MUSCULAR SYSTEM PT. 1 Flashcards
contribute to homeostasis by stabilizing body position, producing movements, regulating organ volume, moving substances within the body, and producing heat.
muscular system and muscular tissue
Almost all of the 700 individual muscles that make up the muscular system, such as the biceps brachii muscle, include both
skeletal muscle tissue and connective tissue
the voluntarily controlled muscles of your body com pose the
muscular system
When a skeletal muscle contracts, it moves one of the
articulating bones
usually do not move equally in response to contraction
two articulating bones
The attachment of a muscle’s tendon to the station ary bone is called the
origin
the attachment of the muscle’s other tendon to the movable bone is called th
insertion
A useful rule of thumb is that the origin is usually ___ and the insertion ___; the insertion is usually pulled toward the origin.
proximal; distal
The fleshy portion of the muscle between the tendons is called the ___
belly (body)
the main move ments that occur when the muscle contracts
actions
This means that during specific movements of the body the actions are reversed; therefore, the positions of the origin and insertion of a specific muscle are switched.
reverse muscle action (RMA)
In the limbs, the ___ of a muscle is usually proximal and the ___ is usually distal.
origin; insertion
In producing movement, bones act as ___, and joints func tion as the ___ of these levers
levers; fulcrums
is a rigid structure that can move around a fixed point called a fulcrum
lever
A lever is acted on at two different points by two different forces:
effort and load
causes movement
effort
opposes movement
load or resistance
The ___ is the force exerted by muscular contraction; the ___ is typi cally the weight of the body part that is moved or some resis tance that the moving body part is trying to overcome (such as the weight of a book you might be picking up).
effort; load
occurs when the effort applied to the bone at the insertion exceeds the load
Motion
When the forearm is raised, the elbow is the ___. The weight of the forearm plus the weight of the object in the hand is the ___. The force of contraction of the biceps brachii pulling the forearm up is the ___.
fulcrum; load; effort
if the load is closer to the fulcrum and the effort farther from the fulcrum, then only a relatively small effort is required to move a large load over a small distance. This is called a
mechanical advan tage
If, instead, the load is farther from the fulcrum and the effort is applied closer to the fulcrum, then a relatively large effort is required to move a small load (but at greater speed). This is called a
mechanical disadvantage
Levers are categorized into three types according to the positions of the fulcrum, the effort, and the load:
first-class levers, second-class levers, and third-class levers
The fulcrum is between the effort and the load (EFL)
first-class levers
examples of first- class levers
Scissors and seesaws
the lever formed by the head resting on the vertebral column. When the head is raised, the contraction of the posterior neck muscles provides the effort (E), the joint between the atlas and the occipital bone (atlanto- occipital joint) forms the fulcrum F , and the weight of the anterior portion of the skull is the load L
first-class levers
The load is between the fulcrum and the effort (ELF)
second-class levers
operate like a wheelbarrow
second-class levers
always produce a mechanical advantage because the load is always closer to the fulcrum than the effort. This arrangement sacrifices speed and range of motion for force; this type of lever produces the most force.
second-class levers
This class of lever is uncommon in the human body
second-class levers
An example is standing up on your toes. The fulcrum F is the ball of the foot. The load L is the weight of the body. The effort (E) is the contraction of the muscles of the calf, which raise the heel off the ground.
second-class levers
The effort is between the fulcrum and the load (FEL)
third-class levers
operate like a pair of forceps and are the most common levers in the body
third-class levers
always produce a mechanical disadvantage because the effort is always closer to the fulcrum than the load.
third-class levers
In the body, this arrangement favors speed and range of motion over force.
third-class levers
example of a third- class lever
elbow joint, the biceps brachii muscle, and the bones of the arm and forearm
Levers are divided into three types based on the placement of the
fulcrum, effort, and load (resistance).
skeletal muscle fibers (cells) within a muscle are arranged in bundles known a
muscle fas cicles
Within a muscle fascicle, all muscle fibers are ___ to one another
parallel
The muscle fascicles, however, may form one of five patterns with respect to the tendons:
parallel, fusiform (spindle- shaped, narrow toward the ends and wide in the middle), circular, triangular, or pennate (shaped like a feather)
affects a muscle’s power and range of motion
Muscle fascicular arrangement
As a muscle fiber contracts, it shortens to about __% of its resting length
70
The longer the fibers in a muscle, the greater the ____ it can produce.
range of motion
How ever, the ____ depends not on length but on its total cross- sectional area, because a short fiber can contract as forcefully as a long one. So the more fibers per unit of cross- sectional area a muscle has, the more power it can produce.
power of a muscle
often represents a compromise between power and range of motion
Muscle fascicular arrangement
have a large number of short- fibered muscle fascicles distributed over their tendons, giving them greater power but a smaller range of motion
Pennate muscles
have comparatively fewer muscle fascicles, but they have long fibers that extend the length of the muscle, giving them a greater range of motion but less power.
parallel muscles
Muscle fascicles parallel to longitudinal axis of muscle; terminate at either end in flat tendons.
Parallel
Example of parallel
Sternohyoid muscle
Muscle fascicles nearly parallel to longitudinal axis of muscle; terminate in flat tendons; muscle tapers toward tendons, where diameter is less than at belly.
Fusiform
Example of fusiform
Digastric muscle
Muscle fascicles in concentric circular arrangements form sphincter muscles that enclose an orifice (opening).
Circular
Example of circular
Orbicularis oculi muscle
Muscle fascicles spread over broad area converge at thick central tendon; gives muscle a triangular appearance.
Triangular
Example of triangular
Pectoralis major muscle
Short muscle fascicles in relation to total muscle length; tendon extends nearly entire length of muscle.
Pennate
Muscle fascicles arranged on only one side of tendon.
Unipennate
Example of unipennate
Extensor digitorum longus muscle
Muscle fascicles arranged on both sides of centrally positioned tendons.
Bipennate
Example of bipennate
Rectus femoris muscle
Muscle fascicles attach obliquely from many directions to several tendons.
