Podcast
Questions and Answers
What is the primary function of the serratus anterior muscle?
What is the primary function of the serratus anterior muscle?
- Extends the arm
- Adducts the scapula
- Flexes the humerus
- Abducts the scapula (correct)
Which of the following actions is performed by the trapezius muscle?
Which of the following actions is performed by the trapezius muscle?
- Flexion of the arm
- Elevation of the ribs
- Adduction of the scapula (correct)
- Abduction of the humerus
What type of movement does the deltoid muscle primarily facilitate?
What type of movement does the deltoid muscle primarily facilitate?
- Abduction of the arm (correct)
- Depression of the scapula
- Rotation of the scapula
- Elevation of the shoulder girdle
Which muscle assists in pushing and punching actions?
Which muscle assists in pushing and punching actions?
What is the function of the muscles that move the pectoral girdle?
What is the function of the muscles that move the pectoral girdle?
What type of muscle is under voluntary control?
What type of muscle is under voluntary control?
What is the role of muscle bellies in muscle anatomy?
What is the role of muscle bellies in muscle anatomy?
In muscle contractions, what happens to the origin and insertion during reverse muscle actions?
In muscle contractions, what happens to the origin and insertion during reverse muscle actions?
Which levers are the most common type found in the human body?
Which levers are the most common type found in the human body?
What mechanical advantage do second-class levers provide?
What mechanical advantage do second-class levers provide?
What is the primary effort involved when standing on your toes?
What is the primary effort involved when standing on your toes?
In a third-class lever, where is the effort located?
In a third-class lever, where is the effort located?
Why are third-class levers used more commonly despite their mechanical disadvantage?
Why are third-class levers used more commonly despite their mechanical disadvantage?
What is the role of the triceps brachii during flexion at the elbow joint?
What is the role of the triceps brachii during flexion at the elbow joint?
What muscles stabilize joints to allow for movement at only one joint?
What muscles stabilize joints to allow for movement at only one joint?
Which muscle is responsible for elevating the mandible during chewing?
Which muscle is responsible for elevating the mandible during chewing?
What is the function of the external obliques in the abdominal muscles?
What is the function of the external obliques in the abdominal muscles?
What does the term 'fixators' refer to in muscle action?
What does the term 'fixators' refer to in muscle action?
What movement is produced when both biceps brachii and triceps brachii contract simultaneously?
What movement is produced when both biceps brachii and triceps brachii contract simultaneously?
Which of the following muscles runs parallel to the midline of the abdomen?
Which of the following muscles runs parallel to the midline of the abdomen?
What is the primary action of the orbicularis oculi muscle?
What is the primary action of the orbicularis oculi muscle?
Which muscle is considered the deepest of the abdominal muscles?
Which muscle is considered the deepest of the abdominal muscles?
What defines the '6–8 pack' in the rectus abdominis?
What defines the '6–8 pack' in the rectus abdominis?
What describes the action of the sternocleidomastoid muscle during unilateral movement?
What describes the action of the sternocleidomastoid muscle during unilateral movement?
What does the diaphragm do during breathing?
What does the diaphragm do during breathing?
What muscle originates from the scapula and stabilizes it during shoulder movement?
What muscle originates from the scapula and stabilizes it during shoulder movement?
Which compartment of muscles functions to flex the wrist?
Which compartment of muscles functions to flex the wrist?
Flashcards are hidden until you start studying
Study Notes
Skeletal Muscle
- All skeletal muscles are under voluntary control
- Functions of skeletal muscle:
- Support body movement
- Generate heat
Muscle Anatomy
- Origin: End of a muscle attached to a stabilized bone (usually proximal)
- Insertion: End of a muscle attached to a moving bone (usually distal)
- Muscle belly is the thicker portion between tendons
- Actions: The movements that are possible when a muscle contracts
- Reverse muscle actions (RMAs) occur when the origin and insertion are reversed. This can happen in some muscles, but NOT when the muscle relaxes
Levers
- Fulcrum: A fixed point that a lever rotates around
- Lever: A rigid bar that pivots around a fulcrum
- Load: Resistance against effort
- Effort: Force required to move a load
- Bones are levers that are moved by the effort of muscle action
Types of Levers
- First-class lever: Fulcrum is between the effort and the load.
- Examples: Scissors, looking up at the ceiling
- Second-class lever: The load is between the effort and the fulcrum.
- Examples: Wheelbarrow, standing on your toes.
- Produce a mechanical advantage
- Third-class lever: The effort is between the fulcrum and the load.
- Examples: Forceps, bending your elbow
- Most common type in the body
- Always produce a mechanical disadvantage
Why so many third-class levers?
- They allow for faster movement of the load.
Muscle Groups
- Muscles usually work in opposing pairs
Agonist & Antagonist Muscles
- Agonist: The muscle that contracts to produce a movement.
- Antagonist: The muscle that opposes the agonist. It must relax to allow the agonist to move the bone.
Synergist Muscles
- Synergist muscles stabilize joints when contracted to allow movement around only one joint.
Fixators
- Fixator muscles stabilize the proximal end of the bone so the distal end can move.
- Fixators often work with agonist muscles.
Compartments
- Compartments are groups of skeletal muscles, nerves, and blood vessels that have specific functions.
- Example: Flexor compartments of the upper limb are the anterior muscles
Naming Muscles
- Muscles are named based on:
- Direction of muscle fibers
- Size
- Shape
- Action
- Number of origins
- Location
- Origin and insertion
Facial Muscles
- Functions:
- Express emotions
- Speech and vocalization
- Chewing (mastication)
Muscles of the Eye and Mouth
- Orbicularis oculi: Closes the eyelid
- Orbicularis oris: Closes the lips and purses lips
- Occipitofrontalis: Has two bellies:
- Frontal belly: Raises eyebrows and wrinkles the forehead.
- Occipital belly: Raises hair and pulls the scalp posteriorly.
- Connected by the epicranial aponeurosis
Muscles that Move the Mandible
- Platysma: Pulls the corners of the mouth laterally and inferiorly; depresses the mandible.
- Masseter and Temporalis: Elevate the mandible.
- Masseter closes the jaw.
Muscles of the Neck
- Sternocleidomastoid: Muscle on each side of the neck, rotates the head.
- Can also extend the head and elevate the sternum.
- Capable of RMAs
Muscles of the Abdomen
- Funtions:
- Protect the abdominal viscera
- Move the vertebral column
- External obliques: Most superficial layer
- Internal obliques: Intermediate layer
- Transversus abdominis: Deepest layer
Rectus Abdominis
- Runs longitudinally along the anterior abdominal cavity
- Divided by tendinous intersections
Diaphragm
- Bound the thoracic cavity inferiorly
- Insertions: Central tendon
- Contracts during breathing
Muscles that Move the Pectoral Girdle
- Functions:
- Move the clavicle and scapula
- Stabilize the scapula during movement of the humerus
Serratus Anterior
- Fan-shaped muscle that abducts the scapula.
- Assists in pushing and punching.
Trapezius
- Muscle that originates on the occipital bone and inserts on the scapula.
- Permits rotation, adduction, depression, and stabilization of the scapula
Muscles that Move the Upper Limb
- Pectoralis major: Permits adduction, medial rotations, and flexion of the arm.
Deltoid
- Wraps the shoulder posteriorly, laterally, and anteriorly.
- Permits abduction, medial/lateral rotation, and flexion/extension of the arm.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
