51 - 75 of 410
Number of results to display per page
TitleDescriptionType
51 Expanded Acute Onset Persistent Vision Loss DifferentialText
52 Figure 17: Bony Structures Relevant to the OrbitThe frontal, sphenoid, maxillary, ethmoid, and lacrimal bones make up the orbit. Structures passing through the optic canal include the optic nerve, oculosympathetic tract and ophthalmic artery. Structures passing through the superior orbital fissure include the superior ophthalmic vein, cranial ner...Image
53 Figure 1: Oculosympathetic Pathway for Pupillary DilationThe oculosympathetic tract is an uncrossed pathway that begins in the hypothalamus, with fibers descending in the brainstem (1st order, commonly affected in a lateral medullary syndrome), synapsing in the lower cervical/upper thoracic spinal cord (interomediolateral cell columns of C8-T2, also refer...Image
54 Figure 24: Typical Visual Field Defects Associated with Discrete Lesions Along the Visual PathwaysSpecific monocular or binocular visual field defects can be highly localizing when the neuroanatomy of the visual pathways is understood. The temporal visual field corresponds to the nasal retina, while the nasal visual field corresponds to the temporal retina. 1) Left optic nerve lesion - while an ...Image
55 Figure 2: Parasympathetic Pathway for Pupillary ConstrictionA bright light is shone in one eye, light enters the pupil and hyperpolarizes retinal photoreceptors which activates retinal ganglion cells. These signals propagate along the optic nerves, chiasm, optic tracts, and fibers responsible for the light reflex then synapse in the dorsal midbrain (prior to...Image
56 Figure 46: The Course of the 6th (VI) NerveThe sixth nucleus is located dorsally, adjacent to the 4th ventricle, in the lower pons. The genu of the facial (7th) nerve wraps around the 6th nucleus, creating the facial colliculus, which bulges into the 4th ventricle. After the 6th nerve leaves the pons, it follows a vertical course along the c...Image
57 Figure 50: Anatomy and Physiology of the Saccadic PathwaysWhen a saccade is desired (or reflexively triggered), signals project from the saccade-related cortical eye fields to the superior colliculus, which serves to integrate and relay commands to the saccade generating brainstem circuitry. The inferior cerebellar peduncle (ICP) carries climbing fibers to...Image
58 Figure 51: Lateral Medullary Lesion Causing Saccadic DysmetriaA lesion of the left lateral medulla and inferior cerebellar peduncle (ICP) will cause decreased climbing fiber inhibition of the left dorsal vermis causing simple-spike (inhibitory) discharge of Purkinje cells to increase. Increased Purkinje cell firing leads to increased inhibition of the ipsilate...Image
59 Figure 51: Lateral Medullary Lesion Causing Saccadic Dysmetria (Supplement)Image
60 Figure 51: Lateral Medullary Lesion Causing Saccadic Dysmetria (Supplement)Image
61 Figure 53: Vascular Distribution and Anatomy Relevant to the Lateral Medullary (Wallenberg) SyndromeThis axial section of the medulla highlights those structures that, when damaged, are responsible for the vestibular and ocular motor features of the Wallenberg syndrome. The nucleus prepositus hypoglossi (NPH) and medial vestibular nucleus (MVN) complex is important for horizontal gaze-holding (neu...Image
62 Figure 53: Vascular Distribution and Anatomy Relevant to the Lateral Medullary (Wallenberg) Syndrome (Supplement)Image
63 Figure 53: Vascular Distribution and Anatomy Relevant to the Lateral Medullary (Wallenberg) Syndrome (Supplement)Image
64 Figure 64: The Course of the 3rd (III) NerveThe 3rd nucleus lies at the ventral border of the periaqueductal gray matter, at the level of the superior colliculus. In between the two nuclei is the midline central caudal nucleus (CCN), which innervates bilateral levator palpebrae muscles (explaining how a unilateral nuclear 3rd can cause bilate...Image
65 Figure 64: The Course of the 3rd (III) Nerve (Supplement)Image
66 Figure 65: Vascular Distribution and Anatomy (Including 3rd Nerve) of the Rostral MidbrainIn this axial section of the midbrain at the level of the superior colliculus, the paired 3rd nuclei are located ventral to the periaqueductal grey, and the midline central caudal nucleus (CCN) is located in between. The fascicles that exit the IIIrd nuclei carry the fibers destined to innervate the...Image
67 Figure 65: Vascular Distribution and Anatomy (Including 3rd Nerve) of the Rostral Midbrain (Supplement)Image
68 Figure 65: Vascular Distribution and Anatomy (Including 3rd Nerve) of the Rostral Midbrain (Supplement)Image
69 Figure 68: The Course of the 4th (IV) NerveThe 4th nucleus lies at the ventral border of the periaqueductal gray matter, at the level of the inferior colliculus. The fascicles exit the nucleus dorsally and decussate at the anterior medullary velum (anterior floor of the fourth ventricle), and then exit the brainstem dorsally. The peripheral ...Image
70 Figure 68: The Course of the 4th (IV) Nerve (Supplement)Image
71 Figure 69: Vascular Distribution and Anatomy (Including 4th Nerve) of the Caudal MidbrainIn this axial section of the midbrain at the level of the inferior colliculus, the 4th nuclei are located ventral to the periaqueductal grey, dorsal to the medial longitudinal fasciculus (MLF) and medial to the oculosympathetic tract. Fascicles exit the nucleus dorsally and decussate at the anterior...Image
72 Figure 69: Vascular Distribution and Anatomy (Including 4th Nerve) of the Caudal Midbrain (Supplement)Image
73 Figure 69: Vascular Distribution and Anatomy (Including 4th Nerve) of the Caudal Midbrain (Supplement)Image
74 Figure 80: Vascular Distribution and Anatomy Relevant to the Medial Medullary SyndromeThis axial section of the medulla highlights those structures that, when damaged, are often responsible for spontaneous upbeat nystagmus (UBN). The nucleus of Roller and nucleus intercalatus normally have an inhibitory influence over the cerebellar flocculus, and when there is a lesion of Roller/int...Image
75 Figure 80: Vascular Distribution and Anatomy Relevant to the Medial Medullary Syndrome (Supplement)Image
51 - 75 of 410