Muscular System

Parts of a Muscle

1. Origin:Point of attachment that does not move when a muscle contracts- usually bone, can be another muscle.

2. Belly: main body- actually contracts

3. Insertion:point of attachment that moves when a muscle contracts.

Muscle Actions

1. Agonist (prime movers)- move body out of anatomical position (flexors, abductors)

2. Antagonists- move body back to original position

3. Fixators- stabilize other muscles

Naming Muscles1. Location of the muscle:

anterior, dorsi, oculi=eye, oris=mouth

2. Size and shape:maximus, minimis, lattismus= broad, trapezius (trapezoid), deltoid (delta)

3. Number of origins:biceps (2), triceps (3), quadraceps (4)

4. Origins/ Insertions: tibialis- tibiafemoris- femursternocleidomastoidus-

origin- sternum and clavicle, insterion- mastoid process

5. Direction of fibers:Orbicularis – in an orbit, rectus- run with midline, oblique – angled to midline

Muscles of the Head and Neck

Muscle Name

Origin Insertion Action

Frontalis Galae Aponeurotia

Skin/eyebrows Raise eyebrows

Orbicularis Oculi Frontal Maxilla Eyelid Closes eye

Orbicularis Oris Maxilla

Mandible

Lips Kissing muscle

Zygomaticus Zygomatic Corner of lips Smile

Mentallis Mandible Lower lips Protrude lower lips (pout)

Muscle Name

Origin Insertion Action

Buccinator Mandible

Maxilla

Lips Sucking muscle

(innate)

Platysma Pectorallis Major Lower mandible Lowers jaw

(to speak)

Messeter Zygomatic Mandible Closes jaw

(to speak)

Temporalis Temporal Mandible Holds jaw closed

Pterygoids lateral mediallis internus

Pterygoid plate Mandible Side to side rotational movement

Muscle Name

Origin Insertion Action

Sternomastoid Sternum/clavicle Mastoid process Lowers chin/rotates ear to chest, flexes head

Semispinalis capitis

Upper thoracic cervical

Upper cervical Extends head

Muscles of the Chest

Muscle Name

Origin Insertion Action

Pectorallis Major Clavical sternum ribs 1-6

Humerus Pull arms forward

Serratus anterior Ribs 1-9 Under arms to scapula

Boxer muscles- pulls arms forward and down

Lattisimus dorsi Thoracic vertebrae, lumbar vertebrae, illiac crest

Humerus Pulls arms down and back

Deltoid Clavicle/ scapula Humerus Raises arms and shoulders (shrugs)

Trapezius Cervical vertebrae

Thoracic vertebrae

Clavicle, scapula Raises shoulders, pulls back shoulders

Muscle Name

Origin Insertion Action

Rectus Abdominus

Pubis Lower ribs/sternum

Flexes trunk

(bend over)

External oblique

(on each side)

Ribs Illiac crest Together- flex

Separate- rotate

Triceps Brachi Scapula 1 head

Humerus 2 heads

Olecronon process of the ulna

Extends elbow

Biceps Brachi Corecoi process humerus

Radius Flex elbow

Supinate forearm

Brachioradiallis Humerus Radius Flex and rotates forearms

Muscle Name

Origin Insertion Action

Flexor-carpi Radiallis

Humerus Matacarpals Flex wrist

Flexor Digitorum superficialis

Humerus/ulna Middle phalangies (2-5)

Flex fingers

Flexor Pollicus Longus

Radius Thumb Flexes thumb inward to grasp

Extensor Carpi Radialis Longus

Humerus 2nd Metacarpal Extends wrist

Extensor digitorum

Humerus Distal phalangies Extends fingers

Hips and Lower Appendages

Muscle Name

Origin Insertion Action

Sartoris Illiac spine Medial tibia

(crosses leg)

Flex and rotate thigh, flex knee

Biceps Femoris Illium femur Fibula tibia Extends thigh flexes knee

Quadraceps Femoris

Rectus femoris Illiac spine Patella Extend knee

Vastus laterallis Trochanter (femur)

Patella Extends knee

Muscle Name

Origin Insertion Action

Vastus mediallus Linea aspera Patella Extends knee

Vastus Intermedius

Femur shaft Patella Extends knee

Gluteus Maximus Illium/ sacrum/ coccyx

Femur Extends thigh and rotates out

Gastrochemius (calf)

Distal femur Calcaneus Extends foot by raising heel

Soleus Tibia Achilles Tendon Extends foot

Muscle Name

Origin Insertion Action

Tibiallis Anterior Tibia Tarsals Flex foot

Flextor digitorum Tibia Distal phalanges Flexes toe

Extensor digitorum longus

Tibia Middle phalanges Extends toe