module 6 appendicular skeleton

agonist (prime mover)

directly performs the desired movement

first muscle recruited for a particular movement

“in charge of” that movement, controlling it , in agony

antagonist

opposes the movement; performs opposite action

needs to be relaxing to allow the agonist’s action 

synergist 

helper 

recruited to assist for extra strength, or to stabilize joint and allow movement 

shoulder (pectoral) girdle: bones 

connects upper extremity to axial skeleton (connects arm to axial skeleton)

clavicle 

manibrum sternum

scapula 

pectoral (shoulder) girdle articulations

sternoclavicular (manubirum --- proximal clavicle)
acromioclavicular (acromion of scapula --- distal clavicle)
both gliding joints
allow for elevation and depression of scapula

scpular muscles/ actions

trapezius- elevates, retracts, and depresses

shoulder (glenohumeral) joint

most freely movable joint in the body
includes the glenoid fossa of the scapula (very shallow) and the humeral head of the humerus (partial sphere)

shoulder bones

scapula (glenoid fossa very shallow)

 humerus (humeral head- only a partial sphere)

shoulder joint category and movements 

Triaxial Ball-and-socket
Movements possible:
 Flexion – Extension
 Abduction – Adduction
Combine first two pair à Circumduction
Rotations: inward (internal; medial) – outward (external; lateral)

muscles and movements (actions at shoulder)

deltoid: abduction, flexion, extension
latissimus dorsi: extension, adduction
supraspinatus: abduction
infraspinatus: external rotation
teres minor: external rotation
triceps: extension
biceps: flexion
subscapularis: internal rotation
pectoralis major: flexion, adduction, internal rotation

deltoid

abduction, flexion, extension

latissimus dorsi

extension, adduction 

supraspinatus

abduction

infraspinatus

external rotation

teres minor 

external rotation 

triceps

extension

biceps

flexion, also supinator

subscapularis 

internal rotation 

pectorals major

flexion, adduction, internal rotation

elbow- composite joint bones

humerus

ulna

radius

elbow movements

flexion and extension at humeroulnar hinge joint

elbow muscles/ actions 

brachialis: flexion
brachioradialis: flexion
biceps brachii: flexion
triceps brachii: extension

elbow flexion

agonist: brachialis
antagonist: triceps
synergist: biceps

radio ulnar joint muscles/ action

biceps brachii: supination
pronator teres: pronation

wrist bones 

radius, ulna, 8 carpals

wrist bone articulation

radoiocarpal- true wrist= condyloid (biaxial) synovial joint

wrist muscles

flexors carpi radialis and ulnaris: flexion
extensors carpi radialis and ulnaris: extension
ulnar flexor and extensor: adduction
radial flexor and extensor: abduction
all you combine to circumduct

pelvic girdle bones 

contains the os coxa (ilium, ischium, pubis) and the sacrum
form around a deep socket called the acetabulum which receives the head of the femur to form the hop joint

pelvic girdle: articulations

sacroiliac: sacrum --- ilium, for gliding
pubic symphysis: fibrocartilaginous, amphiarthrosis
lumbosacral: gliding and symphysis

pelvic girdle muscles

rectus abdominus: flexion
erector spinae: extension
quadratus lumborum: lateral tilts (hip hiking)

hip bones 

femoral head of femur and acetabulum
ball-and-socket joint

hip muscles

psoas major: flexion
gluteus medius: abduction, internal rotation
gluteus maximus: extension, external rotation
gluteus minimus: abduction, internal rotation
adductors: adduct
rectus femoris (quads): flexion
sartorious: flexion, abductuon, external rotation
hamstrings

hamstring muscles

extend hip
biceps femoris, semitendinosus, semimembranosus

knee bones 

femur (femoral condyles), tibia (tibial condyles), patella (kneecap)

knee articulations

double condyloid (oval) joint
medial condyles of femur --- tibia
lateral condyles of femur --- tibia
patellar articulation rests on distal end of femur

knee movement

flexion and extension
soft tissue is necessary for stability

special articulations of knee 

soft tissues that stabilize knee
menisci: two fibrocartilage pads that cushion condyles of each joint
cruciate ligaments: stability, flexion, extension, ACL, MCL, and PCL
collateral ligaments
bursae and fat pads: reduce friction

knee muscles

hamstrings: flexion
gastrocnemius: flexion
quads: extension
vasti: lateralis, medialis, intermedius
sartorius: flexion

patella

forms inside of a tendon
patellar ligament and quadriceps tendon
functions: protection, mechanical advantage for knee extension

biceps brachii

supination

pronator teres

pronate

flexion of wrist

flexor carpi ulnaris and radials

extension of wrist

extensors carpi ulnaris and radialis

adduction of wrist 

ULNAR flexor and extensor 

abduction of wrist

RADIAL flexor and extensor