chapter 8: the appendicular skeleton 1. appendicular skeleton 126 bones consists of limbs and limb...

Chapter 8:The Appendicular

Skeleton

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Appendicular Skeleton

• 126 bones• Consists of limbs and limb girdles

to provide movement1. Pectoral girdle: 4 bones2. Upper limbs: 60 bones3. Pelvic girdle: 2 bones4. Lower limbs: 60 bones

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Upper limbs

• Carpal tunnel syndrome– Carpals arranged in two rows of four bones– Creates a U shape enclosed by the flexor

retinaculum (ligament)– All tendons, vessels, and nerves of the hand must

pass through channels between bones and ligaments (no extra space)

– Any inflammation = pressure on nerves leading to pain

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The Appendicular Skeleton

• Allows us to move and manipulate objects

• Includes all bones besides axial skeleton:– the limbs – the supportive girdles

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The bones of the pectoral girdle, their functions, and features.

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The Pectoral Girdle

Figure 8–2a7

The Pectoral Girdle

• Also called the shoulder girdle• Connects the arms to the body • Positions the shoulders• Provides a base for arm movement

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The Pectoral Girdle

• Consists of:– 2 clavicles – 2 scapulae

• Connects with the axial skeleton only at the manubrium

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The Clavicles

Figure 8–2b, c10

The Clavicles

• Also called collarbones• Long, S-shaped bones• Originate at the manubrium (sternal end)• Articulate with the scapulae (acromial end)• Costal Tuberosity:

– Attachment for the costoclavicular ligament which articulates with the cartilage of the ribs

• Conoid Tubercle:– Attachment for the conoid ligament which

articulates with the coracoid process of the scapula 11

The Scapulae

• Also called shoulder blades• Broad, flat triangles• Articulate with arm and collarbone

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The Scapula

• Anterior surface: the subscapular fossa– attachment for the

subscapularis muscle• Function to rotate the

head of the humerus medially (internal rotation)

• Function to draw the humerus forward and downward when the arm is raised

Figure 8–3a13

Structures of the Scapula

• Posterior surface• Supraspinous

fossa– Origin for the

supraspinatus muscle, which abducts (toward midline) the arm at the shoulder

– Origin for the infraspinatus muscle, which adducts that armFigure 8–3c

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Why would a broken clavicle affect the mobility of the scapula?

A. Muscles attach the clavicle to the scapula.

B. Clavicle is attached to the sternum which is attached to the scapula.

C. Clavicle attaches the scapula to the humerus.

D. Clavicle attaches the scapula to the sternum.

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The bones of the upper limbs, their

functions, and features.

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The Upper Limbs

• Arms, forearms, wrists, and hands

Note: arm (brachium) = 1 bone, the humerus

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The Humerus

• Also called the arm

• The long, upper armbone

• Greater tuberosity– Attachment for

suprasinatus and infrapinatus

• Lesser tuberosity– Attachment for

tendon of subscapularus

Figure 8–418

The Humerus• Epicondyle

– Attachment for ligaments of the elbow-joint

– Lateral: tendon of supinator muscle

– Medial: tendon of flexor muscles of the forearm

• Olecranon fossa– Receives process for the

extension of the forearm

• Coronoid fossa– Receives the coronoid

process of the ulna during flexion (joint angle decreases) of the forearm

Figure 8–419

The Forearm• Also called the

antebrachium• Consists of 2 long

bones:– ulna (medial)– radius (lateral)

• Radial Tuberosity– Insertion of bicep

brachii

• Ulnar Tuberosity– Insertion of brachialis

• Styloid Process– Muscle attachment for

ulna or radiusFigure 8–5

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The rounded projections on either side of the elbow are

parts of which bone?

A. humerusB. ulnaC. radiusD. both A and B

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Which bone of the forearm is lateral in the anatomical

position?

A. ulnaB. radiusC. scaphoidD. depends on hand position

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The Wrist

Figure 8–623

Bill accidentally fractures his first distal phalanx with a

hammer. Which finger is broken?

A. thumbB. small fingerC. ring fingerD. index finger

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The bones of the pelvic girdle, their

functions, and features.

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The Pelvic Girdle

• Made up of 2 hipbones (ossa coxae)

• Strong to bear body weight, stress of movement

• Part of the pelvis

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Pelvic Girdle

• 2 os coxae• Note:

– “pelvis” (no anatomical) = pelvic girdle (2 os coxae) + sacrum + coccyx

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The Pelvic Girdle

Figure 8–728

The Pelvis

Figure 8–829

The Pelvis

• Consists of 2 ossa coxae, the sacrum, and the coccyx

• Stabilized by ligaments of pelvic girdle, sacrum, and lumbar vertebrae

• Obturator Foramen– Opening for nerves and muscles to pass through

• Acetabulum– Head of the femur meets with the pelvis; hip-

joint

• Ischial Tuberosity– Point of insertion for the semimembranosus,

head of biceps femoris, and semitendinosus30

Which three bones make up the os coxae?

