Transcript Muscles of the Body

Muscles of the Body
Muscles of the Body
• Ligaments connect bone to bone
• Tendons connect muscle to bone
• The origin of a muscle is the
attachment of a muscle’s tendon
to the stationary bone
• The insertion of a muscle is the
attachment of the muscle’s
other tendon to the moveable
bone
• In producing movement, bones
act as levers and joints function
as the fulcrums of these levers
• Movement is produced by a
mechanical advantage
Archimedes (287 - 212 B.C.)
• Scientist, mathematician, and engineer of ancient Greece
• Invented a planetarium
• Invented a hydraulic musical organ
• Invented the Screw of Archimedes, which moved water
uphill
• Figured out while taking a bath how to tell whether King
Hiero’s crown was made of gold, and ran naked through
the streets shouting “Eureka!”
• Invented a machine to lever ships between the dock and
the water
“Give me a lever long enough, and a
place to stand, and I will move the
earth.”
Fascicle Arrangement
Learn How Muscles Are Named!
Learn How Muscles Are Named!
Muscles of Facial Expression
• Orbicularis oris = kissing
muscle
• Occipitofrontalis (frontal
belly) = surprise muscle
• Zygomaticus major = smile
muscle
• Buccinator = whistling
muscle
• Orbicularis oculi = winking
muscle
• Corrugator supercilii = scowl
muscle
• Zygomaticus minor = snarl
muscle
• Mentalis = pout muscle
• Risorius = grimace muscle
Botox!
Muscles That Move the Eyeballs
• All rectus muscles originate on the common
tendinous ring attached to orbit around optical
foramen
• Superior oblique originates on sphenoid
• Inferior oblique originates on maxilla
• All rectus muscles insert on
the eyeball on the same side
as their name
• Oblique muscles insert on
the eyeball between the
adjacent rectus muscles
Muscles of the Head and Neck
• Platysma depresses the mandible and
also “pouts”
• Occipitofrontalis (occipital belly)
draws scalp posteriorly
• Masseter elevates the mandible
• Temporalis elevates and retracts
the mandible
• Medial pterygoid elevates and
retracts the mandible
• Lateral pterygoid depresses and
protracts the mandible
Muscles of the Head and Neck
• Digastric elevates the hyoid and
depresses the mandible
• Stylohyoid elevates the hyoid
• Both originate at least in part on the
temporal bone, and insert on the hyoid
• Useful in speaking and swallowing
• Omohyoid originates on the
scapula and depresses the hyoid
• Sternohyoid originates on the
clavicle and sternum, and
depresses the hyoid
• Once again useful in speaking and
swallowing
Muscles of the Head and Neck
• Sternocleidomastoid laterally extends and rotates the head to the side
opposite the muscle
• Originates on the sternum and clavicle
• Inserts on the mastoid process of the temporal bone
Muscles That Move the Shoulder Girdle
• Trapezius (posterior):
elevates and adducts the
scapula
• Levator scapulae (posterior):
elevates and rotates scapula
• Rhomboid major (posterior):
elevates and adducts scapula
• Pectoralis minor (anterior): abducts
scapula, elevates ribs 3 - 5
• Serratus anterior (anterior): abducts
scapula, elevates ribs, the “boxer’s muscle”
Muscles That Move the Arm
• Supraspinatus: assists in abducting
the arm
• Infraspinatus: laterally rotates and
adducts arm
• Subscapularis: medially rotates
arm
• Teres major: extends, adducts, and
medially rotates arm
• Teres minor: extends, adducts, and
laterally rotates arm
• Deltoid: abducts arm
Muscles That Move the Arm
• Supraspinatus, infraspinatus,
subscapularis, and teres minor
form the rotator cuff
• These muscles and their tendons
form a cuff or sleeve around the
shoulder joint
• The supraspinatus is most commonly
affected
• The muscle tears, or suffers impingement
of the tendon
• Common in baseball players, swimmers,
tennis players, and various workers
Muscles That Move the Arm
The rotator cuff
Muscles That Move the Arm
• Pectoralis major: adducts and
medially rotates the arm
• Originates on the clavicle, sternum,
and costal cartilages
• Inserts on the humerus
• Latissimus dorsi: extends, adducts, and
medially rotates the arm
• Originates on vertebrae, sacrum, ilium,
and ribs
• Inserts on the humerus
Muscles That Move the Forearm
• Triceps brachii:
extends forearm
• Lateral and medial
heads originate on the
humerus
• Long head originates on
infraglenoid tubercle
• Insert on the
olecranon process of
the ulna
• Brachialis: flexes
forearm
• Biceps brachii: flexes and supinates forearm
• Short head originates on coracoid process of scapula
• Long head originates on tubercle above glenoid cavity
• Inserts on the radial tuberosity
• Originates on the
humerus
• Inserts on the ulna
Muscles That Move the Forearm
• Supinator: supinates forearm
• Originates on the lateral
epicondyle of the humerus
• Inserts on the radius
