Chapter 11 - The Muscular System Flashcards
origin
Attachment of a muscle’s tendon to the stationary bone (usually proximal)
insertion
attachment of a muscle’s other tendon to the movable bone (usually distal and pulled toward origin)
belly (body)
Fleshy portion of the muscle between the tendons
actions
Main movements during muscle contraction
reverse muscle action
Specific revered movements, where positions of origin and insertion are switched
lever system and leverage (fulcrum, effort, load/resistance)
Lever = rigid structure that moves around fixed point(fulcrum). Two different forces = efforts, causes movement, load/resistance opposes movement
first-class levers
Like a see-saw, produces adv or disadv depending on loads distance to fulcrum
second-class levers
wheelbarrow, always mech adv
third-class levers
forceps, always mech disadv, favours range of motion and speed over force
fascicles
Skeletal muscle fibers within a muscle are arranged in bundles called fascicles, five different patterns
prime mover or agonist
Leader contracts to cause an action
antagonist
Stretches and yields to the effects of leader
synergist
Contract and stabilized to prevent unwanted movements
fixator
Stabilize origin of the prime mover for efficiency
compartment
group of skeletal muscles, associated blood vessels, associated nerves
location and action of: occipitofrontalis: frontal belly and occipital belly
facial 7 nerve, draws scalp anteriorly, raises eyebrows vs draws scalp posteriorly
location and action of: orbicularis oris
facial 7 nerve, closes and protrudes lips, shapes during speech
location and action of: zygomaticus major
facial 7 nerve, draws angle of mouth superiorly and laterally, smiling
location and action of: buccinator
facial 7 nerve, presses cheeks against teeth and lips, whistling, chewing
location and action of: orbicularis oculi
facial 7 nerve, closes eye
location, action, origins, insertion of: masseter
mandibular division of trigeminal 5 nerve. Elevates mandible, closing mouth. O=maxilla and zygomatic arch. I= angle and ramus of mandible
location, action, origins, insertion of: temporalis
mandibular division of trigeminal 5 nerve. Elevates and retracts mandible. O=temporal bone. I= Coronoid process and ramus of mandible.
location, action, origins, insertion of: sternocleidomastoid
Accessory 11 nerve, C2, C3. Extend head, rotate head, elevate sternum. O=sternal head, manubrium of sternum, clavicular head: medial third of clavicle. I=Mastoid process of temporal bone and lateral half of superior nuchal line of occipital bone.
location, action, origins, insertion of: rectus abdominis
Thoracic spinal nerves T7-T12. Flexes vertebral column, compresses abdomen. O= pubic crest and pubic symphysis. I=Cartilage of ribs 5-7 and xiphoid process.
location and action of: external oblique
Thoracic spinal nerves T7-T12 and the iliohypogastric nerve. Bilaterally compresses abdomen and flexes vertebral column, unilaterally flex vertebral column rotates
location and action of: internal oblique
Thoracic spinal nerves T8–T12, the iliohypogastric nerve, and ilioinguinal nerve.
Bilaterally compresses abdomen and flexes vertebral column, unilaterally flex vertebral column rotates
location and action of: transversus abdominis
Thoracic spinal nerves T8–T12, iliohypogastric nerve, and ilioinguinal nerve.
Compresses abdomen
location and action of: diaphragm
Phrenic nerve, which contains axons from C3-C5. Flattens to increase or relaxes to decrease vertical dimension of thoracic cavity
location and action of: external intercostal
Thoracic spinal nerves T2-T12, elevates ribs or depresses ribs
location and action of: internal intercostal
Thoracic spinal nerves T2-T12, ribs together
location and action of: pectoralis minor
Subclavian nerve. Depresses and moves clavicle anteriorly to stabilize pectoral girdle
location, action, origins, insertion of: trapezius
Accessory (XI) nerve and cervical spinal nerves C3–C5.