Multipennate
Example of multipennate
deltoid muscle
penetrates the skin and sub cutaneous layer to enter the muscle itself.
intramuscular (IM) injection
are preferred when prompt absorption is desired, when larger doses than can be given subcutaneously are indicated, or when the drug is too irritating to give subcutaneously.
intramuscular (IM) injection
The common sites for intramuscular injections include the
gluteus medius muscle of the buttock, lateral side of the thigh in the midportion of the vastus lateralis muscle, and the deltoid muscle of the shoulder
are given deep within the muscle, away from major nerves and blood vessels to avoid injury
intramuscular (IM) injection
have a faster speed of delivery than oral medications but are slower than intravenous infusions
intramuscular (IM) injection
Within oppos ing pairs, one muscle, called the ___ or agonist, contracts to cause an action while the other muscle, the ___, stretches and yields to the effects of the prime mover.
prime mover; antagonist
In the process of flexing the forearm at the elbow, for instance, the biceps brachii is the +++, and the triceps brachii is the ___
prime mover; antagonist
For example, while extending the forearm at the elbow against resistance , the triceps brachii becomes the ___, and the biceps brachii is the ___.
prime mover; antagonist
If a prime mover and its antagonist contract at the same time with equal force, there will be
no movement
To prevent unwanted movements at intermediate joints or to otherwise aid the movement of the prime mover, muscles called ___ contract and stabilize the intermediate joints.
synergists
As an example, muscles that flex the fingers (___) cross the intercarpal and radiocarpal joints (___). If movement at these intermediate joints were unrestrained, you would not be able to flex your fin gers without flexing the wrist at the same time.
prime movers; intermediate joints
stabilizes the wrist joint and prevents unwanted movement, while the flexor muscles of the fingers contract to bring about the primary action, efficient flexion of the fingers.
Synergistic con traction of the wrist extensor muscles
are usually located close to the prime mover.
Synergists
Some muscles in a group also act as ___, stabilizing the origin of the prime mover so that the prime mover can act more efficiently.
fixators
steady the proximal end of a limb while movements occur at the distal end
fixators
For example, the scapula is a freely movable bone that serves as the origin for several muscles that move the arm. When the arm muscles contract, the scapula must be held steady. In abduction of the arm, the deltoid muscle serves as the __, and fixa tors (pectoralis minor, trapezius, subcla vius, serratus anterior muscles, and others) hold the scapula firmly against the back of the chest. The insertion of the deltoid muscle pulls on the humerus to abduct the arm.
prime mover
is a group of skeletal mus cles, their associated blood vessels, and associated nerves, all of which have a common function.
compartment
Most movements require several skeletal muscles acting in ___ rather than individually.
groups
The overall goal of ____ is to achieve normal range of motion of joints and mobility of soft tissues surrounding the joints.
stretching
For most individuals, the best stretching routine involves ___, that is, slow sustained stretching that holds a muscle in a lengthened position. The muscles should be stretched to the point of slight discomfort (not pain) and held for about 30 seconds.
static stretching
should be done after warming up to increase the range of motion most effectively.
stretching
A flexible joint has the ability to move through a greater range of motion, which improves performance.
Improved physical performance
Stretching decreases resistance in various soft tissues so there is less likelihood of exceed ing maximum tissue extensibility during an activity (i.e., injuring the soft tissues).
Decreased risk of injury
Stretching can reduce some of the muscle soreness that results after exercise.
Reduced muscle soreness
Poor posture results from improper position of various parts of the body and the effects of gravity over a number of years. Stretching can help realign soft tissues to improve and maintain good posture.
Improved posture
What are the 4 benefits of stretching?
Improved physical performance, Decreased risk of injury, Reduced muscle soreness, and Improved posture
You can learn the names of muscles by remembering the terms that refer to muscle features, such as
pattern of the muscle’s fascicles; the size, shape, action, number of origins, and location of the muscle; and the sites of origin and insertion of the muscle
Orientation of muscle fascicles relative to the body’s midline
Direction
Parallel to midline
Rectus
Example of rectus
Rectus abdominis
Perpendicular to midline
Transverse
Example of transverse
Transversus abdominis
Diagonal to midline
Oblique
Example of oblique
External abdominal oblique
Relative size of the muscle
Size
Largest
Maximus
Example of maximus
Gluteus maximus
Smallest
minimus
Example of minimus
Gluteus minimus
Long
Longus
Example of longus
Adductor longus
Short
Brevis
Example of brevis
Adductor brevis
Widest
Latissimus
Example of latissimus
Latissimus dorsi
Longest
Longissimus
Example of longissimus
Longissimus capitis
Large
magnus
Example of magnus
Adductor magnus
Larger
Major
Example of Major
Pectoralis major
Smaller
Minor
Example of minor
Pectoralis minor
Huge
Vastus
Example of vastus
Vastus lateralis
least to greatest when it comes to large size
magnus > major > maximus
least to greatest when it comes to small size
minor > minimus
least to greatest when it comes to shortness
brevis
least to greatest when it comes to longness
longus > longissimus
least to greatest when it comes to wideness
latissimus
least to greastest when it comes to hugeness
vastus
Relative shape of the muscle
Shape
Triangular
Deltoid
Example of deltoid
Deltoid
Trapezoid
Trapezius
Example of trapezius
Trapezius
Saw- toothed
Serratus
Example of serratus
Serratus anterior
Diamond- shaped
Rhomboid
Example of rhomboid
Rhomboid major
Circular
Orbicularis
Example of orbiculars
orbicularis oculi
Comblike
Pectinate
Example of pectinate
Pectineus
Pear- shaped
Piriformis
Example of piriformis
Piriformis
Flat
Platys
Example of platys
Platysma
Square, four- sided
Quadratus
Example of quadratus
Quadratus femoris
Slender
Gracilis
Example of gracilis
Gracilis
principal action of the muscle
Action
Decreases joint angle
flexor
Example of flexor
Flexor carpi radialis
Increases joint angle
extensor
Example of extensor
Extensor carpi ulnaris
Moves bone away from midline
Abductor
Example of abductor
Abductor pollicis longus
Moves bone closer to midline
Adductor
Example of adductor
Adductor longus
Raises or elevates body part
levator
Example of levator
Levator scapulae
Lowers or depresses body part
Depressor
Example of depressor
Depressor labii inferioris
Turns palm anteriorly
Supinator
Example of supinator
Supinator
Turns palm posteriorly
Pronator
Example of pronator
Pronator teres
Decreases size of an opening
Spinchter
Example of sphincter
External anal sphincter
Makes body part rigid
Tensor
Example of tensor
Tensor fasciae latae
Rotates bone around longitudinal axis
Rotator
Example of rotator
Rotatore
Number of tendons of origin
number of origins
Two origins
Biceps
Example of biceps
Biceps brachii
Three origins
Triceps
Example of triceps
Triceps brachii
Four origins
Quadriceps
Example of quadriceps
Quadriceps femoris
Structure near which a muscle is found
Location
Example of location
Temporalis, muscle near temporal bone.