• Pronator teres: pronates forearm
• Originates on the medial
epicondyle of the humerus
• Inserts on the radius
• Brachioradialus: flexes the forearm, pronates and supinates back to neutral position
• Originates on the humerus
• Inserts on the radius
Muscles That Move the Wrist
• Flexor digitorum
superficialis, Flexor
carpi radialis, Flexor
carpi ulnaris, and
Palmaris longis
• All originate at least
in part on the medial
epicondyle of the
humerus
• All insert on the
carpals or phalanges
• Flexor pollicis longus
flexes the thumb
• It originates on the
interosseous
membrane and inserts
on the thumb
Muscles That Move the Wrist
• Extensor carpi radialis
longus/brevis, Extensor carpi
ulnaris, and Extensor digitorum all
extend the hand and digits
• All originate at least in part on the
lateral epicondyle of the humerus
• All insert on the metacarpals or
phalanges
• Abductor pollicis longus abducts
the hand and thumb, and extends
the thumb
• It originates on the interosseous
membrane and inserts on the first
metacarpal
Muscles That Move the Wrist
• Extensor pollicis longus/brevis
extend the thumb and abduct the
hand
• Both originate at least in part on
the interosseus membrane
• Both insert on the thumb
Muscles of the Thorax
• The diaphragm produces inhalation
when it contracts, exhalation when
it relaxes
• It originates on the xiphoid
process, as well as some vertebrae
and ribs
• It inserts on the central tendon
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Muscles of the Thorax
• Contraction of the external
intercostals elevates the ribs during
inhalation, relaxation depresses the
ribs during exhalation
• They originate on the inferior border
of the rib above, and insert on the
superior border of the rib below
• Contraction of the internal
intercostals draws the ribs together
during exhalation
• They originate on the superior border
of the rib below, and insert on the
inferior border of the rib above
Muscles That Move the Thigh
• Psoas major and iliacus flex and
rotate the thigh laterally
• Both insert on the lesser
trochanter of the femur
• Tensor fasciae latae flexes and
abducts the thigh
• It originates on the iliac crest
and inserts on the tibia
• Pectineus flexes and adducts the
thigh
• It originates on the pubis and
inserts on the femur
• Adductor longus adducts and
flexes the thigh
• It originates on the pubis and
ischium and inserts on the femur
Muscles That Move the Thigh
• Adductor magnus adducts and
laterally rotates the thigh
• It originates on the ischium and
pubis and inserts on the linea
aspera of the femur
• Gracilis adducts and medially
rotates the thigh
• It originates on the pubis and
inserts on the tibia
Muscles That Move the Thigh
• Gluteus maximus extends and
laterally rotates the thigh
• It originates on the iliac crest,
sacrum, and coccyx
• It inserts on the femur
• Gluteus medius abducts and
medially rotates the thigh
• It originates on the ilium
• It inserts on the greater
trochanter of the femur
Muscles That Move the Leg
• Sartorius flexes the leg, also
flexes, abducts, and laterally
rotates the thigh
• It originates on the ilium and
inserts on the tibia
• Sartorius is the longest muscle in
the body
• Rectus femoris, vastus lateralis,
vastus medialis, and vastus
intermedius together form the
quadriceps femoris, which extend
the leg
• All originate on the ilium or femur
• All insert on the patella and the
tibia
Muscles That Move the Leg
• Biceps femoris flexes the leg and
extends the thigh
• The long head originates on the
ischium and the short head on the
femur
• Inserts on the tibia and fibula
• Semitendinosus and semimembranosus
flex the leg and extend the thigh
• Both originate on the ischial
tuberosity
• Both insert on the tibia
• All three muscles together are known
as the hamstrings
Muscles That Move the Foot
• Tibialis anterior dorsiflexes and
inverts the foot
• It originates on the tibia and inserts
on the first metatarsal and cuneiform
• Soleus plantar flexes the foot
• It originates on the fibula and tibia
and inserts on the calcaneus
• Fibularis longus/brevis (peroneus)
plantar flex and evert the foot
• Fibularis longus originates on the tibia
and fibula and inserts on the first
metatarsal and first cuneiform
• Fibularis brevis originates on the
fibula and inserts on the fifth
metatarsal
Muscles That Move the Foot
• Gastrocnemius plantar flexes the
foot, and flexes the leg
• It originates on the condyles of the
femur and inserts on the calcaneus
• Flexor digitorum longus plantar flexes
the foot and flexes the toes
• It originates on the tibia and inserts
on the distal phalanges 2 - 5
• Flexor hallucis longus plantar flexes
the foot and flexes the great toe
• It originates on the fibula and inserts
on the great toe