Educational panel illustrating the anatomy of the glossopharyngeal nerve (CN IX) and its relationships in the medulla oblongata. Figure (a) is an anatomical diagram of a transverse section of the medulla at the level of the inferior olive, highlighting efferent nuclei—nucleus ambiguus (1) and inferior salivatory nucleus (2)—and afferent nuclei—solitary nucleus (3) and spinal trigeminal nucleus (4). Other shown structures include the dorsal motor nucleus of vagus (5), pyramidal tract (6), and hypoglossal nerve (7). Figure (b) is a schematic drawing of the lower cranial nerves (1: spinal, 2: CN IX, 3: vagus, 4: hypoglossal) showing their course from the brainstem to the jugular foramen in relation to the pons (P), pyramid (Py), and occipital bone (OB). Figures (c) and (d) provide clinical correlation via a Nissl-stained micrographic slice and an axial T2-weighted MRI, respectively. These images demonstrate the retro-olivary groove (rog), inferior olivary nucleus (O), and inferior cerebellar peduncle (icp), identifying the precise exit point and internal nuclear organization of the glossopharyngeal nerve within the upper medulla.

This medical illustration presents an anatomical diagram of an axial section of the lower medulla oblongata, specifically at the level of the spinal trigeminal tract, approximately 11 mm below the obex. The diagram highlights the spatial organization of sensory and motor pathways. Centrally located are the Central Gray (GM) and the large, prominent Pyramidal Decussation occupying the ventral aspect. Dorsally, the Gracile Nucleus (NG) and Cuneate Nucleus (NC) are positioned near the midline. The lateral aspect features the Spinal Trigeminal Nucleus (STN) and Spinal Trigeminal Tract (STT). Further peripherally along the lateral margin, the diagram identifies the Dorsal Spinocerebellar Tract (DSCT), Ventral Spinocerebellar Tract (VSCT), and the Lateral Spinothalamic Tract (LSTT). This illustration is designed for neurological education, demonstrating the transition between the spinal cord and brainstem, specifically focusing on the anatomical structures involved in pain modulation and motor decussation.

Two light microscopy images (A and B) showing transverse histological sections of the human medulla oblongata, stained with Luxol Fast Blue (LFB) and Hematoxylin and Eosin (H&E). The sections demonstrate an aberrant hypertrophied fiber bundle, identified as the Anterior External Arcuate Fasciculus (AEAF). In the rostral section (A), the fiber bundle (arrows) is located medially, adjacent to the anterior sulcus (AS) and ventral to the medullary pyramid (PY). In the more caudal section (B), the bundle demonstrates a lateral progression, coursing over the ventral surface of the pyramid and the lateral aspect of the inferior olivary nucleus (ION). The LFB stain highlights these bundles in blue, confirming they are myelinated white matter tracts. The surrounding structures, including the convoluted gray matter of the ION and the densely packed fibers of the pyramid, maintain their characteristic neuroanatomical architecture. This visual comparison illustrates the anatomical trajectory and myelination status of a rare anatomical variant in the lower brainstem.

This light microscopy image features a Cresyl Violet (CV) stained transverse section of a chimpanzee brainstem at the level of the medulla oblongata, illustrating the comparative neuroanatomy of the inferior olivary complex. The principal nucleus of the inferior olive (IOpr) is the most prominent structure, appearing as a bilateral, elongated, ribbon-like band characterized by complex, serpentine infoldings and convolutions. The image demonstrates notable left-right asymmetry in the precise folding pattern of the IOpr ribbon. Related anatomical structures are identified: the dorsal nucleus of the inferior olive (IOD) is positioned dorsomedial to the IOpr, while the medial nucleus of the inferior olive (IOM) lies more medially near the midline. Ventrolateral to the olivary complex are the pyramidal tracts (pt), which appear as large, pale-staining bundles of longitudinal fibers. A scale bar representing 1 mm is included at the bottom right. This visual serves as an educational resource for evolutionary neuroanatomy, highlighting the morphological expansion and increased gyrification of the inferior olive in great apes compared to lower mammals.