Sites where muscle originates and inserts
Origin and insertion
Example of origin and insertion
Sternocleidomastoid, originating on sternum and clavicle and inserting on mastoid process of temporal bone.
enable us to express a wide variety of emotions, lie within the subcutaneous layer
muscles of facial expression
Among the noteworthy muscles in this group are those sur rounding the orifices (openings) of the head such as the eyes, nose, and mouth. These muscles function as ___, which close the orifices, and ___, which dilate or open the orifices.
sphincters; dilators
muscle closes the eye, and the levator palpebrae superioris mus cle opens it
orbicularis oculi
The occipitofrontalis is an unusual muscle in this group because it is made up of two parts: an anterior part called the ___, which is superficial to the frontal bone, and a posterior part called the ___, which is superficial to the occipital bone.
frontal belly (frontalis); occipital belly (occipitalis)
The two muscular portions are held together by a strong
aponeurosis
covers the superior and lateral surfaces of the skull
epicranial aponeurosis (galea aponeurotica)
muscle forms the major muscular portion of the cheek. The duct of the parotid gland (a salivary gland) passes through the buccinator muscle to reach the oral cavity.
buccinator
It functions in whistling, blowing, and sucking and assists in chewing.
buccinator
relating muscle to facial expression
(1) those that act on the mouth and (2) those that act on the eyes.
is a unilateral paralysis of the muscles of facial expression. It is due to dam age or disease of the facial (VII) nerve. Possible causes include inflammation of the facial nerve due to an ear infection, ear surgery that damages the facial nerve, or infection by the her pes simplex virus. The paralysis causes the entire side of the face to droop in severe cases. The person cannot wrinkle the forehead, close the eye, or pucker the lips on the affected side. Drooling and difficulty in swallowing also occur. Eighty percent of patients recover completely within a few weeks to a few months. For others, paralysis is permanent. The symptoms of Bell’s palsy mimic those of a stroke.
Bell’s palsy (facial paralysis)
When they contract, muscles of facial expression move the ___ rather than a joint.
skin
What muscle has its origin at the epicranial aponeurosis?
Frontal belly of the Occipitofrontalis
What muscle inserts at the skin superior to the supraorbital margin?
Frontal belly of the Occipitofrontalis
What muscle draws the scalp anteriorly, raises eyebrows, and wrinkles the forehead horizontally as in a look of surprise?
Frontal belly of the Occipitofrontalis
What muscle is innervated by the Facial (VII) nerve?
Frontal belly of the Occipitofrontalis
What muscle has its origin at the occipital bone and mastoid process of the temporal bone?
Occipital belly of the Occipitofrontalis
What muscle inserts at the epicranial aponeurosis?
Occipital belly of the Occipitofrontalis
What muscle draws the scalp posteriorly?
Occipital belly of the Occipitofrontalis
What muscle is innervated by the Facial (VII) nerve?
Occipital belly of the Occipitofrontalis
What muscle has its origin at the muscle fibers surrounding the opening of the mouth?
Orbicularis oris
What muscle inserts at the skin at the corner of the mouth?
Orbicularis oris
What muscle closes and protrudes lips, as in kissing; compresses lips against teeth; and shapes lips during speech?
Orbicularis oris
What muscle is innervated by the Facial (VII) nerve?
Orbicularis oris
What muscle has its origin at the zygomatic bone?
Zygomaticus major
What muscle inserts at the skin at the angle of the mouth and orbicularis oris?
Zygomaticus major
What muscle draws the angle of the mouth superiorly and laterally, as in smiling?
Zygomaticus major
What muscle is innervated by the Facial (VII) nerve?
Zygomaticus major
What muscle has its origin at the zygomatic bone?
Zygomaticus minor
What muscle inserts at the upper lip?
Zygomaticus minor
What muscle raises (elevates) the upper lip, exposing the maxillary (upper) teeth?
Zygomaticus minor
What muscle is innervated by the Facial (VII) nerve?
Zygomaticus minor
What muscle has its origin superior to the infraorbital foramen of the maxilla?
Levator labii superioris
What muscle inserts at the skin at the angle of the mouth and orbicularis oris?
Levator labii superioris
What muscle raises the upper lip?
Levator labii superioris
What muscle is innervated by the Facial (VII) nerve?
Levator labii superioris
What muscle has its origin at the mandible?
Depressor labii inferioris
What muscle inserts at the skin of the lower lip?
Depressor labii inferioris
What muscle depresses (lowers) the lower lip?
Depressor labii inferioris
What muscle is innervated by the Facial (VII) nerve?
Depressor labii inferioris
What muscle has its origin at the mandible?
Depressor anguli oris
What muscle inserts at the angle of the mouth?
Depressor anguli oris
What muscle draws the angle of the mouth laterally and inferiorly, as in opening the mouth?
Depressor anguli oris
What muscle is innervated by the Facial (VII) nerve?
Depressor anguli oris
What muscle has its origin at the alveolar processes of the maxilla and mandible and pterygomandibular raphe?
Buccinator
What muscle inserts at the orbicularis oris?
Buccinator
What muscle presses the cheeks against teeth and lips, as in whistling, blowing, and sucking; draws the corner of the mouth laterally; and assists in mastication?
Buccinator
What muscle is innervated by the Facial (VII) nerve?
Buccinator
What muscle has its origin at the fascia over the parotid (salivary) gland?
Risorius
What muscle inserts at the skin at the angle of the mouth?
Risorius
What muscle draws the angle of the mouth laterally, as in grimacing?
Risorius
What muscle is innervated by the Facial (VII) nerve?
Risorius
What muscle has its origin at the mandible?
Mentalis
What muscle inserts at the skin of the chin?
Mentalis
What muscle elevates and protrudes the lower lip and pulls the skin of the chin up, as in pouting?
