Chapter 6: Gross Anatomy of Muscles

What is the Pectoralis Major?

A large, superficial convergent muscle of the chest that originates on the shoulder girdle and the first six ribs and inserts into the humerus

What is the Brachialis?

A muscle in the upper arm deep to biceps brachii that originates on the humerus and inserts into the proximal end of the ulna

*Quadcriceps* What is the Vastus Lateralis?

A muscle located on the lateral anterior thigh

*Quadriceps* What is the Vastus Medialis?

A muscle located on the medial anterior thigh

*Quadriceps* What is the Vastus Intermedius?

A muscle that is deep to rectus femoris and "between" the vastus mediales and vastus lateralis

What is the Gluteus Medius?

A muscle that originates on the ilium and inserts into the femur underneath the gluteus maximus

What is the Brachioradialis?

A muscle that originates on the lateral supracondylar ridge of the humerus and inserts into the distal styloid process of radius

What are the External Obliques?

Superficial muscles that compose the lateral walls of the abdomen - Their fibers run at an angle, *downward and medially* from the last 8 ribs and insert into the ilium

What is the Occipitalis responsible for?

Pulling the scalp posteriorly

What is the Deltoid?

"Triangle" shaped paired muscles of the shoulder that originate across the shoulder girdle and insert into the proximal end of the humerus

What is the Orbicularis Oris responsible for?

*Kissing* (kissing muscle)

What is the Masseter responsible for?

*Prime mover* of closing the jaw

What is the Zygomaticus responsible for?

*Smiling* (smiling muscle)

What is the Gluteus Medius responsible for?

- *Abducting* the hip - Assists in steadying the pelvis when walking

What is the Gluteus Maximus responsible for?

- *Extending* the hip (bringing the thigh in a straight line with the pelvis) - Important for climbing stairs, performing squats, and jumping

What is the Buccinator responsible for?

- *Whistling* - Flattening the cheek - Chewing - Compressing the cheek to hold food between the teeth during mastication (whistling muscle)

What is the Orbicularis Oculi responsible for?

- *Winking* - Closing the eyes - Squinting - Blinking (winking muscle)

What is the Tensor Fascia Lata responsible for?

- Abducting the thigh and assisting with internal rotation and flexion of the hip inward (medial rotation) - Steadying the coxal bones on the head of the femur and the condyles of the femur on the articular surfaces of the tibia

What is the Iliopsoas responsible for?

- Acts as *prime mover* of *flexing the hip* - Maintaining posture (keeps the upper body from falling backward when standing erect)

What is the Triceps Brachii responsible for?

- Acts as a *prime mover* of *extending* the elbow - *Antagonist* of biceps brachii

What is the Biceps Brachii responsible for?

- Acts as a *prime mover* of flexing the forearm - *Supinating the forearm*

Internal intercostals __________ the rib cage during __________

- Depress - Exhalation

What is the Brachialis responsible for?

- Flexing the arm when hand is pronated - Acts as a *synergist* to biceps brachii

What is the Trapezius responsible for?

- Holding head upright - Shrugging shoulders

What is the Sternocleidomastoid responsible for?

- Lowering the head (if both muscles contract) - Turning the head (if only one muscle contracts)

What is the Fascia Lata responsible for?

- Maintaining structural integrity - Providing support and protection - Shock absorber

What is the Platysma responsible for?

- Opening jaw - Frowning mouth - Wrinkling skin of neck

What is the Pectoralis Major responsible for?

- Pulling arms across chest - *Prime mover* of pushing motion of arms

External intercostals ________ the rib cage during _________

- Raise - Inhalation

What is the Frontalis responsible for?

- Raising eyebrows - Wrinkling forehead

What is the Transverse Abdominus responsible for?

- Reinforcing the body trunk by containing and protecting abdominal contents - Depressing abdominal contents during defecation and childbirth, and forced breathing - Sucking in stomach

What is the Rectus Abdominus responsible for?

- Reinforcing the body trunk by containing and protecting abdominal contents - Flexing the vertebral column - Doing sit-ups

What is the Iliopsoas?

A fused muscle that originates on the iliac bone and lower vertebrae deep inside to the pelvis and inserts on the lesser trochanter of the femur

Many muscles of the lower limbs span ______ joints

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*Quadriceps* What are the Vastus Muscles?

