Muscle Actions and Functions part 2

What is the action of the masseter?

Elevates mandible (chewing)

What is the action of the temporalis?

Elevates mandible

What is the most powerful muscle?

Masseter

What is the belly of a muscle?

Middle portion between origin and insertion

What determines a muscle's action?

Location of origin and insertion

What happens if insertion is on the skin?

Produces facial expression

What is the action of the corrugator supercilii?

Depresses eyebrows (frowning)

What is the action of the frontalis?

Raises eyebrows

What is the action of the depressor anguli oris?

Frowning (pulls mouth corners down)

What are the two phases of breathing?

Inspiration and expiration

What type of process is quiet expiration?

Passive

What type of process is quiet inspiration?

Active

What happens to the thoracic cavity during inspiration?

Increases in size

What happens to the thoracic cavity during expiration?

Decreases in size

What happens to lung volume during inspiration?

Increases

What happens to lung volume during expiration?

Decreases

What happens to air pressure during inspiration?

Decreases

What happens to air pressure during expiration?

Increases

What is the action of the scalenes?

Elevate ribs 1 and 2

What is the action of the sternocleidomastoid?

Elevates sternum and flexes neck

Where are the internal intercostals located?

Deep to external intercostals

Where are the external intercostals located?

Superficial between ribs

What happens when ribs elevate?

Thoracic cavity widens

What happens when ribs depress?

Air forced out

What is the action of the rectus abdominis?

Flex trunk and assist expiration

What is the action of the external oblique?

Compress abdomen and assist expiration

What is the action of the internal oblique?

Compress abdomen and assist expiration

What is the action of the transversus abdominis?

Compress abdomen

What is coactivation?

Agonist and antagonist contract together for stability

What do fixators do?

Stabilize origin of muscle

What is the action of the supraspinatus?

Stabilizes shoulder joint

What is the action of the infraspinatus?

Rotates arm laterally

What is the action of the teres minor?

Rotates arm laterally

What is the action of the teres major?

Rotates arm medially

What is the action of the coracobrachialis?

Flexes and adducts arm

What is the insertion of the triceps brachii?

Olecranon of ulna

What is the insertion of the biceps brachii?

Radial tuberosity

What motion does the biceps brachii perform?

Flexion and supination

What motion does the triceps brachii perform?

Extension

What is the action of the pronator teres?

Pronates forearm

What is the action of the flexor digitorum superficialis?

Flexes fingers

What is the action of the flexor carpi radialis?

Flexes wrist

What is the action of the extensor digitorum?

Extends fingers

What is the action of the extensor carpi ulnaris?

Extends wrist

What do retinacula do?

Hold tendons in place

What is carpal tunnel?

Passageway for tendons and median nerve

What causes carpal tunnel syndrome?

Inflammation compresses median nerve

What is De Quervain tenosynovitis?

Inflammation of thumb tendons

What is the insertion of the deltoid?

Deltoid tuberosity of humerus

What is the action of the deltoid?

Arm elevation

What is the action of the gluteus maximus?

Extends thigh

What is the action of the gluteus medius?

Abducts thigh

Why is the gluteus medius safer for injections?

Avoids sciatic nerve

What happens if the sciatic nerve is hit?

Pain, weakness, possible paralysis

What is the action of the rectus femoris?

Extends leg and flexes thigh

What is the action of the vastus lateralis?

Extends leg

What is the action of the vastus medialis?

Extends leg

What is the quadriceps group action?

Extends knee

What is the action of the tibialis anterior?

Dorsiflexes foot

What is the insertion of the gastrocnemius?

Calcaneus

What is the action of the gastrocnemius?

Plantar flexion

What is the action of the soleus?

Plantar flexion

What is the action of the fibularis longus?

Plantar flexion

What does dorsiflexion mean?

Toes move upward

What does plantar flexion mean?

Toes point downward