Mentalis
What muscle is innervated by the Facial (VII) nerve?
Mentalis
What muscle has its origin at the fascia over the deltoid and pectoralis major muscles?
Platysma
What muscle inserts at the mandible, blends with muscles around the angle of the mouth, and the skin of the lower face?
Platysma
What muscle draws the outer part of the lower lip inferiorly and posteriorly as in pouting and depresses the mandible?
Platysma
What muscle is innervated by the Facial (VII) nerve?
Platysma
What muscle has its origin at the medial wall of the orbit?
Orbicularis oculi
What muscle inserts in a circular path around the orbit?
Orbicularis oculi
What muscle closes the eye?
Orbicularis oculi
What muscle is innervated by the Facial (VII) nerve?
Orbicularis oculi
What muscle has its origin at the medial end of the superciliary arch of the frontal bone?
Corrugator supercilii
What muscle inserts at the skin of the eyebrow?
Corrugator supercilii
What muscle draws the eyebrow inferiorly and wrinkles the skin of the forehead vertically as in frowning?
Corrugator supercilii
What muscle is innervated by the Facial (VII) nerve?
Corrugator supercilii
Muscles that move the eyeballs are called
extraocular (extrin sic eye) muscles
some of the fastest contracting and most precisely controlled skeletal muscles in the body.
extraocular (extrin sic eye) muscles
Three pairs of extraocular muscles control movements of the eyeballs:
(1) superior and inferior recti, (2) lateral and medial recti, and (3) superior and inferior obliques.
move the eyeballs superiorly and inferiorly
superior and inferior recti
move the eyeballs laterally and medially, respectively
lateral and medial recti
muscle originates pos teriorly near the tendinous ring, then passes anteriorly superior to the medial rectus muscle, and ends in a round tendon.
superior oblique
The tendon extends through a pulleylike loop of fibrous cartilage tissue called the __ on the anterior and medial part of the roof of the orbit.
trochlea
muscle originates on the maxilla at the anteromedial aspect of the floor of the orbit. It then passes posteriorly and laterally and inserts on the posterolateral aspect of the eyeball. Because of this arrangement, the inferior oblique muscle moves the eyeballs superiorly and laterally
inferior oblique
does not move the eyeballs, since its tendon passes the eyeball and inserts into the upper eyelid. Rather, it raises the upper eyelids, that is, opens the eyes. It is therefore an antagonist to the orbicularis oculi, which closes the eyes.
levator palpe brae superioris
Arrange the muscles in this section according to their actions on the eyeballs
(1) elevation, (2) depression, (3) abduction, (4) adduction, (5) medial rotation, and (6) lateral rotation.
What muscle has its origin at the common tendinous ring (attached to the orbit around the optic foramen)?
Superior rectus
What muscle inserts at the superior and central part of the eyeballs?
Superior rectus
What muscle moves the eyeballs superiorly (elevation) and medially (adduction) and rotates them medially?
Superior rectus
What muscle is innervated by the Oculomotor (III) nerve?
Superior rectus
What muscle has its origin at the common tendinous ring (attached to the orbit around the optic foramen)?
Inferior rectus
What muscle inserts at the inferior and central part of the eyeballs?
Inferior rectus
What muscle moves the eyeballs inferiorly (depression) and medially (adduction) and rotates them laterally?
Inferior rectus
What muscle is innervated by the Oculomotor (III) nerve?
Inferior rectus
What muscle has its origin at the common tendinous ring (attached to the orbit around the optic foramen)?
Lateral rectus
What muscle inserts at the lateral side of the eyeballs?
Lateral rectus
What muscle moves the eyeballs laterally (abduction)?
Lateral rectus
What muscle is innervated by the Abducens (VI) nerve?
Lateral rectus
What muscle has its origin at the common tendinous ring (attached to the orbit around the optic foramen)?
Medial rectus
What muscle inserts at the medial side of the eyeballs?
Medial rectus
What muscle moves the eyeballs medially (adduction)?
Medial rectus
What muscle is innervated by the Oculomotor (III) nerve?
Medial rectus
What muscle has its origin at the sphenoid bone, superior and medial to the common tendinous ring in the orbit?
Superior oblique
What muscle inserts at the eyeball between the superior and lateral recti via a tendon that passes through the trochlea?
Superior oblique
What muscle moves the eyeballs inferiorly (depression) and laterally (abduction) and rotates them medially?
Superior oblique
What muscle is innervated by the Trochlear (IV) nerve?
Superior oblique
What muscle has its origin at the maxilla in the floor of the orbit?
Inferior oblique
What muscle inserts at the eyeballs between the inferior and lateral recti?
Inferior oblique
What muscle moves the eyeballs superiorly (elevation) and laterally (abduction) and rotates them laterally?
Inferior oblique
What muscle is innervated by the Oculomotor (III) nerve?
Inferior oblique
What muscle has its origin at the roof of the orbit (lesser wing of the sphenoid bone)?
Levator palpebrae superioris
What muscle inserts at the skin and tarsal plate of the upper eyelids?
Levator palpebrae superioris
What muscle elevates the upper eyelids (opens eyes)?
Levator palpebrae superioris
What muscle is innervated by the Oculomotor (III) nerve?
Levator palpebrae superioris
is a condition in which the two eyeballs are not properly aligned. This can be hered itary or it can be due to birth injuries, poor attachments of the mus cles, problems with the brain’s control center, or localized disease.
Strabismus
each eye sends an image to a different area of the brain and because the brain usually ignores the messages sent by one of the eyes, the ignored eye becomes weaker, hence “lazy eye,” or amblyopia, develops.
Strabismus
results when a lesion in the oculo motor (III) nerve causes the eyeball to move laterally when at rest, and results in an inability to move the eyeball medially and inferi orly.
External strabismus
A lesion in the abducens (VI) nerve results in___, a condition in which the eyeball moves medially when at rest and cannot move laterally.
internal strabis mus
The muscles that move the mandible (lower jawbone) at the temporomandibular joint (TMJ) are known as the
muscles of mastication (chewing)
Of the four pairs of muscles involved in mastication, three are powerful closers of the jaw and account for the strength of the bite
masseter, temporalis, and medial pterygoid
is the strongest mus cle of mastication.
masseter
assist in mastication by moving the mandible from side to side to help grind food. Additionally, the lateral pterygoid muscles protract (protrude) the mandible.
medial and lateral pterygoid
Arrange the muscles in this section according to their actions on the mandible:
(1) elevation, (2) depression, (3) retraction, (4) protraction, and (5) side- to- side movement.
