Anatomy: Difference between revisions

[[File:Vesalius-copy.jpg|thumb|350px|One of the large, detailed illustrations in [[Andreas Vesalius]]'s ''[[De humani corporis fabrica]]'' 16th century, marking the rebirth of anatomy<ref>{{Cite web |title=De humani corporis fabrica libri septem. Cum indice rerum & uerborum memorabilium locupletissimo |url=https://ia801207.us.archive.org/10/items/bub_gb_5Xby3nxU3XMC/bub_gb_5Xby3nxU3XMC.pdf}}</ref>]]

'''Anatomy''' ({{etymology|grc|''{{wikt-lang|grc|ἀνατομή}}'' ({{grc-transl|ἀνατομή}})|[[dissection]]}}) is the branch of [[Morphology (biology)|morphology]] concerned with the study of the internal structure of [[organisms]] and their parts.<ref>{{cite Merriam-Webster|anatomy}}</ref> Anatomy is a branch of [[natural science]] that deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times.<ref>{{cite web |last=Rotimi |first=Booktionary |title=Anatomy |url=https://www.preps.ng/jamb-subject-combination-for-anatomy/ |url-status=live |archive-url=https://web.archive.org/web/20170801080440/https://www.booktionary.com.ng/index_files/Page1935.htm |archive-date=1 August 2017 |access-date=18 June 2017}}</ref> Anatomy is inherently tied to [[developmental biology]], [[embryology]], [[comparative anatomy]], [[evolutionary biology]], and [[phylogeny]],<ref name="intro HGray">{{cite web |last=Gray |first=Henry |year=1918 |title=Introduction |url=https://www.bartleby.com/107/1.html |archive-url=https://web.archive.org/web/20070316005206/https://www.bartleby.com/107/1.html |archive-date=16 March 2007 |access-date=19 March 2007 |website=Anatomy of the Human Body |via=[[Bartleby.com]] |edition=20th}}</ref> as these are the processes by which anatomy is generated, both over immediate and long-term timescales. Anatomy and [[physiology]], which study the structure and [[function (biology)|function]] of organisms and their parts respectively, make a natural pair of related disciplines, and are often studied together. [[Human anatomy]] is one of the essential [[basic sciences]] that are applied in medicine, and is often studied alongside [[physiology]].<ref>{{cite journal |author=Arráez-Aybar |display-authors=etal |year=2010 |title=Relevance of human anatomy in daily clinical practice |journal=[[Annals of Anatomy]] |volume=192 |issue=6|pages=341–48 |doi=10.1016/j.aanat.2010.05.002 |pmid=20591641 }}</ref>

Anatomy is a complex and dynamic field that is constantly evolving as discoveries are made. In recent years, there has been a significant increase in the use of advanced imaging techniques, such as [[MRI]] and [[CT scan]]s, which allow for more detailed and accurate visualizations of the body's structures.

Anatomy can be studied using both invasive and non-invasive methods with the goal of obtaining information about the structure and organization of organs and systems.<ref name="intro HGray" /> Methods used include [[dissection]], in which a body is opened and its organs studied, and [[endoscopy]], in which a [[video camera]]-equipped instrument is inserted through a small incision in the body wall and used to explore the internal organs and other structures. [[Angiography]] using [[X-ray]]s or [[magnetic resonance angiography]] are methods to visualize blood vessels.<ref>{{cite journal | title=Use of Angiography to Outline the Cardiovascular Anatomy of the Sand Crab Portunus pelagicus Linnaeus |vauthors=Gribble N, Reynolds K | journal=Journal of Crustacean Biology | year=1993 | volume=13 | issue=4 | pages=627–637 | doi=10.1163/193724093x00192 | jstor=1549093|bibcode=1993JCBio..13..627. }}</ref><ref>{{cite journal | title=Characterization of the Renal Portal System of the Common Green Iguana (Iguana iguana) by Digital Subtraction Imaging |vauthors=Benson KG, Forrest L | journal=Journal of Zoo and Wildlife Medicine | year=1999 | volume=30 | issue=2 | pages=235–241|pmid=10484138 }}</ref><ref>{{cite web |url=https://www.hopkinsmedicine.org/healthlibrary/test_procedures/cardiovascular/magnetic_resonance_angiography_mra_135,14/ |title=Magnetic Resonance Angiography (MRA) |publisher=Johns Hopkins Medicine |access-date=29 April 2014 |archive-date=7 October 2017 |archive-url=https://web.archive.org/web/20171007124356/https://www.hopkinsmedicine.org/healthlibrary/test_procedures/cardiovascular/magnetic_resonance_angiography_mra_135,14 |url-status=live }}</ref><ref>{{cite web | url=https://www.nhs.uk/conditions/angiography/Pages/Introduction.aspx | title=Angiography | publisher=[[National Health Service]] | access-date=29 April 2014 | archive-date=7 September 2017 | archive-url=https://web.archive.org/web/20170907045854/https://www.nhs.uk/conditions/Angiography/Pages/Introduction.aspx | url-status=live }}</ref>

