Study Guide
The Muscular System Study Guide
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University:
Kentucky State University -
Course:
BIO 301 | Human Anatomy Academic year:
2021
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Views:
387
Pages:
15
Author:
flugeldarmn7
Muscles of Scalp
Occipito-frontalis Muscle
• Scalp has only ONE muscle which is the
occipito-frontalis muscle.
•This muscle consists of:
1. Two frontal bellies anteriorly.
2. Two occipital bellies posteriorly.
3. The Epicranial aponeurosis connecting the
frontal and occipital bellies.
Frontal bellies attach to eyebrows
Occipital bellies attach to occipital
bone
Aponeurosis sheet like tendon
that attach between frontal and
occipital bellies • Epicranial Aponeurosis: A sheet of strong fibrous tissue on the skull
cap. Receives the insertion of the frontal and occipital bellies.
Origin and insertion:
▪ Frontal bellies → attached to the skin of the eyebrows and are
inserted in epicranial aponeurosis.
▪ Occipital bellies → arises from occipital bone and are inserted in
epicranial aponeurosis.
• Action of muscle: Pull the scalp backwards and raise the eyebrows
thus causing the transverse wrinkles of forehead (giving expression of
fear or surprise).
• Nerve supply: Facial nerve. Muscles of Face
Muscles of Face (Muscles of Facial Expressions)
• General characteristics :
Layer under the skin
1. They are in the superficial fascia.
2. With origins from either bone or fascia.
3. And insertions into the skin.
4. All are supplied by the Facial Nerve.
• They serve 2 main functions:
1. They act as sphincters or dilators to the orifices in face (i.e. the
orbits, nose, and mouth).
2. They control expressions of the face. Orbicularis Oculi (orbital group)
• Completely surrounds each orbital opening and extends into each
eyelid.
• It has two major parts:
A. The outer orbital part: closes the eye more forcefully (for protection
from dust & light).
B. The inner palpebral part: (palpebral =eyelid () ﺟﻔنcloses the eye
gently (during sleeping &blinking)
Orbicularis Oris (oral group)
• Circular muscle completely surround the mouth. (forming ellipse
around the mouth)
• Action: narrows the mouth and closes the lips. (Help in whistling and
speech) Buccinator
• It is the muscle of the cheeks.
• It is in the space between the mandible and the
maxilla, and inserted into the lips.
• Action:
1. Prevents the accumulation of the food in the
vestibule of the mouth (by pressing cheeks against teeth).
2. Whistling (trumpet) and blowing of air. 3. Suckling (in babies).
3. Suckling (in babies).
3- Upper group of oral muscles
4- Lower group of oral muscles Muscles of Mastication
•They are 4 muscles:
1- Temporalis
2- Masseter
3- Medial pterygoid 4- Lateral pterygoid
• They are all supplied by the mandibular nerve.
• All act on temporo-mandibular joint (TMJ).
vertical and
oblique (fiber) Muscles of Neck
Sternocleidomastoid Muscle
• Origin:
- Sternal head: manubrium sterni
- Clavicular head: medial 1/3 of the
clavicle
• Insertion: mastoid process of the temporal bone.
• Nerve supply: spinal part of the accessory nerve
Action: Two muscle acting together extend the head. One muscle
rotates head to opposite side • Sternocleidomastoid divides the side of the neck into 2 triangles:
1. Anteriortriangle:
in front of the muscle
2. Posterior triangle
behind the muscle
Suprahyoid and Infrahyoid Muscles
Suprahyoid muscles. ﻓوق ھﯾوﯾد
Hyoid bone doesn’t attach to
• 4 muscles superior to the hyoid
any bone
• They pass in a superior direction from the
hyoid
bone to the skull or mandible
• Action: Raise the hyoid bone, as occurs during swallowing.
Infrahyoid muscles .ﺗﺣت ھﯾوﯾد
• 4 muscles inferior to the hyoid
• They attach the hyoid bone to inferior structures
• Action: depress the hyoid bone Muscles of Trunk
Intercostal Muscles
• The intercostal muscles are three flat muscles found in each
intercostal space that pass between adjacent ribs
• Three layers of flat muscles from Outside
Intercostal Muscles
inwards are:
1- External intercostal
2- Internal intercostal
3- Innermost Intercostal
External Intercostal Muscle
• Direction of fibers: run obliquely
downwards & forwards.
• Origin: lower border of rib above.
• Insertion: upper border of rib below.
• Action: elevate the ribs (active during
inspiration) Internal Intercostal Muscle
• Direction of fibers: run obliquely downwards & & backward.
• Origin: costal groove of rib above.
• Insertion: upper border of rib below.
• Action: depress the ribs (Active during
expiration)
Innermost Intercostal Muscle
• Direction of fibers: run obliquely downwards & backward.
• Origin: costal groove of rib above.
• Insertion: upper border of rib below.
• Action: depress the ribs (Active during
expiration) Diaphragm
• The diaphragm is a musculotendinous structure separates the
thoracic cavity from the abdominal cavity.
• Dome-shaped
Thin +large
• Has convex upper surface (thoracic cavity
(ﺑﺎﺗﺟﺎهand concave lower surface (abdominal
cavity )ﺑﺎﺗﺟﺎه
• Origin:
1. Sternal origin: from back of
xiphoid process.
2. Costal origin: from the inner surfaces of
the lower 6 costal cartilages.
3. Vertebral origin: from upper 3 lumbar vertebrae.
• Insertion: Central tendon
• Action:
▪ Diaphragm is the main muscle
of inspiration.
▪ When contracts, it descends to increase the
vertical diameter of the thoracic cavity.
Right side higher than left side The diaphragm has three main openings:
1. The caval opening:
▪ Lies at the level of the T8 vertebra
▪ For Inferior vena cava
2. The esophageal opening:
▪ Lies at the level of the T10 vertebra
▪ For esophagus
3. The aortic opening:
▪ Lies anterior to the body of the T12
vertebra
▪ For aorta
Muscles of Anterior Abdominal Wall
• Three flat muscles whose fibers begin posterolaterally, pass
anteriorly, and are replaced by an aponeurosis as the muscle continues
towards the midline:
1 - External Oblique
2 - Internal Oblique
3 - Obdominis3 - Transversus Obdominis
• The Rectus Abdominis is a vertical muscle, near the midline, which is
enclosed within a tendinous sheath (Rectus heath) formed by the
aponeuroses of the flat muscles.
External
&oblique
Enternal
&oblique
Transverseus aponeurosis
Muscles of Posterior Abdominal Wall
Straight= rectus
Rectus abdominal near to midline
Six pack =segment in rectus
Muscles of Posterior Abdominal Wall
• They are 4 muscles:
1. Psoas major.
2. Psoas minor (may be absent).
3. Quadratus lumborum.
4. Iliacus.
❤
Aponeurosis
Rectus
Rectus sheath
muscle fibers
Midline
mid اوmedian insegen
connective
line insegen
linia alba
tissue Psoas Major
• Origin:from lumber vertebrae
• Insertion:into lesser trochanter of
femur.
• Action:
1- The main flexor of thigh (hip joint). 2- It can flex the trunk on the
thigh.
Quadratus Lumborum
• Origin: from iliac crest of hip bone.
• Insertion:into last rib
• Action:
1- Lateral flexion of the trunk. 2- Extension
of trunk.
Iliacus
• Origin:from the hip bone
• Insertion:lesser trochanter of femur
• Action:
Helps in flexion of thigh (hip joint).
The Muscular System Study Guide
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