What is the origin of the masseter muscle?
Maxilla and zygomatic arch
Where does the masseter muscle insert?
Angle and ramus of mandible
What action does the masseter muscle perform?
Elevates mandible, as in closing mouth
What is the innervation of the masseter muscle?
Mandibular division of trigeminal (V) nerve
What is the origin of the temporalis muscle?
Temporal bone
Where does the temporalis muscle insert?
Coronoid process and ramus of mandible
What action does the temporalis muscle perform?
Elevates and retracts mandible
What is the innervation of the temporalis muscle?
Mandibular division of trigeminal (V) nerve
What is the origin of the medial pterygoid muscle?
Medial surface of lateral portion of pterygoid process of sphenoid bone; maxilla
Where does the medial pterygoid muscle insert?
Angle and ramus of mandible
What action does the medial pterygoid muscle perform?
Elevates and protracts (protrudes) mandible and moves mandible from side to side
What is the innervation of the medial pterygoid muscle?
Mandibular division of trigeminal (V) nerve
What is the origin of the lateral pterygoid muscle?
Greater wing and lateral surface of lateral portion of pterygoid process of sphenoid bone
Where does the lateral pterygoid muscle insert?
Condyle of mandible; temporomandibular joint (TMJ)
What action does the lateral pterygoid muscle perform?
Protracts mandible, depresses mandible as in opening mouth, and moves mandible from side to side
What is the innervation of the lateral pterygoid muscle?
Mandibular division of trigeminal (V) nerve
three of the four muscles of mastication close the mandible and only the __ opens the mouth.
lateral pterygoid
offsets this imbalance. When the masseter, temporalis, and medial pterygoid muscles relax, the mandible drops. Now you know why the mouth of many persons, particularly the elderly, is open while the person is asleep in a chair. In contrast, astronauts in zero gravity must work hard to open their mouths.
gravity on the mandible
a highly mobile structure that is vital to diges tive functions such as mastication (chewing), detection of taste, and deglutition (swallowing). It is also important in speech. T
tongue
greatly aided by its attach ment to the mandible, styloid process of the temporal bone, and hyoid bone.
tongue’s mobility
The tongue is divided into lateral halves by a
median fibrous septum
Inferiorly, the septum attaches to the
hyoid bone
Muscles of the tongue are of two principal types:
extrinsic and intrinsic
originate outside the tongue and attach to it. They move the entire tongue in various directions, such as anteriorly, posteriorly, and laterally.
Extrinsic tongue muscles
originate and insert within the tongue. These muscles alter the shape of the tongue rather than moving the entire tongue.
Intrinsic tongue muscles
pulls the tongue downward and forward
genioglossus
pulls the tongue upward and backward
stylo glossus
pulls the tongue downward and flattens it
hyoglossus
raises the back portion of the tongue
palatoglossus
Arrange the muscles in this section according to the following actions on the tongue:
(1) depression, (2) elevation, (3) protrac tion, and (4) retraction.
are arranged in both lateral halves of the tongue.
extrinsic and intrinsic muscles of the tongue
What muscle has its origin at the mandible?
Genioglossus
What muscle inserts at the undersurface of the tongue and hyoid bone?
Genioglossus
What muscle depresses the tongue and thrusts it anteriorly (protraction)?
Genioglossus
What muscle is innervated by the Hypoglossal (XII) nerve?
Genioglossus
What muscle has its origin at the styloid process of the temporal bone?
Styloglossus
What muscle inserts at the side and undersurface of the tongue?
Styloglossus
What muscle elevates the tongue and draws it posteriorly (retraction)?
Styloglossus
What muscle is innervated by the Hypoglossal (XII) nerve?
Styloglossus
What muscle has its origin at the greater horn and body of the hyoid bone?
Hyoglossus
What muscle inserts at the side of the tongue?
Hyoglossus
What muscle depresses the tongue and draws down its sides?
Hyoglossus
What muscle is innervated by the Hypoglossal (XII) nerve?
Hyoglossus
What muscle has its origin at the anterior surface of the soft palate?
Palatoglossus
What muscle inserts at the side of the tongue?
Palatoglossus
What muscle elevates the posterior portion of the tongue and draws the soft palate down on the tongue?
Palatoglossus
What muscle is innervated by the pharyngeal plexus, which contains axons from the vagus (X) nerve?
Palatoglossus
is administered during surgery, a total relaxation of the muscles results. Once the various types of drugs for anesthesia have been given (especially the paralytic agents), the patient’s airway must be protected and the lungs ventilated because the muscles involved with respiration are among those paralyzed.
general anesthesia
Paralysis of the ___ muscle causes the tongue to fall poste riorly, which may obstruct the airway to the lungs.
genioglossus
mandible is either manually thrust forward and held in place (known as the “sniffing position”), or a tube is inserted from the lips through the laryngopharynx (inferior portion of the throat) into the trachea
endotracheal intubation
Two groups of muscles are associated with the anterior aspect of the neck:
suprahyoid muscles and infrahyoid muscles
Both groups of muscles stabilize the hyoid bone, allowing it to serve as a firm base on which the tongue can move.
suprahyoid muscles and infrahyoid muscles
elevate the hyoid bone, floor of the oral cavity, and tongue during deglutition (swallowing).
