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