Chapter 6 part 2. Skeletal Muscles of the Body

Transcription

1 Chapter 6 part 2 Skeletal Muscles of the Body

2 Basic Principles muscles in the human body (you are required to learn 45, lucky kids)! Skeletal Muscles pull on bones Origin of a muscle = point of attachment on a stationary bone Insertion of a muscle = point of attachment on the bone that is moving

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

4 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 balland-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.

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

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

7 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.

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

9 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.

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

11 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.

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

13 Special Movements Dorsiflexion 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.

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

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

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

17 Special Movements Supination 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.

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

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

20 Figure 6.13h Body movements. Opposition (h) Opposition

21 Interactions of Skeletal Muscles in the Body In general, groups of muscles that produce opposite actions lie on opposite sides of a joint 2015 Pearson Education, Inc.

22 Figure 6.14a Muscle action. (a) A muscle that crosses on the anterior side of a joint produces flexion* Example: Pectoralis major (anterior view) * These generalities do not apply to the knee and ankle because the lower limb is rotated during development. The muscles that cross these joints posteriorly produce flexion, and those that cross anteriorly produce extension.

23 Figure 6.14b Muscle action. (b) A muscle that crosses on the posterior side of a joint produces extension* Example: Latissimus dorsi (posterior view) The latissimus dorsi is the antagonist of the pectoralis major. * These generalities do not apply to the knee and ankle because the lower limb is rotated during development. The muscles that cross these joints posteriorly produce flexion, and those that cross anteriorly produce extension.

24 Figure 6.14c Muscle action. (c) A muscle that crosses on the lateral side of a joint produces abduction Example: Deltoid middle fibers (anterolateral view)

25 Figure 6.14d Muscle action. (d) A muscle that crosses on the medial side of a joint produces adduction Example: Teres major (posterolateral view) The teres major is the antagonist of the deltoid.

26 Types of Muscles Prime mover muscle with the major responsibility for a certain movement Antagonist muscle that opposes or reverses a prime mover Synergist muscle that aids a prime mover in a movement and helps prevent rotation Fixator stabilizes the origin of a prime mover 2015 Pearson Education, Inc.

27 There are 7 different ways that muscles have been named

28 Naming of muscles Relative Size of the muscle Example = gluteus maximus gluteus minimus

29 Naming muscles Direction the muscle fibers run Example = rectus (straight) abdominis

30 Naming muscles Location of the muscle in the body Example = frontalis lies over the frontal bone (anatomical terms)

31 Naming of muscles Number of origins Example = triceps (three heads)

32 Naming muscles Location of Origin and insertion Example = sternocleidomastoid Attaches to the sternum, clavicle and the mastoid process of the temporal bone

33 Naming muscles Shape of the muscle Example = deltoid (triangle)

34 Naming of muscles Action the muscle makes Example extensor carpi extends flexor carpi flexes