Suprahyoid muscle
has two bellies, anterior and posterior, united by an intermediate tendon that is held in position on the hyoid bone by a fibrous loop. This muscle elevates the hyoid bone and larynx (voice box) during swallowing and speech. When the hyoid is stabi lized, the digastric depresses the mandible and is therefore synergistic to the lateral pterygoid in the opening of the mouth.
digastric
elevates and draws the hyoid bone pos teriorly, thus elongating the floor of the oral cavity during swal lowing.
stylohyoid
elevates the hyoid bone and helps press the tongue against the roof of the oral cavity during swallowing to move food from the oral cavity into the throat.
mylohyoid
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. It also depresses the mandible.
geniohyoid
are sometimes called “strap” mus cles because of their ribbonlike appearance. Most of the infrahy oid muscles depress the hyoid bone and some move the larynx during swallowing and speech.
infrahyoid muscles
is composed of two bellies connected by an intermediate tendon. In this case, however, the two bellies are referred to as superior and inferior, rather than anterior and posterior.
omohyoid
depress the hyoid bone together
omohyoid, sternohyoid, and thyrohy oid
depresses the thyroid cartilage (Adam’s apple) of the larynx to produce low sounds; the thyrohyoid muscle also elevates the thyroid cartilage to produce high sounds
sternot hyroid
Arrange the muscles in this section according to the following actions on the hyoid bone:
(1) elevating it, (2) drawing it anteri orly, (3) drawing it posteriorly, and (4) depressing it
Arrange the muscles in this section according to the following actions on the thyroid cartilage
(1) elevating it and (2) depressing it
What muscle has its origin at the inner side of the inferior border of the mandible for the anterior belly and at the temporal bone for the posterior belly?
Digastric
What muscle inserts at the body of the hyoid bone via an intermediate tendon?
Digastric
What muscle elevates the hyoid bone and has a reverse muscle action (RMA) that depresses the mandible, as in opening the mouth?
Digastric
What muscle is innervated by the mandibular division of the trigeminal (V) nerve for the anterior belly and the facial (VII) nerve for the posterior belly?
Digastric
What muscle has its origin at the styloid process of the temporal bone?
Stylohyoid
What muscle inserts at the body of the hyoid bone and elevates it while drawing it posteriorly?
Stylohyoid
What muscle is innervated by the facial (VII) nerve?
Stylohyoid
What muscle has its origin at the inner surface of the mandible?
Mylohyoid
What muscle inserts at the body of the hyoid bone and elevates the hyoid bone and floor of the mouth while also depressing the mandible?
Mylohyoid
What muscle is innervated by the mandibular division of the trigeminal (V) nerve?
Mylohyoid
What muscle has its origin at the inner surface of the mandible and inserts at the body of the hyoid bone?
Geniohyoid
What muscle elevates the hyoid bone, draws it and the tongue anteriorly, and depresses the mandible?
Geniohyoid
What muscle is innervated by the first cervical spinal nerve (C1)?
Geniohyoid
What muscle has its origin at the superior border of the scapula and the superior transverse ligament?
Omohyoid
What muscle inserts at the body of the hyoid bone and depresses it?
Omohyoid
What muscle is innervated by branches of spinal nerves C1–C3?
Omohyoid
What muscle has its origin at the medial end of the clavicle and manubrium of the sternum?
Sternohyoid
What muscle inserts at the body of the hyoid bone and depresses it?
Sternohyoid
What muscle is innervated by branches of spinal nerves C1–C3?
Sternohyoid
What muscle has its origin at the manubrium of the sternum?
Sternothyroid
What muscle inserts at the thyroid cartilage of the larynx and depresses it?
Sternothyroid
What muscle is innervated by branches of spinal nerves C1–C3?
Sternothyroid
What muscle has its origin at the thyroid cartilage of the larynx?
Thyrohyoid
What muscle inserts at the greater horn of the hyoid bone and elevates the thyroid cartilage of the larynx?
Thyrohyoid
What muscle has a reverse muscle action (RMA) that depresses the hyoid bone?
Thyrohyoid
What muscle is innervated by branches of spinal nerve C1 via the descending hypoglossal (XII) nerve?
Thyrohyoid
elevate the hyoid bone, the floor of the oral cavity, and the tongue during swallowing.
suprahyoid muscles
flexes the cervical portion of the vertebral column and flexes the head. Acting singly (unilaterally), each sternocleidomas toid muscle laterally flexes and rotates the head to the opposite side of the contracting muscle. They consist 2 bellies
sternocleidomastoid (SCM)
The two heads attach as ___ and ___ of the SCM
sternal head and clavicular head
Bilateral contraction of the ___ extends the head
spenalis capitis, semispinalis capitis, splenius capitis, and longissimus capitis
The sternocleidomastoid muscle is an important landmark that divides the neck into two major triangles:
anterior and pos terior
is bordered superiorly by the mandi ble, medially by the cervical midline, and laterally by the anterior border of the sternocleidomastoid muscle. It has its apex at the sternum
anterior triangle
The anterior triangle is subdivided into three paired triangles:
submandibular, carotid, and muscular
An unpaired ____ is formed by the upper part of the combined right and left anterior triangles.
submental triangle
contains submental, submandibular, and deep cervical lymph nodes; the submandibular salivary gland and a portion of the parotid salivary gland; the facial artery and vein; carotid arteries and internal jugular vein; the thyroid gland, sublingual salivary gland, infrahyoid muscles; and the following cranial nerves: glosso pharyngeal (IX), vagus (X), accessory (XI), and hypoglossal (XII).
anterior triangle
is bordered inferiorly by the clavicle, anteriorly by the posterior border of the sternocleidomastoid muscle, and posteriorly by the anterior border of the trapezius muscle
posterior triangle
The posterior triangle is subdivided into two triangles
occipital and supraclavicular (omoclavicular)
contains part of the subclavian artery, external jugular vein, cer vical lymph nodes, brachial plexus, and the accessory (XI) nerve.
posterior triangle
Arrange the muscles in this section according to the following actions on the head:
(1) flexion, (2) lateral flexion, (3) extension, (4) rotation to side opposite contracting muscle, and (5) rota tion to same side as contracting muscle.
What muscle has its origin at the sternal head: manubrium of sternum; clavicular head: medial third of clavicle?
Sternocleidomastoid
What muscle inserts at the mastoid process of temporal bone and lateral half of superior nuchal line of occipital bone?
Sternocleidomastoid
What muscle, acting together (bilaterally), flexes the cervical portion of the vertebral column, extends the head at atlanto-occipital joints, and acting singly (unilaterally), laterally flexes the neck and head to the same side and rotates the head to the opposite side of the contracting muscle?
Sternocleidomastoid
What muscle is innervated by the Accessory (XI) nerve, C2, and C3?
Sternocleidomastoid
What muscle has its origin at the articular processes of C4–C6 and transverse processes of C7–T7?
Semispinalis capitis
What muscle inserts at the occipital bone between superior and inferior nuchal lines?