A. ilium, ischium, and femurB. ilium, ischium, and pubisC. ilium, acetabulum, and

pubisD. ilium, femur, and pubis

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When you are seated, which part of the pelvis bears your

body’s weight?

A. obturator foramenB. posterior inferior iliac

spinesC. ischial tuberositiesD. pubic tubercle

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Divisions of the Pelvis

Figure 8–933

Divisions of the Pelvis

• True pelvis:– encloses pelvic cavity– 2 regions:

• Pelvic brim: encloses pelvic inlet • Perineum region: perineal muscles

support organs of pelvic cavity

• False pelvis:– blades of ilium above arcuate line

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The structural and functional differences between the male and

female pelvis.

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Comparing the Male and Female Pelvis

• Female pelvis:– Smoother and lighter– less prominent muscle and ligament

attachments

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Pelvis Modifications for Childbearing

• Enlarged pelvic outlet• Broad pubic angle (> 100°)• Less curvature of sacrum and

coccyx• Wide, circular pelvic inlet• Broad, low pelvis

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How is the pelvis of females adapted for childbearing?

A. narrow pubic angleB. greater curvature on

sacrumC. broad, low pelvisD. oval pelvic inlet

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The bones of the lower limbs, their

functions, and features.

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The Lower Limbs

• Functions:– weight bearing– motion

Note: leg = lower leg; thigh = upper leg

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Bones of the Lower Limbs

• Femur (thigh)• Patella (kneecap)• Tibia and fibula (leg)• Tarsals (ankle)• Metatarsals (foot)• Phalanges (toes)

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The Femur• The longest, heaviest bone

Figure 8–1142

Femur

• Trochanters– Greater and lesser trochanters– tendon attachments

• Shaft:– attaches hip muscles

• Epicondyle:– Lateral and Medial epicondyle– Attachments for ligaments of the knee

joint43

The Patella

Figure 8–1244

The Patella

• Also called the kneecap• A sesamoid bone• Formed within tendon of

quadriceps femoris• Base attaches quadriceps femoris• Apex attaches patellar ligament

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The Tibia

Figure 8–1346

The Tibia

• Also called the shinbone• Supports body weight• Larger than fibula• Medial to fibula• Tibial Tuberosity

– Attachment for the ligamentum patellae

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The Fibula

• Attaches muscles of – feet and toes

• Smaller than tibia• Lateral to tibia

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The fibula neither participates in the knee join nor bears weight. When it

is fractured, however, walking becomes difficult. Why?

A. Fibula helps stabilize the ankle joint.

B. Fibula attaches many leg muscles.

C. Both A and B.D. None of the above.

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The Ankle

• Also called the tarsus:– consists of 7 tarsal

bones• Talus:

– carries weight from tibia across trochlea

• Calcaneus (heel bone):– transfers weight from talus

to ground– attaches Achilles tendon

Figure 8–14a50

Feet: Arches

• Arches transfer weight from 1 part of the foot to another

Figure 8–14b51

While jumping off the back steps at his house, 10-year-old Joey lands on his

right heel and breaks his foot. Which foot bone is most likely broken?

A. talusB. calcaneusC. navicular boneD. first metatarsal bone

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Which foot bone transmits the weight of the body from the

tibia toward the toes?

A. calcaneusB. navicular boneC. cuboid boneD. talus

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Which foot bone transmits the weight of the body from the

tibia toward the toes?

A. calcaneusB. navicular boneC. cuboid boneD. talus

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KEY CONCEPT

• Pectoral girdle is highly mobile, stabilized primarily by muscles

• Pelvic girdle is more massive, stronger, and less mobile

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The skeleton reveals significant

information about an individual.

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Studying the Skeleton

• Reveals characteristics:– muscle strength and mass (bone ridges,

bone mass)– medical history (condition of teeth,

healed fractures)– sex and age (bone measurements and

fusion)– body size

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The skeletal differences between

males and females.

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Male and Female Skeletons

Table 8–159

How aging affects the skeletal system.

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Age-Related Skeletal Changes

Table 8–261

SUMMARY• Components of the:

– appendicular skeleton– pectoral girdle, and relationship to axial

skeleton– upper limbs, and relationship to pectoral girdle

• Components of the:– pelvic girdle, and relationship to axial skeleton– lower limbs, and relationship to pelvic girdle

• Differences between male and female pelvises

• Individual skeletal variations • Effects of aging

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