The [[Kingdom (biology)|kingdom]] [[Animalia]] contains [[multicellular organism]]s that are [[heterotroph]]ic and [[motile]] (although some have secondarily adopted a [[Sessility (zoology)|sessile]] lifestyle). Most animals have bodies differentiated into separate [[Tissue (biology)|tissues]] and these animals are also known as [[eumetazoa]]ns. They have an internal [[digestion|digestive]] chamber, with one or two openings; the [[gamete]]s are produced in multicellular sex organs, and the [[zygote]]s include a [[blastula]] stage in their [[Embryogenesis|embryonic development]]. Metazoans do not include the [[sponge]]s, which have undifferentiated cells.<ref name=Dorit549>{{cite book |title=Zoology |url=https://archive.org/details/zoology0000dori |url-access=registration |last1=Dorit |first1=R. L. |last2=Walker |first2=W. F. |last3=Barnes |first3=R. D. |year=1991 |publisher=Saunders College Publishing |isbn=978-0-03-030504-7 |pages=[https://archive.org/details/zoology0000dori/page/547 547–549] }}</ref>

Unlike [[plant cell]]s, [[animal cells]] have neither a cell wall nor [[chloroplast]]s. Vacuoles, when present, are more in number and much smaller than those in the plant cell. The body tissues are composed of numerous types of cells, including those found in muscles, nerves and skin. Each typically has a cell membrane formed of [[phospholipid]]s, [[cytoplasm]] and a [[Cell nucleus|nucleus]]. All of the different cells of an animal are derived from the embryonic [[germ layer]]s. Those simpler invertebrates which are formed from two germ layers of ectoderm and endoderm are called [[diploblastic]] and the more developed animals whose structures and organs are formed from three germ layers are called [[triploblastic]].<ref name=Ruppert60>{{cite book |title=Invertebrate Zoology, 7th edition |last1=Ruppert |first1=Edward E. |last2=Fox |first2=Richard, S. |last3=Barnes |first3=Robert D. |year=2004 |publisher=[[Cengage Learning]] |isbn=978-81-315-0104-7 |pages=59–60 }}</ref> All of a triploblastic animal's tissues and organs are derived from the three germ layers of the embryo, the [[ectoderm]], [[mesoderm]] and [[endoderm]].

[[Connective tissue]]s are fibrous and made up of cells scattered among inorganic material called the [[extracellular matrix]]. Often called [[fascia]] (from the Latin "fascia," meaning "band" or "bandage"), connective tissues give shape to organs and holds them in place. The main types are loose connective tissue, [[adipose tissue]], fibrous connective tissue, [[cartilage]] and bone. The extracellular matrix contains [[protein]]s, the chief and most abundant of which is [[collagen]]. Collagen plays a major part in organizing and maintaining tissues. The matrix can be modified to form a skeleton to support or protect the body. An [[exoskeleton]] is a thickened, rigid [[cuticle]] which is stiffened by [[mineralisation (biology)|mineralization]], as in [[crustacean]]s or by the cross-linking of its proteins as in [[insect]]s. An [[endoskeleton]] is internal and present in all developed animals, as well as in many of those less developed.<ref name="Ruppert60" />

