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