Most often, body movements result from the contraction of how many muscles?

Several muscles acting together.

Muscles that are responsible for producing a certain movement are called what?

Agonists or prime movers

Muscles that oppose or reverse a movement are called what?

Antagonists

When an agonist is active, the fibers of the antagonists are affected in which two states?

1. Stretched

2. Relaxed

How does the antagonist regulate the agonist in 2 ways?

1. Prevent overshoot of the agonist

2. Stop action of the agonist

The biceps muscle is an agonist of what arm movement?

Flexion

The biceps is an antagonist of what arm movement?

Extension

The triceps is an agonist of what arm movement?

Extension

The triceps is an antagonist of what arm movement?

Flexion

The biceps muscle is antagonized by what muscle?

Triceps muscle

The triceps muscle is antagonized by what muscle?

Biceps muscle

How do synergists help the action of agonists?

1. Reduce undesirable movement

Without synergists, contraction of a muscle crossing two or more joints would cause movement at how many joints?

All joints

Do synergists stabilize certain joints?

Yes.

The muscles that flex the fingers cross both the wrist and finger joints, how can you make a fist without bending at the wrist?

The synergist muscles stablize the wrist joint.

Fixators are what type of specialized muscles?

Specialized synergists

What is the function of fixator muscles in regard to the origin and insertion of a prime mover?

They immobilize the origin of a prime mover so that all the tension is exerted at the insertion.

Muscles that help maintain posture are what type of skeletal muscles?

Fixators

Muscles of the back that stabilize the scapular during arm movements are what type of skeletal muscles?

Fixators

Muscles are named on what 7 criteria?

1. Direction of muscle fibers

2. Relative size of the muscle

3. Location of the muscle

4. Number of origins

5. Location of the muscle's origin and insertion

6. Shape of the muscle

7. Action of the muscle

Direction: Some muscles are named in reference to what kinda of line?

Imaginary line

Direction: That imaginary line is usually what type of line of the body?

Midline of the body

Direction: A muscle with fibers running parallel to that imaginary line will have what term in its name?

Rectus (straight)

Direction: The rectus abdominis is what type of muscle of the abdomen?

Straight muscle of the abdomen

Direction: The term transverse indicates muscles running at which type of angles relative to the imaginary line?

Right angles

Direction: The term oblique indicates muscles running how directionally to the imaginary line?

Diagonally

Muscle structure is determined by what type of arrangement?

Fascicle arrangement

Relative size of the muscle:

1. Maximus means what?

2. Minimus means what?

3. Longus means what?

4. Brevis means what?

1. Largest

2. Smallest

3. Longest

4. Shortest

Location of the muscle: Some muscles are named for the ____ with which they are associated.

bone

The temporalis muscle overlies which bone?

Temporal bone

Number of origins:

1. The term biceps has what number of origins or heads?

2. The term triceps has what number of origins or heads?

3. The term quadriceps has what number of origins or heads?

1. 2

2. 3

3. 4

Location of the muscle's origin and insertion: The sternocleidomastoid muscle has its origin in which 2 bones and inserts in which process?

Origin in the sternum (sterno) and clavicle (cleido) and inserts on the mastoid process of the temporal bone.

Shape of the muscle: The deltoid muscle is what type of shape?

Triangular (deltoid=shape)

Shape of the muscle: The trapezius muscle is what type of shape?

Trapezoid

Action of the muscle: All the adductor muscles of the thigh bring about what type of movement?

Adduction

Action of the muscle: All the extensor muscles of the wrist do what to the hand?

Extend the hand

How do the muscles of facial expression differ from most skeletal muscles?

They insert into the skin or other muscles rather than into bone.

The muscles of facial expression move what feature of the face?

Facial skin

The muscles of mastication move which bone?

Mandible

The six extrinsic eye muscles do what to the eye?

Aim the eye

Neck muscles are concerned primarily with movement of what 2 body parts?

1. Head

2. Shoulder girdle

Raise your eyebrow to wrinkle your forehead. You are using the frontal belly of what muscle?

Epicranius muscle

Blink your eyes. You are contracting which muscle?

Orbicularis oculi

Close your lips and pucker up. You are contracting which muscle?

Orbicularis oris.

Smile. You are using which muscle?

Zygomaticus muscle.

Clench your teeth. You are using which muscle?

Temporalis.

Primary action of the orbicularis oculi?

Close eye

Primary action of the orbicularis oris?

Close and protrude lips

Primary action of the zygomaticus?

Create smile

Origin and insertion of zygomaticus?

Origin: Zygomatic bone

Insertion: Skin and muscles at corners of mouth

Primary action of buccinator?

Compress cheeks (i.e. whisle, suck)

Primary action of platysma?

Depress mandible (aka open jaw).

Origin and insertion of platysma?

Origin: Fascia of chest

Insertion: Mandible

Primary action of temporalis?

Close jaw

Origin and Insertion of temporalis?

Origin: Temporal bone

Insertion: Coronoid process of mandible

Primary action of masseter?

Close jaw

Origin and insertion of masseter?

Origin: Zygomatic arch

Insertion: Angle of mandible

Primary action of digastric?

Open mouth

Primary action of mylohyoid?

Elevate tongue during swallowing

Primary action of sternohyoid?

Depress larynx

Origin and insertion of sternohyoid?

Origin: Manubrium

Insertion: Hyoid

2 primary actions of sternocleidomastoid?

1. Flex neck

2. Rotate head

Origin and insertion of sternocleidomastoid?

Origin: manubrium and clavicle

Insertion: Mastoid process of temporal bone

Identify the missing features.

Identify the missing features.

Identify the missing features.

Identify the missing features.

Identify the missing features.

Identify the missing features.

Identify the missing features.

Identify the missing features.