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Myology
shandong university
Liu Zhiyu
Section 1.
Introduction
smooth m.
cardiac m.
skeleton m.
skeletal musclevoluntary m.。
Ⅰ. Shape and structure of the muscle
1. Classification
long m.
short m .
flat m.
orbicular m.
Shape and structure of the muscle
2. Structure
muscle belly
tendon ：
aponeurosis
Ⅱ. Origin and insertion
1 2、 Origin）、
insertion，
3
agonist
synergist 、
antagonist
fixator
Ⅲ. Name of muscles
Location of the muscle.
Shape of the muscle.
Size of the muscle
Direction of muscle
Ⅳ. Accessory structure
Ⅰ) fascia
1、 superficial
fascia
2、 deep fascia ：
Ⅱ） synovial bursa
Ⅲ）Tendinous sheath
fibrous layer
Synovial layer
synovial sheath of
tendon
Viscerasl layer
Parietal layer
Section2
The muscles of head
and neck
Ⅰ. The muscles of head
一、Muscles of head
Facial muscles : includ
Epicranius (or
occipitofrontalis)
Frontal belly
Occipital belly
Galea aponeurotica
Orbicularis oculi
Buccinator
Orbicularis oris
Nasalis
Frontal belly of
occitofrontalis
orbicularis
oculi
Levator anguli oris
Orbicularis
oris
Levator labii
superioris
Depressor labii
inferioris
Depressor anguli oris
（二） masticatory muscles
masseter ：
Origin－inferior border and
medial surface of
zygomatic arch
Insertion－lateral surface of
ramus of mandible and
angle of mandible
temporalis ：
Origin－temporal fossa
Insertion－coronoid
process of mandible
action： masseter, temporalis
--- elevates mandible—
close the mouth
（二） masticatory muscles
medial pterygoid ：
 lateral pterygoid ：
action：
medial pterygoid
--- elevates mandible—close
the mouth
lateral pterygoid ：pull
the head of mandible
forwards--- open the mouth
Ⅱ. Muscles of neck
Platysma
 Sternocleidomastoid
Origins: manubrium and
medial1/3 of clavicle
Insertion: mastoid
process of temporal bone;
Actions: acting alone,
the head is inclined
ipsilateral and the face is
rotated to opposite side;
acting together, they
extend the head.
1、suprahyoid
digastric
muscles
Anterior belly
Posterior belly
Mylohyoid
Stylohyoid
Geniohyoid
Action:
elevate (raise) hyoid bone and
depress mandible.
2、infrahyoid muscles
sternohyoid
omohyoid
sternothyroid
Thyrohyoid
Action: depress hyoid or
larynx
1、lateral goup
（三）The
scalenus anterior
scalenus medius
scalenus posterior
scalene fissure ：
it is bounded by the scalenus
anterior and medius and first rib ，
it contains the subclavian a and
brachial plexus.
2、medial group：
longus colli
longus capitis
deep cervical m.
section 3
The muscles of trunk
Ⅰ. The muscles of back
1、superficial group
（ 1）Trapezius
trapezius
a large, triangular m. lying on
the back of the neck and thorax;
Origin: external occipital
protuberance, superior nuchal
line, ligamentum nuchae, the
spinous processes of 7th
cervical vertebrae and all
thoracic vertebrae;
Insertion: lateral 1/3 of clavicle,
acromion and spine of scapula.
1、superficial group
（ 1）Trapezius
trapezius
Action：
raises, descends, and rotates
the scapula and extends the
head.
1、superficial group
（2）Latissimus Dorsi
It is a largest and triangular m. lying
the back and lateral wall of thorax;
Origins: the spinous processes of
lower 6 thoracic vertebrae and all
lumbar vertebrae;
Insertion: inserted into the floor of
the intertubercular sulcus
Action:
Extend, adduct， and rotate
the shoulder joint medially
Latissimus
dorsi
1、superficial group
（3）levator scapulae
origin：the transverse
processes of the upper 4
cervical vertebrae;
insertion：superior angle
of scapula.
Action：raise the scapula.
（4）rhomboideus
Lies deep to the trapezius，
Levator scapulae
Rhomboideus
2、The deep group
Erector Spinae
position：
It lies in the vertebral groove on
each side of vertebral spines;
Action：extend the spinal
column and head
Splenius
position：
Action：
Ⅱ. The muscles of thorax
1.
Extrinsic muscles

Pectoralis major

Pectoralis minor

Serratus anterior
Pectoralis major



Origin: medial half of
clavicle,sternum,1th-6th
costal cartilages.
Insertion: crest of
greater tubercle of
humerus.
Action: flexes, adducts
and rotates arm medially;
arm fixed, elevates trunk;
elevates ribs 1-6,aidding
in forced inspiration.
Pectoralis minor
Deep to the pectoralis major



Origin: 3rd-5th ribs
Insertion: coracoid
process of scapula
Action:
Draw the scapula
forwards and
downwards,when the
scapula is fixed it helps
the inspiration(by
elevation the ribs)
Serratus
anterior
It overlies the laeral wall of
thorax
Origin: external surfaces
of the upper 8~9 ribs
Insertion: medial border of
scapula
Action: holds the scapula
against the chest wall；
Pulls the scapula forwards
in throwing and pushing.
2. Intrinsic muscles
Intercostales externi
Origin: lower border of
rib
Insertion: upper border
of rib below origin
external intercostals
membrane .
Action: elevate ribs
adding in forced
inspiration
Intercostales interni

Origin: upper border of rib；

Insertion: lower border of
rib above origin
Replaced posteriorly by
internal intercostals
membrane.

