Transcript Muscular system1

Muscular system
Golden rules of skeletal muscles
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All muscles cross at least one joint.
The muscle bulk lies proximal to the joint.
Muscles have origin and insertion.
Muscle can only pull.
During contraction insertion move
towards origin.
The origin is attached to less movable
bone, insertion to the movable one.
Types of body movements
• Flexion: bring two bones together.
Hinge joint, knee, elbow.
• Extension: opposite of flexion, hyperextension, more
than 180 degrees, like neck.
• Rotation: movement around longitudinal axis,
shoulder, atlas around axis.
• Abduction: Moving a limb away from medial plane,
faning of fingers, shoulder.
• Adduction: moving limb toward midline.
• Circumduction: combination of all movements,
moving in a circle.
Supination and
pronation:
Supination occur when
the forearm rotate
laterally
Palm anterior
Radius and ulna are
parallel.
Pronation occur when
forearm rotate medially.
Palm face posteriorly
Radius bone cross the
ulna like X.
• Dorsiflextion and planter flexion:
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up and down movements of ankle.
• Inversion and eversion: invert turn sole
medially, eversion turn sole laterally.
Opposition: the thumb touches the other
fingers.
Types of muscles
• Antagonist: muscle that do the
opposite function.
• Synergist: help other muscle to do the
same function.
How to name the muscle?
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Direction of muscle fiber e.g. rectus
mean straight.
Size of muscle e.g. gluteus maximums
i.e. largest.
Location of the muscle e.g. temporalis
over temple.
Number of origins e.g. biceps, two,
triceps three.
Location of origin and insertion e.g.
sternomastoid
Shape of the muscle e.g. deltoid
meaning triangular.
Action of the muscle e.g. flexor,
extensor.
Important muscles of
shoulder girdle
Pectoralis major
Fan shaped muscle, cover
front of the chest.
Origin: first 6 ribs and
shoulder girdle
Insertion: upper humerus
Action: flex shoulder,
adduct the arm.
Posterior muscles
Trapezius: most superficial
muscle of the back of the
neck, and upper trunk.
Origin: occipital bone of skull,
back of neck back of chest.
Insertion: scapular spine, and
clavicle.
Action: extend the head,
elevate, and depress the
shoulder adduct arm.
Latissimus dorsi:
large, flat muscle.
Important muscle in
swimming
Origin: lower spine, and
ilium.
Insertion: upper humerus
Action: extend and adduct
the arm.
Deltoid: fleshy, triangular
shaped muscle, bulky.
Favorite site for injection.
Origin: spine of scapula, and
clavicle.
Insertion: deltoid tuberosity,
upper humerus.
Action: abduct the arm.
Muscle of upper arm
The anterior group cause elbow
flexion.
The posterior group cause
elbow extension.
Biceps brachii:
originate by two heads from
the scapula and inserted into
radial tuberosity of radius.
Action: it flexes and supinates the
elbow.
Brachialis lies deep to biceps.
Triceps brachii:
origin by three heads
from scapula and
humerus,
inserted in olecranon
process of ulna.
Action: it extends the
elbow.
Muscles of the lower limb
 Largest and strongest muscles of the body.
 Muscles causing movement at hip joint.
 Lower limb is limb of stability, upper limb is for mobility
 Anti gravity muscles, back of hip, front of thigh, back of leg
 Act on two joints, hip and knee during walking
 Movement appear to be done by pelvis, but done by lumbar
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vertebrae
Anterior abdominal wall muscles flex pelvis, by flexing
lumbar vertebrae
Hamstring muscles back of thigh
Quadriceps front of the thigh
Gluteus maximus: origin, from
sacrum and iliac bone,
insertion into gluteal tuberosity
of femur.
Action the most important
muscle of extension of the hip.
Gluteus medius: lie under the
gluteus maximus.itis the site
for intra muscular injections.
Stabilize pelvis during walking.
The medial part of each buttock
covers the important sciatic
nerve.
Action: it abducts the hip.
Iliopsoas: is two muscles, iliacus, and psoas major.
Origin from lumbar vertebrae, and iliac bone
Inserted into lesser trochanter of femur. Action it flex the
hip.
Adductor muscles
Small muscles, they adduct the thigh.
Muscles causing movement at knee joint
Hamstring group
Three muscles biceps femoris, semimembrenosus,
semitendenosus.
Origin: from ischial tuberosity
Insertion: proximal medial tibia, and head of fibula.
Action: it flexes the knee.
Quadriceps muscles:
four muscles
Rectus femoris, and three
vastus(medialis,lateralis,intermedius).A
nterior thigh
Origin from femur
Insertion: tibial tuberosity, via patellar
ligament.
Action: extend the knee.
Can use vastus lateralis for intramuscular
injections.
Muscles of the back of the leg
Gasrocnemius
Two bellies that form the curved calf
Origin: two head from distal femur
Insertion into calcaneus bone by tendon
Achilles'.
Soleus: lie deep to gastrocnemius.
Origin: from tibia, back of fibula.
Insertion: same
Action of both muscles: planter flexion of
the ankle.
Muscles of the abdominal
wall
Anterior abdominal muscles
are:
Rectus abdominis, external
oblique, internal oblique,
transverses abdominis.
Their fibers run in three
directions.
Protect abdominal contents.
Rectus abdominis: straplike,
rectus muscles, most
superficial. Run from pubis
to rib cage, enclosed in
aponeurosis.
• Action: Flex the trunk
• Increase intra abdominal pressures in
defecation, delivery, help respiration.
• Protect the viscera.
• External oblique: paired superficial
lateral muscles.
• Fibers run downward and medially.
• Internal oblique: deep to Eo.
• Fibers run at right angle to Eo.
• Transversus abdominis.: deepest
muscles, fibers run horizontal.
• Point to remember
• Linea Alba is the medial border of
rectus muscle.
• Linea semilunaris is the lateral border
of rectus.
• Both are bloodless point used to open
abdomen.
Head and neck
muscles
Two groups
Facial muscles
chewing muscles
Facial muscles
Frontalis: rise eye brow.
Orbicularis oculi: close
eyes, blink,wink and
squint
Orbicularis oris: close
mouth,
Buccinator: flattens
check, whistle.
Chewing muscles
Masseter, temporalis, and
ptyregoid muscles.
Neck muscles
Sternocleidomastoid:
Origin: sternum and
clavicle
Insertion: mastoid process
of temporal bone
Action: both flex the neck
One side rotate head to
other side
Intramuscular injections
• Intramuscular injections are used when rapid
absorption is needed, because muscle has a good
blood supply. Common sites are the buttock (gluteus
medius), the lateral thigh (vastus lateralis), and the
shoulder (deltoid). These sites are shown; also
shown are the large nerves to be avoided when
giving such injections.
ORGANIAZATION OF SKELETAL MUSCLE
• Endomysium – muscle fiber
• Perimysium – fascicle
• Epimysium – entire muscle
• The membrane of the muscle fiber is the sarcolemma.
• Within the muscle fiber are thousands of individual
contracting units called sarcomeres, which are arranged
end to end in cylinders called myofibrils.
• Myosin and actin are the contractile proteins of a muscle
fiber.
ORGANIZATION OF SKELETAL MUSCLE
SKELETAL MUSCLE
CARDIAC MUSCLE
SMOOTH MUSCLE
COMPARISON BETWEEN THE
THREE TYPES OF MUSCLES