Editing Anatomical terms of location (section)

==Other animals and organisms==
Different terms are used because of different [[body plan]]s in animals, whether animals stand on two or four legs, and whether an animal is symmetrical or asymmetrical. For example, as humans are [[symmetry in biology|bilaterally symmetrical]], anatomical descriptions usually use the same terms as those for other vertebrates.<ref name="Hyman"/> However, the standard human anatomical position means that their anterior/posterior and ventral/dorsal directions are the same, so the inferior/superior directions are used due to longstanding tradition instead of cranial/caudal, which apply regardless of position, as in other species.<ref name= "Latin Tucker">{{cite book | author= Tucker, T. G.| title = A Concise Etymological Dictionary of Latin | publisher = Max Niemeyer Verlag | location = Halle (Saale)| year = 1931 }}</ref> The term "rostral" used to refer to the beak or nose in some animals is used less frequently in humans, with the exception of parts of the brain;<ref name="Purves1"/> while humans do not have a visible tail (the [[coccygeal vertebrae]] are present and commonly called the "tailbone") the term "caudal" that refers to the tail-end is also sometimes used in humans and animals without tails to refer to the hind part of the body.<ref name="Purves1"/> [[Flounder]] and other flatfish which lie on the seabed on their left or right side are asymmetric, with both eyes on the 'up' side, making anatomical nomenclature a challenge.<ref>{{cite web |title=Flatfish such as Flounder and Sole |url=https://ioa.factsanddetails.com/article/entry-217.html |website=Sealife, Islands and Oceania: Facts and Details |access-date=12 March 2025}}</ref>

[[Invertebrates]] have a large variety of body shapes that can present a problem when trying to apply standard directional terms. Depending on the organism, some terms are taken by analogy from vertebrate anatomy, and appropriate novel terms are applied as needed. Some such borrowed terms are widely applicable in most invertebrates; for example proximal, meaning "near" refers to the part of an appendage nearest to where it joins the body, and distal, meaning "standing away from" is used for the part furthest from the point of attachment. In all cases, the usage of terms is dependent on the body plan of the organism.

<gallery>
Direcoes anatomicas.svg|Anatomical terms of location in a [[dog]]
Anatomical-directions-kangaroo.svg|Anatomical terms of location in a [[kangaroo]]
Anatomical Directions and Axes.JPG|Anatomical terms of location in most [[fish]]
Horse Axes.JPG|Anatomical terms of location in a [[horse]]
File:Pseudopleuronectes americanus.jpg|[[Flatfish]] are asymmetric, with both eyes lying on the same side of the head. 

</gallery>

===Non-bilaterian organisms===
[[Image:Asymmetrical and Spherical.JPG|thumb|right|250px|Asymmetrical and spherical [[body plan|body shapes]]. (a) An organism with an asymmetrical, amoeboid body plan (''Amoeba proteus''{{snd}} an amoeba). (b) An organism with a spherical amoeboid body plan (''Actinophrys sol''{{snd}} a [[heliozoan]]).]]

In [[non-bilaterian]] organisms with a changeable shape, such as [[amoeboid]] organisms, most directional terms are meaningless, since the shape of the organism is not constant and no distinct axes are fixed. Similarly, in [[radially symmetrical]] organisms, there is nothing to distinguish one line through the centre of the organism from any other. An indefinite number of triads of mutually perpendicular axes could be defined, but any such choice of axes would be useless, as nothing would distinguish a chosen triad from any others. In such organisms, only terms such as ''superficial'' and ''deep'', or sometimes ''proximal'' and ''distal'', are usefully descriptive.

