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The dataset generation failed

Error code:   DatasetGenerationError
Exception:    CastError
Message:      Couldn't cast
embedding_model: string
embedding_dim: int64
num_chunks: int64
sources: struct<textbooks: int64, pubmed: int64>
  child 0, textbooks: int64
  child 1, pubmed: int64
source: string
id: string
text: string
title: string
to
{'id': Value('string'), 'source': Value('string'), 'title': Value('string'), 'text': Value('string')}
because column names don't match
Traceback:    Traceback (most recent call last):
                File "/usr/local/lib/python3.12/site-packages/datasets/builder.py", line 1872, in _prepare_split_single
                  for key, table in generator:
                                    ^^^^^^^^^
                File "/usr/local/lib/python3.12/site-packages/datasets/packaged_modules/json/json.py", line 289, in _generate_tables
                  self._cast_table(pa_table, json_field_paths=json_field_paths),
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                File "/usr/local/lib/python3.12/site-packages/datasets/packaged_modules/json/json.py", line 124, in _cast_table
                  pa_table = table_cast(pa_table, self.info.features.arrow_schema)
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                File "/usr/local/lib/python3.12/site-packages/datasets/table.py", line 2272, in table_cast
                  return cast_table_to_schema(table, schema)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                File "/usr/local/lib/python3.12/site-packages/datasets/table.py", line 2218, in cast_table_to_schema
                  raise CastError(
              datasets.table.CastError: Couldn't cast
              embedding_model: string
              embedding_dim: int64
              num_chunks: int64
              sources: struct<textbooks: int64, pubmed: int64>
                child 0, textbooks: int64
                child 1, pubmed: int64
              source: string
              id: string
              text: string
              title: string
              to
              {'id': Value('string'), 'source': Value('string'), 'title': Value('string'), 'text': Value('string')}
              because column names don't match
              
              The above exception was the direct cause of the following exception:
              
              Traceback (most recent call last):
                File "/src/services/worker/src/worker/job_runners/config/parquet_and_info.py", line 1347, in compute_config_parquet_and_info_response
                  parquet_operations = convert_to_parquet(builder)
                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^
                File "/src/services/worker/src/worker/job_runners/config/parquet_and_info.py", line 980, in convert_to_parquet
                  builder.download_and_prepare(
                File "/usr/local/lib/python3.12/site-packages/datasets/builder.py", line 884, in download_and_prepare
                  self._download_and_prepare(
                File "/usr/local/lib/python3.12/site-packages/datasets/builder.py", line 947, in _download_and_prepare
                  self._prepare_split(split_generator, **prepare_split_kwargs)
                File "/usr/local/lib/python3.12/site-packages/datasets/builder.py", line 1739, in _prepare_split
                  for job_id, done, content in self._prepare_split_single(
                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^
                File "/usr/local/lib/python3.12/site-packages/datasets/builder.py", line 1922, in _prepare_split_single
                  raise DatasetGenerationError("An error occurred while generating the dataset") from e
              datasets.exceptions.DatasetGenerationError: An error occurred while generating the dataset

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id string	source string	title string	text string
Anatomy_Gray_0	textbooks	Anatomy_Gray	What is anatomy? Anatomy includes those structures that can be seen grossly (without the aid of magnification) and microscopically (with the aid of magnification). Typically, when used by itself, the term anatomy tends to mean gross or macroscopic anatomy—that is, the study of structures that can be seen without using ...
Anatomy_Gray_1	textbooks	Anatomy_Gray	Observation and visualization are the primary techniques a student should use to learn anatomy. Anatomy is much more than just memorization of lists of names. Although the language of anatomy is important, the network of information needed to visualize the position of physical structures in a patient goes far beyond si...
Anatomy_Gray_2	textbooks	Anatomy_Gray	How can gross anatomy be studied? The term anatomy is derived from the Greek word temnein, meaning “to cut.” Clearly, therefore, the study of anatomy is linked, at its root, to dissection, although dissection of cadavers by students is now augmented, or even in some cases replaced, by viewing prosected (previously diss...
Anatomy_Gray_3	textbooks	Anatomy_Gray	This includes the vasculature, the nerves, the bones, the muscles, and all other structures and organs located in the region of the body defined as the thorax. After studying this region, the other regions of the body (i.e., the abdomen, pelvis, lower limb, upper limb, back, head, and neck) are studied in a similar fas...
Anatomy_Gray_4	textbooks	Anatomy_Gray	Each of these approaches has benefits and deficiencies. The regional approach works very well if the anatomy course involves cadaver dissection but falls short when it comes to understanding the continuity of an entire system throughout the body. Similarly, the systemic approach fosters an understanding of an entire sy...
