PowerPoint ® Lecture Slides prepared by Barbara Heard, Atlantic Cape Community College C H A P T E R © 2013 Pearson Education, Inc.© Annie Leibovitz/Contact

PowerPoint® Lecture Slidesprepared byBarbara Heard,Atlantic Cape Community College

C H A P T E R

© 2013 Pearson Education, Inc.© Annie Leibovitz/Contact Press Images

10

The Muscular System: Part A

The Muscular System: Part A

© 2013 Pearson Education, Inc.

The Muscular System

• Muscle tissue – all contractile tissues– Skeletal, cardiac, smooth muscle

• Focus on skeletal muscle– How muscles interact to movement– Criteria for naming muscles– Principles of leverage


Actions and Interactions of Skeletal Muscles

• Muscles can only pull; never push

• What one muscle group "does", another "undoes"


Actions and Interactions of Skeletal Muscles

• Functional Groups– Prime mover (agonist)

• Major responsibility for producing specific movement

– Antagonist• Opposes or reverses particular movement

– Prime mover and antagonist on opposite sides of joint across which they act


Figure 10.1 The action of a muscle can be inferred by the position of the muscle relative to the joint it crosses. (Examples given relate to the shoulder joint.)

A muscle that crosses on the anterior side of a joint produces flexion*

A muscle that crosses on the posterior side of a joint produces extension*

A muscle that crosses on the lateral side of a joint produces abduction

A muscle that crosses on the medial side of a joint produces adduction

Example:Pectoralis major(anterior view)

Example: Latissimusdorsi (posterior view)

The latissimus dorsiis the antagonist ofthe pectoralis major.

Example: Deltoidmiddle fibers(anterolateral view).

Example:Teres major(posterolateral view)

The teres major is theantagonist of thedeltoid.

*These generalities do not apply to the knee and ankle because the lower limb is rotated during development. The muscles that cross these joints posteriorly produce flexion, and those that cross anteriorly produce extension.


Skeletal Muscles: Functional Groups

• Same muscle may be– Prime mover of one movement– Antagonist for different movement– Synergist for third movement


Naming Skeletal Muscles

• Muscle location—bone or body region with which muscle associated

• Muscle shape—e.g., deltoid muscle (deltoid = triangle)

• Muscle size—e.g., maximus (largest), minimus (smallest), longus (long)

• Direction of muscle fibers or fascicles—e.g., rectus (fibers run straight), transversus (fibers run at right angles), and oblique (fibers run at angles to imaginary defined axis)


Naming Skeletal Muscles

• Number of origins—e.g., biceps(2 origins) and triceps (3 origins)

• Location of attachments—named according to point of origin and insertion (origin named first)

• Muscle action—named for action they produce, e.g., flexor or extensor

• Several criteria can be combined, e.g., extensor carpi radialis longus


Figure 10.5 Superficial muscles of the body: Anterior view.

Head

Neck

Epicranius, frontal bellyOrbicularis oculiZygomaticusOrbicularis orisTemporalis

MasseterPlatysmaSternohyoidSternocleidomastoid

ThoraxPectoralis minorPectoralis majorSerratus anteriorIntercostalsAbdomenRectus abdominisExternal obliqueInternal obliqueTransversus abdominis

ThighTensor fasciae lataeSartoriusAdductor longusGracilis

LegGastrocnemius

Soleus

LegFibularis longusExtensor digitorumlongusTibialis anterior

ThighRectus femorisVastus lateralisVastus medialis

Pelvis/thighIliopsoasPectineus

ForearmPronator teresBrachioradialisFlexor carpi radialisPalmaris longus

ArmTriceps brachiiBiceps brachiiBrachialis

ShoulderTrapezius

Deltoid

Facial


Figure 10.6 Superficial muscles of the body: Posterior view.

NeckEpicranius, occipital bellySternocleidomastoidTrapezius

ShoulderDeltoidInfraspinatusTeres major

Rhomboid majorLatissimus dorsi

HipGluteus mediusGluteus maximus

Adductor magnus

Biceps femorisHamstrings:

SemitendinosusSemimembranosus

LegGastrocnemiusSoleusFibularis longusCalcaneal(Achilles) tendon

Iliotibial tract

ArmTriceps brachiiBrachialisForearmBrachioradialisExtensor carpi radialislongusFlexor carpi ulnaris

Extensor carpi ulnarisExtensor digitorum

Thigh


Muscles of the Head

• Two groups– Muscles of facial expression– Muscles of mastication and tongue movement


Muscles of Mastication

• Four pairs involved in mastication; all innervated by cranial nerve V (trigeminal nerve)– Prime movers of jaw closure

• Temporalis and masseter

– Grinding movements• Medial and lateral pterygoids

– Chewing role - holds food between teeth• Buccinator


Figure 10.8a Muscles promoting mastication and tongue movements.

Orbicularisoris

Buccinator

Temporalis

Masseters


Figure 10.8b Muscles promoting mastication and tongue movements.

Lateralpterygoid

Masseterpulled away

Medialpterygoid


Muscles of the Anterior Neck and Throat

• Two groups – Suprahyoid muscles– Infrahyoid muscles

• Most involved in swallowing


Muscles of the Neck and Vertebral Column

• Two functional groups– Muscles that move head– Muscles that extend trunk and maintain

posture


Muscles of the Neck and Vertebral Column: Head Movement

• Sternocleidomastoid—major head flexor – Suprahyoid and infrahyoid—synergists to

head flexion

• Sternocleidomastoid and scalenes—lateral head movements

• Splenius capitis and cervicis portions - head extension, rotation, and lateral bending

• Semispinalis capitis—synergist with sternocleidomastoid


Figure 10.10a Muscles of the neck and vertebral column that move the head and trunk.