[[Muscle cells]] (myocytes) form the active contractile tissue of the body. [[Muscle tissue]] functions to produce force and cause motion, either locomotion or movement within internal organs. Muscle is formed of contractile [[Myofibril|filaments]] and is separated into three main types; [[smooth muscle]], [[skeletal muscle]] and [[cardiac muscle]]. Smooth muscle has no [[Striated muscle tissue|striations]] when examined microscopically. It contracts slowly but maintains contractibility over a wide range of stretch lengths. It is found in such organs as [[sea anemone]] tentacles and the body wall of [[sea cucumber]]s. Skeletal muscle contracts rapidly but has a limited range of extension. It is found in the movement of appendages and jaws. Obliquely striated muscle is intermediate between the other two. The filaments are staggered and this is the type of muscle found in [[earthworm]]s that can extend slowly or make rapid contractions.<ref name=Ruppert103>{{cite book |title=Invertebrate Zoology, 7th edition |last1=Ruppert |first1=Edward E. |last2=Fox |first2=Richard, S. |last3=Barnes |first3=Robert D. |year=2004 |publisher=Cengage Learning |isbn=978-81-315-0104-7 |page=103 }}</ref> In higher animals striated muscles occur in bundles attached to bone to provide movement and are often arranged in antagonistic sets. Smooth muscle is found in the walls of the [[uterus]], [[bladder]], [[intestines]], [[stomach]], [[oesophagus]], [[respiratory airways]], and [[blood vessel]]s. [[Cardiac muscle]] is found only in the [[heart]], allowing it to contract and pump blood round the body.

[[Nervous tissue]] is composed of many nerve cells known as [[neuron]]s which transmit information. In some slow-moving [[radially symmetrical]] marine animals such as [[ctenophore]]s and [[cnidarian]]s (including [[sea anemone]]s and [[jellyfish]]), the nerves form a [[nerve net]], but in most animals they are organized longitudinally into bundles. In simple animals, receptor neurons in the body wall cause a local reaction to a stimulus. In more complex animals, specialized receptor cells such as [[chemoreceptor]]s and [[photoreceptor cell|photoreceptors]] are found in groups and send messages along [[biological neural network|neural networks]] to other parts of the organism. Neurons can be connected together in [[ganglia]].<ref name=Ruppert104>{{cite book |title=Invertebrate Zoology, 7th edition |last1=Ruppert |first1=Edward E. |last2=Fox |first2=Richard, S. |last3=Barnes |first3=Robert D. |year=2004 |publisher=Cengage Learning |isbn=978-81-315-0104-7 |page=104 }}</ref> In higher animals, specialized receptors are the basis of sense organs and there is a [[central nervous system]] (brain and spinal cord) and a [[peripheral nervous system]]. The latter consists of [[Sensory neuron|sensory nerves]] that transmit information from sense organs and [[motor nerves]] that influence target organs.<ref>{{cite book|title=Grey's Anatomy: Descriptive and Applied |year=1944 |edition=28 |page=1038 |publisher=Langmans |editor1-last=Johnston | editor1-first= T.B |editor2-last=Whillis | editor2-first=J }}</ref><ref name=Ruppert107>{{cite book |title=Invertebrate Zoology, 7th edition |last1=Ruppert |first1=Edward E. |last2=Fox |first2=Richard, S. |last3=Barnes |first3=Robert D. |year=2004 |publisher=Cengage Learning |isbn=978-81-315-0104-7 |pages=105–107 }}</ref> The peripheral nervous system is divided into the [[somatic nervous system]] which conveys sensation and controls [[voluntary muscle]], and the [[autonomic nervous system]] which involuntarily controls [[smooth muscle]], certain glands and internal organs, including the [[stomach]].<ref>{{cite web | url=https://www.inkling.com/read/essential-clinical-anatomy-keith-moore-4th/introduction-to-clinical-anatomy/nervous-system | title=Essesntial Clinical Anatomy | publisher=Inkling | work=Nervous System | date=2010 | edition=4th | access-date=30 April 2014 | author1=Moore, K. | author2=Agur, A. | author3=Dalley, A. F. | archive-date=8 March 2021 | archive-url=https://web.archive.org/web/20210308131326/https://www.inkling.com/read/essential-clinical-anatomy-keith-moore-4th/introduction-to-clinical-anatomy/nervous-system | url-status=live }}</ref>