Anatomy_Gray_5	textbooks	Anatomy_Gray	The anatomical position The anatomical position is the standard reference position of the body used to describe the location of structures (Fig. 1.1). The body is in the anatomical position when standing upright with feet together, hands by the side and face looking forward. The mouth is closed and the facial expressio...
Anatomy_Gray_6	textbooks	Anatomy_Gray	Three major groups of planes pass through the body in the anatomical position (Fig. 1.1). Coronal planes are oriented vertically and divide the body into anterior and posterior parts. Sagittal planes also are oriented vertically but are at right angles to the coronal planes and divide the body into right and left parts...
Anatomy_Gray_7	textbooks	Anatomy_Gray	Three major pairs of terms are used to describe the location of structures relative to the body as a whole or to other structures (Fig. 1.1). Anterior (or ventral) and posterior (or dorsal) describe the position of structures relative to the “front” and “back” of the body. For example, the nose is an anterior (ventral)...
Anatomy_Gray_8	textbooks	Anatomy_Gray	Superior and inferior describe structures in reference to the vertical axis of the body. For example, the head is superior to the shoulders and the knee joint is inferior to the hip joint. Proximal and distal, cranial and caudal, Other terms used to describe positions include proximal and distal, cranial and caudal, an...
Anatomy_Gray_9	textbooks	Anatomy_Gray	Cranial (toward the head) and caudal (toward the tail) are sometimes used instead of superior and inferior, respectively. Rostral is used, particularly in the head, to describe the position of a structure with reference to the nose. For example, the forebrain is rostral to the hindbrain. Two other terms used to describ...
Anatomy_Gray_10	textbooks	Anatomy_Gray	Superficial and deep can also be used in a more absolute fashion to define two major regions of the body. The superficial region of the body is external to the outer layer of deep fascia. Deep structures are enclosed by this layer. Structures in the superficial region of the body include the skin, superficial fascia, a...
Anatomy_Gray_11	textbooks	Anatomy_Gray	X-rays are photons (a type of electromagnetic radiation) and are generated from a complex X-ray tube, which is a type of cathode ray tube (Fig. 1.2). The X-rays are then collimated (i.e., directed through lead-lined shutters to stop them from fanning out) to the appropriate area of the body. As the X-rays pass through ...
Anatomy_Gray_12	textbooks	Anatomy_Gray	Modifications to this X-ray technique allow a continuous stream of X-rays to be produced from the X-ray tube and collected on an input screen to allow real-time visualization of moving anatomical structures, barium studies, angiography, and fluoroscopy (Fig. 1.3).
Anatomy_Gray_13	textbooks	Anatomy_Gray	To demonstrate specific structures, such as bowel loops or arteries, it may be necessary to fill these structures with a substance that attenuates X-rays more than bowel loops or arteries do normally. It is, however, extremely important that these substances are nontoxic. Barium sulfate, an insoluble salt, is a nontoxi...
Anatomy_Gray_14	textbooks	Anatomy_Gray	For some patients it is necessary to inject contrast agents directly into arteries or veins. In this case, iodine-based molecules are suitable contrast agents. Iodine is chosen because it has a relatively high atomic mass and so markedly attenuates X-rays, but also, importantly, it is naturally excreted via the urinary...
Anatomy_Gray_15	textbooks	Anatomy_Gray	During angiography it is often difficult to appreciate the contrast agent in the vessels through the overlying bony structures. To circumvent this, the technique of subtraction angiography has been developed. Simply, one or two images are obtained before the injection of contrast media. These images are inverted (such ...
Anatomy_Gray_16	textbooks	Anatomy_Gray	Ultrasonography of the body is widely used for all aspects of medicine. Ultrasound is a very high frequency sound wave (not electromagnetic radiation) generated by piezoelectric materials, such that a series of sound waves is produced. Importantly, the piezoelectric material can also receive the sound waves that bounce...
Anatomy_Gray_17	textbooks	Anatomy_Gray	Developments in ultrasound technology, including the size of the probes and the frequency range, mean that a broad range of areas can now be scanned. Traditionally ultrasound is used for assessing the abdomen (Fig. 1.6) and the fetus in pregnant women. Ultrasound is also widely used to assess the eyes, neck, soft tissu...
Anatomy_Gray_18	textbooks	Anatomy_Gray	Doppler ultrasound enables determination of flow, its direction, and its velocity within a vessel using simple ultrasound techniques. Sound waves bounce off moving structures and are returned. The degree of frequency shift determines whether the object is moving away from or toward the probe and the speed at which it i...
