10 the muscular system

© 2011 Pearson Education, Inc.

PowerPoint® Lecture Presentations prepared byAlexander G. CheroskeMesa Community College at Red Mountain

10The Muscular System


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

1. Axial muscles• Support and position axial skeleton

2. Appendicular muscles• Support, move, and brace the limbs

© 2011 Pearson Education, Inc.Figure 10 Section 1

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%

Integumentarysystem

16%

Skeletalsystem

20%

Muscular system44%

The two divisions of the muscular system:axial muscles and appendicular muscles

Axialmuscles

AppendicularmusclesTendons conduct the

forces of contraction toperform specific tasks.


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 (belly)

• Can contract until shortened by ~30%

• Due to muscle fiber shortening

• Example: biceps brachii

© 2011 Pearson Education, Inc.Figure 10.1 1

A parallel muscle:the biceps brachii

Fascicle

Body(belly)

(1)

1



• 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


Base ofmuscle

Tendon

A convergent muscle:the pectoralis major

(2)

2




• 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




• Pennate muscle (continued)

• Three types

1. Unipennate (all fibers on one side of tendon)

• Example: extensor digitorum

2. Bipennate (fibers insert on both sides of tendon)

• Example: rectus femoris

3. Multipennate (tendon branches within pennate muscle)

• Example: deltoid


Three pennate muscles

Extensor digitorum muscle Rectus femoris muscle Deltoid muscle

Extendedtendon

Tendons

If all the muscle fibers areon the same side of thetendon, the pennatemuscle is unipennate.

If a pennate musclehas fibers on bothsides of the tendon, itis called bipennate.

If the tendon branches within apennate muscle, the muscle issaid to be multipennate.

(3c)

(3a)

(3b)

3


A circular muscle, or sphincter

Contracted Relaxed

(4)

4



• 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



• Levers and Leverage (continued)

• Lever classes

1. 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


A first-class lever

LoadFulcrum

Appliedforce




• Lever classes (continued)

2. Second-class lever

• Load is between applied force and fulcrum

• Always farther from fulcrum than load so small force moves large load, but slowly and short distance

• Acts like wheelbarrow


A second-class lever

Appliedforce

Fulcrum

Load




• Lever classes (continued)

3. Third-class lever

• Most common lever in body

• Force applied between load and fulcrum

• Speed and distance traveled increased at expense of effective force


A third-class lever

Fulcrum

Appliedforce

Load

Biceps brachiimuscle


Module 10.1 Review

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

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

c. 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

• Specific movement


The origins, insertion, and actionof the biceps brachii muscle

Origins of bicepsbrachii muscle

Insertion of bicepsbrachii muscle

Action



• 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, work)

• Muscle that helps larger agonist work efficiently

• May provide additional pull or stabilize origin

• Example: brachioradialis for elbow flexion



• Muscles working together (continued)

• Antagonist

• Muscle whose action opposes particular agonist

• Example: triceps brachii for elbow flexion (to biceps brachii)

• Agonist for elbow extension


Descriptions of musclesbased on their function

Antagonist

Origin ofbrachioradialismuscle

Insertion ofbrachioradialis

muscle

Synergist

Agonist, or prime mover



• 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)



• 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)



• Muscle terminology examples (continued)

• Terms indicating actions

• General• Abductor

• Adductor

• Depressor

• Extensor

• Specific• Buccinator (trumpeter)

• Risorius (laugher)

• Sartorius (like a tailor)


Module 10.2 Review

a. Define the term synergist as it relates to muscle action.

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

c. 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

• Stabilize or move appendicular skeleton

• Remaining 40% of all skeletal muscles


Module 10.3 Review

a. What is the function of the axial muscles?

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

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


Section 2: Axial Muscles


• 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.




• 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.



• 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. Muscles of pelvic floor

© 2011 Pearson Education, Inc.Figure 10 Section 2

The muscles of the headand neck that are notassociated withthe vertebral column

The muscles of thevertebral column

The oblique andrectus muscles ofthe trunk

The muscles of the pelvic floor


Module 10.4: Facial expression muscles

• Muscles of facial expression

• Originate on skull surface

• Insert into superficial fascia and dermis of skin

• Actions move skin

A&P Flix: Buccinator

Animation: Axial Muscles: Head and Neck


An anterior view showingsuperficial muscles onthe right side of the face,and deeper muscles onthe left side of the face.

