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The Muscular System

PowerPoint ® Lecture Presentations prepared by Alexander G. Cheroske Mesa Community College at Red Mountain

Section 1: Functional Organization of the Muscular System

• Learning Outcomes •

10.1

Describe the arrangement of fascicles in the various types of muscles, explain the resulting functional differences, and explain how different classes of levers affect muscle efficiency.

•

10.2

Explain how the name of a muscle can help identify its location, appearance, or function.

•

10.3

Describe the separation of muscles into axial and appendicular divisions.

Section 1: Functional Organization of the Muscular System

•

Muscular system

• • Accounts for almost half body weight Contains ~700 muscles • Vary widely in size, shape, and function • Performance varies on how fibers are organized and how muscle attaches to skeleton • Divided into two divisions

Axial muscles

• Support and position axial skeleton

Appendicular muscles

The proportion of total body weight contributed by the muscular system Urinary system 0.7% Respiratory system 1.7% Nervous system 2% Digestive system 6% Lymphatic system 0.3% Reproductive system 0.15% Endocrine system 0.15% Cardiovascular system 9% Integumentary system 16% Skeletal system 20% Muscular system 44% The two divisions of the muscular system: axial muscles and appendicular muscles Axial muscles Tendons conduct the forces of contraction to perform specific tasks.

Appendicular muscles Figure 10 Section 1

Module 10.1: Fascicle organization and range of motion

•

Fascicle organization

•

Parallel muscle

• Fascicles parallel to muscle long axis • Most skeletal muscles in the body are parallel • Some flat with broad attachments (aponeuroses) • Some plump and cylindrical with tendon attachments • Has central

body

A parallel muscle: the biceps brachii 1 Fascicle Body (belly)

(1) Figure 10.1 1

Module 10.1: Fascicle organization and range of motion

•

Fascicle organization

(continued) •

Convergent muscle

• Fascicles extending over broad area converge on common attachment site • Versatile action • Different portions can contract to produce different actions • Entire muscle can contract • Pulls less on attachment compared to parallel • Example: pectoralis major © 2011 Pearson Education, Inc.

A convergent muscle: the pectoralis major Base of muscle 2 Tendon

(2) Figure 10.1 2

Module 10.1: Fascicle organization and range of motion

•

Fascicle organization

(continued) •

Pennate muscle

(

penna,

feather) • Fascicles form common angle with tendon • Pull at an angle on tendon • Shorter movement of tendon versus parallel • Contain more fibers than parallel of same size so produces more tension © 2011 Pearson Education, Inc.

Module 10.1: Fascicle organization and range of motion

•

Fascicle organization

(continued) •

Pennate muscle

(continued) • Three types

•

Unipennate

(all fibers on one side of tendon) Example: extensor digitorum •

Bipennate

(fibers insert on both sides of tendon) Example: rectus femoris •

Multipennate

Three pennate muscles Extensor digitorum muscle Rectus femoris muscle Deltoid muscle Tendons 3 Extended tendon If all the muscle fibers are on the same side of the tendon, the pennate muscle is unipennate.

If a pennate muscle has fibers on both sides of the tendon, it is called bipennate.

If the tendon branches within a pennate muscle, the muscle is said to be multipennate.

(3c) (3a) (3b) Figure 10.1 3

A circular muscle, or sphincter Contracted 4 Relaxed (4) Figure 10.1 4

Module 10.1: Fascicle organization and range of motion

• Levers and Leverage • Skeletal muscle force, speed, and direction depend on how it is attached to a lever • Lever moves when applied force overcomes load • Lever = rigid structure (bone) • Fulcrum = fixed point on which lever pivots (joint) • Applied force = muscle action Animation: Classes of Levers © 2011 Pearson Education, Inc.

Module 10.1: Fascicle organization and range of motion

• Levers and Leverage (continued) • Lever classes

• • •

First-class lever

Fulcrum (F) between applied force (AF) and load (L) • Acts like seesaw Balance depends on sizes of force and load and distribution on lever Few examples in body but important © 2011 Pearson Education, Inc.

A first-class lever Load Fulcrum Applied force

Figure 10.1 5

Module 10.1: Fascicle organization and range of motion

• Levers and Leverage (continued) • Lever classes (continued)

• •

Second-class lever

A second-class lever Fulcrum Load Applied force

Figure 10.1 6

Module 10.1: Fascicle organization and range of motion

• Levers and Leverage (continued) • Lever classes (continued)

• • •

Third-class lever

A third-class lever Applied force Load Biceps brachii muscle Fulcrum

Figure 10.1 7

Module 10.1 Review

Define a lever, and describe the three classes of levers.

The joint between the occipital bone of the skull and the first cervical vertebra (atlas) is which part of which class of lever system?

Why does a pennate muscle generate more tension than does a parallel muscle of the same size?