3 muscles responsible for extending the knee that originate on the femur and insert into the tibial tuberosity by way of the patellar tendon

What is the Quadriceps Group?

4 muscles that compose the anterior thigh, including: 1. Rectus Femoris 2. Vastus Medialis 3. Vastus Intermedius 4. Vastus Lateralis

What are the Adductor Muscles?

A group of muscles located at the medial side of each thigh that adduct the thighs (bring them together)

What are the Forearm Flexors?

A group of muscles on the anterior aspect of the forearm that flex the wrist and fingers

What are the Forearm Extensors?

A group of muscles on the posterior aspect of the forearm that extend wrist and fingers

What is the Biceps Brachii?

A "2-headed" muscle whose heads originate on shoulder girdle, fuse, and insert into the radial tuberosity of the radius

What is the Triceps Brachii?

A "3-headed" muscle whose heads originate on the shoulder girdle and proximal humerus, fuse, and insert into the olecranon process of the ulna

What is the Tensor Fascia Lata?

A "band-like" muscle on the "side" on the body that originates on the coxal bones and inserts into the facia lata of the thigh

What is the Splenius Capitis?

A "bandage-like" muscle of the "head" that originates on the spinous processes of the seventh cervical vertebra and upper three or four thoracic vertebrae and inserts into the mastoid process and occipital bone underneath the sternocleidomastoid

What is the Gluteus Maximus?

A "big" and powerful muscle that originates on the sacrum and ilium and inserts in the gluteal tuberosity of the femur

What is the Platysma?

A "flat, broad" muscle on the anterior, superficial neck that originates on the fascia of pectoral muscles and inserts below the mouth and chin

What is the Galea Aponeurotica?

A "helmet"-shaped, connective aponeurosis between occipitalis and frontalis

*Adductor Muscles* What is the Adductor Longus?

A "long" adductor muscle that originates on the anterior surface of the pubis bone, just lateral to the pubic symphysis and inserts into the femur - Superior to magnus

*Adductor Muscles* What is the Adductor Brevis?

A "short" adductor muscle that originates on the inferior ramus of the pubis bone and inserts into the proximal femur - Superior to magnus

*Adductor Muscles* What is the Gracilis?

A "slender, thin," medial, and deep adductor muscle that originates on the inferior ramus of pubis bone and inserts into the knee - Deep to all

*Quadriceps* What is the Rectus Femoris?

A "straight," bipennate muscle on the femur that originates on pelvis and inserts into the tibial tuberosity by way of the patellar tendon

What is the Sternocleidomastoid?

A 2-headed muscle that originates on the sternum and clavicle that fuse before inserting into the mastoid process

What is the Temporalis?

A fan-shaped (convergent) muscle that originates on temporalis and inserts into the mandible

What is the Flexor Carpi Radialis?

A flexor muscle that originates on the distal end of the humerus and inserts into the second and third metacarpals

What is the Flexor Carpi Ulnaris?

A flexor muscle that originates on the distal end of the humerus and posterior ulna and inserts into the carpals and fifth metacarpal

What is the Iliotibial Tract?

A long, fibrous reinforcement of the fascia lata that extends from the iliac crest to the lateral condyle of the tibia (The thickened part of the fascia lata at its lateral side)

What is the Frontalis?

A muscle covering the *frontal bone* that inserts into the orbicularis oculi and originates on the galea aponeurotica

What is the Occipitalis?

A muscle covering the *occipital bone* that inserts into the galea aponeurosis and originates on the skull

What is the Fascia Lata?

A reinforcing "band" of connective tissue on the side of the leg that originates from many areas of the thigh including bone, muscle, and other tissues - Interpenetrates and surrounds muscles, bones, organs, nerves, blood vessels and other structures

What is an Aponeurosis?

A sheet of pearly-white fibrous tissue that takes the place of a tendon in sheetlike muscles having a wide area of attachment

What is the Masseter?

A strong muscle that inserts into the mandible and originates on the zygomatic process

What is the Flexor Digitorum Superficialis?

A superficial flexor muscle that originates on the distal end of the humerus, radius, and ulna and inserts into the middle phalanges of the second to fifth fingers

What is the Pectoralis Minor?

A thin deep muscle of the upper thorax, beneath the pectoralis major

What is the Buccinator?

A thin muscle running horizontally across the *cheek* that inserts into orbicularis oris and originates on the maxilla (buccinator means "trumpeter")

What is the Sartorius?

