Transcript 10 - Dr. Jerry Cronin

PowerPoint® Lecture Slides
prepared by
Barbara Heard,
Atlantic Cape Community
College
CHAPTER
10
The Muscular
System:
Part A
© Annie Leibovitz/Contact Press Images
© 2013 Pearson Education, Inc.
The Muscular System
• Muscle tissue – all contractile tissues
– Skeletal, cardiac, smooth muscle
• Focus on skeletal muscle
– How muscles interact to  movement
– Criteria for naming muscles
– Principles of leverage
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Actions and Interactions of Skeletal Muscles
• Muscles can only pull; never push
• What one muscle group "does", another
"undoes"
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Actions and Interactions of Skeletal Muscles
• Functional Groups
– Prime mover (agonist)
• Major responsibility for producing specific
movement
– Antagonist
• Opposes or reverses particular movement
– Prime mover and antagonist on opposite
sides of joint across which they act
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Skeletal Muscles: Functional Groups
• Synergist helps prime movers
– Adds extra force to same movement
– Reduces undesirable or unnecessary
movement
• Fixator
– Synergist that immobilizes bone or muscle's
origin
– Gives prime mover stable base on which to
act
© 2013 Pearson Education, Inc.
Figure 10.1 The action of a muscle can be inferred by the position of the muscle relative to the joint it crosses.
(Examples given relate to the shoulder joint.)
A muscle that crosses on the anterior side of a joint produces flexion*
Example:
Pectoralis major
(anterior view)
A muscle that crosses on the posterior side of a joint produces extension*
Example: Latissimus
dorsi (posterior view)
The latissimus dorsi
is the antagonist of
the pectoralis major.
A muscle that crosses on the lateral side of a joint produces abduction
Example: Deltoid
middle fibers
(anterolateral view).
A muscle that crosses on the medial side of a joint produces adduction
Example:
Teres major
(posterolateral view)
The teres major is the
antagonist of the
deltoid.
*These generalities do not apply to the knee and ankle because the lower limb is rotated during development. The
muscles that cross these joints posteriorly produce flexion, and those that cross anteriorly produce extension.
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Skeletal Muscles: Functional Groups
• Same muscle may be
– Prime mover of one movement
– Antagonist for different movement
– Synergist for third movement
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Naming Skeletal Muscles
• Muscle location—bone or body region with
which muscle associated
• Muscle shape—e.g., deltoid muscle (deltoid =
triangle)
• Muscle size—e.g., maximus (largest), minimus
(smallest), longus (long)
• Direction of muscle fibers or fascicles—e.g.,
rectus (fibers run straight), transversus (fibers
run at right angles), and oblique (fibers run at
angles to imaginary defined axis)
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Naming Skeletal Muscles
• Number of origins—e.g., biceps
(2 origins) and triceps (3 origins)
• Location of attachments—named
according to point of origin and insertion
(origin named first)
• Muscle action—named for action they
produce, e.g., flexor or extensor
• Several criteria can be combined, e.g.,
extensor carpi radialis longus
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Muscle Mechanics: Importance of Fascicle
Arrangement and Leverage
• Additional factors contributing to muscle
force and speed
– Fascicle arrangement
– Lever systems
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Arrangement of Fascicles
• Most common patterns – circular,
convergent, parallel, fusiform, pennate
• Circular
– Fascicles arranged in concentric rings (e.g.,
orbicularis oris)
• Convergent
– Broad origin; fascicles converge toward single
tendon insertion (e.g., pectoralis major)
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Muscle Mechanics: Arrangement of
Fascicles
• Parallel
– Fascicles parallel to long axis of straplike
muscle (e.g., sartorius)
• Fusiform
– Spindle-shaped muscles with parallel fibers
(e.g., biceps brachii)
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Muscle Mechanics: Arrangement of
Fascicles
• Pennate
– Short fascicles attach obliquely to central
tendon running length of muscle (e.g., rectus
femoris)
• Three forms
– Unipennate – fascicles attach only to one side of tendon
(e.g., extensor digitorum longus)
– Bipennate – fascicles insert from opposite sides of
tendon (e.g., rectus femoris)
– Multipennate –appears as feathers inserting into one
tendon (e.g., deltoid)
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Figure 10.2 Patterns of fascicle arrangement in muscles.