Module 10.2: Muscle names

• Individual muscle parts • • • •

Origin

Fixed attachment Most are bones, some are connective tissue sheaths or bands (examples:

intermuscular septa

or interosseus membranes) Typically proximal to insertion in anatomical position • •

Insertion

Movable attachment • •

Action

The origins, insertion, and action of the biceps brachii muscle Origins of biceps brachii muscle Action Insertion of biceps brachii muscle Figure 10.2 1

Module 10.2: Muscle names

• • • Muscles working together • •

Agonist

(prime mover) Muscle whose contraction chiefly responsible for producing particular movement Example: biceps brachii is agonist for elbow flexion • • •

Synergist

(

syn-,

together +

ergon,

Module 10.2: Muscle names

• • Muscles working together (continued) • •

Antagonist

Descriptions of muscles based on their function Agonist, or prime mover Synergist Insertion of brachioradialis muscle

Antagonist Origin of brachioradialis muscle Figure 10.2 2

Module 10.2: Muscle names

• Muscle terminology examples • Terms indicating specific body regions • Abdominis (abdomen) • Anconeus (elbow) • Auricularis (auricle of ear) • Brachialis (brachium) • Terms indicating position, direction of fascicle organization • Anterior (front) • Externus (superficial) • Extrinsic (outside) • Inferioris (inferior) © 2011 Pearson Education, Inc.

Module 10.2: Muscle names

• Muscle terminology examples (continued) • Terms indicating structural characteristics of muscle • Name of origin • • Biceps (two heads) Triceps (three heads) • Shape • • Deltoid (triangle) Orbucularis (circle) • Other striking features • • Alba (white) Brevis (short) © 2011 Pearson Education, Inc.

Module 10.2: Muscle names

• Muscle terminology examples (continued) • Terms indicating actions • General • • • • Abductor Adductor Depressor Extensor • Specific • • • Buccinator (trumpeter) Risorius (laugher) Sartorius (like a tailor) © 2011 Pearson Education, Inc.

Module 10.2 Review

Define the term

synergist

as it relates to muscle action.

Muscle A abducts the humerus, and muscle B adducts the humerus. What is the relationship between these two muscles?

What does the name

flexor carpi radialis longus

tell you about this muscle?

Module 10.3: Axial and appendicular divisions

•

Axial muscles

• Arise on axial skeleton • Encompass ~60% of skeletal muscles in body • Position head and spinal column • Move rib cage, assist breathing •

Appendicular muscles

Module 10.3 Review

What is the function of the axial muscles?

Identify the division (axial or appendicular) to which each of the following muscles belongs: biceps brachii, external oblique, temporalis, and vastus medialis.

Which structures labeled in the figures in this module are not muscles?

Section 2: Axial Muscles

• Learning Outcomes •

10.4

Identify the principal muscles of facial expressions, along with their origins, insertions, and actions. •

10.5

Identify the principal muscles of the eye and jaw, along with their origins, insertions, and actions.

•

10.6

Identify the principal muscles of the tongue, pharynx, and neck, along with their origins, insertions, and actions.

Section 2: Axial Muscles

• Learning Outcomes •

10.7

Identify the principal muscles of the vertebral column, along with their origins, insertions, and actions. •

10.8

Identify the principal muscles of the trunk, along with their origins, insertions, and actions.

•

10.9

Identify the principal muscles of the pelvic floor, along with their origins, insertions, and actions.

Section 2: Axial Muscles

• • • Axial Muscles Involved in stabilizing and positioning head, neck, and trunk Four groups 1.

Muscles of head and neck 2.

Muscles of vertebral column 3.

Muscles of thoracic and abdominal walls 4.

The muscles of the head and neck that are not associated with the vertebral column The muscles of the vertebral column The muscles of the pelvic floor The oblique and rectus muscles of the trunk

Figure 10 Section 2

Module 10.4: Facial expression muscles

• • • •

Muscles of facial expression

A&P Flix: Buccinator Animation: Axial Muscles: Head and Neck

Frontal belly of occipitofrontalis Orbicularis oculi Nasalis Zygomaticus minor Zygomaticus major Orbicularis oris Risorius Platysma Mentalis (cut) Epicranial aponeurosis An anterior view showing superficial muscles on the right side of the face, and deeper muscles on the left side of the face.

Temporalis Corrugator supercilii Procerus Levator labii superioris Levator anguli oris Masseter Buccinator Depressor anguli oris Depressor labil inferioris

Thyroid cartilage of the larynx Clavicle

Figure 10.4 1

A lateral view showing the major facial muscles Occipital belly of the occipito frontalis muscle Frontal belly of the occipitofrontalis muscle Temporalis Masseter Orbicularis oculi Nasalis Muscles of the Mouth and Cheek Levator labii superioris Zygomaticus minor Zygomaticus major Buccinator Orbicularis oris Risorius Mentalis (cut) Depressor labil inferioris Depressor anguli oris Figure 10.4 2

Module 10.4 Review

Identify the muscles associated with the mouth.