Anatomy_Gray_19	textbooks	Anatomy_Gray	A CT scanner obtains a series of images of the body (slices) in the axial plane. The patient lies on a bed, an X-ray tube passes around the body (Fig. 1.7), and a series of images are obtained. A computer carries out a complex mathematical transformation on the multitude of images to produce the final image (Fig. 1.8).
Anatomy_Gray_20	textbooks	Anatomy_Gray	Nuclear magnetic resonance imaging was first described in 1946 and used to determine the structure of complex molecules. The process of magnetic resonance imaging (MRI) is dependent on the free protons in the hydrogen nuclei in molecules of water (H2O). Because water is present in almost all biological tissues, the hyd...
Anatomy_Gray_21	textbooks	Anatomy_Gray	By altering the sequence of pulses to which the protons are subjected, different properties of the protons can be assessed. These properties are referred to as the “weighting” of the scan. By altering the pulse sequence and the scanning parameters, T1-weighted images (Fig. 1.10A) and T2-weighted images (Fig. 1.10B) can...
Anatomy_Gray_22	textbooks	Anatomy_Gray	MRI can also be used to assess flow within vessels and to produce complex angiograms of the peripheral and cerebral circulation. Diffusion-weighted imaging provides information on the degree of Brownian motion of water molecules in various tissues. There is relatively free diffusion in extracellular spaces and more res...
Anatomy_Gray_23	textbooks	Anatomy_Gray	X-rays is that gamma rays are produced from within the nucleus of an atom when an unstable nucleus decays, whereas X-rays are produced by bombarding an atom with electrons. For an area to be visualized, the patient must receive a gamma ray emitter, which must have a number of properties to be useful, including: a reaso...
Anatomy_Gray_24	textbooks	Anatomy_Gray	The most commonly used radionuclide (radioisotope) is technetium-99m. This may be injected as a technetium salt or combined with other complex molecules. For example, by combining technetium-99m with methylene diphosphonate (MDP), a radiopharmaceutical is produced. When injected into the body this radiopharmaceutical s...
Anatomy_Gray_25	textbooks	Anatomy_Gray	Depending on how the radiopharmaceutical is absorbed, distributed, metabolized, and excreted by the body after injection, images are obtained using a gamma camera (Fig. 1.11). Positron emission tomography (PET) is an imaging modality for detecting positron-emitting radionuclides. A positron is an anti-electron, which i...
Anatomy_Gray_26	textbooks	Anatomy_Gray	PET has become an important imaging modality in the detection of cancer and the assessment of its treatment and recurrence. Single photon emission computed tomography (SPECT) is an imaging modality for detecting gamma rays emitted from the decay of injected radionuclides such as technetium-99m, iodine-123, or iodine-13...
Anatomy_Gray_27	textbooks	Anatomy_Gray	Plain radiographs are undoubtedly the most common form of image obtained in a hospital or local practice. Before interpretation, it is important to know about the imaging technique and the views obtained as standard. In most instances (apart from chest radiography) the X-ray tube is 1 m away from the X-ray film. The ob...
Anatomy_Gray_28	textbooks	Anatomy_Gray	The chest radiograph is one of the most commonly requested plain radiographs. An image is taken with the patient erect and placed posteroanteriorly (PA chest radiograph; that is, with the patient’s back closest to the X-ray tube.). Occasionally, when patients are too unwell to stand erect, films are obtained on the bed...
Anatomy_Gray_29	textbooks	Anatomy_Gray	Plain abdominal radiographs are obtained in the AP supine position. From time to time an erect plain abdominal radiograph is obtained when small bowel obstruction is suspected.
Anatomy_Gray_30	textbooks	Anatomy_Gray	High-density contrast medium is ingested to opacify the esophagus, stomach, small bowel, and large bowel. As described previously (p. 6), the bowel is insufflated with air (or carbon dioxide) to provide a double-contrast study. In many countries, endoscopy has superseded upper gastrointestinal imaging, but the mainstay...
Anatomy_Gray_31	textbooks	Anatomy_Gray	Intravenous urography is the standard investigation for assessing the urinary tract. Intravenous contrast medium is injected, and images are obtained as the medium is excreted through the kidneys. A series of films are obtained during this period from immediately after the injection up to approximately 20 minutes later...
Anatomy_Gray_32	textbooks	Anatomy_Gray	Computed tomography is the preferred terminology rather than computerized tomography, though both terms are used interchangeably by physicians. It is important for the student to understand the presentation of images. Most images are acquired in the axial plane and viewed such that the observer looks from below and upw...