All [[vertebrate]]s have a similar basic [[body plan]] and at some point in their lives, mostly in the [[embryogenesis|embryonic]] stage, share the major [[chordate]] characteristics: a stiffening rod, the [[notochord]]; a dorsal hollow tube of nervous material, the [[neural tube]]; [[pharyngeal arch]]es; and a tail posterior to the anus. The [[spinal cord]] is protected by the [[vertebral column]] and is above the notochord, and the [[gastrointestinal tract]] is below it.<ref>{{cite web |last=Waggoner |first=Ben |title=Vertebrates: More on Morphology |url=https://www.ucmp.berkeley.edu/vertebrates/vertmm.html |publisher=UCMP |access-date=13 July 2011 |archive-date=10 October 2018 |archive-url=https://web.archive.org/web/20181010104933/https://www.ucmp.berkeley.edu/vertebrates/vertmm.html |url-status=dead }}</ref> Nervous tissue is derived from the [[ectoderm]], connective tissues are derived from [[mesoderm]], and gut is derived from the [[endoderm]]. At the posterior end is a tail which continues the spinal cord and vertebrae but not the gut. The mouth is found at the anterior end of the animal, and the [[anus]] at the base of the tail.<ref>{{cite book |title=The Vertebrate Body |last=Romer |first=Alfred Sherwood |year=1985 |publisher=Holt Rinehart & Winston |isbn=978-0-03-058446-6 }}</ref> The defining characteristic of a vertebrate is the [[vertebral column]], formed in the development of the segmented series of [[vertebra]]e. In most vertebrates the notochord becomes the [[nucleus pulposus]] of the [[intervertebral disc]]s. However, a few vertebrates, such as the [[sturgeon]] and the [[coelacanth]], retain the notochord into adulthood.<ref>{{cite book|title=Functional anatomy of the vertebrates: an evolutionary perspective|year=2001|publisher=Harcourt College Publishers|isbn=978-0-03-022369-3|author=Liem, Karel F.|author2=Warren Franklin Walker|page=277}}</ref> [[Jawed vertebrates]] are typified by paired appendages, fins or legs, which may be secondarily lost. The limbs of vertebrates are considered to be [[Homology (biology)|homologous]] because the same underlying skeletal structure was inherited from their [[last common ancestor]]. This is one of the arguments put forward by [[Charles Darwin]] to support his theory of [[evolution]].<ref>{{cite web |url=https://ncse.com/evolution/science/what-is-homology |title=What is Homology? |work=NCSE |date=17 October 2008 |publisher=National Center for Science Education |access-date=28 June 2013 |archive-date=31 March 2019 |archive-url=https://web.archive.org/web/20190331065618/https://ncse.com/evolution/science/what-is-homology |url-status=live }}</ref>