location, action, origins, insertion of: levator scapulae
Dorsal scapular nerve and cervical spinal nerves C3-C5. Elevates scapula and rotates it downward. O= transverse processes of C1-C4, Superior vertebral border of scapula.
location and action of: rhomboid major
Dorsal scapular nerve. Elevates and adducts scapula and rotates it downward; stabilizes scapula.
location, action, origins, insertion of: pectoralis major
Medial and lateral pectoral nerves. Adducts and medially rotates arm at shoulder joint, flexes arm. O= clavicle, sternum, costal cart. of ribs 2-6, sometimes ribs 1-7. I= greater tubercle and lateral lip of intertubercular sulcus of humerus.
location and action of: latissimus dorsi
Thoracodorsal nerve. Extends, adducts, and medially rotates arm at shoulder joint, draws arm inferiorly and posteriorly.
location, action, origins, insertion of: deltoid
Axillary nerve, moves shoulder joint, o= acromial extremity of clavicle, acromion of scapula, spine of scapula. I= deltoid tuberosity of humerus.
location and action of: subscapularis
Upper and lower subscapular nerve. Medially rotates arm at shoulder joint.
location, action, origins, insertion of: supraspinatus
Suprascapular nerve. assists deltoid muscle in abducting arm at shoulder joint. O=supraspinous fossa of scapula. I=greater tubercle of humerus.
location and action of: infraspinatus
Suprascapular nerve. Laterally rotates arm at shoulder joint.
location and action of: teres major
Lower subscapular nerve. Extends arm, assists in adduction and rotation at shoulder joint
location and action of: teres minor
Axillary nerve. laterally rotates and extends arm at shoulder joint.
location, action, origins, insertion of: biceps brachii
Musculocutaneous nerve. Flexes forearm. O=long head originates from tubercle above glenoid cavity of scapula. I= Radial tuberosity of radius and bicipital aponeurosis.
location and action of: brachialis
Musculocutaneous. Flexes forearm at elbow joint.
location and action of: brachioradialis
Radial nerve. Flexes forearm at elbow joint.
location, action, origins, insertion of: triceps brachii
Radial nerve. extends forearm and arm.
O=Long head originates from infraglenoid tubercle, a projection inferior to glenoid cavity of scapula.
Lateral head originates from lateral and posterior surface of humerus.
Medial head originates from entire posterior surface of humerus inferior to a groove for the radial nerve.
I=olecranon of ulna
location and action of: pronator teres
median nerve. pronates forearm at radioulnar joints.
location and action of: supinator
deep radial nerve. supinates forearm at radioulnar joints.
location, action, origins, insertion of: flexor carpi radialis
median nerve. flexes and abducts hand at wrist joint. O=medial epicondyle of humerus. I=metacarpals 2&3
location and action of: palmaris longus
Median nerve, weakly flexes hand at wrist joint.
location, action, origins, insertion of: flexor carpi ulnaris
Ulnar nerve. flexes and adducts hand at wrist joint. O=Medial epicondyle of humerus and superior posterior border of ulna. I= Pisiform, hamate, and base of metacarpal V.
location, action, origins, insertion of: flexor digitorum superficialis
Median nerve. Flexes middle phalanx of each finger at proximal interphalangeal joint, proximal phalanx of each finger at metacarpophalangeal joint, and hand at wrist joint.
O= Medial epicondyle of humerus, coronoid process of ulna, and ridge along lateral margin or anterior surface (anterior oblique line) of radius.
I= Middle phalanx of each finger.*
location and action of: extensor carpi radialis longus
Radial nerve. Extends and abducts hand at wrist joint.
location, action, origins, insertion of: extensor digitorum
Radial nerve. Extends and abducts hand at wrist joint. O=Lateral epicondyle of humerus. I=Metacarpal 3.
location, action, origins, insertion of: extensor carpi ulnaris
Deep radial nerve. Extends and adducts hand at wrist joint. O=Lateral epicondyle of humerus and posterior border of ulna. I=Metacarpal 5.
location and action of: iliocostalis group
Cervicis: Cervical and thoracic spinal nerves.