Anatomy_Gray_33	textbooks	Anatomy_Gray	The great advantage of CT scanning is the ability to extend and compress the gray scale to visualize the bones, soft tissues, and visceral organs. Altering the window settings and window centering provides the physician with specific information about these structures. There is no doubt that MRI has revolutionized the ...
Anatomy_Gray_34	textbooks	Anatomy_Gray	Most nuclear medicine images are functional studies. Images are usually interpreted directly from a computer, and a series of representative films are obtained for clinical use. Whenever a patient undergoes an X-ray or nuclear medicine investigation, a dose of radiation is given (Table 1.1). As a general principle it i...
Anatomy_Gray_35	textbooks	Anatomy_Gray	Imaging modalities such as ultrasound and MRI are ideal because they do not impart significant risk to the patient. Moreover, ultrasound imaging is the modality of choice for assessing the fetus. Any imaging device is expensive, and consequently the more complex the imaging technique (e.g., MRI) the more expensive the ...
Anatomy_Gray_36	textbooks	Anatomy_Gray	The skeletal system consists of cartilage and bone. Cartilage is an avascular form of connective tissue consisting of extracellular fibers embedded in a matrix that contains cells localized in small cavities. The amount and kind of extracellular fibers in the matrix varies depending on the type of cartilage. In heavy w...
Anatomy_Gray_37	textbooks	Anatomy_Gray	There are three types of cartilage: hyaline—most common; matrix contains a moderate amount of collagen fibers (e.g., articular surfaces of bones); elastic—matrix contains collagen fibers along with a large number of elastic fibers (e.g., external ear); fibrocartilage—matrix contains a limited number of cells and ground...
Anatomy_Gray_38	textbooks	Anatomy_Gray	There are two types of bone, compact and spongy (trabecular or cancellous). Compact bone is dense bone that forms the outer shell of all bones and surrounds spongy bone. Spongy bone consists of spicules of bone enclosing cavities containing blood-forming cells (marrow). Classification of bones is by shape. Long bones a...
Anatomy_Gray_39	textbooks	Anatomy_Gray	Bones are vascular and are innervated. Generally, an adjacent artery gives off a nutrient artery, usually one per bone, that directly enters the internal cavity of the bone and supplies the marrow, spongy bone, and inner layers of compact bone. In addition, all bones are covered externally, except in the area of a join...
Anatomy_Gray_40	textbooks	Anatomy_Gray	Developmentally, all bones come from mesenchyme by either intramembranous ossification, in which mesenchymal models of bones undergo ossification, or endochondral ossification, in which cartilaginous models of bones form from mesenchyme and undergo ossification. The sites where two skeletal elements come together are t...
Anatomy_Gray_41	textbooks	Anatomy_Gray	First, a layer of cartilage, usually hyaline cartilage, covers the articulating surfaces of the skeletal elements. In other words, bony surfaces do not normally contact one another directly. As a consequence, when these joints are viewed in normal radiographs, a wide gap seems to separate the adjacent bones because the...
Anatomy_Gray_42	textbooks	Anatomy_Gray	A second characteristic feature of synovial joints is the presence of a joint capsule consisting of an inner synovial membrane and an outer fibrous membrane. The synovial membrane attaches to the margins of the joint surfaces at the interface between the cartilage and bone and encloses the articular cavity. The synovia...
Anatomy_Gray_43	textbooks	Anatomy_Gray	The fibrous membrane is formed by dense connective tissue and surrounds and stabilizes the joint. Parts of the fibrous membrane may thicken to form ligaments, which further stabilize the joint. Ligaments outside the capsule usually provide additional reinforcement. Another common but not universal feature of synovial j...
Anatomy_Gray_44	textbooks	Anatomy_Gray	Descriptions of synovial joints based on shape and movement Synovial joints are described based on shape and movement: based on the shape of their articular surfaces, synovial joints are described as plane (flat), hinge, pivot, bicondylar (two sets of contact points), condylar (ellipsoid), saddle, and ball and socket; ...
Anatomy_Gray_45	textbooks	Anatomy_Gray	Hinge joints—allow movement around one axis that passes transversely through the joint; permit flexion and extension (e.g., elbow [humero-ulnar] joint) Pivot joints—allow movement around one axis that passes longitudinally along the shaft of the bone; permit rotation (e.g., atlanto-axial joint) Bicondylar joints—allow ...
Anatomy_Gray_46	textbooks	Anatomy_Gray	Ball and socket joints—allow movement around multiple axes; permit flexion, extension, abduction, adduction, circumduction, and rotation (e.g., hip Solid joints are connections between skeletal elements where the adjacent surfaces are linked together either by fibrous connective tissue or by cartilage, usually fibrocar...
