© 2012 Pearson Education, Inc. PowerPoint ® Lecture Presentations prepared by Jason LaPres Lone Star College—North Harris 11 The Muscular System

© 2012 Pearson Education, Inc. An Introduction to the Muscular System Learning Outcomes 11-1 Describe the arrangement of fascicles in the various types of muscles, and explain the resulting functional differences Describe the classes of levers, and explain how they make muscles more efficient Predict the actions of a muscle on the basis of its origin and insertion, and explain how muscles interact to produce or oppose movements Explain how the name of a muscle can help identify its location, appearance, or function.

© 2012 Pearson Education, Inc. An Introduction to the Muscular System Learning Outcomes 11-5 Identify the principal axial muscles of the body, plus their origins, insertions, actions, and innervation Identify the principal appendicular muscles of the body, plus their origins, insertions, actions, and innervation, and compare the major functional differences between the upper and lower limbs Identify age-related changes of the muscular system.

© 2012 Pearson Education, Inc. An Introduction to the Muscular System Learning Outcomes 11-8 Explain the functional relationship between the muscular system and other body systems, and explain the role of exercise in producing various responses in other body systems.

© 2012 Pearson Education, Inc. An Introduction to the Muscular System The Muscular System Consists only of skeletal muscles Muscle Organization and Function Muscle organization affects power, range, and speed of muscle movement Fascicles Muscle cells (fibers) are organized in bundles (fascicles)

© 2012 Pearson Education, Inc Fascicle Arrangement Classification of Skeletal Muscles By the way fascicles are organized By relationships of fascicles to tendons

© 2012 Pearson Education, Inc Fascicle Arrangement Organization of Skeletal Muscle Fibers Four patterns of fascicle organization 1. Parallel 2. Convergent 3. Pennate 4. Circular

© 2012 Pearson Education, Inc Fascicle Arrangement Parallel Muscles Fibers parallel to the long axis of muscle For example, biceps brachii Depends on total number of myofibrils Directly relates to cross section of muscle 1 in. 2 (6.45 cm 2 ) of cross section develops 50 lb (23 kg) of tension

© 2012 Pearson Education, Inc. Figure 11-1a Muscle Types Based on Pattern of Fascicle Organization Parallel muscle (Biceps brachii muscle) Fascicle Cross section Body (belly)

© 2012 Pearson Education, Inc Fascicle Arrangement Convergent Muscles A broad area converges on attachment site (tendon, aponeurosis, or raphe) Muscle fibers pull in different directions, depending on stimulation For example, pectoralis muscles

© 2012 Pearson Education, Inc. Figure 11-1b Muscle Types Based on Pattern of Fascicle Organization Base of muscle Convergent muscle (Pectoralis muscles) Tendon Cross section

© 2012 Pearson Education, Inc Fascicle Arrangement Pennate Muscles Form an angle with the tendon Do not move as far as parallel muscles Contain more myofibrils than parallel muscles Develop more tension than parallel muscles

© 2012 Pearson Education, Inc Fascicle Arrangement Pennate Muscles Unipennate Fibers on one side of tendon For example, extensor digitorum Bipennate Fibers on both sides of tendon For example, rectus femoris Multipennate Tendon branches within muscle For example, deltoid

© 2012 Pearson Education, Inc. Figure 11-1c Muscle Types Based on Pattern of Fascicle Organization Extended tendon Unipennate muscle (Extensor digitorum muscle)

© 2012 Pearson Education, Inc. Figure 11-1d Muscle Types Based on Pattern of Fascicle Organization Bipennate muscle (Rectus femoris muscle)

© 2012 Pearson Education, Inc. Figure 11-1e Muscle Types Based on Pattern of Fascicle Organization Cross section Tendons Multipennate muscle (Deltoid muscle)

© 2012 Pearson Education, Inc Fascicle Arrangement Circular Muscles Also called sphincters Open and close to guard entrances of body For example, orbicularis oris muscle of the mouth

© 2012 Pearson Education, Inc. Figure 11-1f Muscle Types Based on Pattern of Fascicle Organization Contracted Relaxed Circular muscle (Orbicularis oris muscle)

© 2012 Pearson Education, Inc Levers Skeletal Motion Skeletal muscles attach to skeleton, produce motion Type of muscle attachment affects power, range, and speed of muscle movement

© 2012 Pearson Education, Inc Levers Levers Mechanically, each bone is a lever (a rigid, moving structure) And each joint a fulcrum (a fixed point) Muscles provide applied force (AF) Required to overcome load (L)

