Download Chapter 8: The Appendicular Skeleton

Chapter 8:
The Appendicular Skeleton
1
Appendicular Skeleton
• 126 bones
• Consists of limbs and limb girdles to
provide movement
1. Pectoral girdle: 4 bones
2. Upper limbs: 60 bones
3. Pelvic girdle: 2 bones
4. Lower limbs: 60 bones
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3
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
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Figure 8–2a
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
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Figure 8–2b, c
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
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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
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Figure 8–3a
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 arm 14
Figure 8–3c
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
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sternum.
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
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Figure 8–4
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
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Figure 8–4
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 radius
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Figure 8–5
The rounded projections on either
side of the elbow are parts of
which bone?
A.
B.
C.
D.
humerus
ulna
radius
both A and B
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Which bone of the forearm is
lateral in the anatomical position?
A.
B.
C.
D.
ulna
radius
scaphoid
depends on hand position
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The Wrist
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Figure 8–6
Bill accidentally fractures his first distal
phalanx with a hammer.
Which finger is broken?
A.
B.
C.
D.
thumb
small finger
ring finger
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
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Figure 8–7
The Pelvis
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Figure 8–8
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 semitendinosus
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Which three bones make up the os
coxae?
A.
B.
C.
D.
ilium, ischium, and femur
ilium, ischium, and pubis
ilium, acetabulum, and pubis
ilium, femur, and pubis
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When you are seated, which part of
the pelvis bears your body’s weight?
A.
B.
C.
D.
obturator foramen
posterior inferior iliac spines
ischial tuberosities
pubic tubercle
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Divisions of the Pelvis
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Figure 8–9
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.
B.
C.
D.
narrow pubic angle
greater curvature on sacrum
broad, low pelvis
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
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Figure 8–11
Femur
• Trochanters
– Greater and lesser trochanters
– tendon attachments
• Shaft:
– attaches hip muscles
• Epicondyle:
– Lateral and Medial epicondyle
– Attachments for ligaments of the knee joint
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The Patella
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Figure 8–12
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
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Figure 8–13
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
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Figure 8–14a
Feet: Arches
• Arches transfer weight from 1 part of
the foot to another
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Figure 8–14b
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.
B.
C.
D.
talus
calcaneus
navicular bone
first metatarsal bone
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Which foot bone transmits the weight
of the body from the tibia toward
the toes?
A.
B.
C.
D.
calcaneus
navicular bone
cuboid bone
talus
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Which foot bone transmits the weight
of the body from the tibia toward
the toes?
A.
B.
C.
D.
calcaneus
navicular bone
cuboid bone
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
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Table 8–1
How aging affects
the skeletal system.
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Age-Related Skeletal Changes
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Table 8–2
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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