Muscular System
Types of Muscle

Skeletal



Smooth



Voluntary
Attached to bone
Involuntary
Walls of blood vessels, digestive system organs, uterus, bladder
Cardiac


Involuntary
Only found in the heart
Types of Muscles
Movement and Muscle



Muscles are attached to bones by flexible connective
tissue called tendons
Origin: attachment of muscle on the bone that does not
move when muscles contracts
Insertion: attachment of muscle on bone does move
when muscle contracts
Naming Skeletal Muscles

Location of the muscle


Shape of the muscle


Biceps (2), triceps (3), quadriceps (4)
Location of the attachments


Rectus (straight), oblique
Number of origins


Maximus, minimus, longus, brevis
Direction of the muscle fibers


Deltoid (triangle), Trapezius (trapezoid)
Relative size of the muscle


E.g. Intercostal muscles
E.g. sternocleidomastoid – sternum and clavicle (cleido)
Action

Flexor, extensor, adductor
Major Muscle Groups: Neck

Sternocleidomastoid

Pulls head to one side, flexes neck or elevates sternum
Chest

Pectorals

Pectoralis Major


Flexes, adducts, and rotates arm medially
Pectoralis Minor

Pulls scapula forward,/downward, raises ribs
Back

Latissimus Dorsi


Trapezius


Moves arm, pulls shoulder
downward and backward
Rotates scapula
Rhomboids


Beneath the trapezius
muscles
Retract, elevate, and rotate
scapula
Arms

Biceps Brachii (bray-kee-i)


Triceps brachii


Flexes forearm at elbow
Extends forearm at elbow
Brachioradialis

Flexes forearm at elbow
Shoulders

Deltoid

Abducts, extends, and flexes arm
Abdominals

Rectus abdominis



Tenses abdominal wall
External obliques
Internal obliques
Legs

Quadriceps femoris


Extends leg at knee
4 muscles:




Rectus femoris
Vastus lateralis
Vastus medialis
Vastus intermedius
Legs

Hamstrings


Flexes and rotates leg
4 muscles:




Biceps femoris
Semitendinosus
Semimebranosus
Sartorisu
Legs

Adductors (inner part of the thighs)



Moves toward midline, press thighs together
3 muscles: brevis, longus, magnus
Calves



Flexes foot, flexes leg at knee
Gastrocnemius (gastroknemeus)
Soleus
Gluteal

Gluteus Maximus



Extends thigh at hip
Gluteus Medius
Gluteus Minimus