Semispinalis capitis
What muscle, acting together, extends the head and vertebral column, and acting singly, rotates the head to the side opposite of the contracting muscle?
Semispinalis capitis
What muscle is innervated by cervical spinal nerves—posterior rami?
Semispinalis capitis
What muscle has its origin at the ligamentum nuchae and spinous processes of C7–T4?
Splenius capitis
What muscle inserts at the occipital bone and mastoid process of the temporal bone?
Splenius capitis
What muscle extends the head, and when acting together, muscles of each region (cervical and thoracic) extend the vertebral column of their respective regions?
Splenius capitis
What muscle is innervated by cervical spinal nerves—posterior rami?
Splenius capitis
What muscle has its origin at the articular processes of T1–T4?
Longissimus capitis
What muscle inserts at the mastoid process of the temporal bone?
Longissimus capitis
What muscle, acting together, extends the head and vertebral column, and acting singly, laterally flexes and rotates the head to the same side as the contracting muscle?
Longissimus capitis
What muscle is innervated by cervical spinal nerves—posterior rami?
Longissimus capitis
What muscle is often absent or very small and arises with semispinalis capitis?
Spinalis capitis
What muscle inserts at the occipital bone?
Spinalis capitis
What muscle extends the head and vertebral column?
Spinalis capitis
What muscle is innervated by cervical spinal nerves—posterior rami?
Spinalis capitis
The anterolateral abdominal wall is composed of skin, fas cia, and four pairs of muscles:
the external oblique, internal oblique, transversus abdominis, and rectus abdominis
the superficial muscle. Its muscle fascicles extend inferiorly and medially.
external abdominal oblique
the intermediate flat muscle. Its muscle fascicles extend at right angles to those of the external abdominal oblique.
inter nal abdominal oblique
the deep muscle, with most of its muscle fascicles directed transversely around the abdominal wall.
transversus abdominis
is a long muscle that extends the entire length of the anterior abdominal wall, orig inating at the pubic crest and pubic symphysis and inserting on the cartilages of ribs 5–7 and the xiphoid process of the sternum.
rectus abdominis
The anterior surface of the muscle is interrupted by three or four transverse fibrous bands of tissue called
tendinous intersections,
There are usually three tendinous intersections
one at the level of the umbilicus, one near the xiphoid process, and one midway between the other two
The aponeuroses (sheathlike tendons) of the external oblique, internal abdominal oblique, and transversus abdom inis muscles form the ___, which enclose the rec tus abdominis muscles.
rectus sheaths
The sheaths meet at the midline to form the ___, a tough, fibrous band that extends from the xiphoid process of the sternum to the pubic symphysis.
linea alba
The inferior free border of the external abdominal oblique aponeurosis forms the ___, which runs from the an terior superior iliac spine to the pubic tubercle
inguinal ligament
Just superior to the medial end of the inguinal ligament is a triangular slit in the aponeurosis referred to as the ___, the outer opening of the inguinal canal
superficial inguinal ring
contains the sper matic cord and ilioinguinal nerve in males, and the round liga ment of the uterus and ilioinguinal nerve in females
inguinal canal
formed by the lumbar ver tebrae, parts of the ilia of the hip bones, psoas major and iliacus muscles, and quadratus lumborum muscle.
posterior abdominal wall
Arrange the muscles in this section according to the following actions on the vertebral column:
(1) flexion, (2) lateral flexion, (3) extension, and (4) rotation.
Which muscle originates from the pubic crest and pubic symphysis?
Rectus abdominis
Which muscle inserts into the cartilage of ribs 5–7 and xiphoid process?
Rectus abdominis
Which muscle flexes the vertebral column and compresses the abdomen?
Rectus abdominis
Which muscle is innervated by the thoracic spinal nerves T7–T12?
Rectus abdominis
Which muscle originates from ribs 5–12?
External abdominal oblique
Which muscle inserts into the iliac crest and linea alba?
External abdominal oblique
Which muscle compresses the abdomen and laterally flexes the vertebral column?
External abdominal oblique
Which muscle is innervated by thoracic spinal nerves T7–T12 and the iliohypogastric nerve?
External abdominal oblique
Which muscle originates from the iliac crest, inguinal ligament, and linea alba?
Internal abdominal oblique
Which muscle inserts into the cartilage of ribs 7–10 and thoracolumbar fascia?
Internal abdominal oblique
Which muscle compresses the abdomen and rotates the vertebral column?
Internal abdominal oblique
Which muscle is innervated by thoracic spinal nerves T8–T12, the iliohypogastric nerve, and the ilioinguinal nerve?
Internal abdominal oblique
Which muscle originates from the iliac crest, inguinal ligament, lumbar fascia, and cartilages of ribs 5–10?
Transversus abdominis
Which muscle inserts into the xiphoid process, linea alba, and pubis?
Transversus abdominis
Which muscle compresses the abdomen?
Transversus abdominis
Which muscle is innervated by thoracic spinal nerves T8–T12, iliohypogastric nerve, and ilioinguinal nerve?
Transversus abdominis
Which muscle originates from the iliac crest and iliolumbar ligament?
Quadratus lumborum
Which muscle inserts into the inferior border of rib 12 and L1–L4?
Quadratus lumborum
Which muscle pulls the 12th ribs inferiorly during forced exhalation and laterally flexes the vertebral column?
Quadratus lumborum
Which muscle is innervated by thoracic spinal nerves T12 and lumbar spinal nerves L1–L3 or L1–L4?
