Chapter 11 Muscular system

Origin

The attachment of the muscle's other tendon to the movable bone

Insertion

The attachment of the muscle's other tendon to the movable bone is called \_____________

Belly

The fleshy portion of the muscle between the tendons

Actions

A muscle are the main movements that occur when the muscle contracts

Reverse Muscle Action (RMA)

This means that during specific movements of the boy the actions are reversed, the positions of the origin and insertion of specific muscle are switched

Lever

A rigid structure that can move around a fixed point

Fulcrum

Symbolized by a pyramid, acted on at two different points by two different forces

Effort

Causes movement

Load/Resistance

Opposes movement

Mechanical Advantage

The load is closer to the fulcrum and the effort farther from the fulcrum, then only a relatively small effort

Mechanical disadvantage

relatively large effort is required to move a small load (but at a great speed)

Types of levers

1. First-class 2. Second-class 3. Third-class

Fascicles

Muscle are arranged in bundles known as \______________.

Intramuscular Injection

Penetrates the skin and subcutaneous layer to enter the muscle itself

Prime mover/Agonist

Contracts to cause an action

Antagonist

Stretches and yields to the effects of the prime mover

Synergists

Contract and stabilize the intermediate joints

Fixators

Stabilizing the origin of prime mover can act more efficiently

Compartment

A group of skeletal muscles, their associated blood vessels, and associated nerves, all of which have a common function

Stretching

Helps to achieve normal range of motion of joints and mobility of soft tissues surrounding the joints

Ways to increase the range of motion most effectively

1. Improved physical Performance 2, Decreased risk of injury 3. Reduced muscle soreness 4. Improved posture

Exhibits are divided into groups:

1. Objective 2. Overview 3. Muscle Names 4. Origins, insertions, and actions 5. Innervation 6. Relating muscles to movements 7. Questions 8.Clinical connections 9. Figures

Orbicularis Oculi

Muscle closes the eye, and the lavatory palpebrae superiors muscle opens it

Occipitofrontalis

An unusual muscle in this group because it is made up of two parts: an anterior part frontal is and occipitalis

Frontal belly (frontalis)

Superficial to the frontal bone

Occipital belly (occipitals)

Superficial to the occipital bone

Aponeurosis

Sheet-like tendon

Epicranial aponeurosis/galea aponeurotica

Covers the superior and lateral surfaces of the skull

Buccinator

The muscle forms the major muscular portion of the cheek

Bell's Palsy

Facial Paralysis, unilateral paralysis

Extrinsic Eye Muscles

Musles that move the eyeballs, they originate outside outside the eyeballs and insert on the outer surface of the sclera

Superior and Inferior Recti

Move the eyeballs superiorly and inferiorly

Lateral and Medial Recti

Move the eyeballs laterally and medially, respectively

Superior oblique

Muscle originates posteriorly near the tendinous ring, then passes anteriorly superior to the medial rectus muscle, and ends in a round tendon

Inferior Oblique

Muscle originates on the maxilla at the anteromedial aspect of the floor of the orbit

Levator Palpebrae Superioris

Does not move the eyeballs, since its tendon passes the eyeball and inserts into the upper eyelid.

Strabismus

A condition in which the two eyeballs are not properly aligned

Muscles of Mastication (chewing)

The muslces that move the mandible at the temporomandibular joint are known as \_______________ \___ \_________________

Masseter, Temporalis, Medial Pterygoid

Four pairs of muscles involved in mastication

Lateral Pterygoid

Muscles assist in mastication by moving the mandible from side to side to help grind food

Gravity on the Mandible

This offsets the the imbalance. When the masseter, temporal is, and medial pterygoid muscles relax, the mandible drops

Extrinsic Tongue Muscles

Muscles that originate outside the tongue and insert into it

Intrinsic Tongue Muscles

Muscles that originate and insert within the tongue

Genioglossus

Pulls the tongue downward and forward

Palatoglossus

Raises the back portion of the tongue

Endotracheal Intubation

Inserting from the lips through the laryngopharynx into the trachea

Groups of muscles that are associated with the anterior aspect of the neck:

1. Suprahyoid muscles 2. Infrahyoid muscles

Diagastric

Muscle that has two bellies, anterior and posterior, united by an intermediate tendon held in position by a fibrous loop

Stylohyoid

Muscle elevates and draws the hyoid bone posteriorly, thus elongating the floor of the oral cavity during swallowing

Mylohyoid

Muscle elevates the hyoid bone and helps press the tongue against the roof of the oral cavity during swallowing

Geniohyoid

Elevates and draws the hyoid bone anteriorly to shorten the floor of the oral cavity and to widen the throat to receive food that is being swallowed

