Muscle Names & Movement October 19-20, 2017

Rules of Muscle Movement All muscles have at least two points of attachment. The origin is attached to the less movable bone The insertion is attached to the more moveable bone. Muscles can only contract / pull. They cannot push. During contraction, the muscle insertion moves toward the origin. interactive animation! If muscles can’t push, how do we do the opposite movement? How do we extend the arm?

Rules of Muscle Movement All muscles have at least two points of attachment. The origin is attached to the less movable bone The insertion is attached to the more moveable bone. Muscles can only contract / pull. They cannot push. During contraction, the muscle insertion moves toward the origin. interactive animation! Different muscles – called antagonists – do the opposite movement. Example: biceps flexes the elbow while the triceps extends the muscle.

Movements Flexion – a movement that decreases the angle between two bones, bringing them closer together. Extension – a movement that increases the angle between two bones, putting them farther apart. Hyperextension – extension of a joint beyond its normal range of motion For each, challenge the students to identify as many different examples as possible … and act them out. Flexion of arm is going up above head

Movements abduction – movement of a limb away from the midline of the body. adduction – movement of a limb towards the midline of the body For each, challenge the students to identify as many different examples as possible … and act them out.

Movements rotation – movement of a bone raround its longitudinal axis circumduction – the proximal end of a limb is stationary while the distal end moves in a circle For each, challenge the students to identify as many different examples as possible … and act them out.

Movements of the foot dorsiflexion – lifting the foot so that its superior surface approaches the shin plantar flexion – pointing the toes inversion – turning sole medially eversion – turning sole laterally For each, challenge the students to identify as many different examples as possible … and act them out.

Movements of radius and ulna supination – turning the palm so that it faces anteriorly mnemonic: cupping a bowl of soup in your palm pronation– turning the palm so that it faces posteriorly Pronation and supination are used as synonyms (almost) for eversion and inversion in foot, too

Movements Contest time! Get bonus points for (correct) unique responses! Contest time! Work with a partner to come up with as many ways to do each of the following movements as possible: Flexion Extension Hyperextension Abduction Adduction circumduction Make this a contest! 1 pt for each correct, 2 pts for each one no one else go!

Types of Muscles Name Definition Example Prime Mover Muscle that has major responsibility for a certain motion Brachialis is prime mover for elbow flexion Antagonist Muscle that reverses/opposes a motion Triceps is the antagonist for elbow flexion Synergist Muscles that assist movement by also producing the motion or stabilizing joints and reducing unwanted movements Biceps brachii and brachioradialis are synergists for elbow flexion Fixator A type of synergist that stabilizes the origin of the prime mover, so that only the insertion moves Rotator cuff muscles are fixators of elbow flexion Rotator cuff muscles are found around scapula Note: Muscles often have different roles for different motions. For example, a prime mover for one motion is usually the antagonist for the opposite motion.

Muscles of the anterior face and neck Name Location Action(s) Masseter Superficial cheek muscle Close jaw Orbicularis oculi Around eye Closes eye Orbicularis oris Around mouth Purses lips (kisses) Sternocleidomastoid Mastoid process of temporal bone to sternum & clavicle Flexes neck & rotates head Temporalis Over temporal bone No muscle diagrams this year!! But you need to know general location and actions … Whoop!

Muscles of respiration Name Location Action(s) diaphragm Dome-shaped muscle between thoracic and abdominal cavities Major muscle for breathing – contraction increases size of thoracic cavity for inspiration; relaxation decreases size of thoracic cavity for expiration external intercostals Under ribcage Elevates ribs to increase size of thoracic cavity for inspiration internal intercostals Deep to external intercostals, under ribcage Depresses ribs for forced expiration

Muscles of abdominal wall Name Location Action(s) Obliques (internal and external) Diagonal (oblique) fibers crossing from sides to center of abdomen Flexes, laterally flexes, or rotates vertebral column Rectus abdominus Straight up and down (rectus)in middle of abdomen Flexes vertebral column Transverse abdominis flexes or laterally flexes vertebral column and compresses abdominal cavity

Muscles that move the humerus Name Location Action(s) Latissimus dorsi Mid back (wrapping around to humerus) Prime mover of humerus extension (swimmer’s muscle), also adducts, & medially rotates arm Pectoralis major chest Primer mover of humerus flexion humerus, also adducts and medially rotates arm Triceps brachii Posterior of humerus Extends & adducts humerus Biceps brachii Anterior of humerus Flexes humerus Rotator cuffs Secure humerus to glenoid cavity Stabilize joint, rotates, abducts, adducts Rotator cuffs: subscapularis, supraspinatus, infraspinatus, teres minor Flexion of arm is lifting above head, extension is down, hyper extension is behind

Muscles that move the forearm Name Location Action(s) Brachialis Anterior and lateral to humerus, posterior to biceps brachii Prime mover of forearm Biceps brachii Anterior to humerus Primer mover of humerus flexion humerus, also adducts and medially rotates arm Triceps brachii Posterior to humerus Extends & adducts humerus Rotator cuffs: subscapularis, supraspinatus, infraspinatus, teres minor Flexion of arm is lifting above head, extension is down, hyper extension is behind Fun Fact: Biceps curls should really be called brachialis curls!

Muscles that move the thigh Name Location Action(s) Gluteus maximus Buttocks Prime mover of thigh extension, also lateral rotation Iliopsoas Anterior hip and thigh Prime mover of thigh flexion Gluteus maximus is one of the strongest muscles of the body Fun Fact: Iliopsoas is combination of psoas and iliacus

Muscles that move the lower leg Name Location Action(s) Quadriceps Anterior thigh, superior to knee Extends lower leg and flexes thigh hamstrings Posterior thigh, superior to knee Flexes leg and extends thigh Quadriceps (four headed) group contains four distinct muscles: rectus femoris, vastus intermedius, vastus lateralis, vastus medialis Hamstrings contains biceps femoris, semimembranosus, and semitendinosus

Practice On your note card, write the name of 3 muscles and their actions. Quiz each other on the muscle names and movements in the “congo line”. If your partner can’t guess the movement, act it out for them.

Closure What were our objectives, and what did you learn about them. How does what we did today address our statement of Inquiry, TOK connection, or Learner profile trait?