Epicranial aponeurosis

Temporalis

Corrugator supercilii

Procerus

Levator labii superioris

Levator anguli oris

Masseter

Buccinator

Depressor anguli oris

Depressor labil inferioris

Thyroidcartilageof the larynx

Clavicle

Frontal belly ofoccipitofrontalis

Orbicularis oculi

Nasalis

Zygomaticus minor

Zygomaticus major

Orbicularis oris

Risorius

Platysma

Mentalis (cut)


A lateral view showing themajor facial muscles

Occipital bellyof the occipito-frontalis muscle

Frontal belly of theoccipitofrontalis

muscle

Orbicularis oculi

Nasalis

Levator labii superioris

Zygomaticus minor

Zygomaticus major

Buccinator

Orbicularis oris

Risorius

Mentalis (cut)

Depressor labil inferioris

Depressor anguli orisTemporalis

Masseter

Epicranial aponeurosis

Muscles of the Mouth and Cheek


Module 10.4 Review

a. Identify the muscles associated with the mouth.

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

c. 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.Figure 10.5 1 – 2

A lateral view of the right eye (left) showing five extrinsic eye muscles, and amedial view of the right eye (right) showing the sixth extrinsic eye muscle

Superior rectus Superior oblique Frontal bone

Optic nerve

MaxillaLateral rectus

Inferior rectus

Inferior oblique

Levator palpebraesuperioris

Trochlea(ligamentous sling)

Superior rectus Superior oblique

Optic nerveMedial rectus


Module 10.5: Muscles of external eye and mastication

A&P Flix: Masseter

A&P Flix: Temporalis


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

Superiorrectus

Lateralrectus

Inferioroblique

Trochlea

Superior oblique

Medial rectus

Inferior rectus

Levatorpalpebraesuperioris

Superiorrectus

Lateral rectus

Inferioroblique

Oculomotornerve (III)

Abducensnerve (VI)

Trochlea

Superioroblique

Medialrectus

Inferiorrectus

Trochlearnerve (IV)

Opticnerve (II)


A superficial lateral view showingthe largest muscles of masticationof the right side of the head

Superior temporal line

Temporalis

Capsule oftemporomandibularjoint

Zygomaticarch

Masseter


A lateral view showing the pterygoidmuscles after removal of the superficialmuscles and the right mandibular ramus

Lateral pterygoid

Medial pterygoid

Cut edge of mandible


Module 10.5 Review

a. Name the extrinsic eye muscles.

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

c. 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

• Muscles of the tongue are closely associated with pharynx and neck muscles

• Actions of these muscles assist in speaking and chewing

• Many help support the hyoid bone


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

Palatoglossus

Styloid process

StyloglossusGenioglossus

Hyoglossus

Hyoid boneMandible

(cut)


A lateral view showing the major groupsof the muscles of the pharynx

Palatal muscles

Laryngealelevators

Pharyngealconstrictors

Esophagus


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)

Small Musclesof the Hyoid Bone

Muscles Originatingat the Sternum

Stylohyoid

Thyrohyoid

Sternothyroid

Sternohyoid

Sternocleidomastoid(sternal head)

Hyoid bone


A superior view of the isolated mandible

Hyoid bone

Geniohyoid

Mylohyoid

Mandible

Genioglossus(cut)


Module 10.6 Review

a. List the muscles of the tongue.

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

c. 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



• Contains many extensors but few flexors

• Vertebral column does not need massive series of flexors because:

1. Many large trunk muscles flex vertebral column

2. Most of body weight is anterior and gravity tends to flex spine


The muscles of the vertebral column

Spinal Extensors, Deep Layer

Semispinalis Group

Semispinalis capitis

Semispinalis cervicis

Semispinalis thoracis

Multifidus

Spinal Flexors

Quadratus lumborum

Longuscapitus

Longuscolli

Muscles of the anteriorcervical spine

Posteriorview

Thoracodorsal fascia

The erector spinaemuscles, consisting ofthe spinalis, longissimus,and iliocostalis musclegroups

Iliocostalis lumborum

Spinalis thoracis

Longissimus thoracis

Iliocostalis thoracis

Iliocostalis cervicis

Longissimus cervicis

Spinalis cervicis

Longissimus capitis

Splenius capitus

Spinal Extensors, Superficial Layer

Erector Spinae Muscles



A&P Flix: Iliocostalis

A&P Flix: Longissimus

A&P Flix: Semispinalis Capitis

A&P Flix: Splenius Capitis

A&P Flix: Spinalis


Module 10.7 Review

a. List the spinal flexor muscles.

