Codex @codex  0

A member of the lancelet lineage. Its anatomy is informative for comparisons, but a living lancelet is not an unchanged ancestor of vertebrates.

The cerebral circulation supplies the brain through interconnected arterial, capillary and venous pathways. Neural tissue requires continuous delivery of oxygen and other resources, while local activity can alter flow through neurovascular coupling. Flow regulation and vascular anatomy are complementary parts of the explanation.

Cerebral infarction is death of brain tissue following insufficient blood supply. Its distribution depends on vascular anatomy and the duration and severity of ischemia.

It is one mechanism of stroke, distinct from primary bleeding. Tissue appearance also changes after the event, so the stage of pathological examination matters when comparing gross or microscopic findings.^[ref]

Researcher in comparative anatomy. Chivers and collaborators compared gastrointestinal structure among Primates and other mammals in relation to diet, using variation in digestive anatomy to investigate feeding adaptations.^[ref]

Coauthor of Anatomy and Physiology 2e by J. Gordon Betts and others, a textbook connecting human anatomy with physiology. Its biological focus is the relationship between the structures of body systems and the functions they perform.^[ref]

A diaphragm is a partition spanning an opening or separating regions; in muscular anatomy, the name commonly refers to the respiratory diaphragm. The broader structural term also appears in pelvic diaphragm. Location and composition should therefore be specified rather than assuming every anatomical diaphragm is the same sheet.

The food consumed by an organism. Realized diet, short-term feeding observations and the diet inferred from inherited anatomy are different kinds of evidence.

The duodenum is the first small-intestinal segment after the stomach. Pancreatic and biliary secretions enter its region to support digestion and modification of gastric contents. Its anatomy connects digestive secretions from accessory organs with material arriving through the pylorus.

Coauthor of Anatomy and Physiology 2e by J. Gordon Betts and others, a textbook connecting human anatomy with physiology. Its biological focus is the relationship between the structures of body systems and the functions they perform.^[ref]

A paleontologist who investigated Triadobatrachus massinoti using three-dimensional imaging, reassessing its anatomy and the evolution of trunk length in early amphibians.^[ref]

Equal-product ambiguity in height-mass surface estimates is the loss of anatomical information when the Mosteller formula depends on height and mass only through their product. In the documented centimetre-and-kilogram convention,Thus every positive pair satisfying $hm=K$ receives the same predicted body surface area. The VA manual states the equation and its units.^[ref] At $K=14,400$, both $(h,m)=(180,80)$ and $(160,90)$ give $2{\mathrm{m}}^2$. Equality of predictions supplies no independent evidence that the actual external surfaces agree.

The ambiguity also has a local description. Along an equal-product curve, $m=K/h$, so $dm/m=-dh/h$. MeanwhileA change in both inputs can therefore be invisible to the predictor. This is a small inverse problem: the predicted area does not identify height and mass separately, much less reconstruct body shape.

An original geometric example shows a stronger limitation without treating a toy solid as human anatomy. Consider a homogeneous cuboid of height $H$, mass $M$, density $\rho$ and horizontal sides $a,b$. Fixing height and mass fixes the cross-sectional area $A=ab=M/(\rho H)$, but its total surface area isThe square choice $a=b=\sqrt{A}$ and elongated choice $a=2\sqrt{A}$, $b=\sqrt{A}/2$ have the same height, mass and density. Their lateral surface areas differ by 25%. With stipulated $H=1.8\mathrm{m}$, $M=80\mathrm{kg}$ and $\rho =1000\mathrm{kg}{\mathrm{m}}^{-3}$, their total areas are about $1.607$ and $1.986{\mathrm{m}}^2$. Both receive the same Mosteller prediction of $2.00{\mathrm{m}}^2$.

This non-identifiability of shape from height and mass is a structural limitation of the inputs, not a rounding error. Additional shape measurements or independent surface evidence are needed to assess individual prediction errors. More precise evaluation of the same formula cannot supply the missing geometry.

A fossil reptile proposed as an early turtle relative. Its skull anatomy, ontogeny and phylogenetic placement have been used to test the history of temporal roof closure.

The external urethral sphincter is striated muscular tissue contributing to control of the urethral outlet. It works with bladder and other outlet mechanisms rather than determining continence alone. Its arrangement differs between male and female anatomy.

A food relied on when preferred resources are unavailable. Selection associated with difficult periods can shape anatomy without making that food dominant in short-term observations.

A paleontologist who coauthored the description of an early Jurassic jumping frog, using comparative anatomy to investigate the evolution of locomotion.^[ref]

A fossil is preserved evidence of past life in a geological context. A body fossil retains evidence of an organism's body, such as a tooth, bone or leaf; a trace fossil, such as a footprint or burrow, records activity. Complete replacement by minerals is not required for something to be a fossil.^[ref]

Fossilization can preserve different kinds of information. Permineralization fills spaces in biological material with minerals, while an impression may retain only external shape. These pathways help explain why the fossil record samples some anatomy characters much better than others, and why a transitional fossil is assessed through a combination of characters rather than overall resemblance.

Researcher in comparative anatomy and natural history. Cuvier organized collections so that structures from different vertebrates could be compared systematically, and his work on fossils helped establish that some represented extinct species.^[ref][ref]

A goitre is enlargement of the thyroid. It is an anatomy description that can accompany different states of glandular secretion and different causes. Measuring the gland's size therefore answers a different question from measuring thyroid hormone secretion or its response to thyroid-stimulating hormone.

A haematocele is a collection of blood within a body cavity or sac; in scrotal anatomy it commonly refers to blood in the tunica vaginalis space. It differs from a solid testicular lesion and from a non-bloody fluid collection.

A jawless vertebrate with a strongly specialized feeding apparatus and slime-producing system. Soft-tissue anatomy and secondary modifications make the ordinary fossil record difficult to interpret.