The Muscular System

Muscle Tissue

One of the four types of tissue in the body

Elongated cells Specialized for contraction Three types of muscle tissue:

1. Skeletal muscle2. Cardiac muscle3. Smooth muscle

Functions of skeletal muscle

1. Produce movement of the skeleton2. Maintaining Posture and body

position3. Support soft tissues4. Guard entrances and exits 5. Maintain body temperature by

generating heat

Axial Musculature

Positions the head and spinal column

Moves the rib cage Does not play a role in

movement or support of the pectoral girdle

Appendicular Musculature

Stabilizes or moves components of the appendicular skeleton

Anatomical Movements: Angular motion

Flexion Extension Abduction Adduction Circumduction

Anatomical movements: Rotation

Lateral rotation Medial rotation Pronation Supination

Special Movements:

Inversion/Eversion Dorsiflexion Plantar flexion Opposition /reposition Protraction/retraction Elevation /depression Lateral and medial excursion

Muscle Terminology

1. Origin = muscle attachment that remains fixed 2. Insertion = muscle attachment that moves3. Primary mover = what joint movement a muscle producesWhen a skeletal muscle contracts, its insertion moves

toward its origin

Muscle Terminology

4. Agonist = primary mover Main muscle in an action

5. Synergist Helper muscle in action

6. Antagonist Oppose or reverse a movement When agonists are in action, antagonists are relaxed

7. Fixator Stabilize the origin of a primary mover Postural muscles are fixators

Terms related to shape of muscle fibers

DeltoidOrbicularisPectinatePiriformisPlatyPyramidalRhomboidSerratusSpleniusTeres

Triangular Circular Comblike Pear Shaped Flat Pyramid Rhomboid Serrated Bandage Long and round

TrapeziusPennateDigastricFusiform

TrapezoidFeather-likeTwo-belliedSpindle

Terms related to size

BrevisGracilisLataLatissimusLongusLongissimus

ShortSlenderWideWidestLongLongest

Terms Related To Size:

MagnusMajorMinimusMinorVastusTendinosus

LargeLargerSmallestSmallGreatTendinous

Terms related to location

Some muscles are named for the bone with which they are associated Ex: temporalis overlays the temporal

bone

Terms related to number of origins

Biceps = two origins Tripceps = three origins Quadriceps = 4 origins

Terms related to location of origin and insertion

Ex: sternocleidomastoid muscle has its origin on the sternum (sterno) and clicel (cleido) and inserts on the mastoid process of the remporal bone

Terms related to muscle action

Flexor, extensor, adductor Ex: extensor muscles of the wrist

extend the wrist.

Direction of muscle fibers

Rectus = straight; fibers run parallel to an imaginary line, usually midline Ex: rectus femoris = straight muscle of

the thighOblique = muscle fibers run at a

slant to an imaginary line

Other muscle terminology

Alba = White

Types of Movements

Flexion and Extension

Flexion = movement which decreases the angle of the joint; brings two bones closer together

Extension = movement which increases the angle of the joint or the distance between two bones

Hyperextension = extension greater than 180o

Common movement of a hinge joint

Flexion and Extension

Flexion and Extension

Flexion and Extension

Rotation

Rotation = movement of a bone around its longitudinal axis

Abduction and Adduction

Abduction = moving away from midline

Adduction = moving toward midline

Circumduction

Circumduction = combination of flexion, extension, abduction and adduction Proximal end of the joint is stationary Distal end moves in a circle

Dorsiflexion and plantar flexion

Dorsiflexion = lifting the foot at the ankle towards the shin Standing on your heels

Plantar flexion = depressing the foot Pointing your toes

Inversion and Eversion

Special movements of the foot Inversion = turning the sole of the foot

mediallyEversion = turning the sole of the foot

laterally

Supination and Pronation

Refer to movements of the radius around the ulnaSupination = turning backward

Palm facing backward; radius and ulna crossPronation = turning forward

Palm facing forward; radius and ulna are parallel

Opposition

Specifically of the thumb Ability to touch your thumb to your

fingertip

Protraction and Retraction

Protraction: moving a body part anteriorly in the horizontal plane Ex: grasp you upper lip with your lower

teethRetraction: moving a body part

posteriorly in the horizontal plane