Anatomy_Gray_47	textbooks	Anatomy_Gray	Gomphoses occur only between the teeth and adjacent bone. In these joints, short collagen tissue fibers in the periodontal ligament run between the root of the tooth and the bony socket. Syndesmoses are joints in which two adjacent bones are linked by a ligament. Examples are the ligamentum flavum, which connects adjac...
Anatomy_Gray_48	textbooks	Anatomy_Gray	Symphyses occur where two separate bones are interconnected by cartilage. Most of these types of joints occur in the midline and include the pubic symphysis between the two pelvic bones, and intervertebral discs between adjacent vertebrae. The skin is the largest organ of the body. It consists of the epidermis and the ...
Anatomy_Gray_49	textbooks	Anatomy_Gray	Superficial (subcutaneous) fascia lies just deep to and is attached to the dermis of the skin. It is made up of loose connective tissue usually containing a large amount of fat. The thickness of the superficial fascia (subcutaneous tissue) varies considerably, both from one area of the body to another and from one indi...
Anatomy_Gray_50	textbooks	Anatomy_Gray	Deep fascia usually consists of dense, organized connective tissue. The outer layer of deep fascia is attached to the deep surface of the superficial fascia and forms a thin fibrous covering over most of the deeper region of the body. Inward extensions of this fascial layer form intermuscular septa that compartmentaliz...
Anatomy_Gray_51	textbooks	Anatomy_Gray	covering the deep surface of the muscles of the abdominal wall (the transversalis fascia). This layer is referred to as extraperitoneal fascia. A similar layer of fascia in the thorax is termed the endothoracic fascia.
Anatomy_Gray_52	textbooks	Anatomy_Gray	The muscular system is generally regarded as consisting of one type of muscle found in the body—skeletal muscle. However, there are two other types of muscle tissue found in the body, smooth muscle and cardiac muscle, that are important components of other systems. These three types of muscle can be characterized by wh...
Anatomy_Gray_53	textbooks	Anatomy_Gray	Skeletal muscle forms the majority of the muscle tissue in the body. It consists of parallel bundles of long, multinucleated fibers with transverse stripes, is capable of powerful contractions, and is innervated by somatic and branchial motor nerves. This muscle is used to move bones and other structures, and provides ...
Anatomy_Gray_54	textbooks	Anatomy_Gray	Cardiac muscle is striated muscle found only in the walls of the heart (myocardium) and in some of the large vessels close to where they join the heart. It consists of a branching network of individual cells linked electrically and mechanically to work as a unit. Its contractions are less powerful than those of skeleta...
Anatomy_Gray_55	textbooks	Anatomy_Gray	The cardiovascular system consists of the heart, which pumps blood throughout the body, and the blood vessels, which are a closed network of tubes that transport the blood. There are three types of blood vessels: arteries, which transport blood away from the heart; veins, which transport blood toward the heart; capilla...
Anatomy_Gray_56	textbooks	Anatomy_Gray	Arteries are usually further subdivided into three classes, according to the variable amounts of smooth muscle and elastic fibers contributing to the thickness of the tunica media, the overall size of the vessel, and its function. Large elastic arteries contain substantial amounts of elastic fibers in the tunica media,...
Anatomy_Gray_57	textbooks	Anatomy_Gray	Small arteries and arterioles control the filling of the capillaries and directly contribute to the arterial pressure in the vascular system. Veins also are subdivided into three classes. Large veins contain some smooth muscle in the tunica media, but the thickest layer is the tunica externa. Examples of large veins ar...
Anatomy_Gray_58	textbooks	Anatomy_Gray	The walls of veins, specifically the tunica media, are thin. The luminal diameters of veins are large. There often are multiple veins (venae comitantes) closely associated with arteries in peripheral regions. Valves often are present in veins, particularly in peripheral vessels inferior to the level of the heart. These...
Anatomy_Gray_59	textbooks	Anatomy_Gray	Lymphatic vessels mainly collect fluid lost from vascular capillary beds during nutrient exchange processes and deliver it back to the venous side of the vascular system (Fig. 1.28). Also included in this interstitial fluid that drains into the lymphatic capillaries are pathogens, cells of the lymphocytic system, cell ...
Anatomy_Gray_60	textbooks	Anatomy_Gray	The fluid in most lymphatic vessels is clear and colorless and is known as lymph. That carried by lymphatic vessels from the small intestine is opaque and milky because of the presence of chylomicrons and is termed chyle. There are lymphatic vessels in most areas of the body, including those associated with the central...