Action: depress ribs for
forced expiration
Ⅲ. Diaphragm
(1) Position and division:
dome-shaped between thorax
and abdomen, consists of
Central tendon
muscular part
Sternal part:
Costal part:
Lumbar part: arises by
left and right crus from upper
2-3 lumbar vertebrae
Insertion: central tendon

(2) Openings of
diaphragm
① Aortic hiatus
inferior vena cava
at the level of 12th thoracic
vertebra, the thoracic aorta
and thoracic duct pass
through it
T8
② Esophageal hiatus
at the level of 10th thoracic
vertebra, the esophagus and vagus
n. pass throught it
③ Vena caval foramen
at the level of 8th thoracic vertebra,
inferior vena cava through it
esophagus
T10
thoracic aorta
T12
(3) Action
Contraction:
the dome moving downward,
increases the volume of thoracic cavity which
results in inspiration.
Relaxation:
the dome returns to the former
position, reduces the volume of the thoracic
cavity, resulting in expiration.
(2) Weak areas: triangular spaces
without muscular tissue

Lumbocostal triangle
between costal and lumbar parts.

Sternocostal triangle
between costal and sternal parts.
Muscles of abdomen
Anterolateral group

Obliquus externus
abdominis

Obliquus internus
abdominis
Transversus
abdominis

Rectus abdominis
Obliquus externus abdominis
Origin:
Arises from the lower 8 ribs,
and the muscular fibers run
obliquely from the superolateal
to the inferomedial, the
anterior part of the m. change
gradually into aponeurosis,
which pass over the rectus
Abdominis;
insertion: Linea alba
.
Obliquus externus absominis
Structures formed by
aponeurosis of this m.
include：
Inguinal ligament

Superficial inguinal ring
triangular-shaped hiatus above
pubic tubercle


Lacunar ligament
Lacunar ligament
Superficial inguinal ring
Obliquus internus abdominis


Origin: thoracolumbar
fascia , iliac crest and the
lateral half of the ingunal
lig.
Insertion: Linea alba
The
muscular fibers run
upwards and forwards, and
become the aponeurosis close
the lateral border of the rectus
abdominis. Its aponeurosis
divided into two layers to
inclose the rectus abdominis.
Transversels abdominis
is the deepest one of the three flat abdominal m.
Origin: it arises from the
costal cartilages of the lower 6
ribs，the thoracolumbar
fascia , the iliac crest and the
lateral 1/3 of the ingunal lig. ,


Insertion: Linea alba
The muscular fibers run
transversly ,and pass deep to
rectus abdominis.

Transversels abdominis


Inguinal falx(conjoined
tendon) or is a common
aponeurosis joined by
obliquus internus
abdominis and
transverse abdomini, it
turns downwards to insert
the pubic crest and pecten
pubis.
Cremaster : around the
spermatic cord and testis
The Sheath of rectus abdominis
Anterior layer－ formed by the
aponeurosis of obliquus
externus abdominis ；
anterior leaf of aponeurosis
of obliquus internus abdominis
Posterior layer：formed by
posterion leaf of aponeurosis
of obliquus internus abdominis ；
aponeurosis of transverses
abdominis
The Sheath of rectus abdominis



arcuate line
semicircular line
at about 4-5cm below
the umbilicus, the lower
free border of the posterior
layer of the sheth present
arcuated.
Below this line the
rectus abdominis in
contact with transverse
fascia directly.
Linea alba
－tendinous raphe between right and left rectus abdominis
from xiphoid process to pubic symphysis.
The functions of the four pairs of muscles



Support and protect the abdominal
viscera
Maintain and increase intraabdominal pressure, aid in vomiting,
coughing, sneezing, defecation,
urination and childbirth.
Flex, lateral flex, and rotate vertebral
column
Posterior group

Quadratus lumborum
Psoas major
Inguinal canal
Position: oblique passage about 4cm long, and passes
downwards and medially, it lies parallel to, and
immediately above medial half of inguinal lig. It has
two openings and four walls.
Four walls
Anterior wall

Aponeurosis of
obliquus externus
abdominis

Obliquus internus
abdominis (lateral third
of wall)

Post wall —
Transverse fascia ；
Inguinal flax medially

Roof－ lower fibers of
obliquus internus and
transversus abdominis

Floor－inguinal ligament．

Two openings

Superficial inguinal
ring
Deep inguinal ring
defect in transverse
fascia，lies at about
1.5cm above midpoint
of inguinal ligament


Structures passing through the inguinal canal


Male: Spermatic cord
female: Round ligament of uterus