State whether the following muscles involve the mouth, eye, nose, ear, scalp, or neck: buccinator, corrugator supercilii, mentalis, nasalis, platysma, procerus, and risorius.

Explain how an individual is able to consciously move the skin on the scalp but is not able to consciously move the skin of the thigh.

Module 10.5: Muscles of external eye and mastication

• • • Extrinsic eye muscles position the eye Six muscles insert on surface of eye and originate in orbit • Muscles of mastication move the lower jaw All mastication muscles are seen on the lateral sides of the skull © 2011 Pearson Education, Inc.

A lateral view of the right eye (left) showing five extrinsic eye muscles, and a medial view of the right eye (right) showing the sixth extrinsic eye muscle Superior rectus Superior oblique Frontal bone

Superior rectus

Optic nerve Levator palpebrae superioris Trochlea (ligamentous sling)

Superior oblique

Inferior oblique Inferior rectus Lateral rectus

Maxilla

Medial rectus

Optic nerve

Figure 10.5 1 – 2

Module 10.5: Muscles of external eye and mastication

Two anterior views of the right eye: the directions of eye movements produced by each extrinsic eye muscle operation independently (left), and the origins of the extrinsic eye muscles in the orbit (right) Superior rectus Lateral rectus Inferior oblique

Trochlea

Superior oblique Medial rectus

Levator palpebrae superioris

Superior rectus

Oculomotor nerve (III)

Lateral rectus

Abducens nerve (VI)

Inferior rectus Inferior oblique

Trochlear nerve (IV)

Trochlea Superior oblique Medial rectus

Optic nerve (II)

Inferior rectus Figure 10.5 3 – 4

Figure 10.5 5

A superficial lateral view showing the largest muscles of mastication of the right side of the head

Superior temporal line

Temporalis

Capsule of temporomandibular joint Zygomatic arch

Masseter Figure 10.5 6

A lateral view showing the pterygoid muscles after removal of the superficial muscles and the right mandibular ramus Lateral pterygoid Medial pterygoid

Cut edge of mandible

Figure 10.5 7

Figure 10.5 8

Module 10.5 Review

Name the extrinsic eye muscles.

Which muscles have their origin on the lateral pterygoid plates and their insertion on the medial surface of the mandibular ramus?

If you were contracting and relaxing your masseter muscle, what would you probably be doing?

Module 10.6: Muscles of the tongue, pharynx, and neck

A lateral view showing the tongue muscles as dissected after removal of the left half of the mandible

Mandible (cut) Styloid process

Palatoglossus Styloglossus Genioglossus Hyoglossus

Hyoid bone

Figure 10.6 1 – 2

A lateral view showing the major groups of the muscles of the pharynx Palatal muscles Laryngeal elevators Pharyngeal constrictors

Esophagus

Figure 10.6 3 – 4

The anterior muscles of the neck

Mandible

Muscles of the Floor of the Mouth Mylohyoid Digastric Geniohyoid Sternocleidomastoid (cut)

Thyroid cartilage of larynx

Omohyoid: Superior belly Inferior belly

Clavicle

Cut heads of sternocleidomastoid

Sternum

Mylohyoid (cut and reflected)

Hyoid bone

Small Muscles of the Hyoid Bone Stylohyoid Thyrohyoid Muscles Originating at the Sternum Sternothyroid Sternohyoid Sternocleidomastoid (sternal head) Figure 10.6 5

Figure 10.6 6

A superior view of the isolated mandible Genioglossus (cut) Mylohyoid Geniohyoid

Mandible Hyoid bone

Figure 10.6 7

Module 10.6 Review

List the muscles of the tongue.

Which muscles associated with the hyoid form the floor of the mouth?

Which muscles elevate the soft palate?

Module 10.7: Muscles of the vertebral column

• • • • Muscles of the vertebral column Arranged in several layers Originate or insert on ribs and processes of vertebrae The mass of muscles extends from sacrum to skull • Each muscle group composed of numerous separate muscles of various lengths • Example:

erector spinae

muscles divide into: • • •

Spinalis group Longissimus group Iliocostalis group

Module 10.7: Muscles of the vertebral column

• • Contains many extensors but few flexors Vertebral column does not need massive series of flexors because: 1.

The muscles of the vertebral column Spinal Extensors, Deep Layer Semispinalis Group Semispinalis capitis Semispinalis cervicis Semispinalis thoracis Multifidus Spinal Flexors Quadratus lumborum Longus capitus Longus colli Muscles of the anterior cervical spine

Posterior view Spinal Extensors, Superficial Layer Splenius capitus Erector Spinae Muscles Longissimus capitis Spinalis cervicis Longissimus cervicis Iliocostalis cervicis Iliocostalis thoracis Longissimus thoracis Spinalis thoracis Iliocostalis lumborum The erector spinae muscles, consisting of the spinalis, longissimus, and iliocostalis muscle groups

Thoracodorsal fascia

Figure 10.7 1

Module 10.7: Muscles of the vertebral column

Module 10.7 Review

List the spinal flexor muscles.

