MUSCLE NAMES & MOVEMENTNovember 8, 2013

Rules of Muscle Movement

1. All muscles have at least two points of attachment.• The origin is attached to the less movable bone• The insertion is attached to the more moveable bone.

2. Muscles can only contract / pull. They cannot push.

3. During contraction, the muscle insertion moves toward the origin.

interactive animation!

If muscles can’t push, how do we do the opposite movement?

How do we extend the arm?

Rules of Muscle Movement

1. All muscles have at least two points of attachment.• The origin is attached to the less movable bone• The insertion is attached to the more moveable bone.

2. Muscles can only contract / pull. They cannot push.

3. During contraction, the muscle insertion moves toward the origin.

interactive animation!

Different muscles – called antagonists – do the opposite movement.

Example: biceps flexes the elbow while the triceps extends the muscle.

Movements• Flexion – a movement that decreases

the angle between two bones, bringing them closer together.

• Extension – a movement that increases the angle between two bones, putting them farther apart.

• Hyperextension – extension of a joint beyond its normal range of motion

Movements• abduction – movement of a limb away from the midline

of the body.

• adduction – movement of a limb towards the midline of the body

Movements• rotation – movement of a bone

raround its longitudinal axis

• circumduction – the proximal end of a limb is stationary while the distal end moves in a circle

Movements of the foot

• dorsiflexion – lifting the foot so that its superior surface approaches the shin

• plantar flexion – pointing the toes

• inversion – turning sole medially

• eversion – turning sole laterally

Movements of radius and ulna

• supination – turning the palm so that it faces anteriorly

mnemonic: cupping a bowl of soup in your palm

• pronation– turning the palm so that it faces posteriorly

Movements

Work with a partner to come up with 5 ways to do each of the following movements:• Flexion• Extension• Hyperextension• Abduction• Adduction• circumduction

Types of Muscles• Prime mover – muscle that has the major responsibility for

a movement

• Antagonist – muscle that opposes / reverse a movement

Muscles can be both a prime mover and an antagonist – of different motions.

Example:

Movement Prime mover Antagonist

Elbow flexion Biceps brachii Triceps brachii

Elbow extension Triceps brachii Biceps brachii

Types of Muscles• Prime mover – muscle that has the major responsibility for

a movement

• Antagonist – muscle that opposes / reverse a movement

• Synergist – muscles that assist movement by also producing the motion or stabilizing joints and reducing unwanted movements.

Ex: brachialis and brachioradialis are synergists of elbow

flexion because they help the biceps

Types of Muscles• Prime mover – muscle that has the major responsibility for a

movement

• Antagonist – muscle that opposes / reverse a movement

• Synergist – muscles that assist movement by also producing the motion or stabilizing joints and reducing unwanted movements.

• Fixator – a type of synergist that stabilizes the origin of the prime mover, so that only the insertion moves.

Example: the rotator cuff muscles of scapula are fixators

for elbow flexion.

Muscle names, locations, & actionsMuscles of the anterior face and neckName Origin Insertion Action

Masseter Temporal bone mandible Close jaw

Temporalis Temporal bone mandible Close jaw

Sternocleidomastoid Sternum & clavical

Mastoid process of temporal bone

Flexes neck & rotates head

You don’t need to memorize origins and insertions – you do need to know where each is and what they do.

Muscle names, locations, & actionsMuscles of the anterior trunkName Origin Insertion Action

Pectoralis major

Sternum, clavicle, and first 6 ribs

Proximal humerus Adducts and flexes humerus

Rectus abdominis

pubis Sternum and ribs 5-7 Flexes vertebral column

External oblique

Lower 8 ribs Iliac crest Flexes & rotates vertebral column

Muscle names, locations, & actionsMuscles of the posterior trunkName Origin Insertion Action

trapezius Occipital bone , cervicle and thoracic vertebrae

Scapular spine and clavicle

Extends neck and adducts scapula

Latissimus dorsi

Lower spine and iliac crest

Proximal humerus Extends and adducts humerus

deltoid Scapula and clavicle humerus Abducts humerus

Muscle names, locations, & actionsMuscles of the armName Origin Insertion Action

Biceps brachii

scapula radius Flexes elbow and supinates forearm

Triceps brachii

Shoulder girdle and humerus

ulna Extends elbow

Muscle names, locations, & actionsMuscles of the anterior hip and thighName Origin Insertion Action

adductor pelvis femur Adducts thigh

sartorius ilium tibia Flex thigh

quadriceps Femur and pelvis tibia Flex hip and extend knee

Muscle names, locations, & actionsMuscles of the posterior hip and thighName Origin Insertion Action

Gluteus maximus Sacrum and ilium femur Extends thigh

Gluteus medius ilium tibia Abducts thigh

hamstrings Femur and pelvis tibia Extend thigh and flex knee

Practice 1• Find as many examples as you can of prime mover –

antagonist pairs in the muscles just listed

• Find as many synergist muscles as you can in the muscles just listed

~5 min

Practice 2 – fill in diagrams

Practice 3

In groups of 4-6, play “Simon Says” using the new vocabulary

(e.g. Simon says abduct your humerus;

Simon says use your quadriceps group)

Simon can use notes. Try to trick each other!

Closure• What were our objectives, and what did you learn about

them.

• How does what we did today address our unit question?

Exit Ticket• Describe the motion of the sartorius and name a synergist

and an antagonist