Anatomy

Epicranius

covers upper part of the cranium and consist of two muscular parts - frontalis over the frontal bone and occipitalis over the occipital bone

Orbicularis oculi

surrounds the eye

orbicularis oris

encircles the mouth

buccinator

located in the wall of the cheek

zygomaticus major and minor

zygomatic arch downward to the corner of the mouth

platysma

extends from the chest over the neck to the face

masseter

ORIGIN lower border of zygomatic archINSERTION lateral surface of mandibleACTION elevates mandible

temporalis

over the temporal bone

medial pterygoid

extends back and downward from the sphenoid, palatine and maxillary bones to the ramus of the mandible

lateral pterygoid

extend forward from the region just below the mandibular conyle to the sphenoid bone.

sternocleidomastoid

ORIGIN - Anterior surface of sternum and upper surface of clavicleINSERTION - Mastoid process of temporal boneACTION - Pulls head to one side, flexes neck or elevates sternum

splenius capitis

LOCATION - back of neck connecting the base of the skull to the vertebrae in the neck and upper thorax

semispinalis cpitis

LOCATION - extends upward from the vertebrae in the neck and thorax to the occipital bone

Erector spinae

LOCATION - run longitudinally along the back and can be divided into lateral, intermediate and medial groups.

Trapezius

ORIGIN - occipital bone and spines of cervical and thoracic verebraeINSERTION - clavicle, spine, and acromion process of scapulaACTION - rotates scapula; various fibers raise scapula, pull scapula medially, or pull scapula and ahoulder downward

Rhomboid major and minor

LOCATION - connect the vertebral column to the scapula

Levator scapulae

ORIGIN - transverse processes of cervical vertebraeINSERTION - medial margin of scapulaACTION - elevates scapula

serratus anterior

LOCATION - side of the chest

pectoralis minor

LOCATION - beneath the pectoralis major. extends laterally upward from the ribs to the scapula

Coracobrachialis

LOCATION - the scapula to the middle of the humerus along the medial suface

pectoralis major

ORIGIN - Clavicle, sternum and costal cartilages of upper ribsINSERTION - intertubercular groove of humerusACTION - flexes, adducts and rotates arm medially

Teres major

ORIGIN - Lateral border of scapulaINSERTION - Intertubercular groove of humerusACTION - extends, adducts and rotates arm medially

Latissimus dorsi

ORIGIN - spines of sacral, lumbar and lower thoracic vertebrae, illiac crest, and lower ribsINSERTION - intertubercular groove of humerusACTION - extends, adducts and rotates the arm mediallly or pulls the shoulder downward and back

Supraspinatus, infraspinatus, teres minor, subscapularis

known as SITS muscle group - forms rotator cuff

Deltoid

ORIGIN - Acromion process, spine of scapula and the clavicleINSERTION - deltoid tuberosity of humerusACTION - abducts, extends, and flexes arm

biceps brachii

ORIGIN - coracoid process and tubercle above glenoid cavity of scapulaINSERTION - radial tuberosity of radiusACTION - flexes elbow and rotates hand laterally

brachialis

LOCATION - beneath the biceps brachii, connects the shaft of the humerus to the ulna and is the strongest flexor of the elbow

brachioradialis

LOCATION - connects the humerus to the radius

Ticeps brachii

ORIGIN - tubercle below glenoid cavity and lateral and medial surfaces of humerusINSERTION - olecranon process of ulnaACTION - exends elbow

supinator

LOACTION - ulna and lateral end of the humerus to the radius

pronator teres

LOCATION - connects the ends of the humerus and ulna to the radius

oblique

LOCATION - slant downward from the lower ribs to the pelvic girdle and the linea alba

internal oblique

LOCATION - beneath the external oblizue and runs up and forward from the pelvic girdle to the lower ribs

transversus abdominis

LOCATION - beneath the external and internal obliques, horizontally from the lower ribs, lumbar vertebrae and ilium to the linea alba and pubic bones.

