Muscle Movements, Types, and Names Pages 196-203

Muscles and Body Movements Movement is attained as a result of a muscle moving an attached bone Muscles are attached to at least two points Origin: attaches to an immovable/less movable bone Insertion: attaches to a movable bone © 2015 Pearson Education, Inc.

Figure 6.12 Muscle attachments (origin and insertion). Muscle contracting Origin Brachialis Tendon Insertion

Table 6.2 The Five Golden Rules of Skeletal Muscle Activity.

Types of Body Movements Flexion Decreases the angle of the joint Brings two bones closer together Typical of bending hinge joints (e.g., knee and elbow) or ball-and-socket joints (e.g., the hip) Extension Opposite of flexion Increases angle between two bones Typical of straightening the elbow or knee Extension beyond 180° is hyperextension © 2015 Pearson Education, Inc.

Figure 6.13a Body movements. Flexion Hyperextension Extension Flexion Extension (a) Flexion, extension, and hyperextension of the shoulder and knee

Figure 6.13b Body movements. Hyperextension Extension Flexion (b) Flexion, extension, and hyperextension

Types of Body Movements Rotation Movement of a bone around its longitudinal axis Common in ball-and-socket joints Example: moving the atlas around the dens of axis (i.e., shaking your head “no”) © 2015 Pearson Education, Inc.

Figure 6.13c Body movements. Rotation Lateral rotation Medial rotation (c) Rotation

Types of Body Movements Abduction Movement of a limb away from the midline Adduction Opposite of abduction Movement of a limb toward the midline © 2015 Pearson Education, Inc.

Figure 6.13d Body movements. Abduction Adduction Circumduction (d) Abduction, adduction, and circumduction

Types of Body Movements Circumduction Combination of flexion, extension, abduction, and adduction Common in ball-and-socket joints Proximal end of bone is stationary, and distal end moves in a circle © 2015 Pearson Education, Inc.

Figure 6.13d Body movements. Abduction Adduction Circumduction (d) Abduction, adduction, and circumduction

Special Movements Dorsiflexion Plantar flexion Lifting the foot so that the superior surface approaches the shin (toward the dorsum) Plantar flexion Depressing the foot (pointing the toes) “Planting” the foot toward the sole © 2015 Pearson Education, Inc.

Figure 6.13e Body movements. Dorsiflexion Plantar flexion (e) Dorsiflexion and plantar flexion

Special Movements Inversion Eversion Turning sole of foot medially Turning sole of foot laterally © 2015 Pearson Education, Inc.

Figure 6.13f Body movements. Inversion Eversion (f) Inversion and eversion

Special Movements Supination Pronation Forearm rotates laterally so palm faces anteriorly Radius and ulna are parallel Pronation Forearm rotates medially so palm faces posteriorly Radius and ulna cross each other like an X © 2015 Pearson Education, Inc.

Figure 6.13g Body movements. Pronation (radius rotates over ulna) Supination (radius and ulna are parallel) P S S (g) Supination (S) and pronation (P)

Special Movements Opposition Moving the thumb to touch the tips of other fingers on the same hand © 2015 Pearson Education, Inc.

Figure 6.13h Body movements. Opposition (h) Opposition

Types of Muscles Prime mover— muscle with the major responsibility for a certain movement Synergist— muscle that aids a prime mover in a movement and helps prevent rotation Fixator— stabilizes the origin of a prime mover Antagonist— muscle that opposes or reverses a prime mover It is the actions of all muscles involved that provide smooth, coordinated and precise movement. © 2015 Pearson Education, Inc.

Naming Skeletal Muscles Skeletal muscles can be named according to: direction of muscle fibers: rectus (straight) relative size of the muscle: maximus (largest) location of the muscle: temporalis (temporal bone) number of origins triceps (three heads) location of origin and insertion: sterno (on the sternum) shape of the muscle: deltoid (triangular) action: flexor/extensor (flex/extend a bone) © 2015 Pearson Education, Inc.

Figure 6.15 Relationship of fascicle arrangement to muscle structure. (b) (c) (a) Circular (orbicularis oris) (b) Converent (pectoralis major) (e) Multipennate (deltoid) (d) (f) (f) Bipennate (rectus femoris) (g) (c) Fusiform (biceps brachii) (d) Parallel (sartorius) (g) Unipennate (extensor digitorum longus)