Inferior cerebellar peduncle
The upper part of the posterior district of the medulla oblongata is occupied by the inferior cerebellar peduncle, a thick rope-like strand situated between the lower part of the fourth ventricle and the roots of the glossopharyngeal and vagus nerves. Each cerebellar inferior peduncle connects the spinal cord and medulla oblongata with the cerebellum, comprises the juxtarestiform body and restiform body. Important fibers running through the inferior cerebellar peduncle include the dorsal spinocerebellar tract and axons from the inferior olivary nucleus, among others; the inferior cerebellar peduncle carries many types of input and output fibers that are concerned with integrating proprioceptive sensory input with motor vestibular functions such as balance and posture maintenance. It consists of the following fiber tracts entering cerebellum: Posterior spinocerebellar tract: unconsciousness proprioceptive information from the lower part of trunk and lower limb; this tract originates at the ipsilateral Clarke's nucleus and travels upward to reach the inferior cerebellar peduncle and synapses within the spinocerebellum.
Cuneocerebellar tract: unconsciousness proprioceptive information from the upper limb and neck. This tract originates at the ipsilateral accessory cuneate nucleus and travels through the inferior cerebellar peduncle to reach the spinocerebellum part of the cerebellum. Trigeminocerebellar tract: unconsciousness proprioceptive information from the face. Olivocerebellar tract: "error signal" in movement originates from the cerebral cortex and spinal cord; this tract originates at contralateral inferior olivary nucleus and enters the cerebellum as a climbing fiber. Vestibulocerebellar tract: vestibular information projects onto the vestibulocerebellum; this peduncle carries information leaving cerebellum: from the Purkinje cells to the vestibular nuclei in the dorsal brainstem located at the junction between the pons and medulla oblongata. Cerebral peduncle Juxtarestiform body Middle cerebellar peduncles Superior cerebellar peduncles This article incorporates text in the public domain from page 775 of the 20th edition of Gray's Anatomy Atlas image: n2a5p2 at the University of Michigan Health System Atlas image: n2a7p4 at the University of Michigan Health System Illustration and text: cere/text/p1/icp.htm at the University of Wisconsin-Madison Medical school
Gray's Anatomy is an English language textbook of human anatomy written by Henry Gray and illustrated by Henry Vandyke Carter. Earlier editions were called Anatomy: Descriptive and Surgical, Anatomy of the Human Body and Gray's Anatomy: Descriptive and Applied, but the book's name is shortened to, editions are titled, Gray's Anatomy; the book is regarded as an influential work on the subject, has continued to be revised and republished from its initial publication in 1858 to the present day. The latest edition of the book, the 41st, was published in September 2015; the English anatomist Henry Gray was born in 1827. He studied the development of the endocrine glands and spleen and in 1853 was appointed Lecturer on Anatomy at St George's Hospital Medical School in London. In 1855, he approached his colleague Henry Vandyke Carter with his idea to produce an inexpensive and accessible anatomy textbook for medical students. Dissecting unclaimed bodies from workhouse and hospital mortuaries through the Anatomy Act of 1832, the two worked for 18 months on what would form the basis of the book.
Their work was first published in 1858 by John William Parker in London. It was dedicated by Gray to 1st Baronet. An imprint of this English first edition was published in the United States in 1859, with slight alterations. Gray prepared a second, revised edition, published in the United Kingdom in 1860 by J. W. Parker. However, Gray died the following year, at the age of 34, having contracted smallpox while treating his nephew, his death had come just three years after the initial publication of his Anatomy Descriptive and Surgical. So, the work on his much-praised book was continued by others. Longman's publication began in 1863, after their acquisition of the J. W. Parker publishing business; this coincided with the publication date of the third British edition of Gray's Anatomy. Successive British editions of Gray's Anatomy continued to be published under the Longman, more Churchill Livingstone/Elsevier imprints, reflecting further changes in ownership of the publishing companies over the years.
The full American rights were purchased by Blanchard and Lea, who published the first of twenty-five distinct American editions of Gray's Anatomy in 1862, whose company became Lea & Febiger in 1908. Lea & Febiger continued publishing the American editions until the company was sold in 1990; the first American publication was edited by Richard James Dunglison, whose father Robley Dunglison was physician to Thomas Jefferson. Dunglison edited the next four editions; these were: the Second American Edition. W. W. Keen edited the next two editions, namely: the New American from the Eleventh English Edition. In September 1896, reference to the English edition was dropped and it was published as the Fourteenth Edition, edited by Bern B. Gallaudet, F. J. Brockway, J. P. McMurrich, who edited the Fifteenth Edition. There is an edition dated 1896 which does still reference the English edition stating it is "A New Edition, Thoroughly Revised by American Authorities, from the thirteenth English Edition" and edited by T. Pickering Pick, F.
