Chapter 10: Muscular System: Gross Anatomy

origin

General Principles of Skeletal Muscle Anatomy

usually the most stationary, proximal end of the muscle; also called the fixed end.

insertion

General Principles of Skeletal Muscle Anatomy

usually the distal end of the muscle attached to the bone being pulled toward the other bone of the joint; also called mobile end.

agonist

General Principles of Skeletal Muscle Anatomy

a muscle that contracts to provide the main force to move or rotate a bone through its joint

antagonist

General Principles of Skeletal Muscle Anatomy

Muscle that works in opposition to another muscle

synergist

General Principles of Skeletal Muscle Anatomy

Muscle that works with other muscles to cause a movement

fixator

General Principles of Skeletal Muscle Anatomy

Muscle that stabilizes the origin of a prime mover

prime mover

General Principles of Skeletal Muscle Anatomy

Muscle that plays a major role in accomplishing a movement

circular

Muscle Shapes / Fascicle Arrangement

• fascicles are arranged in a circle around an opening, and act as sphincters to close the opening

• Ex: Orbicularis oris, orbicularis oculi

convergent

Muscle Shapes / Fascicle Arrangement

• broadly distributed fascicles converge at a single tendon

• Ex: pectoralis major, pectoralis minor

parallel

Muscle Shapes / Fascicle Arrangement

• fascicles lie parallel to one another and to the long axis of the muscle

• Ex: trapezius, rhomboideus, rectus abdominus

pennate

Muscle Shapes / Fascicle Arrangement

fascicles originate from a tendon that runs the length of the entire muscle. There are three different patterns

unipennate

Muscle Shapes / Fascicle Arrangement

• fascicles are on only one side of the tendon

• Ex: Palmar interosseus, semimembranosus

bipennate

Muscle Shapes / Fascicle Arrangement

• fascicles are on both sides of the tendon

• Ex: rectus femoris

multipennate

Muscle Shapes / Fascicle Arrangement

• fascicles are arranged at many places around the central tendon. They are spread out at angles to many smaller tendons

• Ex: deltoid

fusiform

Muscle Shapes / Fascicle Arrangement

• fascicles lie parallel to the long axis of the muscle. The belly of the muscle is larger in diameter than the ends

• Ex: Biceps bracii (two-headed; shown), Triceps brachii (three-headed)

pectoralis

Muscle Names

chest muscle

gluteus

Muscle Names

buttock muscle

brachial

Muscle Names

arm muscle

maximus

Muscle Names

large muscle

minimus

Muscle Names

small muscle

longus

Muscle Names

long muscle

brevis

Muscle Names

short muscle

deltoid

Muscle Names

triangular muscle

quadratus

Muscle Names

quadrate muscle

teres

Muscle Names

round muscle

rectus

Muscle Names

straight or parallel muscle

biceps

Muscle Names

muscle with two heads (origins)

triceps

Muscle Names

muscle with three heads (origins)