Chelicerate arthropods, typically with four adult walking-leg pairs and lacking antennae.

An air-conducting tube of an arthropod respiratory system; distinct from the vertebrate trachea.

The aorta is the main arterial outflow from the left ventricle into systemic circulation. Its elastic wall stores and releases mechanical energy during the cardiac cycle, moderating the pulsatile input. It is therefore more than a rigid Pipe carrying a constant flow.

The ophthalmic artery supplies the orbit and its contents through multiple branches. It usually arises from the internal carotid route and enters near the optic nerve. Orbital supply and the more specific retinal supply should be distinguished within this branching system.

The internal carotid artery is a major arterial route from the neck into the skull, supplying substantial anterior intracranial territories and the orbit through branches. Its usual lack of cervical branches distinguishes its route from the external carotid distribution.

The axillary artery is the continuation of the subclavian arterial route through the axilla toward the arm. Its divisions and branches are described relative to pectoralis minor. These spatial relations organize upper-limb vascular anatomy around a common muscular landmark.

A pulmonary artery carries blood from the right ventricle toward the lungs. Its relatively low oxygen content illustrates why artery and vein are directional terms. Branching distributes flow to exchanging regions where oxygenation occurs.

An arteriole is a small arterial vessel whose smooth-muscle wall can strongly influence local flow resistance. Changes in caliber redistribute perfusion and affect pressure drop toward capillary networks. Its function therefore differs from that of a large elastic conducting artery.

The profunda brachii artery is a deep branch of the brachial artery associated with the posterior arm. It accompanies the radial-nerve region along the humerus and contributes to collateral pathways around the elbow. Its course links vascular and nerve anatomy.

The internal pudendal artery is a pelvic arterial branch supplying much of the perineum. Its route includes passage into the pudendal canal with accompanying structures. Its branches distribute supply to different muscular, cutaneous and erectile regions.

A vertebral artery ascends from the subclavian arterial system through the cervical region toward the skull. The paired arteries contribute to posterior cerebral and brainstem supply and unite in the basilar system. Their route differs from the carotid supply pathway.

The basilar artery forms from the vertebral arteries and courses along the ventral brainstem. Its branches contribute to brainstem and posterior intracranial circulation. A named main trunk therefore supports several functionally different neural territories.

The popliteal artery is the arterial continuation through the region behind the knee toward the leg vessels. Its close relations to the joint and surrounding structures make changes with knee position anatomically important. It supplies branches rather than serving only as an undivided transit tube.

Disease with plaque formation in arterial walls; plaque can restrict flow or provide a site of thrombosis.

The anterior spinal artery runs along the anterior aspect of the spinal cord and contributes to its blood supply through regional branches and supporting inputs. Its territory is not identical to the entire cord. Vascular distribution helps explain selective patterns of spinal-cord ischemia.

A lumped arterial reservoir stores blood by elastic expansion. Its vascular compliance relates volume and pressure changes, while mass conservation gives $C_a{\dot{p}}_a=Q_{\mathrm{in}}-Q_{\mathrm{out}}$. This storage smooths intermittent ventricular input into continuing peripheral flow.

Historical pharmaceutical preparation; its composition and clinical use must be identified by edition. ^[ref]

The hydrated arsenic(III) compound $\mathrm{As}(\mathrm{OH}{)}_3$; distinguish it from the historical dry product called arsenious acid, arsenic trioxide.

Store an integer in a nonempty array of numeral digits, with the least significant digit first and a fixed radix $b\ge 2$. Normalized digits satisfy $0\le a_i<b$. High-order zeros do not change the value. Adding digit arrays coefficientwise or multiplying them by discrete convolution gives the correct value before normalization, because these operations add or multiply the corresponding powers of the radix. Exact temporary arithmetic, or a radix and accumulator size chosen to prevent integer overflow, is required.