This document provides information about various muscles and muscle-related topics. It includes diagrams labeling different muscles and their locations. Key muscles that are identified include the trapezius, hamstring group, gastrocnemius, and latissimus dorsi. The document also outlines muscle anatomy from the individual muscle fibers up to the full muscle. Additionally, it discusses muscle movement including the roles of flexor and extensor muscles. Common muscle disorders such as strains, ruptures, spasms, cramps, tetanus, and polio are also summarized.

1. Location
of Muscles
 Skeletal
Muscles
 Posterior
view
Hamstring
group
Trapezius
Hamstring
group
Gastrocnemius
Latissimus dorsi
Gluteus
maximus
Triceps brachii

2. F
A
D
C
B
E
L
K
J
H
G
P
O
N
M
I
Muscles You Need to Know
 1. brachioradialis
 2. biceps brachii
 3. deltoid
 4. external oblique
 5. frontalis
 6. gastrocnemius
 7. gluteus maximus
 8. hamstring group
 9. latissimus dorsi
 10. masseter
 11. pectoralis major
 12. quadriceps group
 13. rectus abdominis
 14. tibialis anterior
 15. trapezius
 16. triceps brachii
9
1
2
3
4
5
6
7
8
10
11
12
13
14
15
16

3. Location of Muscles
 Involuntary
Muscles
 Diaphragm
 Digestive organs
 Arrector pili
 Heart
 Urinary bladder
 Muscles around
blood vessels

4. Muscle Tissue Anatomy
bundle of muscle
fibers – fascicle

5. M
u
s
c
l
e
T
I
s
s
u
e
A
n
a
t
o
m
y
Muscle
Filaments
Myofibrils
Muscle Fibers
Fascicle
 Muscles are made up of bundles
of muscle fibers, called fascicles
 Fascicle is a bundle of muscle
fibers
 A muscle fiber is a muscle
cell….made up of many
small myofibrils
 Myofibrils
contain filaments
 Two types of
protein
filaments

6. Muscle Movement
 ______- Muscle that bends the joint when
contracted.
 ________- Muscle that straightens the joint
when contracted.
 __________ muscle
is short, firm, tight
and thicker around.
 _______ muscle is
stretched, long, loose
and thinner around.
Flexor
Extensor
Relaxed
Contracted

7. Muscle Movement
 When the biceps in the arm contracts the triceps
________ causing ________ of the arm.
 When the triceps in the arm _________ the biceps
relaxes causing ____________ of the arm.
relaxes
 ______ of muscles are
needed because the
only active _________
of a muscle is to
_______, to lengthen it
must be _________ by
the action of an
opposing _______.
bending
contracts
straightening
Pairs
movement
contract
stretched
muscle

8. Muscle + Bone Interaction
 Let’s review the structures involved in
movement at a joint.
 Ligament
 Tendon
 Cartilage
 Body (Belly)
 Origin
 Insertion
 Contracted muscle
 Relaxed muscle
 Flexor
 Extensor
B
C
F F
B
F
B
C
D
E
G
D C
A

9. Muscle Disorders
 A strain is an injury to a muscle or
tendon, and is often caused by
overuse, force, or stretching.
 Injured area
experiences:
 pain and
soreness
 swelling
 warmth, bruising,
or redness
 difficulty using or
moving the
injured area in a
normal manner
Strain

10. Muscle Disorders
 There are three degrees of
muscle ruptures
 A muscle tear may be
partial or complete and
caused either by a direct
blow or by overexertion.
Muscle Bruise

11. Muscle Disorders
 Muscle spasm- when A muscle (or even a few
fibers of a muscle) involuntarily contract
 Muscle cramp- involuntarily + forcibly
contracted muscle that does not relax
CrampsSpasms

12. Muscle Disorders
 Tetanus is a preventable disease through vaccination
 Caused by bacteria that enters the body
through the skin
 Found in soil, dust and manure
 Toxin bacteria produces interferes with nerve
transmission to your muscles and causes
them to seize up in painful spasms.
 Tetanus typically starts in the jaw and muscles
of the face, quickly spreading to the arms and legs.
 “Lockjaw”
 Difficulty swallowing
 Intestines often seize up
 Bladder fails to empty
 Cardiac arrest
Tetanus

13. Muscle Disorders
 Poliomyelitis, often called polio is an acute
viral infectious disease which is spread from
person-to-person via the fecal-oral route.
 The majority of polio infections are asymptomatic.
 In about 1% of cases the virus enters the (CNS) via the
blood stream.
 Within the CNS, poliovirus infects and
destroys motor
neurons.
Polio
Old Polio
Asymmetric atrophy
& weakness
Atrophic right leg
(arrow) in patient
with paralytic polio 70
years in past
 The destruction of
motor neurons
causes muscle
weakness and
flaccid paralysis
 Vaccination created
by Jonas Salk in
1955 has eliminated
the disease