Which muscles enable you to extend the neck?

Module 10.8: Muscles of the trunk wall

• Muscles of the trunk wall • Oblique and rectus muscles form the muscular walls of the trunk • Actions of many trunk wall muscles assist in breathing • Many are layered with fibers running perpendicular to other muscles producing antagonist actions © 2011 Pearson Education, Inc.

The scalene muscles

Anterior view Scalenes Figure 10.8 1

Module 10.8: Muscles of the trunk wall

External oblique Tendinous inscription Serratus anterior Internal intercostal External intercostal External oblique (cut) Internal oblique Cut edge of rectus sheath Linea alba Rectus abdominis The muscles of the trunk: the superficial muscles on the right side of the body, and deeper muscles of the oblique and rectus groups on the left side of the body

Figure 10.8 2

The muscles of the trunk: In the anterior view, the superficial muscles are shown on the right side of the body, and deeper muscles of the oblique and rectus groups are shown on the left side Rectus abdominis

Xiphoid process Costal cartilages

External oblique

Inferior vena cava

External intercostal Internal intercostal Central tendon of diaphragm

Esophagus

Serratus anterior Diaphragm

Thoracic aorta

Spinal cord Erector spinae group

Superior view through the thoracic cavity looking down at the diaphragm Figure 10.8 3

L 3

Quadratus lumborum Thoracolumbar fascia

Horizontal section through the abdominal cavity Figure 10.8 4

An inferior view of the diaphragm Central tendon of diaphragm

Inferior vena cava

Impression for liver

12th rib Sternum L 2 L 3 L 4

Quadratus lumborum (cut)

Xiphoid process Costal cartilages Esophagus in esophageal hiatus

Impression for stomach

Aorta

Figure 10.8 6

Figure 10.8 7

Module 10.8 Review

Which muscle connects the ribs and sternum to the pubic bones?

Which muscle forms the deepest layer of the abdominal wall muscles?

What is the action of the external oblique muscle?

Module 10.9: Muscles of the pelvic floor

• • • • Muscles of the pelvic floor Form the

perineum

(muscular sheet that spans pelvic outlet) Females and males have different superficial muscles • No differences in deep perineal musculature Urogenital and pelvic diaphragms do not completely close outlet • Urethra, vagina, and anus all pass through • Muscular sphincters surround openings and control urination and defecation • Muscles, nerves, and blood vessels also pass © 2011 Pearson Education, Inc.

Superficial Dissections The muscles of the pelvic floor Ischiocavernosus Bulbospongiosus

Vagina

Superficial transverse perineal

Anus

Gluteus maximus The muscles of the pelvic floor in females Female

Urethra

Deep Dissections Urogenital Diaphragm External urethral sphincter Deep transverse perineal

Central tendon of perineum

Pelvic Diaphragm Pubococcygeus Iliococcygeus Levator ani External anal sphincter Coccygeus

Sacrotuberous ligament

Figure 10.9 1

Superficial Dissections

Testis

The muscles of the pelvic floor Ischiocavernosus Bulbospongiosus Superficial transverse perineal

Anus

Gluteus maximus

Urethra (connecting segment removed)

UROGENITAL TRIANGLE OF PERINEUM Urogenital Diaphragm External urethral sphincter Deep transverse perineal

Central tendon of perineum

Pelvic Diaphragm Pubococcygeus Iliococcygeus Levator ani External anal sphincter Coccygeus

Sacrotuberous ligament

ANAL TRIANGLE The muscles of the pelvic floor in males Male

Figure 10.9 2

Module 10.9 Review

Which muscles make up the urogenital diaphragm?

In females, what is the action of the bulbospongiosus muscle?

The coccygeus muscle extends from the sacrum and coccyx to which structure?

Section 3: Appendicular Muscles

• Learning Outcomes •

10.10

Identify the principal appendicular muscles. •

10.11

Identify the principal muscles of the pectoral girdle, along with their origins, insertions, and actions. •

10.12

Identify the principal muscles that move the arm, along with their origins, insertions, and actions.

Section 3: Appendicular Muscles

• Learning Outcomes •

10.13

Identify the principal muscles that move the forearm and hand, along with their origins, insertions, and actions. •

10.14

Identify the principal muscles that move the hand and fingers, along with their origins, insertions, and actions.

•

10.15

Identify the principal intrinsic hand muscles, along with their origins, insertions, and actions.

Section 3: Appendicular Muscles

• Learning Outcomes •

10.16

Identify the principal muscles that move the thigh, along with their origins, insertions, and actions. •

10.17

Identify the principal muscles that move the leg, along with their origins, insertions, and actions.

