Muscle Origin Insertion Action LIST PDF

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A complete guide of muscle origins, insertions, and action lists absolutely required to know for this class!...

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Required Origins, Insertions, Actions List Fall BIOL 2740, 2018 O = origin, I = insertion, A = action ** =Muscles to also know for lab practical (brachioradialis, biceps brachii, triceps brachii, coracobrachialis, brachialis) FACIAL EXPRESSION  get mirror and think about it  usually thin muscles that insert on skin not on bone 

Epicranius (AKA occipitofrontalis), it is a bipartite muscle, main muscle of scalp o Frontal Belly (Frontalis) O – galea aponeurotica (tendon that separates the 2 muscles) I – subcutaneous tissue (skin) of eyebrows A – raises eyebrows, forehead wrinkles o Occipital Belly (Occipitalis) O – nuchal line of occipital and temporal bones I - galea aponeurotica (tendon that separates the 2 muscles) A – fixes aponeurosis and pulls scalp posteriorly

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Orbicularis oculi O – medial bones of orbit I – into eyelid tissue A – closes eyelids, produces blinking

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Orbicularis oris (kissing muscle), fibers surround mouth, doesn’t attach to bone O – corners of mouth I – dermis of lips A – causes lips to protrude, pucker, close NOTE: whistling muscle

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Zygomaticus (pair of muscles) O – zygomatic bone I – corner of mouth A – pull corners of mouth laterally in smiling and laughing

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Platysma (sheet-like) O – upper chest specifically in the fascia over pectoral muscles and deltoid I – lower part of mandible, skin of mouth at corners A - depresses mandible, tenses skin of neck as when shaving, opens and widens mouth

MASTICATION chewing –, if hurt in something like car accident then have trouble with these muscles 

Temporalis O –temporal fossa I – coronoid process of mandible A – raises mandible into maxillae for biting and chewing, closes jaw

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Masseter (powerful muscle) O – zygomatic arch, zygomatic bone I –angle and ramus of mandible A – prime mover of jaw closure, elevates mandible for biting, pulls mandible a little to the side

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Buccinator O – maxilla and mandible (in molar regions) I – orbicularis oris A – compresses cheek, pushes food between teeth, prevents food from getting into space between teeth and cheek, also keeps saliva in the right place Notes: large cheek muscle. If people have stroke they often loose control of this muscle, they may have to push food back onto teeth, some of these people may drip saliva, deep to masseter muscle, well developed in nursing infants

NECK MUSCLEs (move head)  Sternocleidomastoid O – sternum (manubrium) and clavicle (2 headed muscle) I – mastoid process of temporal bone A – when contracts causes flexion and rotation of head (atlas and occipital condyles move against each other to give YES movement, if contract singularly get rotation of head at the axis/atlas joint)

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RESPIRATION MUSCLES 

Diaphragm O – sternum, lumbar vertebrae, inferior internal surface of rib cage (this muscle is a composite,meaning complex and inserts on lots of places) I – central tendon A – inspiration prime mover Notes: domed when relaxed, flat when contracts  lung cavity volume increases, pressure inside lungs becomes subatmospheric, spinal nerve that supplies diaphragm is phrenic nerve, phrenic nerve starts in neck and goes down along heart to diaphragm, if hurt nerve in neck injury then can cause breathing problems. The aorta, interior vena cava, and esophagus all go through the diaphragm. *We work to get air in, cost energy – ACTIVE PROCESS *We don’t spend a penny to breath out – PASSIVE PROCESS

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Intercostals are short muscles that run from rib to rib o External Intercostals – action causes upwards and outwards movement of rib cage, aids in inspiration o Internal Intercostals – action depresses rib cage, involved in forced expiration, like when sing a song, pushes more than normal amount of air out

ABDOMINAL WALL The action of all 4 of these muscles is to flex the veterbral column. Note the linea alba (band of connective tissue) and the transverse intersections that give 6 pack abs! 

Rectus abdominus (this muscle allows you to touch your toes) O – pubic bone I – xiphoid process of sternum, costal cartilage of ribs A – flexes and rotates lumbar vertebral column Notes: (rectus means straight), shows up well on body builders segmented by 3 tendinous intersections 

External oblique (MOST SUPERFICIAL), fibers run like feather O – lower 8 ribs I – linea alba (connective tissue that runs down abdominal region) A – flex vertebral column, rotation of trunk when contracted individually

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Internal oblique (lies under external oblique muscle layer), fibers run like upside-down feather O – iliac crest of hip bone I – linea alba A – flexes vertebral column, rotates trunk if just one side contracts

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Transverse abdominus O – iliac crest of hip bone I – linea alba A – compresses abdominal contents Notes: this sheet of muscle lies under internal oblique layer), fibers run somewhat transversely

VERTEBRAL COLUMN MUSCLES (back muscles) 

Erector spinae A – helps to pull you up when bent over, prime mover of spinal extension Made up of 3 columns 1. iliocostalis – lateral 2. longissimus – middle 3. spinalis - medial

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Quadratus lumborum O – iliac crest of hip bone I – upper lumbar vertebrae and T12 A – causes lateral flexion of vertebral column when acting separately, when acting together lumbar spine is extended

