Muscle Names & Movement November 8, 2013

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.

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 Work with a partner to come up with 5 ways to do each of the following movements: Flexion Extension Hyperextension Abduction Adduction circumduction

Types of Muscles Prime mover – muscle that has the major responsibility for a movement Antagonist – muscle that opposes / reverse a movement Muscles can be both a prime mover and an antagonist – of different motions. Example: Movement Prime mover Antagonist Elbow flexion Biceps brachii Triceps brachii Elbow extension

Types of Muscles Prime mover – muscle that has the major responsibility for a movement Antagonist – muscle that opposes / reverse a movement Synergist – muscles that assist movement by also producing the motion or stabilizing joints and reducing unwanted movements. Ex: brachialis and brachioradialis are synergists of elbow flexion because they help the biceps

Types of Muscles Prime mover – muscle that has the major responsibility for a movement Antagonist – muscle that opposes / reverse a movement Synergist – muscles that assist movement by also producing the motion or stabilizing joints and reducing unwanted movements. Fixator – a type of synergist that stabilizes the origin of the prime mover, so that only the insertion moves. Example: the rotator cuff muscles of scapula are fixators for elbow flexion.

Muscle names, locations, & actions Muscles of the anterior face and neck Name Origin Insertion Action Masseter Temporal bone mandible Close jaw Temporalis Sternocleidomastoid Sternum & clavical Mastoid process of temporal bone Flexes neck & rotates head You don’t need to memorize origins and insertions – you do need to know where each is and what they do.

Muscle names, locations, & actions Muscles of the anterior trunk Name Origin Insertion Action Pectoralis major Sternum, clavicle, and first 6 ribs Proximal humerus Adducts and flexes humerus Rectus abdominis pubis Sternum and ribs 5-7 Flexes vertebral column External oblique Lower 8 ribs Iliac crest Flexes & rotates vertebral column

Muscle names, locations, & actions Muscles of the posterior trunk Name Origin Insertion Action trapezius Occipital bone , cervicle and thoracic vertebrae Scapular spine and clavicle Extends neck and adducts scapula Latissimus dorsi Lower spine and iliac crest Proximal humerus Extends and adducts humerus deltoid Scapula and clavicle humerus Abducts humerus Trapezius b/c trapezoid- shaped; deltoid = triangle shaped

Muscle names, locations, & actions Muscles of the arm Name Origin Insertion Action Biceps brachii scapula radius Flexes elbow and supinates forearm Triceps brachii Shoulder girdle and humerus ulna Extends elbow Trapezius b/c trapezoid- shaped; deltoid = triangle shaped

Muscle names, locations, & actions Muscles of the anterior hip and thigh Name Origin Insertion Action adductor pelvis femur Adducts thigh sartorius ilium tibia Flex thigh quadriceps Femur and pelvis Flex hip and extend knee Trapezius b/c trapezoid- shaped; deltoid = triangle shaped

Muscle names, locations, & actions Muscles of the posterior hip and thigh Name Origin Insertion Action Gluteus maximus Sacrum and ilium femur Extends thigh Gluteus medius ilium tibia Abducts thigh hamstrings Femur and pelvis Extend thigh and flex knee Trapezius b/c trapezoid- shaped; deltoid = triangle shaped

Practice 1 Find as many examples as you can of prime mover – antagonist pairs in the muscles just listed Find as many synergist muscles as you can in the muscles just listed ~5 min

Practice 2 – fill in diagrams

Practice 3 In groups of 4-6, play “Simon Says” using the new vocabulary (e.g. Simon says abduct your humerus; Simon says use your quadriceps group) Simon can use notes. Try to trick each other!

Closure What were our objectives, and what did you learn about them. How does what we did today address our unit question?

Exit Ticket Describe the motion of the sartorius and name a synergist and an antagonist