•

10.18

Section 3: Appendicular Muscles

• Learning Outcomes •

10.19

Identify the principal intrinsic foot muscles, along with their origins, insertions, and actions. •

10.20

Section 3: Appendicular Muscles

• • Appendicular Muscles • • • Upper limb Muscles That Position the Pectoral Girdle • Originate on axial skeleton and insert on clavicle and scapula Muscles That Move the Arm • Originate on pectoral girdle and thoracic cage and insert on humerus Muscles That Move the Forearm and Hand • Primarily originate on pectoral girdle and arm, and insert on radius, ulna, and carpals © 2011 Pearson Education, Inc.

Section 3: Appendicular Muscles

• • • Upper limb (continued) • Extrinsic Muscles of the Hand and Fingers Primarily originate on humerus and insert on metacarpals and phalanges • • Intrinsic Muscles of the Hand Perform fine movements Primarily originate on carpals and metacarpals and insert on phalanges © 2011 Pearson Education, Inc.

Section 3: Appendicular Muscles

• • • • • Lower Limb • Muscles That Move the Thigh Originate in pelvic region and typically insert on femur • Muscles That Move the Leg Originate on pelvis and femur and insert on tibia and/or fibula Extrinsic Muscles that Move the Foot and Toes • Originate on tibia and fibula and insert on tarsals, metatarsals, and/or phalanges • Intrinsic Muscles of the Foot Primarily originate on tarsals and metatarsals and insert on phalanges © 2011 Pearson Education, Inc.

Module 10.10: Large muscles originating on the trunk

• • • • Large muscles originating on the trunk In general, control gross movements of limbs • Are often large and powerful Distally, limb muscles get smaller and more numerous • Actions become more precise Appendicular muscles on posterior of trunk often originate on large girdle bones and proximal limb bones © 2011 Pearson Education, Inc.

Module 10.10 Review

Which axial muscle is often known as the “six pack” in fit individuals?

Describe the appearance of the appendicular muscles as you move proximally to distally.

Identify to which division, axial or appendicular, the following muscles belong: deltoid, external oblique, gluteus maximus, pectoralis major, platysma, and rectus femoris.

Module 10.11: Muscles that position pectoral girdle

• Muscles that position the pectoral girdle • Also serve to anchor pectoral girdle to axial skeleton • Smaller range of motion than other appendicular muscles • Help increase upper limb mobility • Trapezius is largest muscle of group © 2011 Pearson Education, Inc.

An anterior view of the muscles that position the pectoral girdle Muscles That Position the Pectoral Girdle Trapezius Levator scapulae Subclavius Pectoralis minor Internal intercostals External intercostals

T 12

Muscles That Position the Pectoral Girdle Pectoralis minor (cut) Serratus anterior Figure 10.11 1

A posterior view of the muscles that position the pectoral girdle Superficial Dissection Muscles That Position the Pectoral Girdle Trapezius

Scapula

Deep Dissection Muscles That Position the Pectoral Girdle Levator scapulae Rhomboid minor Rhomboid major Serratus anterior

T 12 vertebra

Figure 10.11 2

Figure 10.11 3

Module 10.11: Muscles that position pectoral girdle

Module 10.11 Review

Identify the largest of the superficial muscles that position the pectoral girdle.

Which muscles enable you to shrug your shoulders?

Which muscle originates on the first rib and inserts on the inferior border of the clavicle?

Module 10.12: Muscles that move the arm

• • Action of muscles positioning the arm are best understood by considering pull or line of force (

action line

) relative to glenoid cavity • •

Rotator cuff

Muscles often injured in sports involving ball throwing Consists of four muscles (SITS) 1.

Animation: Appendicular Muscles: Arm

Superficial Dissection

Sternum Clavicle

Muscles That Move the Arm Deltoid Pectoralis major An anterior view of the muscles that move the arm

Deep Dissection

Ribs (cut)

Muscles That Move the Arm Subscapularis Coracobrachialis Teres major

Vertebra T 12

Figure 10.12 1

Module 10.12: Muscles that move the arm

A&P Flix: Rotator Cuff Muscles: An Overview A&P Flix: Rotator Cuff Muscles A&P Flix: Movement from the Rotator Cuff Muscles A&P Flix: Muscles that Cross Glenohumeral Joint © 2011 Pearson Education, Inc.

Module 10.12: Muscles that move the arm

A&P Flix: Scapular Muscles of the Glenohumeral Joint A&P Flix: Axial Muscles of the Glenohumeral Joint A&P Flix: Movement at the Glenohumeral Joint: An Overview A&P Flix: Movement at the Glenohumeral Joint © 2011 Pearson Education, Inc.