Rectus abdominis

ORIGIN - crest of pubis and symphysis pubisINSERTION - xiphoid process of sternum and costal cartilagesACTION - tenses abdominal wall and compresses abdominal contents, also flexes vertebral column

Levator ani

ORIGIN - pubic bone and ischial spine INSERTION - coccyx ACTION - supports pelvic viscera and provides sphincterlike action in anal canal and vagina

Psoas Major

ORIGIN - Lumbar interverebral discs; bodies and transverse processes of lumbar vertebraeINSERTION - Lesser trochanter of femurACTION - flexes thigh

Illiacus

LOCATION - lateral side of the psoas major

Gluteus Maximus

ORIGIN - Sacrum, coccyx, and posterior surface of iliumINSERTION - posterior surface of femur and fascia of thighACTION - extends hip

gluteus medius

LOCATION - partly beneath gluteus maximus and extends from the ilium to the femur

gluteus minimus

LOCATION - beneath gluteus medius

piriformis

LOCATION - shaped like a pyramid inferior to gluteus minimus

tensor fasciae latae

LOCATION - connects the ilium to the iliotibial tract which continues down to the tibia

pectineus

LOCATION - from the spine of the pubis to the femur

adductor longus

LOCATION - triangular that runs from the pubic bone to the femur

adductor brevis

LOCATION - short, triangular muscle that runs from the pubic bone to the femur

adductor magnus

LOCATION - largest adductor in thigh, triangular, connects ischium to the femur

gracilis

ORIGIN - lowere edge of symphysis pubisINSERTION - medial surface of tibiaACTION - adducts thigh and flexes knee

biceps femoris

ORIGIN - ischial tuberosity and linea aspera of femurINSERTION - head of fibula and laeral condyle of tibiaACTION - flexes knee, rotates leg laterally and extends thigh

semitendinosus

LOCATION - back of the thigh toward the medial side connecting he ischium to the proximal end of the tibia

semimembranosus

LOCATION - most medially located muscle in the back of the thigh connects the ischium to the tibia

sartorius

ORIGIN - anterior superior iliac spineINSERTION - medial surface of tibiaACTION - flexes knee and hip, abducts and rotates thigh laterally

quadriceps femoris group

LOCATION - front and sides of the thigh.composed of four parts - rectus femoris, vastus lateratlis, vastus medialis, and vastus intermedius

tibialis anterior

LOCATION - front of the tibia

fibularis tertius

LOCATION - connects fibula to lateral side of the foot

extensor digitorum longus

ORIGIN - lateral condyle of tibia and anterior surface of fibulaINSERTION - dorsal sufaces of second and third phalanges of four lateral toesACTION - dorsiflexion and eversion of foot, extends toes

extensor hallucis longus

ORIGIN - anterior suface of fibulaINSERTION - distal phalanx of the great toeACTION - extends great toe, dorsiflexion and inversion of foot

gastrocnemius

ORIGIN - lateral and medial condyles of femurINSERTION - posterior suface of calcaneusACTION - plantar flexion of foot, flexes knee

soleus

LOCATION - beneath the gatrocnemius and helps form calf of leg

plantaris

LOCATION - connects the femur to the heel

flexor digitorum longus

ORIGIN - poserior suface of tibiaINSERTION - Distal phalanges of four lateral toesACTION - plantar flexion and inversion of foot, flexes four lateral toes

tibialis posterior

LOCATION - deepest of muscles on the back of leg connecting the fibula and tibia to the ankle bones

fibularis longus

LOCATION - lateral side of the leg connecting the tibia and the fibula to the foot

fascia

dense connective tissue that hold skeletal muscle in position

tendon

cordlike fascia that projecs beyond the ends of its muscle fibers that may intertwine with those in the perioseum of a bone

aponeuroses

broad, fibrous sheets that may attach to bone or the coverings of adjacent muscles.

four layers of skeletal muscle

fascia - covers the surface of the muscleepimysium - lies beneath the fasciaperimysium - extends into the structure of the muscle where it separates muscle cells into fasciclesendomysium - separates individual muscle fibers

steps of muscle contraction

- brain sends signal to neuromuscular junction and neuron releases ACH into the muscle fiber- muscle impulse travels into transverse tubules- then throughout the sarcoplasmic reticulum- Ca+ is released into the sarcoplasm- as Ca+ increases it releases troponin tropomyosin from actin binding sites allowing myosin to link with actin

steps of muscle relaxation

- acetylcholinesterase degrade ach-Ca+ decreases- troponin/tropomysin goes back to ends of actin- myosin lets go and muscle relaxes

isotonic contraction

shortening of muscle occurs also called concentric

isometric contraction

muscle remains same length

origin

immovable end

insertion

movable end

prime mover or agonist

muscle primarily responsible for producing an action

synergists

muscles that contract and assist a prime mover

antagonists

resist a prime mover's action and cause movement in the opposite direction