Download Muscles of the Body

Muscles of
the Body
http://www.rad.washington.edu/academics/academi
c-sections/msk/muscle-atlas
"Copyright 2003-2004 University of Washington. All
rights reserved including all photographs and images. No
re-use, re-distribution or commercial use without prior
written permission of the authors and the University of
Washington."
"Musculoskeletal Images are from the University of
Washington "Musculoskeletal Atlas: A Musculoskeletal
Atlas of the Human Body" by Carol Teitz, M.D. and Dan
Graney, Ph.D."
Other copies materials from Marieb, 5th ed., Martini, 6th ed.
or online with reference
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Fascicles
 Bundles of fibers
*
Skeletal muscle
Epimysium:
surrounds
whole muscle
Perimysium
is around
fascicle
Endomysium is around each
muscle fiber
Different
arrangements
of fascicles
Arrangement of fascicles influences
movement and power
 Skeletal muscles can shorten by about 1/3
of their resting length
 The more nearly parallel to the axis, the more
they can shorten
 This results in a larger distance of movement
 The power depends on the total number of
fibers
 Stocky muscles (like bipennate vs parallel)
have more fibers, therefore more powerful
even though shorten very little
Interactions of Skeletal Muscles
 Muscles can only pull, they can’t push
 Actions must be “undone” by a different
muscle
 Muscles that produce opposite movements
usually lie on opposite sides of a given
joint
Interactions, continued
 Agonist: prime mover, major responsibility for
producing a specific movement
 Antagonist: oppose or reverse a particular
movement
 Usually contract a little to prevent overshooting the
mark or slow the agonist’s action near the end
 Are being stretched or can remain relaxed when
agonist works
Antagonists for one movement can be agonists
for another
 Synergists help prime movers
 Add a little extra force to the same movement
 Or reduce undesirable extra movements (e.g.
making a fist without flexing at wrist)
 Fixators: hold a bone firmly so agonist has
a stable base on which to move a body
part (e.g. fixing scapula when arm moves)
Compartments
Upper limb: 2 compartments
Lower limb: 3 compartments
 Contain muscles of similar
developmental origin and function
 Dense fibrous connective tissue
separates
Naming skeletal muscles (examples)
 Location: brachialis is in arm (brachium = arm)
 Shape: deltoid is triangular (delta = triangle)
 Size: minimus (smallest), longus (long), brevis
(short)
 Direction of fascicles and fibers: rectus (straight);
transversus (right angle) and oblique (oblique) to
midline
 Number of origins: biceps (“two heads”), triceps
(“three heads”), quadriceps (“four heads”)
 Action: “flexor,” “extensor,” “adductor” or
“abductor” appear in the name
 Combinations of the above, e.g. extensor carpi
radialis longus
Axial muscles
 Lie anterior and posterior to body axis
(vertebral column)
 Move trunk; maintain posture
 Skeletal muscles of thorax, abdomen, and
pelvis
 Many muscles of neck
 A few muscles in head
Limb muscles
 Arise from ventral region as limb buds
 Muscles develop from lateral parts of myotomes
 In general: dorsal (posterior) muscles become
extensors and ventral (anterior) become flexors
 Lower limb rotates during embryonic
development:
 Extensors on anterior (ventral) side: extend leg at
knee, dorsiflex foot at ankle and extend toes
 Flexors on posterior (dorsal) side: flex leg at knee,
plantarflex foot at ankle, flex toes
to use for studying...
anterior
Text
Text
posterior
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Muscles of the Head and Neck
 Scalp Muscle: epicranius
 frontal belly
 occipital belly
 gala aponeurotica
 Muscles of Facial Expression: insert on
skin or another muscle
 Muscles of Mastication (chewing): all have
insertions on the mandible
 Anterior Neck Muscles
 Posterior Neck Muscles
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Mastication:
•Jaw closure: masseter
and temporalis
•Side to side grinding:
pterygoids
•Buccinator: compresses
cheek
“glossus” = tongue
Extrinsic tongue muscles
Tongue itself (instrinsic muscles): digestive tract section
Deep chewing muscles
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Pharyngeal constrictors
Muscles of the Anterior Neck
Above hyoid (suprahyoid): form floor of oral cavity, anchor tongue,
elevate hyoid, move larynx superiorly during swallowing
Below hyoid (infrahyoid): depress hyoid and larynx during swallowing
and speaking
Right side (of
slide) is deeper
than left
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Sternocleodomastoid
Neck
Anterolateral neck
Scalenes elevate first 2 ribs
Posterior neck
Splenius’ (capitis and cervicis)
extend head
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Deep muscles of back
Right side:
deeper
Quadratus lumborum
(lateral flexion)
Erector spinae
(extend back):
Iliocostalis
Longissimus
Spinalis
Labeled cervicis,
thoracics, lumborum
depending on where they
are
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Per Marieb… (worthwhile to know)
“During full flexion (i.e. when touching fingertips
to floor), erector spinae are relaxed and strain is
borne entirely by ligaments of back; on reversal
of the movement, these muscles are initially
inactive, and extension is initiated by hamstring
muscles of thighs and gluteus maximus muscles
of buttocks. As a result of this peculiarity, lifting a
load or moving suddenly from a bent over
position is potentially injurious to muscles and
ligaments of back and intervertebral discs;
erector spinae muscles readily go into painful
spasms following injury to back structures.”
