Gross Anatomy of the Muscular System Lab Week of February 18, 2008 Marieb & Mitchell: Exercise 15...

Gross Anatomy of the Muscular System

Lab

Week of February 18, 2008

Marieb & Mitchell: Exercise 15

Martini: Chapter 11

• muscle– fascicles

• fibers

• fibers of a single fascicle always parallel

• fascicles of a muscle can be arranged in various ways

Organization of Skeletal Muscle Fibers

Muscles are classified by how the fascicles are organized

1. Parallel (e.g., biceps brachii muscle)• most common arrangement

2. Convergent (e.g.,pectoralis muscle)• fascicles fan or triangle shaped, converge to attach

Muscles are classified by how the fascicles are organized

3. Pennate (unipennate, bipennate and multipennate)• fasicles form angle toward tendon

4. Circular (e.g.,orbicularis oris)• sphincter, contracts to reduce diameter of opening

Origins and Insertions

• The ends of skeletal muscles are always attached to other structures– fixed end is called ORIGIN

• usually attached to bone or cartilage

– movable end is called INSERTION• usually proximal to insertion

How are muscles named?

1. location in the body • e.g., temporalis muscle

2. Origin and Insertion• first part = origin, 2nd part = insertion

3. Fascicle Organization• e.g., Rectus means “straight”• e.g., transverse means “across”• e.g., oblique means “oblique angle”

How are muscles named?

4. Relative Position• e.g., superficialis, internus, lateralis, etc…

5. Structural Characteristics (shape and size)• e.g., deltoid, rhomboid, major, longus, etc…

6. Action• e.g., abductor, extensor, rotator, etc…

Muscular Actions

• Agonists (prime mover)– responsible for a particular movement

• Antagonist– against movement of agonist

• Synergists– aid agonists, stabilize an action

• Fixators– specialized synergists– immobilize the origin of agonist so all tension is

exerted at the insertion point

Muscles of the Head and Neck

• Epicranius – frontalis

• action: raises eyebrows, wrinkles forehead


• Epicranius– occipitalis

• action: tenses and pulls scalp posteriorly


• Orbicularis Oculi– action: closes eye, squinting


• Orbicularis oris– action: constricts mouth (whistle, kissing)


• Zygomaticus– action: the elevates corners of mouth and

upper lip• smiling muscle • antagonist to depressor

anguli oris


• Levator Labii Superioris– action: raises upper lip, opens lips


• Depressor Labii Inferioris– action: depresses lower lip


• Depressor Anguli Oris– action: draws corners of mouth down

• frowning muslce• antagonist to

zygomaticus


• Masseter– origin: zygomatic arch– insertion: mandibular ramus– action:

• elevates mandible• closes jaw


• Temporalis– action:

• elevates mandible• closes jaw


• Sternocleidomastoid– origin: clavicle or manubrium– insertion: mastoid process– action:

• together: flex neck• 1 side: bends head

towards shoulder and

turns face to opposite

side


• Scalenes– origin: cervical vertebrae – insertion: Ribs 1-2– action: elevates ribs,

flexes neck


• Splenius Capitis– action: extend and hyperextend head

Muscles of the Trunk and Back

• Erector Spinae– iliocostalis– spinalis– longissimus

• together: extends vertebral column

• along: lateral flexion


• External Intercostals– origin: rib above – insertion: rib below– action: elevates ribs

• inspiration


• Internal Intercostals– origin: rib below – insertion: rib above– action: depresses ribs

• breath out


• Diaphragm– origin: xiphoid process,

cartilage of ribs 4-10, lumbar

vertebrae– action: expands thoracic

cavity, compresses abdominopelvic cavity


• Transverse Abdominus– insertion: linea alba– action: compresses

abdominopelvic cavity


• Internal Oblique– insertion: linea alba– action: compresses

abdomen, depresses ribs, flexes or bends spine


• External Oblique– insertion: linea alba– action: compresses

abdomen, depresses ribs, flexes or bends spine


• Rectus Abdominus– origin: pubic symphesis– insertion: xyphoid

process– action: depresses ribs,

compresses abdomen, flexes vertebral column


• Trapezius– origin: midline of neck

and back– insertion: clavicles and

scapular spines– action: elevation,

depression, rotation, adduction of scapula, extension of head


• Rhomboid Major– origin: T2-T5 spinous

processes– insertion: vertebral

border of scapula– action: adduction of

scapula


• Rhomboid Minor– origin: C7 and T1

spinous process– insertion: vertebral

border of scapula– action: adduction of

scapula


• Levator Scapulae– origin: C1-4 transverse

process– insertion: vertebral

border of scapula– action: elevates scapula


• Pectoralis Minor– origin: anterior surface of

ribs 3-5– insertion: coracoid

process of scapula– action: depresses and

contracts scapular end of clavicle (in complement with subclavius muscle)


