Chapter 6 The Muscular System Lecture Presentation by

Chapter 6 The Muscular System Lecture Presentation by Patty Bostwick-Taylor Florence-Darlington Technical College © 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 1. Origin: attachment to a moveable bone 2. Insertion: attachment to an immovable bone © 2015 Pearson Education, Inc.

Figure 6. 12 Muscle attachments (origin and insertion). Muscle contracting Origin Brachialis Tendon Insertion © 2015 Pearson Education, Inc.

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. 13 a Body movements. Flexion Hyperextension Extension Flexion Extension (a) Flexion, extension, and hyperextension of the shoulder and knee © 2015 Pearson Education, Inc.

Figure 6. 13 b Body movements. Hyperextension Extension Flexion (b) Flexion, extension, and hyperextension © 2015 Pearson Education, Inc.

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. 13 c Body movements. Rotation Lateral rotation Medial rotation (c) Rotation © 2015 Pearson Education, Inc.

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. 13 d Body movements. Abduction Adduction Circumduction (d) Abduction, adduction, and circumduction © 2015 Pearson Education, Inc.

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. 13 d Body movements. Abduction Adduction Circumduction (d) Abduction, adduction, and circumduction © 2015 Pearson Education, Inc.

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.

Figure 6. 13 e Body movements. Dorsiflexion Plantar flexion (e) Dorsiflexion and plantar flexion © 2015 Pearson Education, Inc.

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

Figure 6. 13 f Body movements. Inversion (f) Inversion and eversion © 2015 Pearson Education, Inc. Eversion

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.

Figure 6. 13 g Body movements. Pronation (radius rotates over ulna) Supination (radius and ulna are parallel) S P (g) Supination (S) and pronation (P) © 2015 Pearson Education, Inc.

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

Figure 6. 13 h Body movements. Opposition (h) Opposition © 2015 Pearson Education, Inc.

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.

Figure 6. 14 a 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. © 2015 Pearson Education, Inc.

Figure 6. 14 b 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. © 2015 Pearson Education, Inc.

Figure 6. 14 c Muscle action. (c) A muscle that crosses on the lateral side of a joint produces abduction Example: Deltoid middle fibers (anterolateral view) © 2015 Pearson Education, Inc.

Figure 6. 14 d 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. © 2015 Pearson Education, Inc.

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. (a) (b) (a) Circular (orbicularis oris) (e) (c) (b) Converent (pectoralis major) (d) (e) Multipennate (deltoid) (f) (g) (c) Fusiform (biceps brachii) © 2015 Pearson Education, Inc. (d) Parallel (sartorius) (f) Bipennate (rectus femoris) (g) Unipennate (extensor digitorum longus)

Table 6. 3 Superficial Anterior Muscles of the Body (See Figure 6. 22) (1 of 3). © 2015 Pearson Education, Inc.

Figure 6. 16 Superficial muscles of the face and neck. Frontalis Cranial aponeurosis Temporalis Orbicularis oculi Occipitalis Zygomaticus Buccinator Orbicularis oris Platysma © 2015 Pearson Education, Inc. Masseter Sternocleidomastoid Trapezius

Table 6. 3 Superficial Anterior Muscles of the Body (See Figure 6. 22) (2 of 3). © 2015 Pearson Education, Inc.

Figure 6. 17 a Muscles of the anterior trunk, shoulder, and arm. Clavicle Deltoid Sternum Pectoralis major Biceps brachii Brachialis Brachioradialis © 2015 Pearson Education, Inc. (a)

Figure 6. 17 b Muscles of the anterior trunk, shoulder, and arm. Pectoralis major Rectus abdominis Transversus abdominis Internal oblique External oblique Aponeurosis (b) © 2015 Pearson Education, Inc.

Table 6. 3 Superficial Anterior Muscles of the Body (See Figure 6. 22) (3 of 3). © 2015 Pearson Education, Inc.