Superficial Dissection

Vertebra T 1

Muscles That Move the Arm Supraspinatus Deltoid Latissimus dorsi

Thoracolumbar fascia

A posterior view of the muscles that move the arm

Deep Dissection Muscles That Move the Arm Supraspinatus Infraspinatus Teres minor Teres major Figure 10.12 2

The actions of muscles that position the arm Abduction Extension Deltoid Flexion Tendons of biceps brachii POSTERIOR Teres minor GLENOID CAVITY ANTERIOR Subscapularis Lateral rotation

Triceps brachii Teres major Adduction Medial rotation Figure 10.12 4

Figure 10.12 3

Module 10.12 Review

Define action line.

Name the muscle that abducts the upper arm.

Which muscle originates on the anterior surface of the scapula and inserts on the lesser tubercle of the humerus?

Module 10.13: Muscles that move the forearm and hand

• • Muscles that move the forearm and hand • • • Special connective tissues

Extensor retinaculum

• Wide band of connective tissue holding extensor muscles in place

Flexor retinaculum

• • Wide band of connective tissue holding flexor muscles in place

Carpal tunnel syndrome

(inflammation of medial nerve passing through)

Synovial tendon sheaths

A posterior view showing the superficial layer of muscles involved in extension at the elbow and wrist Elbow Extensors Triceps brachii Anconeus

Olecranon of ulna

Flexor carpi ulnaris

Radius Ulna

Extensor retinaculum Wrist Extensors Extensor carpi ulnaris Extensor carpi radialis longus Extensor carpi radialis brevis Figure 10.13 1

Module 10.13: Muscles that move the forearm and hand

An anterior view showing the superficial muscles involved in flexion at the elbow and wrist

Coracoid process of scapula Humerus

Elbow Flexors Biceps brachii Brachialis Brachioradialis Elbow Extensors Triceps brachii Wrist Flexors Flexor carpi radialis Palmaris longus Flexor carpi ulnaris

Medial epicondyle of humerus

Pronators and Supinators Pronator teres Supinator Pronator quadratus Flexor retinaculum Figure 10.13 2

A cross section of the right wrist (palm up) showing the synovial tendon sheaths and nearby structure Median nerve Flexor retinaculum Synovial tendon sheaths Carpal tunnel Pisiform Triquetrum Lunate Scaphold Carpal bones Figure 10.13 4

Module 10.13 Review

Define retinaculum.

On which surface, anterior or posterior, are the wrist extensors located?

Which muscles are involved in turning a doorknob?

Module 10.14: Muscles that move the hand and fingers

• • • Muscles that move the hand and fingers Extensors usually lie along the posterior and lateral surfaces of the forearm • Muscles that extend fingers can only be seen after removal of those that extend the wrist Flexors usually lie along the anterior and medial surfaces © 2011 Pearson Education, Inc.

Tendon of biceps brachii Brachioradialis (retracted) LATERAL Two anterior views of the muscles that move the hand and fingers

Median nerve Brachial artery Radius

Flexor carpi ulnaris (retracted) Muscles That Flex the Fingers and Thumb Flexor digitorum superficialis Flexor digitorum profundus Flexor pollicis longus Supinator MEDIAL Cut tendons of flexor digitorum superficialis Anterior View, Middle Layer Anterior View, Deepest Layer Figure 10.14 1 – 2

Module 10.14: Muscles that move the hand and fingers

A&P Flix: Muscles that Act on the Wrist and Fingers: An Overview A&P Flix: Anterior Muscles of the Wrist and Fingers A&P Flix: Posterior Muscles of the Wrist and Fingers A&P Flix: Carpal Tunnel A&P Flix: Movements of the Wrist and Fingers © 2011 Pearson Education, Inc.

MEDIAL Two posterior views of the muscles that move the hand and fingers Anconeus Muscles That Extend the Fingers Extensor digitorum Extensor digiti minimi Abductor pollicis longus Extensor pollicis brevis Tendon of extensor pollicis longus Extensor indicis

Ulna

Anconeus Supinator Muscles That Move the Thumb Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis

Radius

Tendon of extensor digiti minimi (cut) Tendon of extensor digitorum (cut) LATERAL Posterior View, Middle Layer Posterior View, Deepest Layer Figure 10.14 3 – 4

Module 10.14 Review

List the muscles that extend the fingers.

Name the muscles that abduct the wrist.

The names of muscles associated with the thumb frequently include what term?

Module 10.15: Intrinsic muscles of the hand

• • • • Intrinsic muscles of the hand • Provide fine movement of hand More powerful movements are controlled by forearm muscles • No muscles originate on phalanges Tendons extend across distal finger joints Responsible for: 1.

Flexion/extension of fingers at metacarpophalangeal joints 2.

Abduction/adduction of fingers at metacarpophalangeal joints 3.