===Elongated organisms===
[[Image:Longitudinal Diatom (Labelled).JPG|thumb|right|Four individuals of ''[[Phaeodactylum tricornutum]]'', a [[diatom]] with a fixed elongated shape]]
In organisms that maintain a constant shape and have one dimension longer than the other, at least two directional terms can be used. The ''long'' or ''longitudinal axis'' is defined by points at the opposite ends of the organism. Similarly, a perpendicular ''transverse axis'' can be defined by points on opposite sides of the organism. There is typically no basis for the definition of a third axis. Usually such organisms are [[planktonic]] (free-swimming) [[protists]], and are nearly always viewed on [[microscope slide]]s, where they appear essentially two-dimensional. In some cases a third axis can be defined, particularly where a non-terminal [[cytostome]] or other unique structure is present.<ref name="Ruppert2004">{{cite book |last1=Ruppert |first1=EE |last2=Fox |first2=RS |last3=Barnes |first3=RD |title=Invertebrate zoology: a functional evolutionary approach |date=2004 |publisher=Thomson-Brooks/Cole |location=Thomson, Belmont |isbn=0-03-025982-7 |edition=7th}}</ref>

<!-- Apical (anatomy) and Basal (anatomy) redirect here -->
[[Image:Labelled Ciliates.JPG|thumb|Organisms where the ends of the long axis are distinct (''[[Paramecium caudatum]]'', above, and ''[[Stentor roeselii]]'', below).]]<!-- Do we need both of these images? They are creating a big blank spot on the page. -->
Some elongated [[protists]] have distinctive ends of the body. In such organisms, the end with a mouth (or equivalent structure, such as the [[cytostome]] in ''[[Paramecium]]'' or ''[[Stentor (ciliate)|Stentor]]''), or the end that usually points in the direction of the organism's [[Animal locomotion|locomotion]] (such as the end with the [[flagellum]] in ''[[Euglena]]''), is normally designated as the '''anterior''' end. The opposite end then becomes the '''posterior end'''.<ref name="Ruppert2004" /> Properly, this terminology would apply only to an organism that is always [[planktonic]] (not normally attached to a surface), although the term can also be applied to one that is [[Sessility (zoology)|sessile]] (normally attached to a surface).<ref>{{cite book |title=On the Origin of Phyla |last=Valentine |first=James W. |year=2004 |publisher=University of Chicago Press |location=Chicago |isbn=978-0-226-84548-7 }}</ref>

{{Anchor|apical}}
[[Image:Venus Flower Basket (sponge-labelled).JPG|thumb|right|A cluster of [[Venus' Flower Basket|''Euplectella aspergillum'' sponges (Venus flower baskets)]], showing the apical–basal axes]]

Organisms that are attached to a [[Substrate (biology)|substrate]], such as [[Porifera|sponges]] and [[Protista|animal-like protists]] also have distinctive ends. The part of the organism attached to the substrate is usually referred to as the '''basal end''' ({{ety|la|basis|support/foundation}}), whereas the end furthest from the attachment is referred to as the '''apical end''' ({{ety|la|apex|peak/tip}}).

===Radially symmetrical organisms===
[[Radial symmetry|Radially symmetrical organisms]] include those in the group [[Radiata]]{{snd}} primarily [[Cnidaria]]ns ([[jellyfish]], [[sea anemones]] and [[corals]], and the [[Ctenophora|comb jellies]]).<ref name="Ruppert2004B">{{cite book |last1=Ruppert |first1=EE |last2=Fox |first2=RS |last3=Barnes |first3=RD |title=Invertebrate zoology: a functional evolutionary approach |date=2004 |page=112|publisher=Thomson-Brooks/Cole |location=Thomson, Belmont |isbn=0-03-025982-7 |edition=7th}}</ref> Adult [[Echinodermata|echinoderms]], such as [[starfish]], [[sea urchin]]s, [[sea cucumber]]s and others are also included, since they have a [[Radial symmetry|pentamerous symmetry]] having five [[rotational symmetry#n-fold rotational symmetry|discrete symmetric parts]] arranged around a central axis.<ref name="Ruppert2004A">{{cite book |last1=Ruppert |first1=EE |last2=Fox |first2=RS |last3=Barnes |first3=RD |title=Invertebrate zoology: a functional evolutionary approach |date=2004 |pages=873–875|publisher=Thomson-Brooks/Cole |location=Thomson, Belmont |isbn=0-03-025982-7 |edition=7th}}</ref> Echinoderm [[larva]]e are not included, since they are [[symmetry in biology|bilaterally symmetrical]].<ref name="Ruppert2004A"/> 