Anatomy_Gray_61	textbooks	Anatomy_Gray	Lymph nodes are small (0.1–2.5 cm long) encapsulated structures that interrupt the course of lymphatic vessels and contain elements of the body’s defense system, such as clusters of lymphocytes and macrophages. They act as elaborate filters that trap and phagocytose particulate matter in the lymph that percolates throu...
Anatomy_Gray_62	textbooks	Anatomy_Gray	A number of regions in the body are associated with clusters or a particular abundance of lymph nodes (Fig. 1.29). Not surprisingly, nodes in many of these regions drain the body’s surface, the digestive system, or the respiratory system. All three of these areas are high-risk sites for the entry of foreign pathogens. ...
Anatomy_Gray_63	textbooks	Anatomy_Gray	Lymph from the right side of the head and neck, the right upper limb, and the right side of the thorax is carried by lymphatic vessels that connect with veins on the right side of the neck. Lymph from all other regions of the body is carried by lymphatic vessels that drain into veins on the left side of the neck. Speci...
Anatomy_Gray_64	textbooks	Anatomy_Gray	The CNS is composed of the brain and spinal cord, both of which develop from the neural tube in the embryo. The PNS is composed of all nervous structures outside the CNS that connect the CNS to the body. Elements of this system develop from neural crest cells and as outgrowths of the CNS. The PNS consists of the spinal...
Anatomy_Gray_65	textbooks	Anatomy_Gray	The details of nerve plexuses are described in chapters dealing with the specific regions in which the plexuses are located. The parts of the brain are the cerebral hemispheres, the cerebellum, and the brainstem. The cerebral hemispheres consist of an outer portion, or the gray matter, containing cell bodies; an inner ...
Anatomy_Gray_66	textbooks	Anatomy_Gray	A further discussion of the brain can be found in Chapter 8. The spinal cord is the part of the CNS in the superior two thirds of the vertebral canal. It is roughly cylindrical in shape, and is circular to oval in cross section with a central canal. A further discussion of the spinal cord can be found in Chapter 2. The...
Anatomy_Gray_67	textbooks	Anatomy_Gray	A further discussion of the cranial meninges can be found in Chapter 8 and of the spinal meninges in Chapter 2. Functional subdivisions of the CNS Functionally, the nervous system can be divided into somatic and visceral parts. The somatic part (soma, from the Greek for “body”) innervates structures (skin and most skel...
Anatomy_Gray_68	textbooks	Anatomy_Gray	The somatic part of the nervous system consists of: nerves that carry conscious sensations from peripheral regions back to the CNS, and nerves that innervate voluntary muscles. Somatic nerves arise segmentally along the developing CNS in association with somites, which are themselves arranged segmentally along each sid...
Anatomy_Gray_69	textbooks	Anatomy_Gray	Cells that migrate posteriorly give rise to the intrinsic muscles of the back (epaxial muscles) and the associated dermis. Developing nerve cells within anterior regions of the neural tube extend processes peripherally into posterior and anterior regions of the differentiating dermatomyotome of each somite. Simultaneou...
Anatomy_Gray_70	textbooks	Anatomy_Gray	Neurons that develop from cells within the spinal cord are motor neurons and those that develop from neural crest cells are sensory neurons. Somatic sensory and somatic motor fibers that are organized segmentally along the neural tube become parts of all spinal nerves and some cranial nerves. The clusters of sensory ne...
Anatomy_Gray_71	textbooks	Anatomy_Gray	Somatic motor fibers carry information away from the CNS to skeletal muscles and are also called somatic motor efferents or general somatic efferents (GSEs). Like somatic sensory fibers that come from the periphery, somatic motor fibers can be very long. They extend from cell bodies in the spinal cord to the muscle cel...
Anatomy_Gray_72	textbooks	Anatomy_Gray	There is overlap in the distribution of dermatomes, but usually a specific region within each dermatome can be identified as an area supplied by a single spinal cord level. Testing touch in these autonomous zones in a conscious patient can be used to localize lesions to a specific spinal nerve or to a specific level in...
Anatomy_Gray_73	textbooks	Anatomy_Gray	Myotomes are generally more difficult to test than dermatomes because each skeletal muscle in the body often develops from more than one somite and is therefore innervated by nerves derived from more than one spinal cord level (Fig. 1.37). Testing movements at successive joints can help in localizing lesions to specifi...
Anatomy_Gray_74	textbooks	Anatomy_Gray	Sensory nerves monitor changes in the viscera. Motor nerves mainly innervate smooth muscle, cardiac muscle, and glands. The visceral motor component is commonly referred to as the autonomic division of the PNS and is subdivided into sympathetic and parasympathetic parts. Like the somatic part of the nervous system, the...