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PECTORAL GIRDLE MUSCLES & MUSCLES CROSSING SHOULDER AND ELBOW JOINTS 

Serratus anterior (origin edge is serrated like a saw) O – upper ribs I – scapula (medial / vertebral border) A – raises scapula up and helps to abduct away from midline, important in arm pushing and punching NOTE: called “boxer’s muscle”

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Trapezius O – occipital bone, thoracic spines (C7-T12) I – clavicle and scapula A – stabilizes, elevates, retracts and rotates scapula

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Levator scapulae (on back and side of neck, deep to the trapezius, strap-like muscle) O – cervical vertebrae 1-4 I –scapula (medial border) A – elevates scapula

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Rhomboid major (shape of rhomboid), under trapezius O – thoracic spines 2 -5 I – scapula (medial border) A – stabilizes scapula

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Pectoralis major (fan shaped muscle) O – sternal end of clavicle and sternum I – humerus A – adducts and medially rotates arm

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Latissimus dorsi (large lower back muscle) O – lower vertebral spine, iliac crest of hip bone I – humerus A – medial rotation of arm at shoulder, prime mover of arm extension (moves limb posteriorly), powerful arm adductor, hammering, swimming

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Deltoid (shoulder muscle) O – clavicle, spine and acromion of scapula I – deltoid tuberosity of humerus A – abducts arms, reach out and get something, prime mover of arm abduction

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Coracobrachialis** O – coracoid process of scapula I – humerus shaft A – adducts arm

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Biceps brachii** O – short head: scapula , Long head: coracoid process I – radial tuberosity of the radius A – supinates forearm, elbow flexion Note: has 2 origins or heads– that’s why we call it “bi” 

Brachialis** O – anterior humerus I – coronoid process of ulna A – flexes elbow Notes: deep to bicecps brachii 

Triceps brachii ** O – long head: scapula, lateral head: humerus, medial head: humerus I – olecranon process of ulna A – extends arm Notes: only muscle of posterior part of arm. This muscle has 3 heads to it, which is where the “tri” comes from (long, lateral, and medial heads)

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Brachioradialis** O – distal end of humerus I – styloid process of radius A – elbow flexion

NOTE: you have to worry about muscles of the wrist and hand except for knowing in general what side of antebrachium (forearm) the extensors and flexors would lie.

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MUSCLES CROSSING HIP AND KNEE JOINTS The thigh region is divided into 3 compartments that are called the anterior, posterior, and medial compartments. These compartments are separated by fascia (layers of connective tissue). 

Iliopsoas (composite of 2 muscles) o Iliacus O – iliac fossa and crest and ala of sacrum I – lesser trochanter of femur A – flexes hip and medial rotation of femur, prime mover of thigh flexion and trunk flexion (like when doing a bow) o Psoas major (butcher’s call it “tenderloin”) O – vertebra I – lesser trochanter of femur A – same as above and lateral flexion of vertebral column

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Tensor fasciae latae O – iliac crest of hip bone I – iliotibial tract (a thickened lateral portion of the fascia lata (the fascia that ensheathes all the muscles of the thigh) A – flexes and abducts thigh

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Gluteus maximus O – ilium (upper part of hip bone) and sacrum, coccyx I – femur A – extends thigh, abduction of thigh Notes: major butt muscle, important for climbing stairs 

Gluteus medius (largely covered by maximus) & Gluteus minimus (deepest of gluteal muscles) O – ilium I – greater trochanter of femur A – abduct and medial rotation of thigh, very important in walking

The adductor muscles all are used to press thighs together. They form the medial part of the thigh. If you strain this muscle group it is called a pulled groin. All originate on the pubis (lower part of hip bone). All insert on the femur. The major action of all three muscles is to adduct femur. o o

Adductor longus (concerned with inside of thigh) Adductor magnus (concerned with inside of thigh)

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Gracilis (long, thin, medial thigh muscle) O – pubis of hip bone I – tibia A – adducts thigh, flexes and medially rotates leg

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Quadriceps (don’t need to know Origins), forms front of thigh and sides), all 4 parts have a common insertion tendon called the “quadriceps tendon” 4 parts 1. rectus femoris 2. vastus lateralis 3. vastus medialis 4. vastus intermedius A – extends knee, kick

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Sartorius (goes hip to inside of knee – crossing both joints), “Sartor” means tailor. This is the longest muscle in the body. O – superior iliac spine I – medial part of tibia A – flexes knee, main muscle when cross legs and try to sit down NOTE: “tailors muscle” because tailor’s often sat on floor cross-legged

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HAMSTRINGS (posterior thigh), action of the hamstring muscles is to extend thigh and flex knee, all have origin on ischium of hip bone o Biceps femoris (2 heads) I – fibula o Semimembranosus I - tibia o Semitendinosus I - tibia

MUSCLES IN LOWER LEG  Gastrocnemius (big calf muscle – 2 bellies) O – femur (medial and lateral condyles of femur) I – calcaneus via calcaneal (Achilles) tendon A – plantar flexion (toes point down) 

Soleus (underneath gastrocnemius – usually shiny / silvery) O – tibia and fibula I – calcaneus A – plantar flexion, posture muscle, point toe

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Tibialis anterior (on front of leg)

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O – tibia I – foot bones A – dorsi flexion, tilts foot up

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