1st cervicalvertebra

Sternocleido-mastoid

Base ofoccipital bone

Mastoidprocess

Middlescalene

Anteriorscalene

Posteriorscalene

Anterior


Figure 10.10c Muscles of the neck and vertebral column that move the head and trunk.

Sternocleidomastoid(cut)

Platysma (cut)

Internal jugular vein

Omohyoid

Sternohyoid

Sternothyroid

Sternocleidomastoid

Pectoralis major


Muscles of the Neck and Vertebral Column: Trunk Extension

• Deep (intrinsic) back muscles– Erector spinae (sacrospinalis) group—

prime movers of back extension and lateral bending

• Iliocostalis• Longissimus• Spinalis

– Semispinalis and quadratus lumborum—synergists in extension and rotation


Mastoid processof temporal bone

Longissimus capitis

Iliocostalis cervicisLongissimus cervicis

Iliocostalis thoracis

Longissimus thoracisSpinalis thoracis

Erectorspinae

Iliocostalislumborum

External oblique

IliocostalisLongissimusSpinalis

LigamentumnuchaeSemispinaliscapitis

Semispinaliscervicis

Semispinalisthoracis

Quadratuslumborum

Multifidus

Figure 10.10d Muscles of the neck and vertebral column that move the head and trunk.


Deep Muscles of the Thorax: Breathing

• Muscles of respiration• External intercostals—more superficial

muscles; elevate ribs for inspiration• Internal intercostals—deeper muscles;

aid forced expiration• Diaphragm

– Partition between thoracic and abdominal cavities

– Most important muscle in inspiration– Innervated by phrenic nerves


Figure 10.11a Muscles of respiration.

Externalintercostal

Internalintercostal


Figure 10.11b Muscles of respiration.

Xiphoid process of sternum

Foramen foresophagus

Costal cartilage

Diaphragm

Lumbarvertebra

Quadratus lumborum

Psoas major

Foramen for inferiorvena cava

Centraltendon ofdiaphragmForamenfor aorta

12th rib


Figure 10.11c Muscles of respiration.

Body of thoracic vertebra

Aorta

Diaphragm (muscular part)

Inferior vena cava

Esophagus

Pericardial sac

Central tendon of diaphragm

Pericardium (cut)


Muscles of the Abdominal Wall

• Four paired muscles, their fasciae and aponeuroses form lateral and anterior abdominal wall– Rectus abdominis – External obliques– Internal obliques– Transversus abdominis


Figure 10.12a Muscles of the abdominal wall.

Linea alba

Pectoralis major

Tendinous intersection

Rectus abdominis

Inguinal ligament(formed by free inferiorborder of the external oblique aponeurosis)

Aponeurosis of the external oblique

Transversus abdominis

Internal oblique

External oblique

Serratus anterior


Muscles of the Abdominal Wall

• run at angles to one another, provide added strength

• All innervated by intercostal nerves

• Actions of these muscles– Lateral flexion and rotation of trunk– Help promote urination, defecation, childbirth,

vomiting, coughing, and screaming


Figure 10.12b Muscles of the abdominal wall.

External oblique

Iliac crest

Rectus abdominis

Internal oblique

Pubic tubercle

Lumbar fascia

Transversusabdominis

Inguinal ligament

Lumbar fascia


Figure 10.12c Muscles of the abdominal wall.

Linea alba

Peritoneum

Skin

Rectus abdominisInternal oblique

Transversus abdominis

External obliqueAponeuroses


PLAYPLAY A&P Flix™: Muscles that act on the shoulder joint and humerus: An overview (b)

PLAYPLAY A&P Flix™: Muscles that act on the shoulder joint and humerus: An overview (a)

Superficial Muscles of the Thorax

• Most - extrinsic shoulder muscles– Act in combination to fix shoulder girdle (mostly

scapula); move it to increase range of arm movements

– Actions - elevation, depression, rotation, lateral and medial movements, protraction, and retraction

• Two groups of muscles: anterior and posterior


PLAYPLAY A&P Flix™: Muscles of the pectoral girdle (b)

PLAYPLAY A&P Flix™: Muscles of the pectoral girdle (a)

Superficial Muscles of the Thorax

• Muscles of anterior thorax– Pectoralis minor– Serratus anterior– Subclavius


PLAYPLAY A&P Flix™: Muscles that act on the shoulder joint and humerus: An overview (b)

Figure 10.14a Superficial muscles of the thorax and shoulder acting on the scapula and arm.

Subclavius

Clavicle

Subscapularis

Pectoralis minor

Coracobrachialis

Serratus anterior

Humerus

Sternocleidomastoid

Deltoid

Pectoralis major

Sternum

Biceps brachii


PLAYPLAY A&P Flix™: Movement of the pectoral girdle

PLAYPLAY A&P Flix™: Muscles of the pectoral girdle (c)

Superficial Muscles of the Posterior Thorax

• Posterior extrinsic shoulder muscles– Trapezius– Levator scapulae– Rhomboids (major and minor)


Figure 10.14c Superficial muscles of the thorax and shoulder acting on the scapula and arm.

Levatorscapulae

Supraspinatus

Clavicle

Spine ofscapulaInfraspinatus

Teres minor

Teresmajor

Humerus

Trapezius

Deltoid

Rhomboidminor

Rhomboidmajor

Latissimusdorsi

Documents

PowerPoint ® Lecture Slides prepared by Barbara Heard, Atlantic Cape Community College C H A P T E R © 2013 Pearson Education, Inc.© Annie Leibovitz/Contact