R. C. S. and published by Lea Brothers & Co. Philadelphia and New York; the Sixteenth Edition was edited by J. C. DaCosta, the Seventeenth by DaCosta and E. A. Spitzka. Spitzka edited the Eighteenth and Nineteenth editions, in October 1913, R. Howden edited the New American from the Eighteenth English Edition; the "American" editions continued with consecutive numbering from the Twentieth onwards, with W. H. Lewis editing the 20th, 21st, 22nd, 23rd, 24th. C. M. Gross edited the 25th, 26th, 27th, 28th, 29th. Carmine D. Clemente extensively revised the 30th edition. With the sale of Lea & Febiger in 1990, the 30th edition was the last American Edition. Sometimes separate editing efforts with mismatches between British and American edition numbering led to the existence, for many years, of two main "flavours" or "branches" of Gray's Anatomy: the U. S. and the British one. This can cause misunderstandings and confusion when quoting from or trying to purchase a certain edition. For example, a comparison of publishing histories shows that the American numbering kept apace with the British up until the 16th editions in 1905, with the American editions either acknowledging the English edition, or matching the numbering in the 14th, 15th and 16th editions.
The American numbering crept ahead, with the 17th American edition published in 1908, while the 17th British edition was published in 1909. This increased to a three-year gap for the 18th and 19th editions, leading to the 1913 publication of the New American from the Eighteenth English, which brought the numbering back into line. Both 20th editions were published in the same year. Thereafter, it was the British numbering that pushed ahead, with the 21st British edition in 1920, the 21st American edition in 1924; this discrepancy continued to increase, so that the 30th British edition was published in 1949, while the 30th and last American edition was published in 1984. The newest, 41st edition of Gray's Anatomy was published on 25 September 2015 by Elsevier in both print and online versions, and
Cranial nerves are the nerves that emerge directly from the brain, in contrast to spinal nerves. 10 of the cranial nerves originate in the brainstem. Cranial nerves relay information between the brain and parts of the body to and from regions of the head and neck. Spinal nerves emerge sequentially from the spinal cord with the spinal nerve closest to the head emerging in the space above the first cervical vertebra; the cranial nerves, emerge from the central nervous system above this level. Each cranial nerve is present on both sides. Depending on definition in humans there are twelve or thirteen cranial nerves pairs, which are assigned Roman numerals I–XII, sometimes including cranial nerve zero; the numbering of the cranial nerves is based on the order in which they emerge from the brain, front to back. The terminal nerves, olfactory nerves and optic nerves emerge from the cerebrum or forebrain, the remaining ten pairs arise from the brainstem, the lower part of the brain; the cranial nerves are considered components of the peripheral nervous system, although on a structural level the olfactory and trigeminal nerves are more considered part of the central nervous system.
Most humans are considered to have twelve pairs of cranial nerves, with the terminal nerve more canonized. They are: the olfactory nerve, the optic nerve, oculomotor nerve, trochlear nerve, trigeminal nerve, abducens nerve, facial nerve, vestibulocochlear nerve, glossopharyngeal nerve, vagus nerve, accessory nerve, hypoglossal nerve. Cranial nerves are named according to their structure or function. For example, the olfactory nerve supplies smell, the facial nerve supplies motor innervation to the face; because Latin was the lingua franca of the study of anatomy when the nerves were first documented and discussed, many nerves maintain Latin or Greek names, including the trochlear nerve, named according to its structure, as it supplies a muscle that attaches to a pulley. The trigeminal nerve is named in accordance with its three components, the vagus nerve is named for its wandering course. Cranial nerves are numbered based on their rostral-caudal position. If the brain is removed from the skull the nerves are visible in their numeric order, with the exception of the last, CN XII, which appears to emerge rostrally to CN XI.
Cranial nerves have paths outside the skull. The paths within the skull are called "intracranial" and the paths outside the skull are called "extracranial". There are many holes in the skull called "foramina" by. All cranial nerves are paired, which means that they occur on both the right and left sides of the body; the muscle, skin, or additional function supplied by a nerve on the same side of the body as the side it originates from, is referred to an ipsilateral function. If the function is on the opposite side to the origin of the nerve, this is known as a contralateral function. Intracranial course of cranial nerves is important regarding diagnosis of various intracranial lesions like brain tumors and intracranial arterial aneurysms. Dysfunction of one or more cranial nerves indicates stimulation by some lesion. For example an acoustic schwanoma may cause disturbance in hearing but with further growth of tumor it may involve other cranial nerves and the patient may present with pain resembling trigeminal neuralgia when the tumor involves trigeminal nerve or diplopia due to abducent nerve involvement facial palsy with facial nerve compression.
These findings along with cerebellar signs will suggest the diagnosis of a cerebellopontine angle lesion. A patient presenting with ptosis may have a posterior communicating artery aneurysm compressing the oculomotor nerve during its intracranial course. Facial pain in the distribution of any one or all divisions of trigeminal nerve suggests stimulation of trigeminal nerve roots by a near by vessel; the cell bodies of many of the neurons of most of the cranial nerves are contained in one or more nuclei in the brainstem. These nuclei are important relative to cranial nerve dysfunction because damage to these nuclei such as from a stroke or trauma can mimic damage to one or more branches of a cranial nerve. In terms of specific cranial nerve nuclei, the midbrain of the brainstem has the nuclei of the oculomotor nerve and trochlear nerve; the fibers of these cranial nerves exit the brainstem from these nuclei. Some of the cranial nerves have sensory or parasympathetic ganglia of neurons, which are located outside the brain.