b. 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


The scalene muscles

Scalenes

Anterior view



Animation: Muscles of the Trunk

Animation: Axial Muscles: Rectus Muscle

A&P Flix: External Intercostals

A&P Flix: Internal Intercostals

A&P Flix: External Obliques



A&P Flix: Internal Obliques

A&P Flix: Rectus Abdominis

A&P Flix: Transversus Abdominis


Serratusanterior

Internal intercostal

External intercostal

External oblique (cut)

Internal oblique

Cut edge ofrectus sheath

Rectus abdominisLinea alba

Tendinousinscription

Externaloblique

The muscles of the trunk: the superficial muscles on theright side of the body, and deeper muscles of the obliqueand rectus groups on the left side of the body


Externalintercostal

Internalintercostal

Esophagus

Serratusanterior

Diaphragm

Rectusabdominis

Xiphoidprocess

Costalcartilages

Externaloblique

Inferiorvena cava

Central tendonof diaphragm

Thoracic aorta Spinal cord Erector spinae group

Superior view through the thoracic cavity lookingdown at the diaphragm

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


Rectus sheathRectus abdominis

Linea alba

Quadratuslumborum

Externaloblique

Transversusabdominis

Internaloblique

Thoracolumbarfascia Horizontal section through

the abdominal cavity

L3

The muscles of the trunk: In the anterior view, the superficialmuscles are shown on the right side of the body, and deepermuscles of the oblique and rectus groups are shown on theleft side


An inferior view of the diaphragm

Impressionfor stomach

Quadratuslumborum (cut)

Impressionfor liver

Central tendonof diaphragm

Inferiorvena cava

12th rib

Aorta

Esophagus in esophageal hiatus

Costal cartilages

Xiphoid process

Sternum

L3

L4

L2


Module 10.8 Review

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

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

c. 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



Superficial Dissections Deep Dissections

The muscles of the pelvic floor in femalesFemale

Urogenital Diaphragm

Pelvic Diaphragm

Ischiocavernosus

Bulbospongiosus

Vagina

Superficialtransverse perineal

Anus

Gluteus maximus Coccygeus

Sacrotuberous ligament

External anal sphincter

Iliococcygeus

PubococcygeusLevatorani

Central tendon of perineum

Urethra

External urethral sphincter

Deep transverse perineal


The muscles of the pelvic floor in malesMale

Urogenital Diaphragm

Pelvic Diaphragm

Coccygeus

Sacrotuberous ligament

External anal sphincter

Iliococcygeus

PubococcygeusLevatorani

Central tendon of perineum

External urethral sphincter

Deep transverse perineal

Urethra (connectingsegment removed)

Ischiocavernosus

Bulbospongiosus

Testis

Superficialtransverse perineal

Anus

Gluteus maximus

UROGENITALTRIANGLE OFPERINEUM

ANALTRIANGLE

Superficial Dissections



Module 10.9 Review

a. Which muscles make up the urogenital diaphragm?

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

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


Section 3: Appendicular Muscles


• 10.10 Identify the principal appendicularmuscles.

• 10.11 Identify the principal muscles of thepectoral girdle, along with their

origins, insertions, and actions.

• 10.12 Identify the principal muscles that movethe arm, along with their origins,

insertions, and actions.




• 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.




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




• 10.19 Identify the principal intrinsic foot muscles, along with their origins, insertions,

and actions.

• 10.20 Describe the deep fascia and its relationship to the various limb muscle compartments.



