A composite medical image illustrating diagnostic manifestations of myasthenia gravis across three modalities. Panel A is a clinical photograph of the periorbital region showing asymmetrical ophthalmoparesis; a red arrow indicates significant ptosis of the right upper eyelid, which obscures the upper half of the pupil compared to the normal left eyelid position. Panel B displays results from a repetitive nerve stimulation (RNS) test of the bilateral accessory and left axillary nerves; yellow arrows highlight a decremental response in compound muscle action potential (CMAP) amplitudes, characteristic of neuromuscular junction dysfunction. Panel C contains two axial computed tomography (CT) images of the chest; white arrows point to an enlarged soft tissue mass in the anterior mediastinum, consistent with thymic hyperplasia. Together, these panels demonstrate the classic clinical triad of ocular symptoms (ptosis), electrophysiological evidence of fatigue, and associated anatomical abnormalities (thymus) often found in autoimmune myasthenia gravis.

This clinical photograph is a side-by-side comparison illustrating a positive Tensilon (edrophonium) test in a patient with Myasthenia Gravis (MG). Panel A shows the patient's orbital region at baseline, demonstrating significant bilateral asymmetrical ptosis (drooping of the upper eyelids). The left eyelid is more severely affected, covering a substantial portion of the visual axis. Panel B shows the same patient after the administration of edrophonium, an acetylcholinesterase inhibitor. There is a marked improvement in the bilateral ptosis, characterized by an increased palpebral fissure width and elevation of the upper lid margins, exposing more of the iris and pupil. This visual change is a classic diagnostic indicator for disorders of the neuromuscular junction, specifically MG associated with anti-acetylcholine receptor (AchR) antibodies. The image serves as a clinical teaching tool for neurology and ophthalmology to demonstrate the transient reversal of fatiguable muscle weakness through pharmacological intervention.

This clinical photograph consists of a side-by-side comparison (labeled A and B) demonstrating the pharmacological management of bilateral eyelid ptosis in a patient with Myasthenia Gravis (MG). Panel A (Baseline): Displays severe bilateral upper eyelid drooping, which obscures approximately 30-40% of the superior iris and limits the palpebral fissure width. The periorbital skin shows significant laxity and skin folds characteristic of chronic ptosis and aged skin. Panel B (Post-Treatment): Shows the same patient 30 minutes after the administration of oxymetazoline hydrochloride 0.1% ophthalmic solution. There is a notable elevation of both upper eyelids, resulting in increased exposure of the iris and sclera, with only 5-10% of the iris remaining covered. Educational Focus: The images illustrate the clinical efficacy of alpha-adrenergic agonists in stimulating Müller’s muscle (sympathetic smooth muscle) to improve eyelid elevation. This comparison highlights a non-surgical management option for symptomatic ptosis in patients with neuromuscular junction disorders or refractory weakness.

Two side-by-side clinical photographs (labeled A and B) documenting ocular symptoms in a pediatric patient. Image A demonstrates moderate bilateral ptosis, where the upper eyelids are abnormally low, partially obscuring the superior portion of the iris and pupil. Image B shows the same patient exhibiting significantly worsened or 'majoré' bilateral ptosis, with the eyelids nearly fully occluding the pupils. This visual progression illustrates muscular fatigability, a classic clinical sign of juvenile ocular myasthenia gravis. The comparison demonstrates how sustained upward gaze or prolonged activity can exacerbate levator palpebrae superioris weakness. The images are categorized under ophthalmology and clinical neurology, serving as an educational resource for identifying ptosis severity and the diagnostic hallmark of fatigability in neuromuscular junction disorders.

This clinical photograph shows a close-up view of a patient's eyes demonstrating bilateral asymmetric ptosis (drooping of the upper eyelids). The right upper eyelid (left side of the image) exhibits a more severe degree of ptosis compared to the left, resulting in a narrower palpebral fissure and significant coverage of the superior iris. Conversely, the left upper eyelid margin is positioned higher, revealing more of the ocular surface. The image captures the clinical response during a neostigmine test, a diagnostic investigation used in the evaluation of Myasthenia Gravis to assess for the temporary reversal of muscle weakness. Mild conjunctival injection is visible, particularly in the nasal region of the right eye. This visual is significant for medical education regarding the diagnostic workup of neuromuscular junction disorders and the clinical manifestation of ocular myasthenia.

This clinical image consists of two side-by-side close-up photographs of a human eye, demonstrating computer vision and machine learning techniques for ophthalmologic assessment. The images utilize annotated overlays to track key anatomical landmarks related to Myasthenia Gravis (MG) evaluation, specifically for ptosis (eyelid droop). Red dots represent machine learning-derived landmarks at the eye corners and lid margins. Green curved lines delineate the upper eyelid contour, the lower eyelid margin, and the limbus (the interface between the iris and sclera). Blue bounding boxes define 'Regions of Interest' (ROI); in the left frame, the box targets the lower eyelid-sclera junction, while in the right frame, it frames the inferior iris-sclera boundary. This methodology is designed for automated, quantitative monitoring of eyelid distance and eye area during sustained upward gaze, providing objective data for telemedicine-based clinical examinations of neuromuscular junction disorders.

