainstem, midbrain, and thalamic regions, blue burst icons symbolize neuronal activation or modification along the second-order neuron pathway. The pathway terminates in the somatosensory cortex, marked by red starburst symbols and radiating lines, illustrating cortical reorganization or the perception of neuropathic pain. The illustration serves as an educational tool for understanding the retrograde effects of peripheral nerve trauma on central processing and chronic pain development.

This clinical photograph set illustrates the induction of an experimental axonotmesis (crush injury) on a peripheral nerve, likely the common peroneal nerve. Panel (a) shows the intraoperative procedure where a specialized metallic, non-serrated clamp with a flat crushing surface is applied perpendicular to the long axis of a taut, whitish nerve bundle. The clamp is used to apply a controlled compressive force to disrupt the axons while maintaining the continuity of the connective tissue sheaths (epineurium and perineurium). Panel (b) depicts the nerve immediately after the removal of the instrument. A white arrow highlights the resulting pathology: a distinct, flattened, and narrowed region corresponding to the crush site. This morphology demonstrates the visual characteristics of a Seddon's second-degree nerve injury. The surgical site shows surrounding muscular tissue and minor hemorrhage, providing a clear demonstration of nerve trauma models used to study peripheral nerve regeneration and functional recovery.

This composite educational resource comprises three Magnetic Resonance Neurography (MRN) coronal views (a, b, c) and a correlating schematic anatomical diagram (d) illustrating a severe traumatic brachial plexus injury. The right side of the images displays normal brachial plexus anatomy, with continuous nerve structures including the upper trunk (1), middle trunk (2), C8 root (3), and Th1 root (4). In contrast, the left side demonstrates a total rupture of the brachial plexus (dashed arrows). This injury is characterized by the complete discontinuity of the neural trunks and cords, accompanied by a large axillary cavity hematoma (curved dashed arrows). The schematic (d) highlights the side-to-side difference, showing the organized right-sided roots (C5-Th1) and trunks versus the disorganized, hemorrhagic area on the left. This material is designed for advanced medical education in radiology and neurosurgery, focusing on diagnostic imaging features of high-grade nerve trauma, specifically Seddon grade 3-5 injuries (neurotmesis) and the identification of postganglionic plexopathy.