© 2012 Pearson Education, Inc Levers Function of a Lever To change: Direction of an AF Distance and speed of movement produced by an AF Effective strength of an AF

© 2012 Pearson Education, Inc Levers The Three Classes of Levers Depend on the relationship between applied force, fulcrum, and resistance 1. First-class lever 2. Second-class lever 3. Third-class lever

© 2012 Pearson Education, Inc Levers First-Class Lever Seesaw or teeter-totter is an example Center fulcrum between applied force and load Force and load are balanced

© 2012 Pearson Education, Inc. Figure 11-2a The Three Classes of Levers First-class lever. The applied force and the load are on opposite sides of the fulcrum. Load Fulcrum Applied force

© 2012 Pearson Education, Inc Levers Second-Class Lever Wheelbarrow is an example Center resistance between applied force and fulcrum A small force moves a large weight

© 2012 Pearson Education, Inc. Figure 11-2b The Three Classes of Levers Second-class lever. The load lies between the applied force and the fulcrum. Load Fulcrum Applied force

© 2012 Pearson Education, Inc Levers Third-Class Lever Most common levers in the body Center applied force between load and fulcrum Greater force moves smaller load Maximizes speed and distance traveled

© 2012 Pearson Education, Inc. Figure 11-2c The Three Classes of Levers Third-class lever. The force is applied between the load and the fulcrum. Biceps brachii muscle Load Fulcrum Applied force

© 2012 Pearson Education, Inc Muscle Attachments to Other Tissues Origins and Insertions Muscles have one fixed point of attachment (origin) And one moving point of attachment (insertion) Most muscles originate or insert on the skeleton Origin is usually proximal to insertion

© 2012 Pearson Education, Inc Muscle Attachments to Other Tissues Actions Movements produced by muscle contraction Body movements For example, flexion, extension, adduction, etc. Described in terms of bone, joint, or region

© 2012 Pearson Education, Inc Muscle Attachments to Other Tissues Muscle Interactions Muscles work in groups to maximize efficiency Smaller muscles reach maximum tension first, followed by larger, primary muscles Muscle Terminology Based on Function Agonist (or prime mover) Antagonist Synergist

© 2012 Pearson Education, Inc Muscle Attachments to Other Tissues Agonist (Prime Mover) Produces a particular movement Antagonist Opposes movement of a particular agonist Synergist A smaller muscle that assists a larger agonist Helps start motion or stabilize origin of agonist (fixator)

© 2012 Pearson Education, Inc Muscle Attachments to Other Tissues Muscle Opposition Agonists and antagonists work in pairs When one contracts, the other stretches Such as flexors–extensors, abductors–adductors, etc.

© 2012 Pearson Education, Inc Naming Skeletal Muscles Names of Skeletal Muscles Correct names of muscles include the term muscle Exceptions: Platysma Diaphragm

© 2012 Pearson Education, Inc Naming Skeletal Muscles Descriptive Names for Skeletal Muscles Location in the body Origin and insertion Fascicle organization Relative position Structural characteristics Action

© 2012 Pearson Education, Inc Naming Skeletal Muscles Location in the Body Identifies body regions For example, temporalis muscle Origin and Insertion First part of name indicates origin Second part of name indicates insertion For example, genioglossus muscle

© 2012 Pearson Education, Inc Naming Skeletal Muscles Fascicle Organization Describes fascicle orientation within muscle For example, rectus (straight), transversus, oblique

© 2012 Pearson Education, Inc Naming Skeletal Muscles Position Externus (superficialis) Visible at body surface Internus (profundus) Deep muscles Extrinsic Muscles outside an organ Intrinsic Muscles inside an organ

© 2012 Pearson Education, Inc Naming Skeletal Muscles Structural Characteristics Number of tendons bi = 2, tri = 3 Shape Trapezius, deltoid, rhomboid Size Many terms refer to muscle size

© 2012 Pearson Education, Inc Naming Skeletal Muscles Action Movements For example, flexor, extensor, retractor Occupations or habits For example, risor = laughter

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Specific Regions of the Body Abdominis (abdomen) Anconeus (elbow) Auricularis (auricle of ear) Brachialis (brachium) Capitis (head) Carpi (wrist) Cervicis (neck) Cleido-/-clavius

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Specific Regions of the Body Coccygeus (coccyx) Costalis (ribs) Cutaneous (skin) Femoris (femur) Genio- (chin) Glosso-/-glossal (tongue) Hallucis (great toe) Ilio- (ilium) Inguinal (groin)