This diagnostic fluorescence microscopy image illustrates the neuromuscular junction (NMJ) architecture. The image features a single motor axon labeled with red fluorescence (TRITC-conjugated anti-neurofilament antibody), showing a characteristic distal branching pattern. These red axonal branches terminate at multiple motor end-plates, which are visualized in green (FITC-conjugated α-bungarotoxin) to reveal the high density of postsynaptic acetylcholine receptors (AChRs). The spatial relationship demonstrates a single axon innervating a cluster of six individual end-plates. Areas of colocalization between the presynaptic nerve terminal and the postsynaptic membrane appear yellow, indicating functional synaptic contact. This visual serves as an educational model for neuroanatomy and toxicology, particularly in the study of neurotoxic snake venoms (like those from the elapid family) that target presynaptic proteins or postsynaptic receptors, leading to neuromuscular paralysis and axonal degeneration.

This composite educational image illustrates the maturation of postsynaptic acetylcholine receptor (AChR) aggregates at the neuromuscular junction (NMJ) and its relationship to synapse elimination. Panel A provides a schematic of morphological progression from ovoid plaque to perforated plaque to an open configuration. Panel B displays grayscale confocal images of P9 mouse soleus AChR aggregates, rotated 45 degrees to highlight central perforations (red arrows). Panel C shows a fluorescence micrograph of P3 sternomastoid NMJs labeled for AChR (red) and Neurofilament (green), demonstrating varied maturation stages: open (red dot), perforated (yellow dot), and ovoid (grey dot) within polyneuronally innervated synapses. Panels D and E are bar graphs comparing AChR maturation across muscle fiber types (Type I vs. Type II) and muscles (Soleus vs. EDL), showing no significant difference ('ns'). Panel F quantifies that the percentage of polyneuronally innervated NMJs does not significantly differ based on postsynaptic morphology. The data indicates that postsynaptic AChR maturation occurs independently of the timing of axonal input removal during development.

A side-by-side comparison of immunofluorescence diagnostic images showing neuromuscular junction (NMJ) pathology in a murine model of C9orf72 amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). The microscopy displays whole-mount staining of the extensor digitorum longus (EDL) muscle. Post-synaptic acetylcholine receptors are labeled with red α-bungarotoxin, while pre-synaptic axons and motor nerve terminals are labeled with green neurofilament antibody. The 'Healthy control' panel shows highly organized, linear axonal projections terminating in distinct, continuous, and robust 'pretzel-like' motor endplates. In contrast, the 'C9FTD/ALS 36x repeat' panel demonstrates significant neurodegeneration characterized by disorganized, fragmented axonal branching and 'dissolving' boutons with reduced or sparse red fluorescence. This visual evidence highlights the pathophysiology of denervation and synaptic instability in motor neuron disease. Scale bars represent 50 µm.

This diagnostic visualization presents cross-sections through a helical reconstruction of a cholinergic postsynaptic membrane, likely derived from cryo-electron microscopy. The image displays the profile of a lipid bilayer at the neuromuscular junction, characterized by two parallel tracks of high-intensity light grey densities representing phospholipid headgroups. The total thickness between these headgroup peaks is approximately 30 Å. Interspersed within this lipid matrix are irregular blocks of density representing nicotinic acetylcholine receptor proteins, including transmembrane (TM) helices and cytoplasmic MX helices. Red arrows highlight localized gaps or weakening of density in the outer leaflet adjacent to protein surfaces, while blue arrows indicate similar regions of weakened density in the inner leaflet above the MX helices. These specific visual gaps are attributed to high concentrations of cholesterol, which lacks a large electron-dense headgroup compared to phospholipids. The arrangement illustrates the non-uniform distribution of cholesterol and its role in forming protein-stabilized microdomains within the postsynaptic membrane.

This diagnostic image contains three axial CT scan slices (labeled A, B, and C) demonstrating different morphological configurations of the thymus in the anterior mediastinum. (A) Displays an 'arrowhead' configuration where the two thymic lobes are confluent, forming a single triangular mass with soft-tissue attenuation similar to skeletal muscle. (B) Shows a 'bilobed' thymus presenting as two distinct, separate soft-tissue masses, appearing diffusely enlarged with density exceeding chest wall musculature. (C) Illustrates a single visualized lobe appearing as an asymmetrical soft-tissue mass. These imaging variants are critical in evaluating patients with myasthenia gravis, where thymic hyperplasia or thymoma may be present. The scans highlight essential anatomical relationships between the thymus and adjacent cardiovascular structures in the superior mediastinum, useful for differentiating normal thymic variants from pathology in adult patients.

