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upper limb in humans. Three long bones form the framework of the arm: the humerus of the upper arm, and the radius (outer bone) and ulna (inner bone) of the forearm. The radius and ulna run parallel but meet at their ends in such a manner that the radius can rotate around the ulna. This arrangement permits turning the forearm to bring the hand palm up (supination) or palm down (pronation). The radius and ulna hinge with the bones of the hand at the wrist, and with the humerus at the elbow. The bicepsbiceps
, any muscle having two heads, or fixed ends of attachment, notably the biceps brachii at the front of the upper arm and the biceps femoris in the thigh. Originating in the shoulder area, the heads of the biceps merge partway down the arm to form a rounded mass of tissue
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 brachii, a muscle of the upper arm, bends the arm at the elbow; the tricepstriceps,
any muscle having three heads, or points of attachment, but especially the triceps brachii at the back of the upper arm. One head originates on the shoulder blade and two on the upper-arm bone, or humerus.
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 brachii straightens the arm. Movement of the arm across the chest and above the head is accomplished by the pectoral muscles of the chest and deltoid muscles of the shoulder, respectively. In an adult the arm is normally five sixths as long as the leg.



the upper extremity in man consisting of the shoulder, forearm, and hand (carpus, metacarpus, and phalanges of the fingers). The arm is a more developed grasping extremity in man than in man’s ancient ancestors, the Anthropomorphidae.

The transformation from Anthropomorphidae to man was largely promoted by freeing the anterior extremities, or arms, from locomotion and body-support functions and converting them into organs capable of performing work operations. As the arm became adapted to work, its structure substantially changed, becoming sharply distinct from the structure of the anterior extremity of Anthropomorphidae.

The most significant structural changes occurred in the hand. In Anthropomorphidae the hand has an underdeveloped thumb and the remaining fingers are greatly elongated; in contrast, the human hand is characterized by a powerfully developed thumb that is essential in performing all work operations. The remaining fingers of the human hand are significantly shorter than those of Anthropoidea but are nevertheless capable of the most delicate and differentiated movements.

In man’s development, the development of the arm as a work organ occurred simultaneously with the progressive development of the brain.

The body processes in brachiopods, the tentacles in cephalopods, and the mobile or nonmobile rays of echinoderms are sometimes called arms.


The upper or superior limb in humans which comprises the upper arm with one bone and the forearm with two bones.
(control systems)
A robot component consiting of an interconnected set of links and powered joints that move and support the wrist socket and end effector.
(engineering acoustics)
A ridge or a spur that extends from a mountain.
A side of an angle.
(naval architecture)
The part of an anchor extending from the crown to one of the flukes.
A long, narrow inlet of water extending from another body of water.
A combat branch of a military force; specifically, a branch of the U.S. Army, such as the Infantry Armored Cavalry, the primary function of which is combat.
(Often plural) Weapons for use in war.
To supply with arms.
To ready ammunition for detonation, as by removal of safety devices or alignment of the explosive elements in the explosive train of the fuse.
The perpendicular distance from the line along which a force is applied to a reference point.


Advanced RISC Machine.

Originally Acorn RISC Machine.


Advanced RISC Machines Ltd.


["The Annotated C++ Reference Manual", Margaret A. Ellis and Bjarne Stroustrup, Addison-Wesley, 1990].




The most widely used microprocessors worldwide. Designed by ARM Holdings plc, Cambridge, England (, the company was founded in 1990 by Acorn Computers, Apple and VLSI Technology. In 2016, ARM was acquired by Japan-based Softbank. The ARM brand originally stood for Acorn RISC Machine and later Advanced RISC Machine.

ARM chips are 32-bit and 64-bit RISC-based CPUs that are known for their low cost and low power requirements (see RISC). Manufactured under license from ARM by more than a dozen semiconductor companies, billions of ARM-based devices are made every year, including smartphones, tablets, game consoles, e-book readers, netbooks, TVs and myriad other consumer and industrial products.

Very often, an ARM CPU is the processor in a system-on-chip (see SoC). For example, Qualcomm's Snapdragon and NVIDIA's Tegra are ARM-based smartphone and tablet SoCs.

Cortex, SecurCore and StrongARM
ARM processor families are designated by the prefix "ARM" and a digit, such as ARM7, ARM9 and ARM11 or with names such as Cortex and SecurCore, the latter used for secure identification products such as smart cards.

The StrongARM was a high-speed version of the ARM chip that was jointly developed with Digital Equipment Corporation. The SA-100, the first StrongARM chip, was delivered in 1995, and Intel acquired the technology from Digital in 1997. See StrongARM, Thumb and big.LITTLE.
References in periodicals archive ?
Depending on the chair and posture, some proportion of the body weight is also transferred to the floor, the work surface, the backrest and the armrests of the chair.
The part needed to be formed at a very slow speed to avoid compromising the thermoplastic because the depth of the tub and the armrests contained in the mold demanded a very deep draw to 26 inches (draw limit is 32 inches).
A servo-assisted mini steering wheel gives featherlight palm of the hand steering, eliminating wrist strain, and the floating armrest prevents stress to the upper arm and shoulders.
coli O157:H7 survived longest (96 hours) on the material from the armrest.
The Chrysler 300 and 300C Luxury Series sedans are offered with a Foligno leather-wrapped instrument panel, and premium Nappa leather covers the door armrest, bolster and centre console armrest.
The SideWinder[TM] II armrest by New Holland, launched on the T7000 Auto Command[TM] tractor, brings driver-foe used ergonomics, convenience, and control to tractor controls--formerly available only on the most advanced self-propelled forage harvesters and combines.
If the center section of the seatback is not in use, it can be folded forward for use as an armrest with integral cupholders.
The seat depth, armrest height, and back recline adjust for proper fit.
In a TPO automotive armrest (photo), 0.3% INT33LCA permitted a decrease in cycle time from 56.4 to 49.3 sec.
The Lincoln has a power seat that moves forward when the backrest is pushed forward; therefore, it is easy to put the two legs and the right-side armrest behind the driver's seat.
Other features include a fridge fitted in the armrest between the front seats, special split-rim 18-inch alloy wheels, Bi-xenon headlights, a mini disc player, with sub-woofer and rear seat headphone sockets, an integratedGSM telephone, rear skidplate, aluminium roof rails, 'Executive' badging, silver square-mesh grille, and body-coloured door handles and waist mouldings.
Features include a fridge fitted in the armrest between the front seats, special split-rim 18in alloy wheels, a mini-disc player and an integrated GSM telephone.