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Specific Regions of the Body Lumborum (lumbar region) Nasalis (nose) Nuchal (back of neck) Oculo- (eye) Oris (mouth) Palpebrae (eyelid) Pollicis (thumb) Popliteus (posterior to knee) Psoas (loin)

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Specific Regions of the Body Radialis (radius) Scapularis (scapula) Temporalis (temples) Thoracis (thoracic region) Tibialis (tibia) Ulnaris (ulna) Uro- (urinary)

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Position, Direction, or Fascicle Organization Anterior (front) Externus (superficial) Extrinsic (outside) Inferioris (inferior) Internus (deep, internal) Intrinsic (inside) Lateralis (lateral) Medialis/medius (medial, middle)

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Position, Direction, or Fascicle Organization Oblique Posterior Profundus (deep) Rectus (straight, parallel) Superficialis Superioris (superior) Transversus (transverse)

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Structural Characteristics of the Muscle Nature of Origin Biceps (two heads) Triceps (three heads) Quadriceps (four heads)

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Structural Characteristics of the Muscle Shape Deltoid (triangle) Orbicularis (circle) Pectinate (comblike) Piriformis (pear-shaped) Platy- (flat) Pyramidal (pyramid)

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Structural Characteristics of the Muscle Shape Rhomboid Serratus (serrated) Splenius (bandage) Teres (long and round) Trapezius (trapezoid)

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Structural Characteristics of the Muscle Other Striking Features Alba (white) Brevis (short) Gracilis (slender) Lata (wide) Latissimus (widest) Longissimus (longest) Longus (long)

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Structural Characteristics of the Muscle Other Striking Features Magnus (large) Major (larger) Maximus (largest) Minimus (smallest) Minor (smaller) Vastus (great)

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Actions General Abductor Adductor Depressor Extensor Flexor Levator Pronator Rotator Supinator Tensor

© 2012 Pearson Education, Inc Naming Skeletal Muscles Terms Indicating Actions Specific Buccinator (trumpeter) Risorius (a laughter) Sartorius (like a tailor)

© 2012 Pearson Education, Inc Naming Skeletal Muscles Divisions of the Muscular System 1. Axial muscles Position head and spinal column Move rib cage 60% of skeletal muscles 2. Appendicular muscles Support pectoral and pelvic girdles Support limbs 40% of skeletal muscles

© 2012 Pearson Education, Inc. Figure 11-3a An Overview of the Major Skeletal Muscles Axial Muscles Frontal belly of occipitofrontalis Temporoparietalis (reflected) Temporalis Sternocleidomastoid Rectus abdominis External oblique Linea alba Trapezius Clavicle Deltoid Pectoralis major Latissimus dorsi Serratus anterior Biceps brachii Triceps brachii Brachialis Pronator teres Brachioradialis Extensor carpi radialis brevis Palmaris longus Flexor carpi radialis Flexor digitorum superficialis Flexor carpi ulnaris Extensor carpi radialis longus Sternum Appendicular Muscles An anterior view. ATLAS: Plates 1a; 39a–d

© 2012 Pearson Education, Inc. Figure 11-3a An Overview of the Major Skeletal Muscles Iliotibial tract Patella Tibia Inferior extensor retinaculum Superior extensor retinaculum Medial malleolus of tibia Lateral malleolus of fibula An anterior view. ATLAS: Plates 1a; 39a–d Gluteus medius Tensor fasciae latae Iliopsoas Pectineus Adductor longus Gracilis Sartorius Rectus femoris Vastus lateralis Vastus medialis Gastrocnemius Fibularis longus Tibialis anterior Soleus Extensor digitorum longus Appendicular Muscles

© 2012 Pearson Education, Inc. Figure 11-3b An Overview of the Major Skeletal Muscles Trapezius Deltoid Teres major Latissimus dorsi Infraspinatus Triceps brachii (long head) Brachioradialis Extensor carpi ulnaris Anconeus Flexor carpi ulnaris Extensor carpi radialis longus External oblique Occipital belly of occipitofrontalis Sternocleidomastoid Extensor digitorum Appendicular Muscles Triceps brachii (lateral head) Teres minor Rhomboid major Axial Muscles A posterior view ATLAS: Plates 1b; 40a,b