The sensory ganglia are directly correspondent to dorsal root ganglia of spinal nerves and are known as cranial sensory ganglia. Sensory ganglia exist for nerves with sensory function: V, VII, VIII, IX, X. There are parasympathetic ganglia, which are part of the autonomic nervous system for cranial nerves III, VII, IX and X; the trigeminal ganglia of the trigeminal nerve occupies a space in the dura mater called Trigeminal cave. This ganglion contains the cell bodies of the sensory fibers of the three branches of the trig
The acoustic tubercle is a nuclei on the end of the cochlear nerve. The cochlear nerve is lateral to the root of the vestibular nerve, its fibers end in two nuclei: one, the accessory nucleus, lies in front of the inferior peduncle. This article incorporates text in the public domain from page 906 of the 20th edition of Gray's Anatomy https://web.archive.org/web/20100714184556/http://braininfo.rprc.washington.edu/centraldirectory.aspx? ID=633
Anterior olfactory nucleus
The anterior olfactory nucleus is a portion of the forebrain of vertebrates. It is involved in olfaction and has strong influence on other olfactory areas like the olfactory bulb and the piriform cortex; the AON is found behind the olfactory bulb and in front of the piriform cortex and olfactory tubercle in a region referred to as the olfactory peduncle or retrobulbar area. The peduncle contains the AON as well as two other much smaller regions, the taenia tecta and the dorsal peduncular cortex; the AON plays a pivotal but poorly understood role in the processing of odor information. Odors enter the interact with the cilia of olfactory receptor neurons; the information is sent via the olfactory nerve to the olfactory bulb. After the processing in the bulb the signal is transmitted caudally via the axons of mitral and tufted cells in the lateral olfactory tract; the tract forms on the ventrolateral surface of the brain and passes through the AON, continuing on to run the length of the piriform cortex, while synapsing in both regions.
The AON distributes the information to the contralateral olfactory bulb and piriform cortex as well as engaging in reciprocal interactions with the ipsilateral bulb and cortex. Therefore, the AON is positioned to regulate information flow between nearly every region where odor information processing occurs; the AON is composed of two separate structures: a) a thin ring of cells encircling the rostral end of the olfactory peduncle known as “pars externa”, b) the large “pars principalis”, seen in coronal sections of most mammalian brains as a two-layered structure. The deepest is a thick ring of pyramidal and other-shaped cells surrounding the anterior limb of the anterior commissure; the outer, cell-poor layer, is subdivided into a superficial zone and a deeper area. Many divide pars principalis on the basis of the ‘compass points,’ yielding pars dorsalis, pars ventralis, pars medialis, pars lateralis, pars posterioralis. Brunjes PC, Illig KR Meyer EA. 2005. A field guide to the anterior olfactory nucleus/cortex.
Brain Res. Reviews. 50, 305-335. PMID 16229895 "1-4". Cranial Nerves. Yale School of Medicine. Archived from the original on 2016-03-03. NIF Search - Anterior Olfactory Nucleus via the Neuroscience Information Framework
The vestibular nuclei are the cranial nuclei for the vestibular nerve. In Terminologia Anatomica they are grouped in the medulla in the brainstem; the fibers of the vestibular nerve enter the medulla oblongata on the medial side of those of the cochlear, pass between the inferior peduncle and the spinal tract of the trigeminal nerve. They divide into ascending and descending fibers; the latter end by arborizing around the cells of the medial nucleus, situated in the area acustica of the rhomboid fossa. The ascending fibers either end in the same manner or in the lateral nucleus, situated lateral to the area acustica and farther from the ventricular floor; some of the axons of the cells of the lateral nucleus, also of the medial nucleus, are continued upward through the inferior peduncle to the roof nuclei of the opposite side of the cerebellum, to which other fibers of the vestibular root are prolonged without interruption in the nuclei of the medulla oblongata. A second set of fibres from the medial and lateral nuclei end in the tegmentum, while the remainder ascend in the medial longitudinal fasciculus to arborize around the cells of the nuclei of the oculomotor nerve.
Fibres from the lateral vestibular nucleus pass via the vestibulospinal tract, to anterior horn cells at many levels in the spinal cord, in order to co-ordinate head and trunk movements. There are 4 subnuclei. Vestibular nerve Vestibulocerebellar syndrome This article incorporates text in the public domain from page 788 of the 20th edition of Gray's Anatomy Illustration and text: Bs97/TEXT/P13/intro.htm at the University of Wisconsin-Madison Medical school https://web.archive.org/web/20080405062814/http://www.lib.mcg.edu/edu/eshuphysio/program/section8/8ch6/s8ch6_29.htm Parkinson.org Motor Systems Cerebellum
Spinal accessory nucleus
The spinal accessory nucleus lies within the cervical spinal cord in the posterolateral aspect of the anterior horn. The nucleus ambiguus is classically said to provide the "cranial component" of the accessory nerve. However, the existence of this cranial component has been questioned and seen as contributing to the vagus nerve; the terminology continues to be used in describing both human anatomy, that of other animals. Sylvius University of New Mexico Georgetown