Anatomy_Gray_75	textbooks	Anatomy_Gray	Visceral motor neurons that arise from cells in lateral regions of the neural tube send processes out of the anterior aspect of the tube. Unlike in the somatic part, these processes, containing general visceral efferent fibers (GVEs), synapse with other cells, usually other visceral motor neurons, that develop outside ...
Anatomy_Gray_76	textbooks	Anatomy_Gray	The cell bodies of the visceral motor neurons outside the CNS often associate with each other in a discrete mass called a ganglion. Visceral sensory and motor fibers enter and leave the CNS with their somatic equivalents (Fig. 1.40). Visceral sensory fibers enter the spinal cord together with somatic sensory fibers thr...
Anatomy_Gray_77	textbooks	Anatomy_Gray	Visceral motor and sensory fibers do not enter and leave the CNS at all levels (Fig. 1.41): In the cranial region, visceral components are associated with four of the twelve cranial nerves (CN III, VII, IX, and X). In the spinal cord, visceral components are associated mainly with spinal cord levels T1 to L2 and S2 to ...
Anatomy_Gray_78	textbooks	Anatomy_Gray	The parasympathetic system is more restricted to innervation of the viscera only. Spinal sympathetic and spinal parasympathetic neurons share certain developmental and phenotypic features that are different from those of cranial parasympathetic neurons. Based on this, some researchers have suggested reclassifying all s...
Anatomy_Gray_79	textbooks	Anatomy_Gray	The sympathetic part of the autonomic division of the PNS leaves thoracolumbar regions of the spinal cord with the somatic components of spinal nerves T1 to L2 (Fig. 1.42). On each side, a paravertebral sympathetic trunk extends from the base of the skull to the inferior end of the vertebral column where the two trunks...
Anatomy_Gray_80	textbooks	Anatomy_Gray	Visceral motor preganglionic fibers leave the T1 to L2 part of the spinal cord in anterior roots. The fibers then enter the spinal nerves, pass through the anterior rami and into the sympathetic trunks. One trunk is located on each side of the vertebral column (paravertebral) and positioned anterior to the anterior ram...
Anatomy_Gray_81	textbooks	Anatomy_Gray	Preganglionic sympathetic fibers that enter a paravertebral ganglion or the sympathetic trunk through a white ramus communicans may take the following four pathways to target tissues: 1. Peripheral sympathetic innervation at the level of origin of the preganglionic fiber Preganglionic sympathetic fibers may synapse wit...
Anatomy_Gray_82	textbooks	Anatomy_Gray	2. Peripheral sympathetic innervation above or below the level of origin of the preganglionic fiber Preganglionic sympathetic fibers may ascend or descend to other vertebral levels where they synapse in ganglia associated with spinal nerves that may or may not have visceral motor input directly from the spinal cord (i....
Anatomy_Gray_83	textbooks	Anatomy_Gray	White rami communicantes only occur in association with spinal nerves T1 to L2, whereas gray rami communicantes are associated with all spinal nerves. Fibers from spinal cord levels T1 to T5 pass predominantly superiorly, whereas fibers from T5 to L2 pass inferiorly. All sympathetics passing into the head have pregangl...
Anatomy_Gray_84	textbooks	Anatomy_Gray	3. Sympathetic innervation of thoracic Preganglionic sympathetic fibers may synapse with postganglionic motor neurons in ganglia and then leave the ganglia medially to innervate thoracic or cervical viscera (Fig. 1.45). They may ascend in the trunk before synapsing, and after synapsing the postganglionic fibers may com...
Anatomy_Gray_85	textbooks	Anatomy_Gray	4. Sympathetic innervation of the abdomen and pelvic regions and the adrenals Preganglionic sympathetic fibers may pass through the sympathetic trunk and paravertebral ganglia without synapsing and, together with similar fibers from other levels, form splanchnic nerves (greater, lesser, least, lumbar, and sacral), whic...
Anatomy_Gray_86	textbooks	Anatomy_Gray	Some of the preganglionic fibers in the prevertebral plexus do not synapse in the sympathetic ganglia of the plexus but pass through the system to the adrenal gland, where they synapse directly with cells of the adrenal medulla. These cells are homologues of sympathetic postganglionic neurons and secrete adrenaline and...
Anatomy_Gray_87	textbooks	Anatomy_Gray	Like the visceral motor nerves of the sympathetic part, the visceral motor nerves of the parasympathetic part generally have two neurons in the pathway. The preganglionic neurons are in the CNS, and fibers leave in the cranial nerves. In the sacral region, the preganglionic parasympathetic fibers form special visceral ...
