Appendicular Muscles

Concentric Contraction

length shortens when picking something up

Eccentric Contraction

length gets longer when lower heavy object

crossing joints

muscles crossing over joints on their way to insertion

synergists

muscles working together to produce the same movement

Antagonists

muscles working against each other to perform opposite movements

Unilateral

"one side" contracts

Bilateral

"both sides" contract

Ipsilateral

the body moves toward the same side of the contracting muscle

Contralateral

the body moves toward the opposite side of the contracting muscle

Frontalis Muscle

raises eyebrows

Orbicularis Oris muscle

purses lips

Orbicularis oculi

closes eyelids

Zygomatic major

lifts mouth corners upward

Depressor anguli oris

depresses corners of mouth

Levator labii superioris

Elevates upper lip

depressor labii inferioris

pulls lower lip down

Platysma

tenses the skin of the neck

temporalmandibular joint (TMJ)

elevates, depresses jaw, and moves side-to-side; acts as a glide and hinge joint (Opens/closes jaw + moves jaw side-to-side)

Masseter

clenches morals; a synergistic to elevate jaw

Temporalis

puts force on front teeth; synergist to elevate jaw

Lateral pterygoid

pulls on jaw anteriorly; jaw depression

Buccinator

compresses cheeks against teeth

Styloglossus

retracts and elevates tongue

hyoglossus

retracts and depresses tongue; attached to the hyoid bone (Pulls tongue back + down.)

genioglossus

protrudes tongue; attaches to mandible

rectus abdominis

flexes spine anteriorly; antagonist of erector spine

external/internal obliques

unilateral; lateral spine flexion & rotation + (turns toward the side)

bilateral: anterior spine flexion (bend forward)

transverse abdominus

compresses abdominal contents, stabilizes spine, voluntary defecation and urination

suprahyoid muscles

swallowing and depression; synergist to infrahyoid

infrahyoid muscle

swallowing and depression; synergist to suprahyoid

Sternocleidomastoid

unilateral: rotates head contralaterally

Bilateral: flexes head

Scalene Muscle

accessory muscle in respiration

unilateral: lateral neck flexion

bilateral: anterior neck flexion

Erector spinae

keep standing erect

unilateral: ipsilateral lateral flexion of spine

bilateral: extension of spine

Quadratus Lumborum

unilateral: lateral flexion lumbar spine

bilateral: assist respiration in rib 12th, stabilize spine and pelvis

Diaphragm

primary muscle of respiration

ext./ intercostals

accessory muscle of respiration

levator ani

group of 3 muscles; supports lower digestion, urinary, and reproductive organs, prevents incontinence

serrates anterior

protracts the scapula and stabilizes it to the body

trapezius

elevates, retracts, and lowers the pectoral girdle

pectoralis major

PRIME MOVER: arm flexion.

Arm flexion, arm adduction, protracting the scapula, medial arm rotation

Latissmus Dorsi

Arm adduction + arm extension (prime mover for both) + internal/medial rotation

Teres major

synergist and a mini latissimus dorsi

Deltoid

PRIME MOVER: arm abduction

arm flexion, arm abduction, arm extension

rotator cuff muscles

Rotator cuff → Supraspinatus: first 15° of arm abduction. Infraspinatus + teres minor: external rotation + arm adduction. Subscapularis: internal rotation + arm adduction.

biceps brachii

flex forearm, supinates

brachialis

flexes forearm

Brachioradialis

flexes forearm; synergist with brachialis and biceps brachia

triceps brachii

extends forearm; antagonist to biceps brachii

flexor carpi radials

radial deviation (unilaterally), wrist flexion (bilaterally)

flexor carpi ulnaris

ulnar deviation(unilaterally), wrist flexion (bilaterally)

flexor digitorum superficialis and profundus

flex digits 2-5 + flex wrist

flexor pollicis longus

flex thumb + flexes wrist

pronator quadratus

pronating palm

extensor carpi ulnaris

ulnar deviation, extends wrist (bilaterally)

extensor carpi radialis

radial deviation, extended wrists (bilaterally) (bends Wrist toward thumb side + bends wrist backward/up.)

extensor digitorum

extends digits 2-5

extensor pollicis longus

extends thumb

thenar muscles

flexes, abducts, opposes thumb

hypothenar muscles

medial, associated with pinky

lumbricals

flex metacarpophalangeal joints 2-5 and extend interphalangeal joints

dorsal interossi abduct (DAB)

Abducts digits 2,3,4

Palmar interossi Adduct (PAD)

adducts digits 2,,4,5

iliopsoas group

iliacus and psoas major; flexes thigh at hip

Tensor fasciae latae

abducts and flexes thigh

Gluteus Maximus

thigh extension

Gluteus minimus and medius

abducts and medially rotates thigh

Quadriceps

a muscle group consisting of four muscles; most important is rectus femoris crosses at hip and knee joint. extend leg at knee. Rectus femoris also flexes thigh at hip.

Hamstrings

flex the leg at knee, extend the thigh at the hip

Adductor Magnus

medial thigh compartment; adducts thigh.

Sartorius

flex at hip, knee, and external rotation at hip

tibialis anterior

dorsiflexes and inverts foot

extensor digitorum (on foot)

extends digits 2-5 + dorsiflexes foot

extensor hallucis

extends big toe + dorsiflexes foot

fibularis longus and breves

eversion of foot

gastrocnemius

flexes knee, plantar flexes foot

soleus

plantarflexion

tibialis posterior

inversion and plantar flex

flexor hallucis longus

flexes big toe

flexor digitorum longus

flexes toes

What are muscle compartments?

Groups of muscles in the same region separated by dense connective tissue; muscles within a compartment are usually synergists

Anterior arm compartment

Flexes forearm

Posterior arm compartment

Extends forearm

Anterior forearm compartment

Flexes wrist and digits

Posterior forearm compartment

Extends wrist and digits

Anterior thigh compartment

Extends leg at knee; quadriceps

Posterior thigh compartment

Flexes leg at knee + extends thigh at hip; hamstrings (bend knee + pull leg backward.)

Medial thigh compartment

Adducts thigh; adductors

Anterior leg compartment

Dorsiflexes foot; also contains toe extensors

Lateral leg compartment

Everts foot; fibularis longus + brevis

Posterior leg compartment

Plantarflexes foot; gastrocnemius + soleus

Medial pterygoid

Elevates jaw; synergist with masseter + temporalis

Pronator teres

Pronates forearm

Supinator

Supinates forearm (turns your palm upward.)

Psoas major

Part of iliopsoas; flexes thigh at hip

Iliacus

Part of iliopsoas; flexes thigh at hip

Rectus femoris

Part of quadriceps; extends leg at knee + flexes thigh at hip

Vastus lateralis

Part of quadriceps; extends leg at knee

Vastus medialis

Part of quadriceps; extends leg at knee

Adductor magnus

Medial thigh; adducts thigh

Calcaneal (Achilles) tendon

Common insertion of gastrocnemius + soleus (Gastrocnemius + soleus both connect to the Achilles tendon)