Omohyoid

The digastric muscle, is composed of two bellies connected by an intermediate tendon

Sternohyoid and thryohyoid

Muscles that depress the hyoid bone

Sternothyroid

Muscle depresses the thyroid cartilage of the larynx to produce low sounds

Dysphagia

A clinical term for difficulty in swallowing

Sternocleidmastoid (SCM)

Muscle flexes the cervical portion of the verbal column and flexes the head

Sternal and Clavicular Head

The two bellies insert as this of the SCM

Spenalis Capitis, semispinalis capitis, splenius capitis, and longissimus capitis

Bilateral contraction of these extend the head

Anterior Triangle

Bordered superiorly by the mandible bedially by the cervical midline, and laterally by the anterior border of the sternocleidomastoid muscle

Posterior Triangle

Bordered inferiorly by the clavicle anteriorly by the posterior border of the sternocleidomastoid

External oblique

The superficial muscle, fascicles extend inferiorly and medially

Internal Oblique

The intermediate flat muscle

Transversus Abdominis

The deep muscle with most of its fascicles directed transversely around the abdominal with most of its fascicles directed transversely around the abdominal wall

Rectus Abdominis

Muscle is a long muscle that extends then entire length of the anterior abdominal wall, originating at the pubic crest and pubic symphsis and interning on the cartilages of ribs

Tendious Intersections

Believed to be remnants of septa that separated my tomes during embryological development

Rectus Sheaths

Enclose the rectus abdmominis muscles

Lina Alba

Sheaths meet at the midline to form this

Inguinal Ligament

Ligament that runs from the anterior superior iliac spine to the pubic tubercle

Superficial Inguinal Ring

The outer opening of the inguinal canal

Inguinal canal

Which runs from the anterior superior iliac spine to the pubic tubercle

Superficial Inguinal Ring

The outer opening of the inguinal canal

Inguinal Canal

Contains the spermatic cord and ilioinguinal nerve in males and the round ligament of the uterus and ilioinguinal nerve in females

Hernia

A protrusion of an organ through a structure that normally contains it, which creates a lump that can be seen or felt through the skin's surface

Inguinal Hernia

A rupture or separation of a portion of the inguinal area of the abdominal wall resulting in the protrusion of a part of the small intestine

Diaphragm

The most important muscle that powers breathing, dome-shaped

Peripheral Muscular Portion

part of the diaphragm originating on the xiphoid process of the sternum, the inferior six ribs and their costal cartilages, and the lumbar vertebrae and their intervertebral discs and the twelfth rib

Central Tendon

A strong aponeurosis located near the center of the muscle

Aortic Hiatus

Where the aorta, thoracic duct, azygous vein

Esophageal Hiatus

And the inferior vena cava, which passes through the caval opening

Intercostals

Spaces between the ribs

External Intercostals

Occupy the superficial layer and their fibers run in a n oblique direction interiorly and anteriorly from the rib above to the rib below

Internal Intercostals

This occupies the intermediate layer of the intercostal spaces

Pelvic Diaphragm

Spans from the pubis anteriorly to the coccyx posteriorly from one lateral wall of the pelvis to the other

Levator ani muscle is made up of:

Pubococcygeus, puborectalis, and iliococcygeus

Ischiococcygeus

Pulls the coccyx anteriorly after it has been pushed posterouly during defecation or childbirth

Urinary stress incontinence

Leakage of urine whenever intra-abdominal pressure is increased

Perineum

The region of the trunk inferior to the pelvic diaphragm

Urogenital Triangle

Contains external genitals

Anal Triangle

Contains the anus

Layers of the perineum

Superficial and deep

The muscles of the superficial layer of the perineum:

1. Superficial Transverse Perineal 2. Bulbospongiosus 3. Ischiocavernosus

Deep transverse perineal and External urethral sphincter

Deep muscles of male perineum

Compressor Urethrae, Sphincter urethrovaginalis

Deep muscles of the female perineum

External anal sphincter

adheres to the skin around the margin of the anus and keeps the anal canal and anus closed except during defecation

Anterior and Posterior thoracic Muscles

Subclavius, pectorals minor, and serratus anterior

Subclavius

Small, cylindrical muscle under the clavicle that extends from the clavicle to the first rib

Pectoralis Minor

A thin, flat, triangular muscle that is deep to the pectorals major

Serratus Anterior

A large, flat, fan-shaped muscle between the ribs and scapula

Trapezius

A large, flat, triangular sheet of muscle extending from the skull and vertebral column medially to the pectoral girdle laterally

Levator Scapulae

A narrow, elongated muscle in the posterior portion of the neck