Quadratus lumborum
is 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.
hernia
The inguinal region is a weak area in the abdominal wall. It is often the site of an ___, a rupture or separation of a portion of the inguinal area of the abdominal wall resulting in the pro trusion of a part of the small intestine.
inguinal hernia
much more common in males than in females because the inguinal canals in males are larger to accommodate the spermatic cord and ilioinguinal nerve. Treatment of hernias most often involves surgery. The organ that protrudes is “tucked” back into the abdominal cavity and the defect in the abdominal muscles is repaired. In addition, a mesh is often applied to reinforce the area of weakness.
hernia
is a painful strain (tear) in the soft tissues (muscles, tendons, and ligaments) in the lower abdomen or groin.
sports hernia
does not cause a visible lump. It occurs more frequently in males and is due to simultaneous contraction of the abdominal and adductor mus cles that attach to the hip bone and pull in different directions. This occurs during activities that involve rapid acceleration and changes in direction, kicking, and side- to- side motions such as those that occur in ice hockey, soccer, football, rugby, tennis, and high jumping. Treatment of sports hernia includes rest, ice, anti- inflammatory medications, physical therapy, and surgery
sports hernia
protect the abdominal viscera, move the vertebral column, and assist in forced exhalation, defecation, urination, and childbirth.
anterolateral abdominal muscles
occurs when the thoracic cavity increases in size
Inhalation (breathing in)
occurs when the thoracic cavity decreases in size.
exhala tion (breathing out)
a dome shaped and most important mus cle that powers breathing
diaphragm
has a convex superior sur face that forms the floor of the thoracic cavity and a concave inferior surface that forms the roof of the abdominal cavity
diaphragm
originates 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
peripheral muscular portion
a strong aponeurosis located near the center of the muscle
central tendon
The diaphragm has three major openings through which various structures pass between the thorax and abdomen.
aortic hiatus, esophageal hiatus, and caval foramen
include the aorta, along with the thoracic duct and azygous vein, which pass through the
aortic hiatus
the esophagus with accompanying vagus (X) nerves, which pass through the
esophageal hiatus
the inferior vena cava, which passes through the
caval foramen (opening)
the stomach protrudes superiorly through the esophageal hiatus.
hiatus hernia
span the intercostal spaces, the spaces between ribs. These muscles are arranged in three layers, only two of which are discussed here.
intercos tals
The 11 pairs of ___ occupy the superficial layer, and their fibers run in an oblique direction interiorly and anteriorly from the rib above to the rib below. They elevate the ribs during inhalation to help expand the thoracic cavity.
external intercos tals
The 11 pairs of ___ occupy the intermediate layer of the intercos tal spaces. The fibers of these muscles run at right angles to the external intercostals, in an oblique direction interiorly and posteriorly from the inferior border of the rib above to the superior border of the rib below. They draw adjacent ribs together during forced exhalation to help decrease the size of the thoracic cavity.
internal intercostals
Arrange the muscles in this section according to the following actions in the thorax
(1) increase in vertical length, (2) increase in lateral and anteroposterior dimensions, and (3) decrease in lateral and anteroposterior dimensions of the thorax.
Openings in the diaphragm permit the passage of the
aorta, esophagus, and inferior vena cava
What is the origin of the diaphragm?
Xiphoid process of sternum, costal cartilages and adjacent portions of ribs 7–12, lumbar vertebrae, and their intervertebral discs.
What is the insertion of the diaphragm?
Central tendon.
What is the action of the diaphragm?
Contraction of diaphragm causes it to flatten and increases vertical dimension of thoracic cavity, resulting in inhalation; relaxation of diaphragm causes it to move superiorly and decreases vertical dimension of thoracic cavity, resulting in exhalation.
What is the innervation of the diaphragm?
Phrenic nerve, which contains axons from cervical spinal nerves (C3–C5).
What is the origin of the external intercostals?
Inferior border of rib above.
What is the insertion of the external intercostals?
Superior border of rib below.
What is the action of the external intercostals?
Contraction elevates ribs and increases anteroposterior and lateral dimensions of thoracic cavity, resulting in inhalation; relaxation depresses ribs and decreases anteroposterior and lateral dimensions of thoracic cavity, resulting in exhalation.
What is the innervation of the external intercostals?
Thoracic spinal nerves T2–T12.
What is the origin of the internal intercostals?
Superior border of rib below.
What is the insertion of the internal intercostals?
Inferior border of rib above.
What is the action of the internal intercostals?
Contraction draws adjacent ribs together to further decrease anteroposterior and lateral dimensions of thoracic cavity during forced exhalation.
What is the innervation of the internal intercostals?
Thoracic spinal nerves T2–T12.
The muscles of the pelvic floor are the
levator ani and ischio coccygeus
Along with the fascia covering their internal and external surfaces, these muscles are referred to as the ___, which stretches from the pubis anteriorly to the coccyx posteriorly, and from one lateral wall of the pelvis to the other. This arrangement gives the pelvic diaphragm the appearance of a funnel suspended from its attachments. The pelvic diaphragm separates the pelvic cavity above from the perineum below
pelvic diaphragm
pierce the pelvic diaphragm in both sexes, and the vagina also goes through it in females.
anal canal and urethra
The three components of the levator ani muscle are the
pubococcygeus, puborectalis, and iliococcygeus
is the largest and most important muscle of the pelvic floor. It supports the pelvic viscera and resists the inferior thrust that accompanies increases in intra- abdominal pressure during functions such as forced exhalation, coughing, vomiting, urination, and defeca tion. The muscle also functions as a sphincter at the anorectal junction, urethra, and vagina.
levator ani
In addition to assisting the levator ani, the ___ pulls the coccyx anteriorly after it has been pushed posteriorly during defecation or childbirth
ischiococcygeus
supports the pelvic viscera.
pelvic diaphragm
Arrange the muscles in this section according to the following actions in the pelvic
(1) supporting and maintaining the position of the pelvic viscera; (2) resisting an increase in intra- abdominal pres sure; and (3) constriction of the anus, urethra, and vagina.
Which muscle is divisible into three parts: pubococcygeus, puborectalis, and iliococcygeus?
Levator ani
Which muscle originates from the pubis and inserts into the coccyx, urethra, anal canal, perineal body of perineum, and anococcygeal ligament?
Pubococcygeus
Which muscle supports and maintains the position of pelvic viscera and resists increases in intra-abdominal pressure?
Pubococcygeus
Which muscle is innervated by sacral spinal nerves S2–S4?
Pubococcygeus
Which muscle originates from the posterior surface of the pubic body and forms a sling posterior to the anorectal junction?
Puborectalis
Which muscle helps maintain fecal continence and assists in defecation?
Puborectalis
Which muscle is innervated by sacral spinal nerves S2–S4?
Puborectalis
Which muscle originates from the ischial spine and inserts into the coccyx?
Iliococcygeus
Which muscle has the same action as the pubococcygeus?
Iliococcygeus
Which muscle is innervated by sacral spinal nerves S2–S4?
Iliococcygeus
