muscle: Quick Facts

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Nov. 11, 2026

News •

Alzheimer’s may have early warning signs outside the brain • Nov. 9, 2026, 8:48 PM ET (Science Daily)

Scientists discover the hidden “muscles” trees use to straighten themselves • Oct. 31, 2026, 10:44 PM ET (Science Daily)

Photos and Videos

Diagram showing the structure of human striated or skeletal muscle, with labeled cross-sections from whole muscle to fascicle, muscle fiber, myofibril, and sarcomere, highlighting actin and myosin filaments.

Diagram showing the structure of human striated or skeletal muscle, with labeled cross-sections from whole muscle to fascicle, muscle fiber, myofibril, and sarcomere, highlighting actin and myosin filaments.

Diagram showing the structure of striated muscle at the myofilament level, with thick myosin filaments, thin actin filaments, crossbridges, Z lines, and one sarcomere labeled.

Diagram showing the oblique arrangement of myofilaments in obliquely striated muscle, with thick myosin filaments, thin actin filaments, crossbridges, and angled Z lines labeled.

diagram of rigid skeletons worked by muscles

Illustration of the human forearm from an anterior view, showing the superficial layer of muscles, tendons, and ligaments. Major structures including the biceps brachii, brachialis, pronator teres, flexor carpi radialis, and palmaris longus muscles are labeled, along with nerves and arteries such as the median nerve and radial artery.

Diagram showing three shapes of a wormlike soft-bodied animal: A is short and round for longitudinal muscle contraction, B is long and thin for circular muscle contraction, and C is curved for localized longitudinal muscle contraction.

details of a tube foot of a sea urchin

Diagram comparing trunk musculature in five vertebrates: a dogfish, salmon, lizard, cat, and dog, with labeled muscles illustrating anatomical differences among fish, reptiles, and mammals.

Lateral anatomical diagram of a salmon showing trunk muscles, with labeled sections for epaxial and hypaxial musculature, myomeres, myosepta, and the horizontal septum.

The science of creating artificial muscles

What parts of the brain control voluntary and involuntary muscle movements?

How Antagonistic Pairs Help Muscles Move

How do cicadas inspire new forms of music?

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Topics

brachialis muscle rotator cuff muscle tone reciprocal innervation muscle contraction muscle bundle origin insertion myocyte myoblast nervous system immune system Circulatory system Respiratory system Integument Endocrine system mucous membrane gland human ear bone

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Key People

Albrecht von Haller, detail of an engraving by Ambroise Tardieu after a portrait by Sigmund Freudenberger

Albrecht von Haller

Swiss biologist

Jean-Martin Charcot

Jean-Martin Charcot

French neurologist

A.V. Hill

A.V. Hill

British physiologist and biophysicist

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Hugh Esmor Huxley

British biologist

Duchenne, Guillaume-Benjamin-Amand

Duchenne de Boulogne

French neurologist

De Motu Animalium by Giovanni Alfonso Borelli

Giovanni Alfonso Borelli

Italian physiologist and physicist

Superficial arteries and veins of face and scalp, cardiovascular system, human anatomy, (Netter replacement project - SSC)

The Human Body