The intrinsic muscles of the hand Intrinsic Muscles of the Hand Lumbricals Palmar interosseus First dorsal interosseus Abductor digiti minimi Flexor digiti minimi brevis Opponens digiti minimi Palmaris brevis (cut)

Anterior view Tendons of flexor digitorum Intrinsic Muscles of the Thumb Adductor pollicis Flexor pollicis brevis Opponens pollicis Abductor pollicis brevis Figure 10.15 1

The intrinsic muscles of the hand Intrinsic Muscles of the Hand First dorsal interosseus muscle Abductor digiti minimi Extensor retinaculum Posterior view

Tendons of extensor digitorum Figure 10.15 2

Module 10.15 Review

Name the intrinsic muscles of the thumb.

Which muscles originate on the phalanges?

If there are no muscles in the fingers, how are we able to move them?

Module 10.16: Muscles that move the thigh

• • • Muscles that move the thigh • Understanding diverse actions of thigh/hip muscles from orientation to hip joint Muscles originating on surface of pelvis and inserting on femur • Produce characteristic movements by position relative to acetabulum • Many muscles are broad and have more than one action line (more than one action at hip) Example: Adductor magnus • Produces flexion, extension, and adduction at hip © 2011 Pearson Education, Inc.

The muscles that move the thigh

Iliac crest

Gluteus medius (cut) Gluteus maximus (cut)

Sacrum

Gluteal muscles, posterior view Gluteal Group Gluteus medius Gluteus maximus Gluteus minimus Tensor fasciae latae Iliotibial tract Lateral view of the gluteal region Figure 10.16 1 – 2

Module 10.16: Muscles that move the thigh

A&P Flix: Muscles that Act on the Hip Joint and Femur: An Overview A&P Flix: Anterior Muscles that Cross the Hip Joint A&P Flix: Medial Muscles that Cross the Hip Joint A&P Flix: Posterior Muscles that Cross the Hip Joint A&P Flix: Movement at the Hip Joint: An Overview A&P Flix: Movement at the Hip Joint © 2011 Pearson Education, Inc.

Module 10.16: Muscles that move the thigh

The muscles that move the thigh Gluteal Group Gluteus maximus (cut) Gluteus medius (cut) Gluteus minimus Tensor fasciae latae Iliopsoas Group Psoas major Iliacus Lateral Rotator Group Piriformis Superior gemellus Obturator internus Obturator externus Inferior gemellus Quadratus femoris

Ischial tuberosity Iliotibial tract

A lateral view of a dissection of the gluteal region

L 5 An anterior view showing the isolated iliopsoas muscle group and the adductor group

Inguinal ligament

Adductor Group Pectineus Adductor brevis Adductor longus Adductor magnus Gracilis Figure 10.16 3 – 4

Module 10.16 Review

Name the muscles that compose the gluteal group.

Identify the muscle whose origin is the lateral border of the ischial tuberosity and whose insertion is the intertrochanteric crest of the femur.

Which leg movement would be impaired by injury to the obturator muscles?

Module 10.17: Muscles that move the leg

• • • Muscles that move the leg

Flexors of the knee

• Originate on pelvic girdle and extend along posterior and medial surfaces of thigh

Extensors of the knee

• Originate on femoral surface and extend along anterior and lateral surfaces of thigh • Collectively called

quadriceps muscles

quadriceps femoris

The flexors of the knee

The muscles that move the leg

Iliac crest

Gluteus medius Tensor fasciae latae Gluteus maximus Adductor magnus Gracilis

Iliotibial tract

Flexors of the Knee Biceps femoris Semitendinosus Semimembranosus Sartorius Popliteus

Anterior superior iliac spine Inguinal ligament

Iliacus Psoas major Iliopsoas

Pubic tubercle

Tensor fasciae latae Pectineus Adductor longus Gracilis Sartorius Extensors of the Knee (Quadriceps muscles) Rectus femoris Vastus intermedius (lies deep to the rectus femoris and vastus lateralis) Vastus lateralis Vastus medialis Quadriceps tendon

Patella

Patellar ligament The extensors of the knee, collectively called the quadriceps muscles or the quadriceps femoris Figure 10.17 1 – 2

Module 10.17: Muscles that move the leg

A&P Flix: Muscles that Cross the Knee Joint: An Overview A&P Flix: Anterior Extensors that Act on the Knee A&P Flix: Posterior Flexors that Act on the Knee A&P Flix: Movement at the Knee Joint © 2011 Pearson Education, Inc.

Module 10.17: Muscles that move the leg

A cross sectional view showing the positions of the major thigh muscles relative to the femur Semitendinosus Biceps femoris Vastus lateralis Vastus intermedius Femur Rectus femoris POSTERIOR ANTERIOR Semimembranosus

Sciatic nerve

Adductor magnus Gracilis Adductor longus

Great saphenous vein

Sartorius Vastus medialis Figure 10.17 4

Module 10.17 Review

Name the quadriceps muscles.

Which muscles flex the knee?

Identify the muscle whose origin is on the lateral condyle of the femur.