Figure 6. 20 c Pelvic, hip, and thigh muscles of the right side of the body. 12 th thoracic vertebra 12 th rib Iliac crest Iliopsoas Psoas major Iliacus 5 th lumbar vertebra Anterior superior iliac spine Quadriceps Sartorius Adductor group Rectus femoris Vastus lateralis Vastus medialis Patellar ligament © 2015 Pearson Education, Inc. (c)

Figure 6. 21 a Superficial muscles of the right leg. Fibularis longus Fibularis brevis Tibialis anterior Extensor digitorum longus Fibularis tertius (a) © 2015 Pearson Education, Inc. Tibia Soleus

Figure 6. 20 d Pelvic, hip, and thigh muscles of the right side of the body. Inguinal ligament Adductor muscles Sartorius Vastus lateralis (d) © 2015 Pearson Education, Inc.

Table 6. 4 Superior Posterior Muscles of the Body (Some Forearm Muscles Also Shown) (See Figure 6. 23) (1 of 3). © 2015 Pearson Education, Inc.

Figure 6. 18 a Muscles of the posterior neck, trunk, and arm. Occipital bone Sternocleidomastoid Trapezius Spine of scapula Deltoid (cut) Deltoid Triceps brachii Latissimus dorsi (a) © 2015 Pearson Education, Inc. Humerus Olecranon process of ulna (deep to tendon)

Figure 6. 18 b Muscles of the posterior neck, trunk, and arm. C 7 T 1 Erector spinae • Iliocostalis • Longissimus • Spinalis Quadratus lumborum (b) © 2015 Pearson Education, Inc.

Figure 6. 19 The fleshy deltoid muscle is a favored site for administering intramuscular injections. Deltoid muscle Humerus © 2015 Pearson Education, Inc.

Table 6. 4 Superior Posterior Muscles of the Body (Some Forearm Muscles Also Shown) (See Figure 6. 23) (2 of 3). © 2015 Pearson Education, Inc.

Figure 6. 18 a Muscles of the posterior neck, trunk, and arm. Occipital bone Sternocleidomastoid Trapezius Spine of scapula Deltoid (cut) Deltoid Triceps brachii Latissimus dorsi (a) © 2015 Pearson Education, Inc. Humerus Olecranon process of ulna (deep to tendon)

Figure 6. 22 Major superficial muscles of the anterior surface of the body. Facial • Temporalis • Masseter Shoulder • Trapezius • Deltoid Facial • Frontalis • Orbicularis oculi • Zygomaticus • Orbicularis oris Neck • Platysma • Sternocleidomastoid Thorax • Pectoralis minor • Pectoralis major • Serratus anterior • Intercostals Arm • Triceps brachii • Brachialis Forearm • Brachioradialis • Flexor carpi radialis Abdomen • Rectus abdominis • External oblique • Internal oblique • Transversus abdominis Pelvis/thigh • Iliopsoas Thigh (Quadriceps) • Rectus femoris • Vastus lateralis • Vastus medialis Leg • Fibularis longus • Extensor digitorum longus • Tibialis anterior © 2015 Pearson Education, Inc. Thigh • Sartorius • Adductor muscle • Gracilis Leg • Gastrocnemius • Soleus

Figure 6. 23 Major superficial muscles of the posterior surface of the body. Neck • Occipitalis • Sternocleidomastoid • Trapezius Arm • Triceps brachii • Brachialis Forearm • Brachioradialis • Extensor carpi radialis longus • Flexor carpi ulnaris • Extensor digitorum Shoulder/Back • Deltoid • Latissimus dorsi Hip • Gluteus medius • Gluteus maximus • Iliotibial tract Leg • Gastrocnemius • Soleus • Fibularis longus Calcaneal (Achilles) tendon © 2015 Pearson Education, Inc. Thigh • Adductor muscle • Hamstrings: Biceps femoris Semitendinosus Semimembranosus