© 2012 Pearson Education, Inc. Figure 11-3b An Overview of the Major Skeletal Muscles Calcaneal tendon Iliotibial tract Calcaneus Gluteus maximus Tensor fasciae latae Semitendinosus Plantaris Adductor magnus Gracilis Sartorius Biceps femoris Semimembranosus Gastrocnemius Soleus Gluteus medius A posterior view ATLAS: Plates 1b; 40a,b Appendicular Muscles

© 2012 Pearson Education, Inc Axial Musculature The Axial Muscles Divisions based on location and function 1. Muscles of the head and neck 2. Muscles of the vertebral column 3. Oblique and rectus muscles 4. Muscles of the pelvic floor

© 2012 Pearson Education, Inc Axial Musculature Muscles of Facial Expression Originate on skull Extrinsic Eye Muscles Originate on surface of orbit Control position of eye Muscles of Mastication Move the mandible Muscles of the Tongue Names end in glossus

© 2012 Pearson Education, Inc Axial Musculature Muscles of the Pharynx Begin swallowing process Anterior Muscles of the Neck Control position of larynx Depress the mandible Support tongue and pharynx

© 2012 Pearson Education, Inc Axial Musculature Muscles of Facial Expression Orbicularis oris constricts the mouth opening Buccinator moves food around the cheeks Muscles of the epicranium (scalp)

© 2012 Pearson Education, Inc Axial Musculature Muscles of Facial Expression Muscles of the epicranium (scalp) Temporoparietalis Occipitofrontalis Frontal and occipital bellies Separated by epicranial aponeurosis Platysma Covers anterior surface of neck

© 2012 Pearson Education, Inc. Figure 11-4a Muscles of Facial Expression Epicranial aponeurosis Depressor labii inferioris Orbicularis oris Mentalis (cut) Zygomaticus major Levator anguli oris Zygomaticus minor Levator labii superioris Nasalis Orbicularis oculi Procerus Frontal belly of occipitofrontalis Depressor anguli oris Omohyoid Platysma (cut and reflected) Lateral view Temporoparietalis (cut and reflected) Temporalis Occipital belly of occipitofrontalis Masseter Buccinator Sternocleidomastoid Trapezius

© 2012 Pearson Education, Inc. Figure 11-4b Muscles of Facial Expression Frontal belly of occipitofrontalis Corrugator supercilii Temporalis (temporoparietalis removed) Orbicularis oculi Nasalis Zygomaticus minor Zygomaticus major Orbicularis oris Risorius Platysma Mentalis (cut) Thyroid cartilage of the larynx Epicranial aponeurosis Temporoparietalis (cut and reflected) Temporalis Procerus Levator labii superioris Levator anguli oris Masseter Buccinator Depressor anguli oris Depressor labii inferioris Sternal head of sternocleidomastoid Clavicular head of sternocleidomastoid Trapezius Clavicle Platysma (cut and reflected) Anterior view

© 2012 Pearson Education, Inc. Table 11-2 Muscles of Facial Expression (Figure 11-4)

© 2012 Pearson Education, Inc. Table 11-2 Muscles of Facial Expression (Figure 11-4)

© 2012 Pearson Education, Inc Axial Musculature Six Extrinsic Eye Muscles (Oculomotor Muscles) 1. Inferior rectus 2. Medial rectus 3. Superior rectus 4. Lateral rectus 5. Inferior oblique 6. Superior oblique

© 2012 Pearson Education, Inc. Figure 11-5a Extrinsic Eye Muscles Inferior oblique Optic nerve Superior rectus Superior oblique Frontal bone Levator palpebrae superioris Trochlea (ligamentous sling) Lateral rectus Inferior rectus Maxilla Lateral surface, right eye

© 2012 Pearson Education, Inc. Figure 11-5b Extrinsic Eye Muscles Trochlea Superior rectus Levator palpebrae superioris Superior oblique Medial rectus Inferior rectus Optic nerve Medial surface, right eye

© 2012 Pearson Education, Inc. Figure 11-5c Extrinsic Eye Muscles Superior rectus Lateral rectus Inferior oblique Trochlea Superior oblique Medial rectus Inferior rectus Anterior view, right eye

© 2012 Pearson Education, Inc. Figure 11-5d Extrinsic Eye Muscles Levator palpebrae superioris Superior rectus Oculomotor nerve (N III) Lateral rectus Abducens nerve (N VI) Inferior oblique Trochlear nerve (N IV) Trochlea Superior oblique Medial rectus Optic nerve (N II) Inferior rectus Anterior view, right orbit