Convergent
Circular
(pectoralis major)
(orbicularis oris)
(a)
(b)
(c)
(e)
(d)
(f)
Fusiform
(biceps brachii)
(g)
Parallel (sartorius)
Multipennate
Bipennate
Unipennate
(deltoid)
(rectus femoris)
(extensor digitorum longus)
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Arrangement of Fascicles
• Determines muscle's range of motion
– Amount of movement when muscle shortens
• Determines muscle's power
– Long fibers more parallel to long axis shorten
more; usually not powerful
– Power depends on number of muscle fibers
• Bipennate, multipennate muscles have most fibers
 shorten little but powerful
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Muscle Mechanics: Lever Systems
• Components of lever system
– Lever—rigid bar (bone) that moves on a fixed
point called fulcrum (joint)
– Effort—force (supplied by muscle
contraction) applied to lever to move
resistance (load)
– Load—resistance (bone + tissues + any
added weight) moved by the effort
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Levers: Power Versus Speed
• Levers allow given effort to move heavier load;
move load farther or faster
– Depends on fulcrum position relative to load and effort
• Mechanical advantage (power lever) – load
close to fulcrum; effort far from fulcrum
– Small effort can move large load
• Mechanical disadvantage (speed lever) – load
far from fulcrum; effort close to fulcrum
– Load moved rapidly over large distance; wide range
of motion
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Figure 10.3a Lever systems operating at a mechanical advantage and a mechanical disadvantage.
Effort x length of effort arm = load x length of load arm
(force x distance) = (resistance x distance)
Effort
10
kg
0.25 cm
Effort
25 cm
Fulcrum
Load
10 x 25 = 1000 x 0.25
250 = 250
1000 kg
Load
Mechanical advantage with a power lever
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Fulcrum
Figure 10.3b Lever systems operating at a mechanical advantage and a mechanical disadvantage.
Effort
100 kg
Effort
Load
25 cm
50 cm
Fulcrum
Fulcrum
50 kg
100 x 25 = 50 x 50
2500 = 2500
Load
Mechanical disadvantage with a speed lever
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Classes of Lever Systems
• Basic principle of levers
– Effort farther than load from fulcrum = lever
operates at mechanical advantage
– Effort nearer than load to fulcrum = lever
operates at mechanical disadvantage
• Three classes of levers
– Depends on relative position of effort, fulcrum,
load
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Classes of Lever Systems
• First-class lever
– Fulcrum between load and effort
• E.g., seesaw, scissors
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Figure 10.4a Lever systems. (1 of 2)
First-class lever
Arrangement of the elements is
load-fulcrum-effort
Load
Effort
L
Fulcrum
Load
L
Fulcrum
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Effort
Figure 10.4a Lever systems. (2 of 2)
First-class lever
Example: scissors
Fulcrum
Load
Effort
In the body: A first-class lever system
raises your head off your chest. The
posterior neck muscles provide the effort,
the atlanto-occipital joint is the fulcrum,
and the weight to be lifted is the facial
skeleton.
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Classes of Lever Systems
• Second-class lever
– Load between fulcrum and effort
• E.g., Wheelbarrow, standing on toes
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Figure 10.4b Lever systems. (1 of 2)
Second-class lever
Arrangement of the elements is
fulcrum-load-effort
Load
L
Effort
Fulcrum
Load
L
Effort
Fulcrum
© 2013 Pearson Education, Inc.
Figure 10.4b Lever systems. (2 of 2)
Second-class lever
Example: wheelbarrow
Effort
Load
Fulcrum
In the body: Second-class leverage is
exerted when you stand on tip-toe. The
effort is exerted by the calf muscles
pulling upward on the heel; the joints of
the ball of the foot are the fulcrum; and
the weight of the body is the load.
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Classes of Lever Systems
• Third-class lever
– Effort applied between fulcrum and load
• E.g., tweezers, forceps, most skeletal muscles
• Speed levers – force lost; speed, range of
movement gained
• Power levers – slower, more stable, used
where strength priority
© 2013 Pearson Education, Inc.
Figure 10.4c Lever systems. (1 of 2)
Third-class lever
Arrangement of the elements is
load-effort-fulcrum
Load
Effort
L
Fulcrum
Load
L
Fulcrum
Effort
© 2013 Pearson Education, Inc.
Figure 10.4c Lever systems. (2 of 2)
Third-class lever
Example: tweezers or forceps
Effort
Load
Fulcrum
In the body: Flexing the forearm by the
biceps brachii muscle exemplifies
third-class leverage. The effort is exerted
on the proximal radius of the forearm, the
fulcrum is the elbow joint, and the load is
the hand and distal end of the forearm.
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Major Skeletal Muscles of the Body
• > 600 in body; grouped by function and
location
• Information for each muscle
– Shape
– Location relative to other muscles
– Origin and insertion—usually a joint between
origin and insertion
– Actions—insertion moves toward origin
– Innervation—name of major nerve that
supplies muscle
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Major Skeletal Muscles of the Body
• To learn
– Be aware of information learned from muscle
name
– Read description; identify on figure; relate
location and description
– Relate attachments to actions
– Act out movements on yourself
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Figure 10.5 Superficial muscles of the body: Anterior view.