[[Reptile]]s are a class of [[animal]]s comprising [[turtle]]s, [[tuatara]]s, [[lizard]]s, [[snake]]s and [[crocodile]]s. They are [[tetrapod]]s, but the snakes and a few species of lizard either have no limbs or their limbs are much reduced in size. Their bones are better ossified and their skeletons stronger than those of amphibians. The teeth are conical and mostly uniform in size. The surface cells of the epidermis are modified into horny scales which create a waterproof layer. Reptiles are unable to use their skin for respiration as do amphibians and have a more efficient respiratory system drawing air into their [[lung]]s by expanding their chest walls. The heart resembles that of the amphibian but there is a septum which more completely separates the oxygenated and deoxygenated bloodstreams. The reproductive system has evolved for internal fertilization, with a [[copulatory organ]] present in most species. The eggs are surrounded by [[Amniote|amniotic membranes]] which prevents them from drying out and are laid on land, or [[Ovoviviparity|develop internally]] in some species. The bladder is small as nitrogenous waste is excreted as [[uric acid]].<ref name=Dorit865>{{cite book |title=Zoology |url=https://archive.org/details/zoology0000dori/page/861 |url-access=registration |last1=Dorit |first1=R. L. |last2=Walker |first2=W. F. |last3=Barnes |first3=R. D. |year=1991 |publisher=Saunders College Publishing |isbn=978-0-03-030504-7 |pages=[https://archive.org/details/zoology0000dori/page/861 861–865] }}</ref>

Generally, students of certain [[biological sciences]], [[paramedic]]s, prosthetists and orthotists, [[physiotherapists]], [[occupational therapy|occupational therapists]], [[nurses]], [[podiatry|podiatrists]], and [[medical school|medical students]] learn gross anatomy and microscopic anatomy from anatomical models, skeletons, textbooks, diagrams, photographs, lectures and tutorials and in addition, medical students generally also learn gross anatomy through practical experience of [[dissection]] and inspection of [[cadaver]]s. The study of microscopic anatomy (or [[histology]]) can be aided by practical experience examining histological preparations (or slides) under a [[microscope]].<ref>{{cite web |url=https://www.medschoolsonline.co.uk/index.php?pageid=135 |title=Studying medicine |publisher=Medschools Online |access-date=27 June 2013 |archive-url=https://web.archive.org/web/20130128114829/https://www.medschoolsonline.co.uk/index.php?pageid=135 |archive-date=28 January 2013 |url-status=dead }}</ref>

Human anatomy, physiology and biochemistry are complementary basic medical sciences, which are generally taught to medical students in their first year at medical school. Human anatomy can be taught regionally or systemically; that is, respectively, studying anatomy by bodily regions such as the head and chest, or studying by specific systems, such as the nervous or respiratory systems.<ref name="intro HGray" /> The major anatomy textbook, [[Gray's Anatomy]], has been reorganized from a systems format to a regional format, in line with modern teaching methods.<ref>{{cite book |url=https://archive.org/details/graysanatomyanat0000unse |title=Publisher's page for Gray's Anatomy. 39th edition (UK).|year=2004 |isbn=978-0-443-07168-3|url-access=registration |last1=Drake |first1=Richard Lee |last2=Gray |first2=Henry |last3=Vogl |first3=Wayne |last4=Mitchell |first4=Adam W. M. |publisher=Elsevier Churchill Livingstone }}</ref><ref>{{cite book |url=https://archive.org/details/graysanatomyanat0000unse |title=Publisher's page for Gray's Anatomy. 39th edition (US).|year=2004 |isbn=978-0-443-07168-3|url-access=registration |last1=Drake |first1=Richard Lee |last2=Gray |first2=Henry |last3=Vogl |first3=Wayne |last4=Mitchell |first4=Adam W. M. }}</ref> A thorough working knowledge of anatomy is required by physicians, especially [[surgery|surgeons]] and doctors working in some diagnostic specialties, such as [[histopathology]] and [[radiology]].<ref name=AAA>{{cite web |url=https://www.anatomy.org/ |title=American Association of Anatomists |access-date=27 June 2013 |archive-url=https://web.archive.org/web/20190404042736/https://www.anatomy.org/ |archive-date=4 April 2019 |url-status=dead }}</ref>