© 2012 Pearson Education, Inc. Table 11-3 Extrinsic Eye Muscles (Figure 11–5)

© 2012 Pearson Education, Inc Axial Musculature Muscles of Mastication Masseter The strongest jaw muscle Temporalis Helps lift the mandible Pterygoid muscles Position mandible for chewing

© 2012 Pearson Education, Inc. Figure 11-6a Muscles of Mastication Superior temporal line Temporalis Capsule of temporomandibular joint Zygomatic arch Masseter Lateral view. The temporalis muscle passes medial to the zygomatic arch to insert on the coronoid process of the mandible. The masseter inserts on the angle and lateral surface of the mandible.

© 2012 Pearson Education, Inc. Figure 11-6b Muscles of Mastication Lateral pterygoid Medial pterygoid Cut edge of mandible Lateral view, pterygoid muscles exposed. The location and orientation of the pterygoid muscles can be seen after the overlying muscles, along with a portion of the mandible, are removed.

© 2012 Pearson Education, Inc. Table 11-4 Muscles of Mastication (Figure 11–6)

© 2012 Pearson Education, Inc Axial Musculature Muscles of the Tongue All named for origin and insertion Palatoglossus Styloglossus Genioglossus Hyoglossus

© 2012 Pearson Education, Inc. Figure 11-7 Muscles of the Tongue Styloid process Palatoglossus Styloglossus Genioglossus Hyoglossus Hyoid bone Mandible (cut)

© 2012 Pearson Education, Inc. Table 11-5 Muscles of the Tongue (Figure 11–7)

© 2012 Pearson Education, Inc Axial Musculature Muscles of the Pharynx Pharyngeal constrictor muscles Move food into esophagus Laryngeal elevator muscles Elevate the larynx Palatal muscles Lift the soft palate

© 2012 Pearson Education, Inc. Figure 11-8 Muscles of the Pharynx Palatal Muscles Levator veli palatini Tensor veli palatini Laryngeal elevators Pharyngeal Constrictors Superior Middle Inferior Esophagus

© 2012 Pearson Education, Inc. Table 11-6 Muscles of the Pharynx (Figure 11–8)

© 2012 Pearson Education, Inc Axial Musculature Anterior Muscles of the Neck Digastric From chin to hyoid And hyoid to mastoid Mylohyoid Floor of the mouth Geniohyoid Between hyoid and chin

© 2012 Pearson Education, Inc Axial Musculature Anterior Muscles of the Neck Stylohyoid Between hyoid and styloid Sternocleidomastoid From clavicle and sternum to mastoid Omohyoid Attaches scapula, clavicle, first rib, and hyoid

© 2012 Pearson Education, Inc. Figure 11-9a Muscles of the Anterior Neck Mandible Mylohyoid Digastric Anterior belly Posterior belly Sternocleidomastoid (cut) Omohyoid Superior belly Inferior belly Clavicle Cut heads of sternocleidomastoid Sternum Anterior view Sternal head Clavicular head Sternocleidomastoid Sternohyoid Sternothyroid Thyroid cartilage of larynx Thyrohyoid Hyoid bone Stylohyoid Geniohyoid Mylohyoid (cut and reflected)

© 2012 Pearson Education, Inc. Figure 11-9b Muscles of the Anterior Neck Superior view Hyoid bone Genioglossus (cut) Mylohyoid Geniohyoid Mandible

© 2012 Pearson Education, Inc. Table 11-7 Anterior Muscles of the Neck (Figure 11–9)

© 2012 Pearson Education, Inc Axial Musculature Muscles of the Vertebral Column Spinal extensors or erector spinae muscles (superficial and deep) Spinal flexors (transversospinalis)

© 2012 Pearson Education, Inc Axial Musculature Muscles of the Vertebral Column Superficial Spinal Extensors Spinalis group Longissimus group Iliocostalis group

© 2012 Pearson Education, Inc Axial Musculature Muscles of the Vertebral Column Deep Spinal Extensors Semispinalis group Multifidus muscle Interspinalis muscles Intertransversarii muscles Rotatores muscles

© 2012 Pearson Education, Inc. Figure Muscles of the Vertebral Column Erector Spinae, Deep Layer Semispinalis Group Semispinalis capitis Semispinalis cervicis Semispinalis thoracis Multifidus Erector Spinae, Superficial Layer Splenius capitis Spinalis, Longissimus, and Iliocostalis Group Longissimus capitis Spinalis cervicis Longissimus cervicis Iliocostalis cervicis Iliocostalis thoracis Longissimus thoracis Spinalis thoracis Iliocostalis lumborum