This diagnostic image is an axial contrast-enhanced computed tomography (CT) scan of the thorax at the level of the great vessels. The scan reveals a large, heterogeneously enhancing mass located in the anterior mediastinum. An annotation on the image indicates that the lesion originates from the thymus and is situated immediately anterior to the great vessels, including the ascending aorta and pulmonary trunk. The mass exhibits irregular borders and varying densities, which are characteristic findings for thymic neoplasms such as thymoma. The surrounding anatomical landmarks, including the vertebral body, descending aorta, and sternum, are clearly visible. This clinical image illustrates a common presentation of an anterior mediastinal tumor, often associated with paraneoplastic syndromes like myasthenia gravis. It serves as an educational example for radiological identification of mediastinal compartment pathologies and the evaluation of tumor relationship to vascular structures.

**Imaging Modality:** Computed Tomography (CT) scan of the chest. **Anatomical Region:** Axial section of the superior mediastinum at the level of the aortic arch. **Observed Pathology:** The image demonstrates a soft-tissue mass located in the anterior mediastinal compartment, specifically within the prevascular space. The morphology and location are consistent with thymic tissue, which in the context of myasthenia gravis, may represent thymic hyperplasia or a thymic neoplasm such as a thymoma. **Characteristic Visual Features:** * **Location:** Anterior to the ascending aorta and the superior vena cava, posterior to the sternum. * **Density:** The lesion exhibits soft-tissue attenuation, appearing denser than the surrounding mediastinal fat. * **Margins:** The mass appears relatively well-defined but lacks clear fatty cleavage planes from adjacent vascular structures, a common finding in thymic pathology. * **Surrounding Structures:** The lungs appear clear and the bony structures of the thoracic cage are intact. **Clinical Context:** Evaluation of the thymus is a critical diagnostic step for patients with myasthenia gravis to identify thymic abnormalities that may necessitate surgical intervention (thymectomy). **Diagnostic Significance:** This imaging is essential for differentiating normal age-related thymic involution (fatty replacement) from pathological thymic persistence or enlargement.

A composite medical image illustrating diagnostic manifestations of myasthenia gravis across three modalities. Panel A is a clinical photograph of the periorbital region showing asymmetrical ophthalmoparesis; a red arrow indicates significant ptosis of the right upper eyelid, which obscures the upper half of the pupil compared to the normal left eyelid position. Panel B displays results from a repetitive nerve stimulation (RNS) test of the bilateral accessory and left axillary nerves; yellow arrows highlight a decremental response in compound muscle action potential (CMAP) amplitudes, characteristic of neuromuscular junction dysfunction. Panel C contains two axial computed tomography (CT) images of the chest; white arrows point to an enlarged soft tissue mass in the anterior mediastinum, consistent with thymic hyperplasia. Together, these panels demonstrate the classic clinical triad of ocular symptoms (ptosis), electrophysiological evidence of fatigue, and associated anatomical abnormalities (thymus) often found in autoimmune myasthenia gravis.

This clinical photograph demonstrates the experimental setup for recording repetitive ocular vestibular evoked myogenic potentials (roVEMP). The procedure involves a patient in a supine position with maximal upward gaze to facilitate recording from the inferior oblique extraocular muscles. A handheld cylindrical metallic mini-shaker is applied to the midline of the forehead at the hairline (standard AFz point) to deliver bone-conducted vibration stimuli. Recording is achieved via a multi-electrode montage on the face: active electrodes (black leads) are placed at the infraorbital margins, reference electrodes (red leads) are positioned directly below them, and a grounding electrode (green lead) is attached to the chin. All electrodes are secured with light-blue adhesive pads. This neurophysiological setup is used to assess vestibular function and neuromuscular transmission, specifically in the diagnosis and monitoring of conditions such as ocular myasthenia gravis, where fatigue or decrement in muscle response to repetitive stimulation is clinically significant.

A multi-panel medical figure documenting a clinical case of metastatic melanoma and secondary myasthenia gravis (MG). Panel A presents a longitudinal timeline (2011–2020) tracking cutaneous melanoma diagnosis, BRAF(+) relapse, brain metastasis, and the subsequent onset of MG during targeted therapy with BRAF/MEK inhibitors (dabrafenib/trametinib). Panel B contains whole-body PET/CT scans and axial CT slices; the 'At melanoma relapse' images show a hypermetabolic focus in the right axilla (indicated by red arrows), which resolves at 'Last follow-up'. Panel C displays axial brain MRI slices (T1 and FLAIR) showing a solitary left frontal lobe metastasis at diagnosis, with subsequent volume reduction and scarring observed 3.5 years post-stereotactic radiosurgery (Cyber-knife). Panel D illustrates neurophysiological diagnostics for MG, including repetitive nerve stimulation (RNS) waveforms from the right trapezius and deltoid muscles. The accompanying table quantifies a pathological decrement in compound muscle action potential (CMAP) amplitude (up to 39.9%), diagnostic of a neuromuscular junction disorder.