• Serratus Anterior– origin: ribs– insertion: scapula– action: abducts scapula,

swings shoulder anteriorly

Gross Anatomy of the Muscular System

Lab

Week of February 25, 2008

Marieb & Mitchell: Exercise 15

Martini: Chapter 11

MUSCLES OF THE UPPER EXTREMITIES

Pectoralis Major

• Origin– Cartilages of ribs 2-6, body of sternum,

inferior medial clavicle• Insertion

– Humerus (greater tubercle and lip of intertubercular groove)

• Action– Flex, adduct, medially rotate shoulder joint

Latissimus Dorsi

• Origin– T6-12, lumbar, sacrum, ileum

• Insertion– Humerus (floor of intertubercular groove)

• Action– Adduction, extension, medial rotation at the

shoulder joint

Coracobrachialis

• Origin– Coracoid process of scapula

• Insertion– Humerus (shaft)

• Action– Adduct, flex at shoulder joint

Supraspinatus

• Origin– Supraspinous fossa of scapula

• Insertion– Humerus (greater tubercle)

• Action– Abduction at shoulder joint, stabilizes joint

• Rotator cuff group

Infraspinatus

• Origin– Infraspinous fossa of scapula


• Action– Lateral rotation at shoulder joint


Teres Minor

• Origin– Lateral border of scapula


• Action– Lateral rotation at shoulder joint, stabilizes


Subscapularis

• Origin– Subscapular fossa of scapula

• Insertion– Humerus (lesser tubercle)

• Action– Medial rotation at shoulder joint

• Rotator Cuff Group

Teres Major

• Origin– Inferior angle of scapula

• Insertion– Humerus (lip of intertubercular groove)

• Action– Extension, adduction, medial rotation at

shoulder joint

Deltoid

• Origin– Clavicle, scapula (spine and acromion)

• Insertion– Deltoid tuberosity of humerus

• Action– Altogether Abduction at shoulder joint– Anterior flexion, medial rotation at shoulder– Posterior extension, lateral rotation at

shoulder

Biceps Brachii

• Origins– Long head

• Supraglenoid tubercle of scapula

– Short head• Coracoid process of scapula

• Insertion– Tuberosity of radius

• Action– Flex at elbow AND shoulder joint, supination

Brachialis

• Origin– Humerus

• Insertion– Ulna

• Action– Flexes forearm (elbow joint)

Triceps Brachii• Origin

– Long: Infraglenoid tubercle of scapula

– Lateral: humerus

– Medial: humerus

• Insertion– Olecranon of Ulna (for all 3)

• Action– Long: extension elbow joint, extension and adduction

at shoulder joint– Lateral and Medial: extension at elbow joint

Brachioradialis

• Origin– Distal humerus

• Insertion– radius

• Action– Flexion at elbow joint

Pronator Teres

• Action– Pronation (forearm)

Flexor Carpi Ulnaris

• Action– Flex, adduct wrist

Flexor Carpi Radialis

• Action– Flex, abduct wrist

Flexor Digitorum Superficialis

• Action– Flexion at proximal interphalangeal– Flexion at metacarpophalangeal– Flexion at wrist

Extensor Carpi Radialis Longus

• Action– Extend, abduct wrist

Extensor Carpi Radialis Brevis

• Action– Extend, abduct wrist

Extensor Carpi Ulnaris

• Action– Extend, adduct wrist

Extensor Digitorum

• Action– Extension at finger joints and wrist joints

Adam Packet 1:muscles of the head, neck, chest and back

• Using the Adam software, identify the muscles in the packet (pgs 8-16).

• Answer questions 1-15 on a SEPARATE piece of notebook paper and turn it in by NEXT LAB PERIOD.

• NOTE:– You will find the answers in Exercise 15 of Marieb and

Chapter 11 of Martini.

Gross Anatomy of the Muscular System Lab Week of February 18, 2008 Marieb & Mitchell: Exercise 15...

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