[[Invertebrate]]s constitute a vast array of living organisms ranging from the simplest unicellular [[eukaryote]]s such as ''[[Paramecium]]'' to such complex multicellular animals as the [[octopus]], [[lobster]] and [[dragonfly]]. They constitute about 95% of the animal species. By definition, none of these creatures has a backbone. The cells of single-cell [[protozoa]]ns have the same basic structure as those of multicellular animals but some parts are specialized into the equivalent of tissues and organs. Locomotion is often provided by [[cilia]] or [[flagella]] or may proceed via the advance of [[pseudopodia]], food may be gathered by [[phagocytosis]], energy needs may be supplied by [[photosynthesis]] and the cell may be supported by an [[endoskeleton]] or an [[exoskeleton]]. Some protozoans can form multicellular colonies.<ref>{{cite book |title=Invertebrate Zoology, 7th edition |last1=Ruppert |first1=Edward E. |last2=Fox |first2=Richard, S. |last3=Barnes |first3=Robert D. |year=2004 |publisher=Cengage Learning |isbn=978-81-315-0104-7 |pages=23–24 }}</ref>

[[Insect]]s possess [[segmentation (biology)|segmented]] bodies supported by a hard-jointed outer covering, the [[exoskeleton]], made mostly of [[chitin]]. The segments of the body are organized into three distinct parts, a head, a [[Thorax (insect anatomy)|thorax]] and an [[abdomen]].<ref>{{cite web|title=O. Orkin Insect zoo |url=https://insectzoo.msstate.edu/Students/basic.structure.html |year=1997 |publisher=Mississippi State University |access-date=23 June 2013 |url-status=dead |archive-url=https://web.archive.org/web/20090602045832/https://www.insectzoo.msstate.edu/Students/basic.structure.html |archive-date=2 June 2009 }}</ref> The head typically bears a pair of sensory [[Antenna (biology)|antennae]], a pair of [[compound eye]]s, one to three simple eyes ([[ocelli]]) and three sets of modified appendages that form the [[insect mouthparts|mouthparts]]. The thorax has three pairs of segmented [[arthropod leg|legs]], one pair each for the three segments that compose the thorax and one or two pairs of [[insect wing|wings]]. The abdomen is composed of eleven segments, some of which may be fused and houses the [[digestion|digestive]], [[Respiration (physiology)|respiratory]], [[excretory]] and reproductive systems.<ref name="Gullan and Cranston">{{cite book |last1=Gullan |first1=P.J. |last2=Cranston |first2=P. S. |title=The Insects: An Outline of Entomology |publisher=Blackwell Publishing |location=Oxford |year=2005 |edition=3 |pages=[https://archive.org/details/isbn_9781405111133/page/22 22–48] |isbn=978-1-4051-1113-3 |url-access=registration |url=https://archive.org/details/isbn_9781405111133/page/22 }}</ref> There is considerable variation between species and many adaptations to the body parts, especially wings, legs, antennae and mouthparts.<ref>{{cite book |title=Invertebrate Zoology, 7th edition |last1=Ruppert |first1=Edward E. |last2=Fox |first2=Richard, S. |last3=Barnes |first3=Robert D. |year=2004 |publisher=Cengage Learning |isbn=978-81-315-0104-7 |pages=218–225 }}</ref>