Facial
Epicranius, frontal belly
Head
Temporalis
Masseter
Shoulder
Trapezius
Deltoid
Arm
Triceps brachii
Biceps brachii
Brachialis
Forearm
Pronator teres
Brachioradialis
Flexor carpi radialis
Palmaris longus
Pelvis/thigh
Iliopsoas
Pectineus
Thigh
Rectus femoris
Vastus lateralis
Vastus medialis
Leg
Fibularis longus
Extensor digitorum
longus
Tibialis anterior
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Orbicularis oculi
Zygomaticus
Orbicularis oris
Neck
Platysma
Sternohyoid
Sternocleidomastoid
Thorax
Pectoralis minor
Pectoralis major
Serratus anterior
Intercostals
Abdomen
Rectus abdominis
External oblique
Internal oblique
Transversus abdominis
Thigh
Tensor fasciae latae
Sartorius
Adductor longus
Gracilis
Leg
Gastrocnemius
Soleus
Figure 10.6 Superficial muscles of the body: Posterior view.
Arm
Triceps brachii
Brachialis
Forearm
Brachioradialis
Extensor carpi radialis
longus
Flexor carpi ulnaris
Extensor digitorum
Extensor carpi ulnaris
Iliotibial tract
Leg
Gastrocnemius
Soleus
Fibularis longus
Calcaneal
(Achilles) tendon
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Neck
Epicranius, occipital belly
Sternocleidomastoid
Trapezius
Shoulder
Deltoid
Infraspinatus
Teres major
Rhomboid major
Latissimus dorsi
Hip
Gluteus medius
Gluteus maximus
Thigh
Adductor magnus
Hamstrings:
Biceps femoris
Semitendinosus
Semimembranosus
Muscles of the Head
• Two groups
– Muscles of facial expression
– Muscles of mastication and tongue movement
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Muscles of Facial Expression
• Insert into skin
• Important in nonverbal communication
• All innervated by cranial nerve VII (facial
nerve)
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Muscles of Facial Expression: The Scalp
• Epicranius (occipitofrontalis)
– Bipartite muscle consisting of
• Galea aponeurotica—cranial aponeurosis
connecting two bellys
• Frontal belly; occipital belly
– Have alternate actions; pull scalp forward and backward
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Muscles of Facial Expression: The Face
• Corrugator
supercilii
• Zygomaticus
• Risorius
• Levator labii
superioris
• Depressor labii
inferioris
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• Depressor anguli
oris
• Orbicularis oris
• Mentalis
• Buccinator
• Platysma
Figure 10.7b Lateral view of muscles of the scalp, face, and neck.
Epicranial
aponeurosis
Corrugator supercilii
Orbicularis oculi
Levator labii
superioris
Zygomaticus
minor and major
Buccinator
Risorius
Orbicularis oris
Mentalis
Depressor
labii inferioris
Depressor anguli oris
Platysma
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Frontal
belly
Occipital
belly
Temporalis
Epicranius
Masseter
Sternocleidomastoid
Trapezius
Splenius
capitis
Muscles of Mastication
• Four pairs involved in mastication; all
innervated by cranial nerve V (trigeminal
nerve)
– Prime movers of jaw closure
• Temporalis and masseter
– Grinding movements
• Medial and lateral pterygoids
– Chewing role - holds food between teeth
• Buccinator
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Figure 10.8a Muscles promoting mastication and tongue movements.
Temporalis
Orbicularis
oris
Buccinator
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Masseters
Figure 10.8b Muscles promoting mastication and tongue movements.
Lateral
pterygoid
Medial
pterygoid
Masseter
pulled away
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Muscles of Mastication and Tongue
Movement
PLAY
A&P Flix™: Temporalis
PLAY
A&P Flix™: Masseter
PLAY
A&P Flix™: Buccinator
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Muscles of Tongue Movement
• Three muscles anchor and move tongue
– Genioglossus
– Hyoglossus
– Styloglossus
• All innervated by cranial nerve XII hypoglossal nerve
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Figure 10.8c Muscles promoting mastication and tongue movements.