Thoracis: Thoracic spinal nerves.
Illiac crest: Lumbar spinal nerves.
Maintain erect posture of vertebral column.
location and action of: scalenes
Anterior, middle, posterior. Cervical spinal nerves. Elevate ribs during deep inhalation, flex/slightly rotate cervical vertebrae.
location, action, origins, insertion of: iliopsoas or psoas major
Lumbar spinal nerves L2-L3. Psoas major and iliacus muscles flex thigh at hip joint, rotate thigh laterally, flex trunk on hip. O=transverse processes and bodies of lumbar vertebrae. I=With iliacus into lesser trochanter of femur.
location and action of: iliacus
Femoral nerve. no action?
location, action, origins, insertion of: gluteus maximus
Inferior gluteal nerve. extends thigh at hip joint, laterally rotates thigh, helps lock knee. O=Iliac crest, sacrum, coccyx, aponeurosis of sacrospinalis. I=iliobtibial tract of fascia lata and superior lateral part of linea aspera under greater trochanter of femur.
location and action of: gluteus medius
Superior gluteal nerve. Abducts thigh at hip joint and medially rotates thigh.
location and action of: adductor longus
Obturator nerve. Adducts and flexes thigh at hip joint, rotates/extends thigh.
location and action of: adductor magnus
Obturator and sciatic nerves. Adducts thigh at hip joint and rotates thigh, flexes thigh at hip joint, extends thigh.
location, action, origins, insertion of: rectus femoris
Femoral nerve. extend leg at knee joint, flexes thigh at hip joint. O= Anterior inferior iliac spine. I= patella via quads tendon and tibial tuberosity via patellar ligament.
location and action of: vastus lateralis/medialis/intermedius
Femoral nerve. extend leg at knee.
location and action of: sartorius
Femoral nerve. Weakly flexes leg at knee. weakly flexes abducts and laterally rotates thigh at hip.
location, action, origins, insertion of: biceps femoris
Tibial and fibular nerves from sciatic nerve. Flexes leg at knee and extends at thigh. O=Long head arises from ischial tuberosity; short head arises from linea aspera of femur.
I=Long head arises from ischial tuberosity; short head arises from linea aspera of femur.
location and action of: semitendinosus & semimembranosus
Tibial nerve from sciatic nerve. Flexes leg at knee and extends thigh at hip.
location, action, origins, insertion of: tibialis anterior
Deep fibular nerve. Dorsiflexes foot at ankle joint and inversts foot at intertarsal joints. O= Lateral condyle and body of tibia and interosseous membrane I=Metatarsal I and first (medial) cuneiform.
location, action, origins, insertion of: extensor digitorum longus
Deep fibular nerve. Dorsiflexes foot at ankle joint and extends distal and middle phalanges of each toe at interphalangeal joints and proximal phalanx of each toe at metatarsophalangeal joint.
O=Dorsiflexes foot at ankle joint and extends distal and middle phalanges of each toe at interphalangeal joints and proximal phalanx of each toe at metatarsophalangeal joint.
I=Middle and distal phalanges of toes II–V.*
location and action of: fibularis (peroneus) longus
Superficial fibular nerve. Plantar flexes foot at ankle, everts foot at intertarsal joints.
location, action, origins, insertion of: gastrocnemius
Tibial nerve. Plantar flexes foot at ankle, and leg at knee. O= Lateral and medial condyles of femur and capsule of knee. I=Calcaneus by way of calcaneal tendon.
location and action of: soleus
Tibial nerve. Plantar flexes foot at ankle.
location, action, origins, insertion of: flexor digitorum longus
Tibial nerve. Plantar flexes foot at ankle joint; flexes distal and middle phalanges of toes II–V at interphalangeal joints and proximal phalanx of toes II–V at metatarsophalangeal joint.
O= Middle third of posterior surface of tibia.
I= Distal phalanges of toes II–V.
