MUSCULAR SYSTEM
BIO 141 Muscles Table You should be able to classify muscles in different ways. The most important part of muscles review is the action of the muscles and location of muscles. Name of muscles: Muscles may be named in many different ways. The following table will help you understand how muscles are named. Make sure you are able to identify and explain the actions of the muscles that are highlighted by an asterisk given a diagram/picture. MAJOR SKELETAL MUSCLES NAMING OF SKELETAL MUSCLES CHARACTERISTIC
EXAMPLES
EXAMPLES IN HUMANS
Orientation of muscle fibers
rectus = parallel/straight transverse = perpendicular oblique = at 45o angle orbicularis = circular
Rectus abdominis Transversus abdominis External Oblique Orbicularis oculi
Location or Specific body region (i.e. the bone or body part that a muscle covers)
frontal bone tibia oris
Frontalis Tibialis Anterior Orbicularis oris
Muscle Size
maximus = largest longus = longest brevis = shortest
biceps = 2 origins triceps = 3 origins quadriceps = 4 origins
Gluteus maximus Palmaris longus Adductor brevis
Biceps brachii Triceps brachii Quadriceps femoris
Muscle Shape
deltoid = triangle trapezius = trapezoid serratus = saw-­‐-­‐-­‐toothed orbicularis = circular
Deltoid Trapezius Serratus anterior Orbicularis oris
Muscle attachments / Location of Origin and/or Insertion
origin = sternum insertion = mastoid process between the ribs
Sternocleidomastoid Muscle Action
flexion extension adduction
Number of Origins (Heads)
intercostals
Flexor carpi radialis Extensor digitorum Adductor longus
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MUSCULAR SYSTEM
The Muscular System: In the following tables, you will find the names, locations, and major actions of some (not all) of the
important muscles in the human body. Given a diagram/picture, you should be able to identify
and explain the actions of all the muscles listed in the following tables. In addition, you should
also know the origin and insertion of the muscles that are marked by an asterisk.
MAJOR SKELETAL MUSCLES A.
Muscles of Facial Expression NAME OF MUSCLE
LOCATION/ DESCRIPTION
Epicranius/Occipitofrontalis Covers cranium Frontalis Occipitalis
over forehead over occipital region
ACTION
Elevates eyebrow when surprised, wrinkles forehead
Orbicularis oris
Circular muscle around the mouth
Closes lips (“kissing muscle”), whistling and speaking
Buccinator
Hollow of cheek
Compresses cheeks and enables suckling (“trumpeter’s muscle”; “suckling muscle”)
Platysma
Lower border of mandible
Expresses horror (“pouting muscle”)
Orbicularis oculi
Circular muscle around eye
Closes eye, blinking, winking, squinting
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MUSCULAR SYSTEM
B.
Muscles of Mastication NAME OF MUSCLE
Masseter* Origin: Zygomatic Arch Insertion: Lateral Mandible
LOCATION/ DESCRIPTION
Over lateral mandible
Temporalis*
Convergent muscle over Origin: Temporal lines of skull temporal bone Insertion: Coronoid process of mandible Other muscles of mastication Lateral pterygoid Medial pterygoid ACTION
Elevates mandible, closes mouth for chewing food
Elevates mandible, biting, raises the jaw C.
Muscles that move the Head and Vertebral Column: NAME OF MUSCLE
LOCATION/ DESCRIPTION
ACTION
Sternocleidomastoid* Origin: sternoclavicular region Insertion: mastoid process of temporal bone
Major neck muscle
Flexion of head toward chest (as synergists) Rotation/abduction of head (as antagonists) , ‘NO’ muscles
Erector Spinae: Spinalis (medial) Longissiumus (Intermediate) Iliocostalis
Group of dorsal midline muscles
Maintain posture, Erect spine
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MUSCULAR SYSTEM
D.
Muscles that move the Pectoral Girdle NAME OF MUSCLE
LOCATION/ DESCRIPTION
ACTION
Trapezius* Origin: occipital bone & spines of C7-­‐-­‐-­‐T12 Insertion: clavicle, spine and acromion process of scapulae
Trapezoid shaped muscle in posterior neck and upper back
Elevates pectoral girdle (“shoulder shrug”) Elevates or retracts or lowers scapula and shoulder
Pectoralis minor
Muscle deep to Pectoralis major
Scapula fixator, abduct scapula
Serratus anterior
Saw-­‐-­‐-­‐toothed lateral thoracic muscle
Scapula fixator, pushing or punching forward (Boxer’s muscle)
Levator Scapulae
Deep to the Trapezius in the back, and lateral to the neck
Elevate/adduct the scapula
E.