Tongue
Styloid process
Styloglossus
Genioglossus
Hyoglossus
Mandibular symphysis
Stylohyoid
Geniohyoid
Thyroid cartilage
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Hyoid bone
Thyrohyoid
Muscles of the Anterior Neck and Throat
• Two groups
– Suprahyoid muscles
– Infrahyoid muscles
• Most involved in swallowing
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Suprahyoid Muscles of the Anterior Neck
and Throat
• Four deep muscles involved in swallowing
(move hyoid bone and larynx)
– Form floor of oral cavity
– Anchor tongue
– Move hyoid bone and larynx
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Infrahyoid Muscles of the Anterior Neck and
Throat
• Straplike muscles; depress hyoid and
larynx as swallowing ends and during
speaking
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Figure 10.9a Muscles of the anterior neck and throat used in swallowing.
Median raphe
Digastric
Anterior
belly
Posterior
belly
Stylohyoid (cut)
Thyrohyoid
Thyroid cartilage
of the larynx
Thyroid gland
Sternothyroid
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Mylohyoid
Stylohyoid
Hyoid bone
Omohyoid
(superior belly)
Sternohyoid
Sternocleidomastoid
Omohyoid
(inferior belly)
Figure 10.9b Muscles of the anterior neck and throat used in swallowing.
Platysma
(cut)
Mylohyoid
Omohyoid
(superior belly)
Sternohyoid
Sternocleidomastoid
© 2013 Pearson Education, Inc.
Figure 10.9c Muscles of the anterior neck and throat used in swallowing.
Tensor veli palatini
Levator veli palatini
Styloid process
Superior pharyngeal
constrictor
Buccinator
Middle pharyngeal
constrictor
Mandible
Hyoid bone
Mylohyoid
(cut)
Thyrohyoid
membrane
Geniohyoid
Inferior
pharyngeal
constrictor
Hyoglossus
Thyroid
Cartilage of larynx
Esophagus
Trachea
© 2013 Pearson Education, Inc.
Infrahyoid Muscles of the Anterior Neck and
Throat
PLAY
Animation: Rotating head
PLAY
Animation: Rotating face
© 2013 Pearson Education, Inc.
Muscles of the Neck and Vertebral Column
• Two functional groups
– Muscles that move head
– Muscles that extend trunk and maintain
posture
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Muscles of the Neck and Vertebral Column:
Head Movement
• Sternocleidomastoid—major head flexor
– Suprahyoid and infrahyoid—synergists to
head flexion
• Sternocleidomastoid and scalenes—
lateral head movements
• Splenius capitis and cervicis portions head extension, rotation, and lateral
bending
• Semispinalis capitis—synergist with
sternocleidomastoid
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Figure 10.10a Muscles of the neck and vertebral column that move the head and trunk.
1st cervical
vertebra
Sternocleidomastoid
Base of
occipital bone
Mastoid
process
Middle
scalene
Anterior
scalene
Posterior
scalene
Anterior
© 2013 Pearson Education, Inc.
Figure 10.10b Muscles of the neck and vertebral column that move the head and trunk.
Mastoid process
Splenius
capitis
Spinous
processes
of the
vertebrae
Splenius
cervicis
Posterior
© 2013 Pearson Education, Inc.
Figure 10.10c Muscles of the neck and vertebral column that move the head and trunk.
Platysma (cut)
Sternocleidomastoid
(cut)
Internal jugular vein
Omohyoid
Sternohyoid
Sternothyroid
Sternocleidomastoid
Pectoralis major
© 2013 Pearson Education, Inc.
Muscles of the Neck and Vertebral Column:
Head Movement
PLAY
A&P Flix™: Splenius capitis
PLAY
A&P Flix™: Semispinalis capitis
© 2013 Pearson Education, Inc.
Muscles of the Neck and Vertebral Column:
Trunk Extension
• Deep (intrinsic) back muscles
– Erector spinae (sacrospinalis) group—
prime movers of back extension and lateral
bending
• Iliocostalis
• Longissimus
• Spinalis
– Semispinalis and quadratus lumborum—
synergists in extension and rotation
© 2013 Pearson Education, Inc.
Figure 10.10d Muscles of the neck and vertebral column that move the head and trunk.
Mastoid process
of temporal bone
Longissimus capitis
Iliocostalis cervicis
Longissimus cervicis
Iliocostalis thoracis
Ligamentum
nuchae
Semispinalis
capitis
Semispinalis
cervicis
Semispinalis
thoracis
Longissimus thoracis
Spinalis thoracis
Iliocostalis
Erector Longissimus
spinae
Spinalis
Iliocostalis
lumborum
External oblique
© 2013 Pearson Education, Inc.
Multifidus
Quadratus
lumborum
Muscles of the Neck and Vertebral Column:
Trunk Extension
PLAY
A&P Flix™: Iliocostalis
PLAY
A&P Flix™: Longissimus
PLAY
A&P Flix™: Spinalis
© 2013 Pearson Education, Inc.