© 2012 Pearson Education, Inc. Table 11-8 Muscles of the Vertebral Column (Figure 11–10)

© 2012 Pearson Education, Inc Axial Musculature Muscles of the Vertebral Column Spinal Flexors Neck Longus capitis and longus colli Rotate and flex the neck Lumbar Quadratus lumborum muscles Flex spine and depress ribs

© 2012 Pearson Education, Inc. Figure Muscles of the Vertebral Column Intervertebral Muscles, Posterior View Rotatores Intertransversarii Spinous process of vertebra Transverse process of vertebra Interspinales Posterior view Spinal Flexors Quadratus lumborum Flexors of the Anterior Cervical and Thoracic Spine Thoracodorsal fascia Longus capitis Longus colli Erector Spinae, Deep Layer

© 2012 Pearson Education, Inc. Table 11-8 Muscles of the Vertebral Column (Figure 11–10)

© 2012 Pearson Education, Inc Axial Musculature Oblique and Rectus Muscles Lie within the body wall Oblique muscles Compress underlying structures Rotate vertebral column Rectus muscles Flex vertebral column Oppose erector spinae

© 2012 Pearson Education, Inc Axial Musculature Oblique Muscles Cervical region Scalene muscles Flex the neck Thoracic region Intercostal muscles (external and internal) Respiratory movements of ribs Transversus thoracis Cross inner surface of ribs

© 2012 Pearson Education, Inc Axial Musculature Oblique Muscles Abdominopelvic region (same pattern as thoracic) External oblique muscles Internal oblique muscles Transversus abdominis

© 2012 Pearson Education, Inc Axial Musculature Rectus Muscles Rectus abdominis Between xiphoid process and pubic symphysis Divided longitudinally by linea alba Divided transversely by tendinous inscriptions

© 2012 Pearson Education, Inc Axial Musculature Rectus Muscles Diaphragmatic muscle or diaphragm Divides thoracic and abdominal cavities Performs respiration

© 2012 Pearson Education, Inc. Figure 11-11a Oblique and Rectus Muscles and the Diaphragm Scalenes Anterior Middle Posterior Anterior view, cervical region

© 2012 Pearson Education, Inc. Figure 11-11b Oblique and Rectus Muscles and the Diaphragm Anterior view Linea alba Tendinous inscription External oblique Rectus abdominis Cut edge of rectus sheath Internal oblique External oblique (cut) External intercostal Internal intercostal Serratus anterior

© 2012 Pearson Education, Inc. Figure 11-11c Oblique and Rectus Muscles and the Diaphragm Superior view at the level of the diaphragm Central tendon of diaphragm Erector spinae group Spinal cord Thoracic aorta Diaphragm Serratus anterior Esophagus Internal intercostal External intercostal T 10 Inferior vena cava External oblique Costal cartilages Xiphoid process Rectus abdominis

© 2012 Pearson Education, Inc. Figure 11-11d Oblique and Rectus Muscles and the Diaphragm Horizontal section view at the level of the umbilicus Linea alba Rectus abdominis Thoracolumbar fascia Internal oblique Transversus abdominis External oblique Rectus sheath L3L3 Quadratus lumborum

© 2012 Pearson Education, Inc. Table 11-9 Oblique and Rectus Muscle Groups (Figure 11–11)

© 2012 Pearson Education, Inc. Table 11-9 Oblique and Rectus Muscle Groups (Figure 11–11)

© 2012 Pearson Education, Inc Axial Musculature Muscles of the Pelvic Floor Functions of pelvic floor muscles 1. Support organs of pelvic cavity 2. Flex sacrum and coccyx 3. Control movement of materials through urethra and anus

© 2012 Pearson Education, Inc Axial Musculature Muscles of the Pelvic Floor Perineum Muscular sheet forming the pelvic floor, divided into: 1. Anterior urogenital triangle 2. Posterior anal triangle

© 2012 Pearson Education, Inc Axial Musculature Perineum Urogenital diaphragm Deep muscular layer between pubic bones Supports the pelvic floor And muscles of the urethra Superficial muscles of the urogenital triangle Support external genitalia

© 2012 Pearson Education, Inc Axial Musculature Muscles of the Pelvic Floor Perineum Pelvic diaphragm Deep muscular layer extending to pubis Supports anal triangle