Exam 4: Chapter 10 The Muscular System

Contractile tissue

What does all muscle tissue consist of?

Prime Mover

Major responsibility for producing specific movement

Antagonist

Opposes or reverses movement

Synergist

muscle that aids a prime mover in a movement and helps prevent rotation

Fixators

type of synergist that immobilizes bone or muscle's origin rather than enhancing movement of prime movers

muscle location

Criteria for naming: bone or body region with which muscle is associated Ex. temporalis

Muscle shape

Criteria for naming: distinctive shapes Ex. Deltoid

muscle size

a criteria for naming skeletal muscle: e.g., maximus (largest), minimus (smallest), longus (long)

Direction of muscle fibers or fascicles

a criteria for naming skeletal muscle: e.g., rectus (fibers run straight), transversus (fibers run at right angles), and oblique (fibers run at angles to imaginary defined axis)

number of origins

a criteria for naming skeletal muscle: Ex. biceps brachii

location of attachments

named according to point of origin or insertion Ex. Sternocleidomastoid

Muscle action

named for action they produce, e.g., flexor or extensor

Flexor

Crosses on the anterior side of a joint Ex. Pectoralis major

Extensor

Crosses on the posterior side of a joint Ex. Latissimus dorsi

Abduction

movement away from the midline

Adduction

Movement toward the midline of the body

Fascicles

bundles of muscle fibers

circular

fascicle arranged in concentric rings Example: orbicularis ores and orbicularis oculi.

Convergent

broad origin; fascicles converge toward single tendon insertion Ex. Pectoralis major

Fusiform

ex. biceps brachii

Parallel

Muscle fibers are parallel to one another Ex. Sartorius

Pennate

short fascicles attach obliquely to central tendon running length of muscle

Unipennate

fascicles attach only to one side of tendon Ex. extensor digitorum longus

Bipennate

Fascicles insert from opposite sides of tendon Ex. Rectus femoris

Multipennate

fascicles appears as feathers inserting into one tendon Ex. Deltoid

lever, effort, load

components of a lever system

lever

rigid bar (BONE) that moved on a fixed point called a fulcrum (JOINT)

Effort

Force (supplied by muscle contraction) applied to a lever to move resistance (load)

load

resistance (bone + tissues + any added weight) moved by the effort

Mechanical advantage (power lever)

load is close to fulcrum, with effort far from the fulcrum (small effort can move a large load)

Mechanical disadvantage (speed lever)

load is far from fulcrum, with effort close to fulcrum
Load moved rapidly over large distance; offers wider range of motion

first class lever

Fulcrum is between the load and effort (Example: raising the head off the chest)

second class lever

Load is between the fulcrum and effort (Example: standing on toes)

third class lever

Effort is applied between the fulcrum and load (Example: most skeletal muscles, bicep curl)

temporal fossa

origin of temporalis

coronoid process of mandible

insertion of temporalis

closes jaw and elevates mandible

action of temporalis

Zygomatic arch + bone

Origin of masseter

angle and ramus of mandible

insertion of masseter

prime mover of jaw closure

action of masseter

sternum and clavicle

origin of sternocleidomastoid

mastoid process

insertion of sternocleidomastoid

Flexes and laterally rotates head

action of sternocleidomastoid

occipital bone, C7 and thoracic vertebrae

origin of trapezius

Spine of scapula and lateral end of clavicle

insertion of trapezius

Stabilizes and moves scapula

action of trapezius

Lateral end of clavicle and spine of scapula

origin of deltoid

deltoid tuberosity of humerus

insertion of deltoid

prime mover of arm abduction

action of deltoid

clavicle and sternum

origin of pectoralis major

intertubercular suleus and greater tubercle

insertion of pectoralis major

adducts and medially rotates arm

action of pectoralis major

pubic crest and symphysis

origin of rectus abdominis

xiphoid process and ribs 5-7

insertion of rectus abdominis

Flexes and rotates vertebral column

action of rectus abdominis

short head: coracoid process
long head: supraglenoid tubercle

origin of biceps brachii

radial tuberosity

insertion of biceps brachii

flexes and supinates forearm

action of biceps brachii

long head: infraglenoid tubercle
Lateral + Medial head: Posterior shaft of humerus

origin of triceps brachii

olecranon of ulna

insertion of triceps brachii

extends forearm

action of triceps brachii

distal humerus

origin of brachialis

coronoid process of ulna

insertion of brachialis

flexes forearm

action of brachialis

distal end of humerus

origin of brachioradialis

radial styloid process

insertion of brachioradialis

flexes forearm

action of brachioradialis

lateral epicondyle of humerus

origin of extensor digitorum

distal phalanges of 2-5th fingers

insertion of extensor digitorum

prime mover of finger extension

action of extensor digitorum

Medial epicondyle of humerus, olecranon and posterior ulna

origin of flexor carpi ulnaris

pisiform, hamate, base of 5th metacarpal

insertion of flexor carpi ulnaris

powerful flexor and adductor of the hand

action of flexor carpi ulnaris

Anterior iliac crest and anterior superior iliac spine

origin of tensor fascia lata

iliotibial tract

insertion of tensor fasciae latae

Steadies leg and trunk on thigh by tightening IT band

action of tensor fascia lata

Anterior inferior iliac spine and acetabulum

origin of rectus femoris

patella and tibial tuberosity via patellar ligament

insertion of rectus femoris

extends leg and flexes thigh at hip

action of rectus femoris

Long head: Ischial tuberosity
Short head: linea aspera and distal femur

origin of biceps femoris

head of fibula and lateral condyle of tibia

insertion of biceps femoris

extends thigh and flexes leg

action of biceps femoris

anterior superior iliac spine

origin of sartorius

medial aspect of proximal tibia

insertion of sartorius

flexes, abducts, and laterally rotates thigh

action of sartorius

Ramus and body of pubis and ischial ramus

origin of gracilis

medial aspect of proximal tibia

insertion of gracilis

adducts thigh, flexes and medially rotates leg

action of gracilis

near pubic symphysis

origin of adductor longus

linea aspera

insertion of adductor longus

adducts, flexes, and medially rotates thigh

action of adductor longus

dorsal ilium, sacrum, and coccyx

origin of gluteus maximus

gluteal tuberosity of femur and IT band

insertion of gluteus maximus

major extensor of thigh

action of gluteus maximus

lateral condyle and tibial shaft

origin of tibialis anterior

medial cuneiform and 1st metatarsal

insertion of tibialis anterior

prime mover of dorsiflexion

action of tibialis anterior

medial and lateral condyles of femur

origin of gastrocnemius

posterior calcaneus

insertion of gastrocnemius

plantar flexes foot

action of gastrocnemius