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Lift rib cage:
inspiratory
Depress rib cage: in
forced expiration
Deep muscles of
the thorax:
breathing
 Intercostals
Short: rib to rib
 Diaphragm
prime mover
of inspiration
Floor of thoracic cavity: when
flattens, air moves in
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Anterior Chest Muscles
Superficial:
Deeper:
sternocleidomastoid
pectoralis major
pectoralis minor
serratus anterior
subclavius
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Muscles of the abdominal wall
From more superficial to deep:
External oblique
Internal oblique
Transversus abdominis
Nearer midline:
Rectus abdominis
 Note inguinal ligamentfrom anterior superior iliac
spine to pubic symphysis:
lower border of external
oblique rolls up on itself to
form it
*
*
The rectus abdominis is the
medial pair of muscles; it is
ensheathed by the aponeurosis of
the lateral muscles, which don’t
come to the midline
Muscles of the
abdominal wall
from the side
Muscles moving the scapula
trapezius
levator scapulae
rhomboids
posterior
9 Muscles crossing shoulder joint:
movement of arm (humerus)
Three most powerful of the nine and prime movers:
pectoralis major
latissimus dorsi
deltoid
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Rotator cuff
supraspinatus, infraspinatus, subscapularis, teres minor
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remaining 2muscles : teres major and coracobrachialis
Forearm extensors (posterior)
 Triceps brachii
 Anconeus helps
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Forearm flexors (anterior)
Brachioradialis
Brachialis
Biceps brachii
3 muscle on right
39 from this site:
http://www.rad.washington.edu/atlas/
 Retinaculae (retinaculum, singular)
 “retainers,” “wrist bands”, “ankle bracelets”
 Bands of fascia holding tendons of wrist and
ankle in place (prevent “bow-stringing”)
 Tendons covered by slippery tendon sheets
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Forearm muscles: movement of
wrist, hand and fingers
 Many arise from distal humerus
 Cross elbow, wrist and finger joints
 Minimal action at elbow
 At wrist joint: flexion, extension, abduction and
adduction of the hand
 At finger joints: mostly just flex and extend (other
movements- by small muscles in the hand itself)
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Forearm muscles, continued
 Two compartments (each with superficial and
deep muscle layers)
Anterior = flexor compartment ( except includes 2
pronators)
Most originate from a common tendon on the medial epicondyle
of humerus
Posterior = extensor compartment (except includes
supinator and brachioradialis)
Many arise from a common tendon from lateral epicondyle of
humerus
 Most muscles that move the palm and fingers are
located in the forearm, not the hand itself
They operate by tendons like strings with puppets
There are some small muscles in the hand itself
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Anterior wrist pronator and flexors
Origin on medial epicondle of humerus: pronator teres, flexor carpi
radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum
superficialis
Pronator teres
Palmaris
longus
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http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Deep anterior
hand muscles
(some)
 Flexor pollicis
longus
 Flexor digitorum
profundus (only
muscle that
flexes DIPs)
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Flexor digitorum
superficialis
Individually
(this is right arm, anterior)
Flexor digitorum profundus
Flexor pollicis longus
Pronator quadratus
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http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
origin on lateral
epicondyl of humerus
 Extensor carpi radialis
(longus & brevis)
 Extensor digitorum
 Extensor carpi ulnaris
See individually in next slide
Superficial extensors
Extensor carpi
radialis longus
Extensor digitorum
Extensor carpi ulnaris
Extensor carpi radialis brevis
http://www.rad.washington.edu/academics/academic-sections/msk/musc
Deep posterior muscles
Abductor
pollicis longus
Supinator
Extensor pollicis
longus & brevis
Extensor indicis
http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Hand
 Thenar
 Hypothenar
 Midpalmar
 Lumbricals
 Interossei
Te
Thenar and hypothenar muscles
http://www.rad.washington.edu/academics/
academic-sections/msk/muscle-atlas
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Right forearm, anterior view, from superficial to deep
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Right forearm, posterior, from superficial to deep
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Muscles crossing the hip and knee joints
 Three groups separated by fascia; all three