Some of the most striking advances in early anatomy and physiology took place in Hellenistic Alexandria.<ref name=Longrigg /> Two of the most famous anatomists and physiologists of the third century were [[Herophilus]] and [[Erasistratus]]. These two physicians helped pioneer human [[dissection]] for medical research, using the cadavers of condemned criminals, which was considered taboo until the Renaissance—Herophilus was recognized as the first person to perform systematic dissections.<ref name = bay>{{cite journal |last1= Bay|first1=Noel Si Yang|last2=Bay|first2=Boon-Huat|title=Greek Anatomists Herophilus: The Father of Anatomy|journal=Anatomy and Cell Biology|date=2010|volume= 43 |issue= 3|pages=280–283|doi=10.5115/acb.2010.43.4.280|pmc=3026179|pmid=21267401}}</ref> Herophilus became known for his anatomical works, making impressive contributions to many branches of anatomy and many other aspects of medicine.<ref>{{cite journal|last1=Von Staden|first1=H|title=The Discovery of the Body: Human Dissection and Its Cultural Contexts in Ancient Greece|journal=The Yale Journal of Biology and Medicine|date=1992|volume=65|issue=3|pages=223–241|pmid=1285450|pmc=2589595}}</ref> Some of the works included classifying the system of the pulse, the discovery that human arteries had thicker walls than veins, and that the atria were parts of the heart. Herophilus's knowledge of the human body has provided vital input towards understanding the brain, eye, liver, reproductive organs, and nervous system and characterizing the course of the disease.<ref name = bay/> Erasistratus accurately described the structure of the brain, including the cavities and membranes, and made a distinction between its cerebrum and cerebellum<ref>{{Cite web |url=https://www.faqs.org/health/bios/12/Erasistratus.html |title= Erasistratus Biography (304B.C-250B.C) |access-date=23 February 2022 |archive-date= 16 November 2018 |archive-url=https://web.archive.org/web/20181116054307/https://www.faqs.org/health/bios/12/Erasistratus.html |url-status=bot: unknown |website=Free Health Encyclopedia - faqs.org }}</ref> During his study in Alexandria, Erasistratus was particularly concerned with studies of the circulatory and nervous systems. He could distinguish the human body's sensory and motor nerves and believed air entered the lungs and heart, which was then carried throughout the body. His distinction between the arteries and veins—the arteries carrying the air through the body, while the veins carry the blood from the heart was a great anatomical discovery. Erasistratus was also responsible for naming and describing the function of the epiglottis and the heart's valves, including the tricuspid.<ref>{{cite encyclopedia|title=Erasistratus of Ceos: Greek Physician|date = April 3, 2018 |url= https://www.britannica.com/biography/Erasistratus-of-Ceos|encyclopedia= Encyclopædia Britannica|access-date=|archive-date=21 April 2019|archive-url= https://web.archive.org/web/20190421000007/https://www.britannica.com/biography/Erasistratus-of-Ceos |url-status=live}}</ref> During the third century, Greek physicians were able to differentiate nerves from blood vessels and tendons<ref>{{cite journal |last1= Wiltse|first1=LL|last2=Pait|first2=TG|title=Herophilus of Alexandria (325-255 B.C.) The Father of Anatomy|journal=Spine|date=1 September 1998|volume= 23 |issue= 17 |pages= 1904–1914|pmid=9762750|doi=10.1097/00007632-199809010-00022}}</ref> and to realize that the nerves convey neural impulses.<ref name="Longrigg"/> It was Herophilus who made the point that damage to motor nerves induced paralysis.<ref name = bay/> Herophilus named the meninges and ventricles in the brain, appreciated the division between cerebellum and cerebrum and recognized that the brain was the "seat of intellect" and not a "cooling chamber" as propounded by Aristotle<ref>{{cite journal|last1=Wills|first1=Adrian|title=Herophilus, Ersasistratus, and the birth of neuroscience|journal=The Lancet |date=1999 |volume= 354|issue=9191|pages=1719–1720|doi=10.1016/S0140-6736(99)02081-4|pmid=10568587|s2cid=30110082|url=https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(99)02081-4/references |access-date=25 November 2015|archive-date=28 October 2019|archive-url=https://web.archive.org/web/20191028095251/https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(99)02081-4/references |url-status=live|url-access=subscription}}</ref> Herophilus is also credited with describing the optic, oculomotor, motor division of the trigeminal, facial, vestibulocochlear and hypoglossal nerves.<ref name="Cambridge University Press">{{cite book|last1=Von Staden|first1=Heinrich |title=Herophilus: The Art of Medicine in Early Alexandria|date=October 2007|publisher=Cambridge University Press|isbn=9780521041782|url=https://www.cambridge.org/us/academic/subjects/classical-studies/ancient-philosophy/herophilus-art-medicine-early-alexandria-edition-translation-and-essays|access-date=25 November 2015|archive-date=8 December 2015|archive-url=https://web.archive.org/web/20151208053822/https://www.cambridge.org/us/academic/subjects/classical-studies/ancient-philosophy/herophilus-art-medicine-early-alexandria-edition-translation-and-essays|url-status=live}}</ref>