Muscles that move the Arm (Humerus) NAME OF MUSCLE
LOCATION/ DESCRIPTION
ACTION
Pectoralis major* Origin: clavicle, sternum, & costal cartilages of ribs 1-­‐-­‐-­‐6 Insertion: between tubercles of humerus
Large, convergent chest muscle
Flexes arm medially (pull arms forward and together) Adducts arm
Latissimus dorsi
Large, back muscle
Adduction of humerus (swimmer’s muscle)
Deltoid*
Origin: acromion & spine of Scapula Insertion: deltoid tuberosity Of humerus Teres Major
Triangular-­‐-­‐-­‐shaped shoulder muscle
Abduction of humerus
Scapula to humerus
Extends arm, adducts and rotates arm medially
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MUSCULAR SYSTEM
F. Muscles of the Rotator Cuff NAME OF MUSCLE
Infraspinatus
Subscapularis
LOCATION/ DESCRIPTION
All muscles are inserted into: Humerus
ACTION
Laterally rotates and adducts arm
Medially rotates arm
Supraspinatus
Abduction of humerus
Rotates arm laterally, abducts arm
Teres Minor
G.
Muscles that move the Forearm (radius & ulna) NAME OF MUSCLE
LOCATION/ DESCRIPTION
ACTION
Biceps Brachii* Origin: Coracoid process Insertion: Radial tuberosity
Fusiform, parallel, anterior upper arm muscle (two origins)
Flexion of arm at elbow (prime mover)
Brachialis
Muscle beneath biceps brachii
Flexion of arm at elbow (synergist)
Brachioradialis
Lateral muscle between upper and forearm
Flexion of arm at elbow (synergist)
Triceps brachii
Posterior upper arm muscle (three heads)
Extension of arm at elbow
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MUSCULAR SYSTEM
H.
Muscles of Respiration NAME OF MUSCLE
Diaphragm
External intercostal muscles
Internal intercostal muscles
LOCATION/ DESCRIPTION
Dome-­‐-­‐-­‐shaped at rest Flattened during contraction
ACTION
Increases the vertical diameter of the chest cavity
Origin: Upper rib Insertion: Lower rib
Elevate ribs
Origin: Lower rib Insertion: Upper rib
Depress ribs
I.
Muscles of the Abdominal Wall NAME OF MUSCLE
LOCATION/ DESCRIPTION
ACTION
Rectus abdominis* Origin: pubic crest & symphysis Insertion: xiphoid process & costal cartilages of 5-­‐-­‐-­‐7th ribs
Strap like muscle from costal cartilages to ilium
Tenses abdominal wall Compresses and flexes trunk
External Oblique
Superficial/lateral oblique abdominal muscle
Tenses abdominal wall Compresses trunk
Internal Oblique
Deep oblique abdominal muscle
Tenses abdominal wall Compresses trunk
Transversus abdominis
Deep abdominal muscle that runs perpendicular to rectus abdominis
Tenses abdominal wall Compresses trunk
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MUSCULAR SYSTEM
J.
Muscles that move the Thigh (Femur) NAME OF MUSCLE
Iliopsoas Two muscles: Iliacus Psoas Major
LOCATION/ DESCRIPTION
Dorsal hip muscles ACTION
Fan-­‐-­‐-­‐shaped muscle in iliac region Attaches bodies of vertebra T12 and lumbar vertebra to the femur
Flexion of thigh Flexion of thigh and flexion of trunk on thigh Maintains the posture
Gluteus Maximus* Origin: dorsal ilium, sacrum, coccyx Insertion: posterior femur
Buttocks, largest muscle in body
Extension of hip at thigh (as in walking or climbing stairs) or running
Gluteus Medius
Lateral hip muscle
Abduction of femur
Adductor muscles: Adductor Magnus Adductor Longus Adductor Brevis
Gracilis
All are located in medial portion of the thigh
Adduction and flexion of femur, medial rotation
Medial thigh muscle
Adduction of femur
Piriformis
Posterior aspect of hip deep to the Gluteus
Rotate and extend thigh laterally
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MUSCULAR SYSTEM
K.
Muscles that move the Tibia & Fibula NAME OF MUSCLE
LOCATION/ DESCRIPTION
ACTION
Rectus femoris (part of quadriceps)
Anterior thigh muscle
Extension of leg at knee
Vastus lateralis (part of quadriceps)
Lateral anterior thigh muscle
Extension of leg at knee
Vastus Medialis (part of quadriceps)
medial anterior thigh muscle
Extension of leg at knee
Vastus intermedius (part of quadriceps)
Deep anterior thigh muscle
Extension of leg at knee
Sartorius* Origin: iliac spine Insertion: medial tibia
Parallel strap-­‐-­‐-­‐like muscle that crosses the anterior thigh
Flexion of knee forward, abducts and laterally rotates thigh (Tailor's muscle)
Biceps femoris (part of hamstring)
Posterior thigh muscle
Flexion of leg at knee, extends thigh at hip
Semitendinosus (part of hamstring)
Posterior thigh muscle
Flexion of leg at knee
Semimembranosus (part of hamstring)
posterior thigh muscle
Flexion of leg at knee
L.
Muscles that move the Foot & Toes NAME OF MUSCLE
LOCATION/ DESCRIPTION
ACTION
Tibialis anterior
Anterior to tibia
Dorsiflexion of foot
Triceps surae muscles: Gastrocnemius & Soleus Posterior lower leg (i.e. calf muscle); two origins
Plantar flexion of foot (prime mover)
Deep to gastrocnemius
Plantar flexion of foot (synergist)
Gastrocnemius* Origin: condyles of femur Insertion: calcaneus
Soleus
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