Module 10.18: Extrinsic muscles that move the foot and toes

• • • Extrinsic muscles that move the foot and toes

Gastrocnemius

and

Soleus

• Largest muscles associated with ankle movement • Produce ankle extension (plantar flexion) Muscles that move toes are much smaller and originate on tibia and/or fibula • Tendons stabilized by

superior

and

inferior retinacula

The multiple muscle layers in the posterior leg Superficial Dissection Ankle Extensors Plantaris Gastrocnemius Soleus Calcaneal tendon

Calcaneus

Popliteus Gastrocnemius (cut and removed) Deep Dissection

Head of fibula

Ankle Extensors (Deep) Tibialis posterior Fibularis longus Fibularis brevis Digital Flexors Flexor digitorum longus Flexor hallucis longus Tendon of flexor digitorum longus Tendon of fibularis brevis Tendon of fibularis longus Figure 10.18 1

Module 10.18: Extrinsic muscles that move the foot and toes

A&P Flix: Muscles that the Act on Ankle and Foot: An Overview A&P Flix: Anterior Muscles that Act on the Ankle and Foot A&P Flix: Lateral Muscles that Act on the Ankle and Foot A&P Flix: Posterior Muscles that Act on the Ankle and Foot A&P Flix: Movements of the Ankle and Foot © 2011 Pearson Education, Inc.

The arrangement of the major superficial muscles that move the foot and toes Ankle Extensors Gastrocnemius Fibularis longus Soleus Fibularis brevis

Superior extensor retinaculum

Calcaneal tendon

Inferior extensor retinaculum

Lateral View

Iliotibial tract Head of fibula

Ankle Flexors Tibialis anterior

Patella Patellar ligament

Digital Extensors Extensor digitorum longus Tendon of extensor hallucis longus Tendon of tibialis anterior

Medial View

Medial surface of tibial shaft

Ankle Extensors Gastrocnemius Soleus Tibialis posterior

Superior extensor retinaculum

Calcaneal tendon

Inferior extensor retinaculum

Figure 10.18 2 – 3

Module 10.18 Review

Name the muscles involved in flexing the toes.

Name the muscles involved in extending the ankle.

How would a torn calcaneal tendon affect movement of the foot?

Module 10.19: Intrinsic muscles of the foot

• • • Intrinsic muscles of the foot Retinacula stabilize tendons descending from leg • More numerous on inferior surface of foot Many are flexors that tense during ankle extension and help “push off” when walking • Provide padding • Assist in maintaining arches of foot © 2011 Pearson Education, Inc.

A superior view of the foot showing the intrinsic muscles of the foot and toes

Lateral malleolus of fibula

Inferior extensor retinaculum Tendons of extensor digitorum longus Intrinsic Muscles of the Foot, Toes 2 –5 Dorsal interossei Tendons of extensor digitorum brevis

Superior extensor retinaculum

Medial malleolus of tibia

Tendon of tibialis anterior Intrinsic Muscles of the Foot, Great Toe Extensor hallucis brevis Abductor hallucis Tendon of extensor hallucis longus Figure 10.19 1

The intrinsic muscles on the inferior surface of the foot Superficial Muscles of the Sole of the Foot Fibrous tendon sheaths Tendons of flexor digitorum brevis Instrinsic Muscles of the Foot Lumbricals Flexor hallucis brevis Flexor digiti minimi brevis Adductor hallucis Quadratus plantae Flexor digitorum brevis Abductor digiti minimi

Plantar aponeurosis (cut) Calcaneus

Deep Muscles of the Sole of the Foot Tendon of flexor hallucis longus Tendon of flexor digitorum longus Tendon of tibialis posterior Tendon of fibularis longus Figure 10.19 2

A cross section showing the intrinsic muscles of the foot Instrinsic Muscles of the Foot

Metatarsal bones

Tendons of extensor digitorum longus Tendon of extensor hallucis brevis Dorsal interossei Adductor hallucis Adductor hallucis Flexor hallucis brevis Lumbricals Tendons of flexor digitorum longus Plantar aponeurosis Instrinsic Muscles of the Foot Tendons of extensor digitorum brevis Flexor digiti minimi brevis Abductor digiti minimi Plantar interossei Tendons of flexor digitorum brevis Figure 10.19 4

Module 10.19 Review

Identify the intrinsic muscle that flexes the great toe.

What are the functions of the superior and inferior retinacula of the foot?

Describe the origin, insertion, and action of the lumbrical muscles.

Module 10.20: Deep fascia

• Deep fascia organizes limb muscles into

compartments

• Muscles within a compartment have compatible functions • Each compartment has characteristic blood supply and innervation • Clinically important because trauma can cause bleeding within compartment • Elevates pressure and compresses blood vessels and nerves • =

Compartment syndrome

Module 10.20 Review

Name the six possible compartments of the muscles of the limbs.

Define compartment syndrome.

Propose a reason why compartment syndrome can be life threatening.