Anatomy_Gray_88	textbooks	Anatomy_Gray	The preganglionic parasympathetic motor fibers in CN III, VII, and IX separate from the nerves and connect with one of four distinct ganglia, which house postganglionic motor neurons. These four ganglia are near major branches of CN V. Postganglionic fibers leave the ganglia, join the branches of CN V, and are carried ...
Anatomy_Gray_89	textbooks	Anatomy_Gray	When present, postganglionic parasympathetic neurons are in the walls of the target viscera. motor fibers. Visceral sensory fibers follow the course of sympathetic fibers entering the spinal cord at similar spinal cord levels. However, visceral sensory fibers may also enter the spinal cord at levels other than those as...
Anatomy_Gray_90	textbooks	Anatomy_Gray	Visceral sensory fibers in X include those from cervical viscera, and major vessels and viscera in the thorax and abdomen. Visceral sensory fibers from pelvic viscera and the distal parts of the colon are carried in S2 to S4. Visceral sensory fibers associated with parasympathetic fibers primarily relay information to ...
Anatomy_Gray_91	textbooks	Anatomy_Gray	Neurons in the enteric system are derived from neural crest cells originally associated with occipitocervical and sacral regions. Interestingly, more neurons are reported to be in the enteric system than in the spinal cord itself. Sensory and motor neurons within the enteric system control reflex activity within and be...
Anatomy_Gray_92	textbooks	Anatomy_Gray	Major somatic plexuses formed from the anterior rami of spinal nerves are the cervical (C1 to C4), brachial (C5 to T1), lumbar (L1 to L4), sacral (L4 to S4), and coccygeal (S5 to Co) plexuses. Except for spinal nerve T1, the anterior rami of thoracic spinal nerves remain independent and do not participate in plexuses. ...
Anatomy_Gray_93	textbooks	Anatomy_Gray	Specific information about the organization and components of the respiratory, gastrointestinal, and urogenital systems will be discussed in each of the succeeding chapters of this text. Fig. 1.1 The anatomical position, planes, and terms of location and orientation. Feet togethertoes forwardHands by sidespalms forward...
Anatomy_Gray_94	textbooks	Anatomy_Gray	Fig. 1.8 Computed tomography scan of the abdomen at vertebral level L2. Fig. 1.9 A T2-weighted MR image in the sagittal plane of the pelvic viscera in a woman. Fig. 1.10 T1-weighted (A) and T2-weighted (B) MR images of the brain in the coronal plane. Fig. 1.11 A gamma camera. Fig. 1.12 The axial skeleton and the append...
Anatomy_Gray_95	textbooks	Anatomy_Gray	Fig. 1.14 A developmental series of radiographs showing the progressive ossification of carpal (wrist) bones from 3 (A) to 10 (D) years of age. Fig. 1.15 T1-weighted image in the coronal plane, demonstrating the relatively high signal intensity returned from the femoral heads and proximal femoral necks, consistent with...
Anatomy_Gray_96	textbooks	Anatomy_Gray	Fig. 1.16 Radiograph, lateral view, showing fracture of the ulna at the elbow joint (A) and repair of this fracture (B) using internal fixation with a plate and multiple screws. Fig. 1.17 Image of the hip joints demonstrating loss of height of the right femoral head with juxta-articular bony sclerosis and subchondral c...
Anatomy_Gray_97	textbooks	Anatomy_Gray	Fig. 1.21 Solid joints. Fig. 1.22 This operative photograph demonstrates the focal areas of cartilage loss in the patella and femoral condyles throughout the knee joint. Fig. 1.23 This radiograph demonstrates the loss of joint space in the medial compartment and presence of small spiky osteophytic regions at the medial...
Anatomy_Gray_98	textbooks	Anatomy_Gray	Fig. 1.27 Photograph demonstrating varicose veins. Fig. 1.28 Lymphatic vessels mainly collect fluid lost from vascular capillary beds during nutrient exchange processes and deliver it back to the venous side of the vascular system. Fig. 1.29 Regions associated with clusters or a particular abundance of lymph nodes. Cer...
Anatomy_Gray_99	textbooks	Anatomy_Gray	Fig. 1.30 Major lymphatic vessels that drain into large veins in the neck. Fig. 1.31 A. This computed tomogram with contrast, in the axial plane, demonstrates the normal common carotid arteries and internal jugular veins with numerous other nonenhancing nodules that represent lymph nodes in a patient with lymphoma. B. ...

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