Posterior external arcuate fibers

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Posterior external arcuate fibers
Diagram showing the course of the arcuate fibers. (Testut.) 1. Medulla oblongata anterior surface. 2. Anterior median fissure. 3. Fourth ventricle. 4. Inferior olivary nucleus, with the accessory olivary nuclei. 5. Gracile nucleus. 6. Cuneate nucleus. 7. Trigeminal. 8. Inferior peduncles, seen from in front. 9. Posterior external arcuate fibers. 10. Anterior external arcuate fibers. 11. Internal arcuate fibers. 12. Peduncle of inferior olivary nucleus. 13. Nucleus arcuatus. 14. Vagus. 15. Hypoglossal.
Section of the medulla oblongata at about the middle of the olive. (Arcuate fibers labeled at center right.)
Latin	fibrae arcuatae externae posteriores
Gray's	subject #187 783
Dorlands/Elsevier	f_05/12361829

The posterior external arcuate fibers (dorsal external arcuate fibers) take origin in the gracile and cuneate nuclei; they pass to the inferior peduncle of the same side.

It is uncertain whether fibers are continued directly from the gracile and cuneate fasciculi into the inferior peduncle.

The term "cuneocerebellar tract" is sometimes used to collectively refer to the posterior external arcuate fibers.^[1]

Contents 1 See also 2 References 3 Additional images 4 External links

See also

• Spinocerebellar tract

References

1. ↑ t_15/12816128 at Dorland's Medical Dictionary

Additional images

Dissection of brain-stem. Lateral view.

Deep dissection of brain-stem. Lateral view.

Dissection of brain-stem. Dorsal view.

External links

• NeuroNames hier-793 - dorsal external arcuate fibers
• NeuroNames hier-800 - cuneocerebellar tract

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

v • d • e Brain: rhombencephalon (hindbrain)
Myelencephalon/medulla	anterior/ventral: Arcuate nucleus of medulla • Pyramid (Decussation) • Olivary body • Inferior olivary nucleus • Anterior median fissure • Ventral respiratory group posterior/dorsal: VII,IX,X: Solitary/tract • XII, X: Dorsal • IX,X,XI: Ambiguus • IX: Inferior salivatory nucleus • Gracile nucleus/Cuneate nucleus/Accessory cuneate nucleus • Area postrema • Posterior median sulcus • Dorsal respiratory group raphe/reticular: Sensory decussation • Reticular formation (Gigantocellular nucleus, Parvocellular reticular nucleus, Ventral reticular nucleus, Lateral reticular nucleus, Paramedian reticular nucleus) • Raphe nuclei (Obscurus, Magnus, Pallidus) tracts: Corticospinal tract (Lateral, Anterior) • Inferior cerebellar peduncle • Olivocerebellar tract • Spinocerebellar (Dorsal, Ventral) • Spinothalamic tract • PCML (Posterior external arcuate fibers, Internal arcuate fibers, Medial lemniscus) • Extrapyramidal (Rubrospinal tract, Vestibulospinal tract, Tectospinal tract)
Metencephalon/pons	anterior/ventral: Superior olivary nucleus • Basis pontis (Pontine nuclei, Middle cerebellar peduncles) posterior/dorsal: Pontine tegmentum (Trapezoid body, Superior medullary velum, Locus ceruleus, MLF, Vestibulocerebellar tract, V Principal Spinal & Motor, VI, VII, VII: Superior salivary nucleus) • VIII-c (Dorsal, Anterior)/VIII-v (Lateral, Superior, Medial, Inferior) raphe/reticular: Reticular formation (Caudal pontine reticular nucleus, Oral pontine reticular nucleus, Tegmental pontine reticular nucleus, Paramedian pontine reticular formation) • Median raphe nucleus Apneustic center • Pneumotaxic center
Metencephalon/cerebellum	Vermis • Flocculus • Arbor vitae • Cerebellar tonsil • Inferior medullary velum Molecular layer (Stellate cell, Basket cell, Parallel fiber) • Purkinje cell layer (Purkinje cell) • Granule cell layer (Golgi cell) • Mossy fibers • Climbing fiber Deep cerebellar nuclei (Dentate, Emboliform, Globose, Fastigial)
Fourth ventricle	apertures (Median, Lateral) • Rhomboid fossa (Vagal trigone, Hypoglossal trigone, Obex, Sulcus limitans, Facial colliculus, Medial eminence) • Lateral recess