• 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



• 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



• 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


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


Module 10.10 Review

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

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

c. 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


An anterior view of the muscles that position the pectoral girdle

Muscles That Positionthe Pectoral Girdle

Trapezius

Levator scapulae

Subclavius

Pectoralis minor

Internal intercostals

External intercostals

Muscles That Positionthe Pectoral Girdle

Pectoralis minor(cut)

Serratus anterior

T12


A posterior view of the muscles that position the pectoral girdle

Superficial Dissection

Muscles ThatPosition thePectoral Girdle

Trapezius

Muscles ThatPosition thePectoral Girdle

Deep Dissection

Levator scapulae

Rhomboid minor

Rhomboid major

Serratus anterior

Scapula

T12 vertebra



A&P Flix: Trapezius

A&P Flix: Levator Scapula

A&P Flix: Serratus Anterior

A&P Flix: Rhomboid Minor

A&P Flix: Rhomboid Major



A&P Flix: Muscles that Act on the Shoulder Joint and Humerus: An Overview

Animation: Muscles of the Pectoral Girdle

A&P Flix: Movement of the Pectoral Girdle


Module 10.11 Review

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

b. Which muscles enable you to shrug your shoulders?

c. 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. Supraspinatus

2. Infraspinatus

3. Teres minor

4. Subscapularis

Animation: Appendicular Muscles: Arm


Superficial Dissection Deep Dissection

Muscles ThatMove the Arm


Ribs (cut)

Sternum

Clavicle

Vertebra T12

Deltoid

Pectoralis majorSubscapularis

Coracobrachialis

Teres major

An anterior view of themuscles that move thearm



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



A&P Flix: Latissimus Dorsi

A&P Flix: Supraspinatus

A&P Flix: Infraspinatus

A&P Flix: Teres Minor

A&P Flix: Teres Major



A&P Flix: Subscapularis

A&P Flix: Pectoralis Major

A&P Flix: Pectoralis Minor

A&P Flix: Deltoid



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





Vertebra T1

Thoracolumbar fascia

Supraspinatus

Deltoid

Latissimus dorsi

A posterior view of themuscles that move thearm

Supraspinatus

Teres major

Teres minor

Infraspinatus


The actions of muscles that position the arm

ExtensionAbduction

Flexion

Lateral rotation

Adduction

Medial rotation

Teres minor

Deltoid Tendons ofbiceps brachii

Subscapularis

Tricepsbrachii

Teresmajor

ANTERIORPOSTERIOR

GLENOIDCAVITY


Module 10.12 Review

a. Define action line.

b. Name the muscle that abducts the upper arm.

c. 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

• Tubular bursae surrounding tendons where they cross bones

Animation: Appendicular Muscles: Forearm and Hand


A posterior view showing the superficial layerof muscles involved in extension at the elbowand wrist

Wrist Extensors

Elbow Extensors

Triceps brachii

Anconeus

Extensor carpi ulnaris

Extensor carpi radialislongus

Extensor carpi radialisbrevis

Extensorretinaculum

Flexor carpiulnaris

Olecranonof ulna

Ulna

Radius



A&P Flix: The Elbow Joint and Forearm: An Overview

A&P Flix: Muscles of the Elbow Joint

A&P Flix: Movement at the Elbow Joint

A&P Flix: Muscles of the Forearm



A&P Flix: Biceps Brachii

A&P Flix: Brachialis

A&P Flix: Triceps Brachii

A&P Flix: Pronator Teres

A&P Flix: Brachioradialis



A&P Flix: Supinator

A&P Flix: Flexor Digitorum Superficialis

A&P Flix: Flexor Carpi Radialis

A&P Flix: Flexor Carpi Ulnaris



A&P Flix: Extensor Digitorum

A&P Flix: Extensor Carpi Radialis Longus

A&P Flix: Extensor Carpi Radialis Brevis

A&P Flix: Extensor Carpi Ulnaris


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

Elbow Flexors

Wrist Flexors

Elbow Extensors

Pronators andSupinators

Biceps brachii

Brachialis

Brachioradialis

Flexor carpi radialis

Palmaris longus

Flexor carpi ulnaris

Triceps brachii

Pronator teres

Supinator

Pronatorquadratus

Flexor retinaculum

Medial epicondyleof humerus

Humerus

Coracoid processof scapula


Median nerve Flexor retinaculum

Synovial tendon sheaths

Carpal tunnel

Pisiform

Triquetrum

Lunate

Scaphold

Carpalbones

A cross section of the right wrist (palm up) showing the synovialtendon sheaths and nearby structure


Module 10.13 Review

a. Define retinaculum.