Cnidarians  have an incomplete digestive system, meaning that one end of the organism has a mouth, the '''oral end''' ({{ety|la|ōrālis|of the mouth}}), and the opposite '''aboral end''' ({{ety|la|ab-|away from}}) has no opening from the gut (coelenteron).<ref name="Ruppert2004B"/> They are radially symmetric around the '''oral-aboral axis'''.<ref name="Ruppert2004B"/> Having only the single distinctive axis, "lateral", "dorsal", and "ventral" have no meaning, and all can be replaced by the generic term '''peripheral''' ({{ety|grc|περιφέρεια|circumference}}). '''Medial''' can be used, but in the case of radiates indicates the central point, rather than a central axis as in vertebrates. Thus, there are multiple possible '''radial axes''' and '''medio-peripheral''' (half-) '''axes'''.<ref name="Oliveira2007">{{cite web |last1=Oliveira |first1=Otto Müller Patrão de |title=Chave de identificação dos Ctenophora da costa brasileira |url=https://www.researchgate.net/figure/Symmetry-planes-of-the-ctenophores-using-Bolinopsis-vitrea-as-model-a-view-of-the_fig1_247853778 |publisher=Biota Neotropica |access-date=6 April 2023 |ref=Oliveira2007}}</ref>

Comb jellies have a biradial symmetry about only two planes, a tentacular plane, and a pharyngeal plane.<ref name="Ruppert2004C">{{cite book |last1=Ruppert |first1=EE |last2=Fox |first2=RS |last3=Barnes |first3=RD |title=Invertebrate zoology: a functional evolutionary approach |date=2004 |page=184|publisher=Thomson-Brooks/Cole |location=Thomson, Belmont |isbn=0-03-025982-7 |edition=7th}}</ref>

<gallery widths="220" heights="110">
Image:Radiate Radial Axes.JPG|''[[Aurelia aurita]]'', another species of [[jellyfish]], showing multiple radial and medio-peripheral axes
File:Porania_pulvillus.jpg|The [[sea star]] ''[[Porania pulvillus]]'', aboral and oral surfaces
</gallery>
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===Spiders===
{{See also|Glossary of spider terms|Spider anatomy}}

Special terms are used for [[spiders]]. Two such terms are useful in describing views of the legs and [[pedipalp]]s of spiders, and other [[arachnid]]s. '''Prolateral''' refers to the surface of a leg that is closest to the anterior end of an arachnid's body. '''Retrolateral''' refers to the surface of a leg that is closest to the posterior end of an arachnid's body.<ref name="Kaston1972">{{cite book|last=Kaston|first=B.J.|author-link=B. J. Kaston|title=How to Know the Spiders|edition=3rd|year=1972|page=19|publisher=W.C. Brown Co.|location=Dubuque, IA|isbn=978-0-697-04899-8 |oclc=668250654 }}</ref> Most spiders have eight eyes in four pairs. All the eyes are on the [[carapace]] of the [[prosoma]], and their sizes, shapes and locations are characteristic of various spider families and other [[taxon|taxa]].<ref name=FOELIX2011>{{cite book|last1=Foelix|first1=Rainer|title=Biology of Spiders|date=2011|publisher=Oxford University Press, US|isbn=978-0-19-973482-5|pages=17–19|url=https://books.google.com/books?id=eOUVDAAAQBAJ&q=arachnid+anatomy|ref=Foelix2011|language=en}}</ref> Usually, the eyes are arranged in two roughly parallel, horizontal and symmetrical rows of eyes.{{r|FOELIX2011}} Eyes are labelled according to their position as anterior and posterior lateral eyes (ALE) and (PLE); and anterior and posterior median eyes (AME) and (PME).{{r|FOELIX2011}}

<gallery>
File:Palystes superciliosus male anterior 2012 03 04 3452.JPG|Aspects of spider anatomy. This aspect shows the mainly prolateral surface of the anterior femora, plus the typical horizontal eye pattern of the [[Sparassidae]].
File:Hogna species female Lycosidae showing eye pattern EOS 027s.jpg|Typical arrangement of eyes in the [[Lycosidae]], with PME being the largest
File:Salticidae Male Anterior annotated.jpg|In the [[Salticidae]] the AME are the largest.
</gallery>