© 2015 Pearson Education, Inc.

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: attachment to a moveable bone Insertion: attachment to an immovable bone © 2015 Pearson Education, Inc.

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

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

Interactions of Skeletal Muscles in the Body In general, groups of muscles that produce opposite actions lie on opposite sides of a joint We will explore examples in Figure 6.14 next © 2015 Pearson Education, Inc.

Example: Pectoralis major (anterior view) 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.

Example: Latissimus dorsi (posterior view) 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.

Example: Deltoid middle fibers (anterolateral view) 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)

Example: Teres major (posterolateral view) 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.

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.

Naming Skeletal Muscles By direction of muscle fibers Example: rectus (straight) By relative size of the muscle Example: maximus (largest) © 2015 Pearson Education, Inc.

Naming Skeletal Muscles By location of the muscle Example: temporalis (temporal bone) By number of origins Example: triceps (three heads) © 2015 Pearson Education, Inc.

Naming Skeletal Muscles By location of the muscle’s origin and insertion Example: sterno (on the sternum) By shape of the muscle Example: deltoid (triangular) By action of the muscle Example: flexor and extensor (flexes or extends 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)

Table 6. 3 Superficial Anterior Muscles of the Body (See Figure 6 Table 6.3 Superficial Anterior Muscles of the Body (See Figure 6.22) (1 of 3).

Figure 6.16 Superficial muscles of the face and neck. Cranial aponeurosis Frontalis Temporalis Orbicularis oculi Occipitalis Zygomaticus Buccinator Masseter Orbicularis oris Sternocleidomastoid Trapezius Platysma

Table 6. 3 Superficial Anterior Muscles of the Body (See Figure 6 Table 6.3 Superficial Anterior Muscles of the Body (See Figure 6.22) (2 of 3).

Figure 6.17a Muscles of the anterior trunk, shoulder, and arm. Clavicle Deltoid Sternum Pectoralis major Biceps brachii Brachialis Brachio- radialis (a)

Figure 6.17b Muscles of the anterior trunk, shoulder, and arm. Pectoralis major Rectus abdominis Transversus abdominis Internal oblique External oblique Aponeurosis (b)

Table 6. 3 Superficial Anterior Muscles of the Body (See Figure 6 Table 6.3 Superficial Anterior Muscles of the Body (See Figure 6.22) (3 of 3).

Anterior superior iliac spine Figure 6.20c Pelvic, hip, and thigh muscles of the right side of the body. 12th thoracic vertebra 12th rib Iliac crest Psoas major Iliopsoas Iliacus 5th lumbar vertebra Anterior superior iliac spine Sartorius Adductor group Rectus femoris Vastus lateralis Quadriceps Vastus medialis Patella Patellar ligament (c)

Figure 6.21a Superficial muscles of the right leg. Fibularis longus Tibia Fibularis brevis Soleus Tibialis anterior Extensor digitorum longus Fibularis tertius (a)

Inguinal ligament Adductor muscles Sartorius Vastus lateralis (d) Figure 6.20d Pelvic, hip, and thigh muscles of the right side of the body. Inguinal ligament Adductor muscles Sartorius Vastus lateralis (d)

Table 6.4 Superior Posterior Muscles of the Body (Some Forearm Muscles Also Shown) (See Figure 6.23) (1 of 3).

Figure 6.18a Muscles of the posterior neck, trunk, and arm. Occipital bone Sternocleidomastoid Spine of scapula Trapezius Deltoid (cut) Deltoid Triceps brachii Latissimus dorsi Humerus Olecranon process of ulna (deep to tendon) (a)

Figure 6.18b Muscles of the posterior neck, trunk, and arm. Erector spinae • Iliocostalis • Longissimus • Spinalis Quadratus lumborum (b)

Deltoid muscle Humerus Figure 6.19 The fleshy deltoid muscle is a favored site for administering intramuscular injections. Deltoid muscle Humerus

Table 6.4 Superior Posterior Muscles of the Body (Some Forearm Muscles Also Shown) (See Figure 6.23) (2 of 3).

Figure 6.18a Muscles of the posterior neck, trunk, and arm. Occipital bone Sternocleidomastoid Spine of scapula Trapezius Deltoid (cut) Deltoid Triceps brachii Latissimus dorsi Humerus Olecranon process of ulna (deep to tendon) (a)

• Sternocleidomastoid • Deltoid Thorax Arm • Pectoralis minor Figure 6.22 Major superficial muscles of the anterior surface of the body. Facial • Frontalis Facial • Orbicularis oculi • Temporalis • Zygomaticus • Masseter • Orbicularis oris Shoulder Neck • Trapezius • Platysma • Sternocleidomastoid • Deltoid Thorax Arm • Pectoralis minor • Triceps brachii • Pectoralis major • Biceps brachii • Serratus anterior • Brachialis • Intercostals Forearm • Brachioradialis Abdomen • Rectus abdominis • Flexor carpi radialis • External oblique Pelvis/thigh • Internal oblique • Iliopsoas • Transversus abdominis Thigh (Quadriceps) Thigh • Rectus femoris • Sartorius • Vastus lateralis • Adductor muscle • Vastus medialis • Gracilis Leg • Fibularis longus Leg • Extensor digitorum longus • Gastrocnemius • Tibialis anterior • Soleus

• Sternocleidomastoid • Trapezius Figure 6.23 Major superficial muscles of the posterior surface of the body. Neck • Occipitalis • Sternocleidomastoid • Trapezius Arm Shoulder/Back • Triceps brachii • Deltoid • Brachialis Forearm • Latissimus dorsi • Brachioradialis • Extensor carpi radialis longus • Flexor carpi ulnaris • Extensor carpi ulnaris Hip • Extensor digitorum • Gluteus medius • Gluteus maximus Thigh • Iliotibial tract • Adductor muscle • Hamstrings: Biceps femoris Semitendinosus Semimembranosus Leg • Gastrocnemius • Soleus • Fibularis longus Calcaneal (Achilles) tendon