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

c. 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


Tendon ofbiceps brachii

Anterior View,Middle Layer

Anterior View,Deepest Layer

Two anterior views of the muscles that move the hand and fingers

Brachioradialis(retracted)

Median nerve

Brachial arteryRadiusFlexor carpi ulnaris(retracted)

Supinator Cut tendons offlexor digitorumsuperficialis

Muscles That Flex theFingers and Thumb

Flexor digitorum superficialis

Flexor digitorum profundus

Flexor pollicis longus

MEDIALLATERAL


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


Two posterior views of the muscles that move the hand and fingers

Muscles ThatExtend the Fingers

Muscles That Movethe Thumb

Posterior View,Middle Layer

Posterior View,Deepest Layer

MEDIAL LATERAL

Anconeus

Extensor digitorum

Extensor digiti minimi

Abductor pollicis longus

Extensor pollicis brevis

Tendon of extensorpollicis longus

Anconeus

Supinator

Abductor pollicis longus

Extensor pollicis longus

Extensor pollicis brevisExtensorindicis

Tendon of extensordigiti minimi (cut)

Tendon of extensordigitorum (cut)

Radius

Ulna


Module 10.14 Review

a. List the muscles that extend the fingers.

b. Name the muscles that abduct the wrist.

c. 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. Opposition/reposition of thumb


The intrinsic muscles of the hand

Intrinsic Musclesof the Hand

Intrinsic Musclesof the Thumb

Anterior view

Lumbricals

Palmar interosseus

First dorsal interosseus

Abductor digiti minimi

Flexor digiti minimi brevis

Opponens digiti minimi

Palmaris brevis (cut)

Tendons of flexor digitorum

Adductor pollicis

Flexor pollicis brevis

Opponens pollicis

Abductor pollicis brevis


The intrinsic muscles of the hand

Posterior view

Intrinsic Muscles of the Hand

First dorsal interosseus muscle


Extensor retinaculum

Tendonsof extensordigitorum


Module 10.15 Review

a. Name the intrinsic muscles of the thumb.

b. Which muscles originate on the phalanges?

c. 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


The muscles that move the thigh

Gluteal muscles, posterior view Lateral view of the gluteal region

Iliac crest Sacrum

Gluteus medius(cut)

Gluteus maximus(cut)

Gluteus maximus

Gluteus medius

Gluteus minimus

Tensor fasciae latae

Iliotibial tract

Gluteal Group



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

A&P Flix: Anterior Muscles that Cross the Hip Joint

A&P Flix: Muscles that Act on the Hip Joint and Femur: An Overview



A&P Flix: Sartorius

A&P Flix: Tensor Fasciae Latae

A&P Flix: Iliiopsoas

A&P Flix: Pectineus



A&P Flix: Rectus Femoris

A&P Flix: Vastus Medialis

A&P Flix: Vastus Intermedius

A&P Flix: Vastus Lateralis



A&P Flix: Gluteus Maximus

A&P Flix: Gluteus Medius

A&P Flix: Semimembranosus

A&P Flix: Semitendinosus

A&P Flix: Biceps Femoris


The muscles that move the thigh

Gluteal Group Iliopsoas Group

Lateral RotatorGroup

Adductor Group

An anterior view showing theisolated iliopsoas musclegroup and the adductor group

A lateral view of a dissection of the gluteal region

Gluteusmaximus

(cut)

Gluteusmedius

(cut)

Gluteusminimus

Tensorfasciaelatae

Psoas major

Iliacus

Piriformis

Superior gemellus

Obturator internus

Obturator externus

Inferior gemellus

Quadratus femoris

Ischial tuberosity

Iliotibial tract

Inguinal ligament

Pectineus

Adductor brevis

Adductor longus

Adductor magnus

Gracilis

L5


Module 10.16 Review

a. Name the muscles that compose the gluteal group.

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

c. 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 or quadriceps femoris

Animation: Appendicular Muscles: Lower Limb

Animation: Appendicular Muscles: Thigh


The muscles that move the leg

Iliac crest

Gluteus medius

Tensor fasciaelatae

Gluteus maximus

Adductor magnus

Gracilis

Iliotibial tract

Flexors of the Knee

Biceps femoris

Semitendinosus

Semimembranosus

Sartorius

Popliteus

Patellar ligament

Patella

Quadriceps tendon

Vastus medialis

Vastus lateralis

Vastus intermedius(lies deep to therectus femoris andvastus lateralis)

Rectus femoris

Extensors of the Knee(Quadriceps muscles)

Sartorius

Gracilis

Adductor longus

Pectineus

Tensor fasciaelatae

Pubic tubercle

Psoas major

IliacusIliopsoas

Inguinal ligament

Anterior superioriliac spine

The flexors of the knee The extensors of the knee, collectively calledthe quadriceps muscles or the quadriceps femoris