Anatomy developed little from classical times until the sixteenth century; as the historian Marie Boas writes, "Progress in anatomy before the sixteenth century is as mysteriously slow as its development after 1500 is startlingly rapid".<ref name=Boas>{{cite book | title=The Scientific Renaissance 1450–1630 | publisher=Fontana | author=Boas, Marie | year=1970 |orig-year=first published by Collins, 1962 | pages=120–143}}</ref>{{rp|120–121}} Between 1275 and 1326, the anatomists [[Mondino de Luzzi]], [[Alessandro Achillini]] and [[Antonio Benivieni]] at [[Bologna]] carried out the first systematic human dissections since ancient times.<ref name="ZimmermanVeith1993">{{cite book | last1=Zimmerman | first1=Leo M. | last2=Veith | first2=Ilza | title=Great Ideas in the History of Surgery | url=https://books.google.com/books?id=ABbCI7z4UwMC | year=1993 | publisher=Norman | isbn=978-0-930405-53-3 | access-date=31 July 2017 | archive-date=15 April 2016 | archive-url=https://web.archive.org/web/20160415082135/https://books.google.com/books?id=ABbCI7z4UwMC | url-status=live }}</ref><ref name="Crombie1959">{{cite book | last=Crombie | first=Alistair Cameron | title=The History of Science From Augustine to Galileo | url=https://books.google.com/books?id=bGDScHy1clsC&pg=PA4 | year=1959 | publisher=Courier Dover Publications | isbn=978-0-486-28850-5 | access-date=31 July 2017 | archive-date=9 April 2016 | archive-url=https://web.archive.org/web/20160409055609/https://books.google.com/books?id=bGDScHy1clsC&pg=PA4 | url-status=live }}</ref><ref name="Thorndike1958">{{cite book | last=Thorndike | first=Lynn | title=A History of Magic and Experimental Science: Fourteenth and fifteenth centuries | url=https://books.google.com/books?id=IbvlQFj4YfUC&pg=PA586 | year=1958 | publisher=Columbia University Press | isbn=978-0-231-08797-1 | access-date=31 July 2017 | archive-date=16 April 2016 | archive-url=https://web.archive.org/web/20160416061340/https://books.google.com/books?id=IbvlQFj4YfUC&pg=PA586 | url-status=live }}</ref> Mondino's ''Anatomy'' of 1316 was the first textbook in the medieval rediscovery of human anatomy. It describes the body in the order followed in Mondino's dissections, starting with the abdomen, thorax, head, and limbs. It was the standard anatomy textbook for the next century.<ref name=Boas/>

Equally important advances have occurred in ''non-invasive'' techniques for examining the body's interior structures. [[X-ray]]s can be passed through the body and used in medical [[radiography]] and [[fluoroscopy]] to differentiate interior structures that have varying degrees of opaqueness. [[Magnetic resonance imaging]], [[computed tomography]], and [[ultrasound imaging]] have all enabled the examination of internal structures in unprecedented detail to a degree far beyond the imagination of earlier generations.<ref name=":1">{{cite web | url=https://www.mhhe.com/biosci/ap/foxhumphys/student/olc/h-reading1.html | title=Anatomical Imaging | publisher=McGraw Hill Higher Education | year=1998 | access-date=25 June 2013 | archive-url=https://web.archive.org/web/20160303232044/https://www.mhhe.com/biosci/ap/foxhumphys/student/olc/h-reading1.html | archive-date=3 March 2016 | url-status=dead }}</ref>

* [[Anatomical model]]

* [[Outline of human anatomy]]

* {{Portal inline|size=tiny|Anatomy}}

*Lyman, Henry Munson. ''[https://digital.sciencehistory.org/works/bg257g476 The Book of Health]'' (1898). [https://digital.sciencehistory.org/ Science History Institute Digital Collections] {{Webarchive|url=https://web.archive.org/web/20190202042542/https://digital.sciencehistory.org/ |date=2 February 2019 }}.