A thin, superficial, long, strap-like muscle that originates from the anterior iliac crest and inserts into the medial side of the tibia

What is the Deltoid responsible for?

Acts as a *prime mover* of *abducting* (raising) the arms

What is the Temporalis responsible for?

Acts as a *synergist* to the massester (Helps close the jaw)

What is the Latissimus Dorsi responsible for?

Adduction and extension (rowing) of the humerus (down and back)

What is the Extensor Digitorum?

An extensor muscle that originates on the distal end of humerus and inserts into the distal phalanges of the second to fifth fingers

What is the Extensor Carpi Radialis?

An extensor muscle that originates on the humerus and inserts into the base of the second and third metacarpals (radius = lateral)

What is the Extensor Carpi Ulnaris?

An extensor muscle that originates on the lateral epicondyle of humerus and inserts into the base of the fifth metacarpal (ulna = medial)

What are the Intercostal Muscles responsible for?

Assisting in breathing

What is the Orbicularis Oculi?

Circular muscles around the eyes (orbicular means "circular," oculi means "eyes")

What is the Orbicularis Oris?

Circular muscles around the lips (orbicular means "circular," oris means "mouth")

What are the Intercostal Muscles?

Deep muscles "between the ribs"

What is the Quadriceps Group responsible for?

Extending the knee

What is the Extensor Carpi Radialis responsible for?

Extending the wrist (on the lateral side)

What is the Extensor Carpi Ulnaris responsible for?

Extending the wrist (on the medial side)

What is the Extensor Digitorum responsible for?

Extending the wrist and *fingers*

*Quadriceps* What is the Rectus Femoris responsible for along with extending the knee?

Flexing the hip

What is the Flexor Carpi Radialis responsible for?

Flexing the wrist (on the lateral side)

What is the Flexor Carpi Ulnaris responsible for?

Flexing the wrist (on the medial side)

What is the Flexor Digitorum Superficialis responsible for?

Flexing the wrist and *fingers* (digit means "finger")

What is the Splenius Capitis responsible for?

Holding the head up (postural muscle)

Where do the Facial Muscles insert?

Into soft tissues such as other muscles or skin rather than bone

What is the origin and insertion of the Trapezius?

Its origin is very broad, each runs from the occipital bone down the vertebral column to the end of the thoracic vertebrae. They then flare laterally to insert into the scapular spine and clavicle

What is the Latissimus Dorsi?

Large, flat paired muscles of the lower back that originate on the lower spine and ilium and insert into the proximal end of the humerus ("broadest muscle of back")

What are the Internal Obliques?

Muscles deep to the external obliques whose *fibers run at right angles to the external oblique's*, originating on the iliac crest and inserting into the last three ribs

What is the Gluteus Medius a common location for?

Needle injections

What is the Trapezius?

Paired muscles on the posterior neck and upper trunk that form a diamond shape together

What is the Brachioradialis responsible for?

Pronating and supinating the arm, depending on position of forearm

What is the Pectoralis Minor responsible for?

Pulling and pushing (functions are similar to pectoralis major)

What are the Internal Obliques responsible for?

Reinforcing the body trunk by containing and protecting abdominal contents (similar functions to rectus abdominus and external obliques)

What are the External Obliques responsible for?

Reinforcing the body trunk by containing and protecting abdominal contents (similar functions to rectus abdominus)

*Adductor Muscles* What is the Adductor Magnus?

The "big" adductor muscle that orginates on the inferior pubic ramus and has a broad insertion on the femur - Lies deep to brevis and longus

What is the Rectus Abdominus?

The "straight," superficial six-pack muscles of the abdomen that extend from the pubis to the rib cage

What is the Transverse Abdominus?

The deepest muscle of abdominal wall whose fibers run *horizontally "across" the abdomen* and originate on the lower ribs and iliac crest and insert into the pubis

*Adductor Muscles* What is the Pectineus?

The most anterior adductor muscle that originates on the pectineal line of the pubis bone and inserts into the proximal femur - Superficial to all

What is the Zygomaticus?

Two muscles (major & minor) superior and superficial to buccinator that insert into orbicularis oris and originate on the zygomatic bone

The muscles of the lower limbs are among the largest, strongest muscles in the body. What are they specialized for?

Walking and balancing the body

What is the Sartorius responsible for?

Weakly flexing the thigh (allows you to sit cross-legged like a "tailor," where its name originates from)