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

A&P Flix: Muscles that Cross the Knee Joint: An Overview



A&P Flix: Tibialis Anterior

A&P Flix: Extensor Digitorum Longus

A&P Flix: Extensor Hallucis Longus

A&P Flix: Fibularis Longus

A&P Flix: Gastrocnemius



A&P Flix: Soleus

A&P Flix: Tibialis Posterior

A&P Flix: Flexor Digitorum Longus

A&P Flix: Flexor Hallucis Longus


A cross sectional view showingthe positions of the major thighmuscles relative to the femur

POSTERIOR

ANTERIOR

Semitendinosus

Biceps femoris

Vastus lateralis

Vastus intermedius

Femur

Rectus femoris

Semimembranosus

Sciatic nerve

Adductor magnus

Gracilis

Adductor longus

Great saphenous vein

Sartorius

Vastus medialis


Module 10.17 Review

a. Name the quadriceps muscles.

b. Which muscles flex the knee?

c. 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

Animation: Appendicular Muscles: Leg and Foot


The multiple muscle layers in the posterior leg


Ankle Extensors

Plantaris

Gastrocnemius

Soleus

Popliteus

Calcanealtendon

Calcaneus

Gastrocnemius(cut and removed)

Head of fibula

Ankle Extensors(Deep)

Tibialis posterior

Fibularis longus

Fibularis brevis

Digital Flexors

Flexor digitorumlongus

Flexor hallucislongus

Tendon of flexor digitorumlongus

Tendon of fibularis brevis

Tendon of fibularislongus


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


The arrangement of the majorsuperficial muscles that movethe foot and toes

Lateral View Medial View

Ankle Extensors

Ankle Flexors

Digital Extensors

Ankle ExtensorsGastrocnemius

Fibularis longus

Soleus

Fibularis brevis

Calcaneal tendon

Superior extensorretinaculum

Inferior extensorretinaculum

Iliotibial tract

Head of fibula

Tibialis anterior

Extensor digitorumlongus

Tendon of extensorhallucis longus

Tendon oftibialis anterior

Patella

Patellarligament

Medial surfaceof tibial shaft

Gastrocnemius

Soleus

Tibialis posterior



Calcaneal tendon


Module 10.18 Review

a. Name the muscles involved in flexing the toes.

b. Name the muscles involved in extending the ankle.

c. 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


A superior view of the footshowing the intrinsic musclesof the foot and toes

Lateral malleolusof fibula

Dorsal interossei


Tendons of extensordigitorum longus

Tendons of extensordigitorum brevis

Tendon of extensorhallucis longus


Medial malleolusof tibia

Tendon of tibialis anterior

Intrinsic Musclesof the Foot, Great Toe

Extensor hallucis brevis

Abductor hallucis

Intrinsic Musclesof the Foot, Toes 2–5


Deep Musclesof the Soleof the Foot

Tendons of flexordigitorum brevis

Tendon of flexorhallucis longus

Tendon offlexor digitorum longus

Flexor hallucis brevis

Superficial Muscles of the Sole of the Foot

Fibroustendon

sheaths Lumbricals

Flexor digiti minimi brevis

Quadratus plantae

Adductor hallucis

Flexor digitorum brevis


Plantar aponeurosis (cut)

Calcaneus

Instrinsic Musclesof the Foot

Tendon of tibialisposterior

Tendon offibularis longus

The intrinsic muscles on the inferior surface of the foot


Tendon of extensorhallucis brevis

Adductor hallucis

Adductor hallucis

Flexor hallucis brevis

Lumbricals

Dorsal interossei

Tendons of flexordigitorum longus

A cross section showing the intrinsic muscles of the foot

Tendons of extensordigitorum longus

Tendons of extensordigitorum brevis


Plantaraponeurosis

Tendons of flexor digitorum brevis

Plantar interossei



Flexor digiti minimibrevis

Metatarsal bones


Module 10.19 Review

a. Identify the intrinsic muscle that flexes the great toe.

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

c. 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

• Can lead to paralysis or death of muscles if not relieved in 2–4 hours


Module 10.20 Review

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

b. Define compartment syndrome.

c. Propose a reason why compartment syndrome can be life threatening.

10 the muscular system

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