enclosed by deep fascia of thigh (fascia lata)
1. Anterior
 Flex femur at hip; extend leg at knee (e.g. foreswing
phase of walking)
2. Posterior
 Mostly extend thigh and flex leg (backswing phase of
walking)
3. Adductor (medial)
 Move thigh only, not leg
Muscles that flex thigh at hip
Originate from vertebral
column and pelvis and
pass anterior to hip joint





Sartorius
Iliopsoas
Tensor fasciae lata
Rectus femoris (only
quad with origin on
pelvis)
Pectineus (medial
compartment)
Muscles that flex thigh at hip: individually
(go between last slide and this one)
Iliopsoas
Pectineus
Tensor fascia lata
Sartorius
Rectus
femoris
Inserts on tibial
tuberosity via
patellar tendon
http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Thigh extensors
(posterior)
Arise posterior to hip joint
_______
 Gluteus maximus
 Hamstrings (cross hip
and knee joints: extend
thigh & flex knee)
 Biceps femoris
 Semitendinosus
 Semimembranosus
(antagonists of quads)
http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Hamstrings
Biceps femoris
long head
cross hip and knee joints:
extend thigh and flex knee
Biceps
femoris
short head
Semitendinosus Semimembranosus
http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Abductors of thigh
Buttocks muscles that
lie lateral to hip joint
 Gluteus medius
 Gluteus minimus
(under medius)
 Tensor fascia lata
Thigh abductors
Buttocks muscles that lie
lateral to the hip joint
Gluteus medius
Gluteus minimus
http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Lateral rotators
 Piriformis
 Also shown are other
rotators and the
gluteus muscles
Piriformis laterally rotates
hip; also helps abduct hip if
it is flexed
http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Adduction of thigh
Muscles originate
medial to hip joint





Gracilis
Adductor magnus
Adductor longus
Adductor brevis
Pectineus
Thigh adductors
Adductor magnus
(originate medial to hip joint)
Pectineus
Adductor brevis
Gracilis
Adductor longus
http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Knee extensors
Quadraceps femoris –
the only extensors of
the leg (lower leg) at
the knee
 Rectus femoris (only
quad with origin on
pelvis)
Rectus
 Vastus lateralis femoris
 Vastus intermedius
 Vastus medialis
Antagonized by hamstrings
http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Rectus femoris
(only quad with
origin on the
pelvis)
Quadriceps
Vastus
lateralis,
intermedius,
and
medialis
Note “o” and
“i”
Insert: tibial tuberosity
via patellar ligament
_________
http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Leg (lower leg)
 3 compartments
 Anterior
 Posterior
 Lateral
 Movements at joints:
 Ankle
 Dorsiflex
 Plantarflex
 Intertarsal
 Inversion of foot
 Eversion of foot
 Toes
 Flex (point)
 Extend
Posterior compartment
of leg
 Superficial: these
plantarflex foot
 Gastrocnemius
 Soleus
 Plantaris
Posterior leg
Plantaris
Soleus
Gastrocnemius
http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Posterior leg continued
 Deep
 Popliteus
 Flexor digitorum longus
 Flexor hallucis longus
 Tibilialis posterior
Deep posterior leg
Popliteus
Flexor digitorum longus
Flexor hallucis
longus
Tibialis
posterior
http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Anterior leg extensors
Mainly extend toes and
dorsiflex foot
 Tibialis anterior
 Extensor digitorum
longus
 Extensor hallucis
longus
More pics
Extensor
hallucis
longus
Tibialis anterior
Extensor digitorum longus
http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas
Lateral compartment
of leg
 Fibularis (peroneus)
longus:
 to first metatarsal
and cuneiform
 Fibularis (peroneus)
brevis:
 to fifth metatarsal
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Sole – third (deepest) layer
Addendum: some rotator cuff tests
(FYI)
FIGURE 2. Apley scratch test. The patient attempts
to touch the opposite scapula to test range of
motion of the shoulder. (Left) Testing abduction and
external rotation. (Right) Testing adduction and
FIGURE 3. Supraspinatus examination
("empty can" test). The patient attempts to
elevate the arms against resistance while the
elbows are extended, the arms are abducted
and the thumbs are pointing downward.
internal rotation.
http://www.aafp.org/afp/20000515/3079.html
FIGURE 4. Infraspinatus/teres minor
examination. The patient attempts to
externally rotate the arms against resistance
while the arms are at the sides and the
elbows are flexed to 90 degrees.
FIGURE 5. Neer's test for impingement of the
rotator cuff tendons under the coracoacromial
arch. The arm is fully pronated and placed in
forced flexion.
FIGURE 6. Hawkins' test for
subacromial impingement or rotator
cuff tendonitis. The arm is forward
elevated to 90 degrees, then forcibly
internally rotated.