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Lab 6,
BIO 105
Appendicular Skeleton
• Allows environmental manipulation and
mobility--locomotion
• Bones of limbs and their girdles
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• Pectoral or Shoulder girdle attaches upper limbs
to trunk of body
• Pelvic or Hip girdle attaches lower limbs
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Pectoral or Shoulder Girdle--flexible structure
• Clavicles (anterior) and scapulae (posterior)
• Provide attachment sites for muscles that move
upper limbs
• Attach upper limbs to axial skeleton-scapulae do not
articulate with spine or ribs
• muscles keep in place
• Allow movable articulation with other bones
• shoulder joint is flexible and has a lot of
movement
• Shoulder joint socket not deep
• Easily dislocated
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Clavicles
• S-shaped bone
• Act as brace to hold scapulae and arms out laterally;
pushes shoulder posteriorly
• acromial (lateral) end articulates with scapula
• sternal (medial) end articulates with sternum
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Scapulae
• on dorsal surface of rib cage, between ribs 2 and 7
• Flat and triangular shaped
• Major markings:
spine
acromion
Coracoid process
glenoid cavity or fossa
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Upper Limb
• Upper Arm
• Humerus
• Forearm
• Radius and ulna
• Hand
• Wrist: carpal bones
• Palm: metacarpal bones
• Fingers: phalanges
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Humerus
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Largest, longest bone of upper limb
Articulates superiorly with glenoid cavity of scapula
Articulates inferiorly with radius and ulna
Major markings: head,
anatomical and surgical necks,
greater and lesser tubercles,
deltoid tuberosity
coronoid fossa
capitulum, trochlea
olecranon fossa
medial and lateral epicondyles
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Forearm Bones
• Radius and Ulna
• Articulate proximally with humerus and distally with
wrist bones
• Articulate with each other proximally and distally at
radioulnar joints
• Flat, flexible interosseous membrane connects bones
along entire length
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• Ulna
– Medial bone in forearm; slightly longer than radius
– Forms major portion of elbow joint with humerus
– Major markings: olecranon process, coronoid process,
trochlear notch, radial notch, styloid process
• Radius
– Lateral bone in forearm
– Head articulates with humerus capitulum and radial
notch on ulna
– Major markings: head, neck, radial tuberosity, styloid
process
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• Hand: Carpus--Skeleton of the hand contains carpal
bones (wrist), metacarpal bones (palm), and
phalanges (fingers); Bones are held together by
ligaments allowing a flexible wrist
• Metacarpus (Palm)
– Five metacarpal bones (#1 to #5) form palm
– articulate proximally with carpals, distally with
phalanges
• Phalanges
– Each finger (digit), except thumb, has three phalanges—distal, middle, and proximal
– Fingers are numbered 1–5, beginning with thumb
(pollex)
– Thumb has no middle phalanx
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Pelvic (Hip) Girdle
• Two hip bones (also called coxal bone, os coxae, or
inominate bone)
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Attach lower limbs to axial skeleton with strong ligaments
Transmit weight of upper body to lower limbs
Support pelvic organs
Is more stable than shoulder because acetabulum (femur
attachment ) is deeper
• Each hip bone consists of three fused bones: ilium,
ischium, and pubis (bones not fused in child—fuse in early
adulthood)
• Together with sacrum and coccyx, forms pelvis
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Hip Bone—3 regions
1. Ilium
• Large, flaring bone which forms superior region of coxal
bone
• Consists of body and superior wing like portion called
“ala”
• articulates with sacrum (sacroiliac joint)
2. Ischium
• Forms postero-inferior part of hip bone
• Thick body articulates with ilium and ramus
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3. Pubis
• Anterior portion of hip bone
• Midline pubic symphysis joint
Major pelvic markings:
ramus,
ilium
ischium
iliac crest
iliac spines (2 on each bone)
acetabulum,
ischial spine
ischial tuberosity
obturator foramen
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Comparison of Male and Female Pelves
• Female pelvis
• Adapted for childbearing; tilted forward
• True pelvis (inferior to pelvic brim) defines birth canal
• Cavity of true pelvis is broad, shallow, and has greater
capacity
• Sacrum is wider, shorter, straighter
• Coccyx is straighter
• Male pelvis
– Tilted less forward
– Adapted for support of heavier body build and stronger
muscles
– Cavity of true pelvis is narrow and deep
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Lower Limb
• Carries weight of body
• Subjected to exceptional forces with running and
jumping
• Three segments --thigh, leg and foot
Femur
• Thigh bone, largest and strongest bone in body
• Articulates proximally with acetabulum of hip and distally
with tibia and patella
• Major markings: head
neck
linea aspera
greater and lesser trochanters
lateral and medial condyles
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Patella or Kneecap
• Triangular bone enclosed in quadriceps tendon;
anchors anterior thigh muscles to tibia
• Protects knee joint anteriorly
• Improves leverage of thigh muscles acting across
knee
• Articulates with medial and lateral condyles of distal
femur and proximal tibia
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Tibia
• Medial leg bone
• Receives weight of the body from femur and transmits it to
foot
• Major markings: medial and lateral condyles, tibial
tuberosity, anterior crest, medial malleolus
• Fibula
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Sticklike bone with slightly expanded ends, lateral to tibia
Not weight bearing; no articulation with femur
Site of muscle attachment
Connected to tibia by interosseous membrane
Articulates with tibia via proximal and distal tibiofibular
joints
• Major markings: head, lateral malleolus
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Foot: Includes tarsals, metatarsals, and phalanges
• Functions—support weight of body
• Acts as a lever to propel body forward
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Tarsals
Seven tarsal bones form posterior half of foot
• Body weight is primarily carried on talus and
calcaneus
• Talus—large, topmost bone which connects to tibia
and fibula
• Calcaneus
• Forms heel; distal to talus
• Point of attachment for Achilles (calcaneal) tendon of calf
muscles
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• Metatarsals:
– Five metatarsal bones (#1 to #5) that articulate with
proximal phalanges (toes)
– Enlarged head of metatarsal 1 forms “ball of foot”
• Phalanges
– toes
–
Each digit (except the hallux—great toe) has three phalanges
– Hallux has no middle phalanx
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Joints (Articulations)
• Articulation—site where two or more bones
meet
• Weakest parts of the skeleton
• Functions of joints:
– Give skeleton mobility
– Hold skeleton together
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Joints
• Classified either structurally or functionally
Structural Classification of Joints
• Based on material (type of tissue) binding bones
together or presence of a joint cavity
Structural classifications:
– Synovial-most common, most movable
– Cartilaginous-slightly movable
– Fibrous-immovable
Functional Classification
• Based on amount of movement allowed
• Functional classifications:
-Diarthroses— freely movable (predominant in limbs)
-Amphiarthroses—slightly movable
Primarily in
-Synarthroses—immovable
axial skeleton
Fibrous or Synarthrotic Joints
• Bones joined by dense fibrous connective
tissue
• Most immovable;
some slightly movable
• No joint cavity
Fibrous or Synarthrotic Joints: Joint held together by a
ligament; Fibrous tissue can vary in length, but
is longer than in sutures.
--Movement varies from immovable to slightly movable;
Example:
Connection between radius and ulna
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Cartilaginous or Amphiarthrotic Joints: (Synchondroses or
Symphyses)
– No joint cavity
Synchondroses—bones connected by hyaline cartilage
ex: Epiphyseal plate; costal cartilage joint between first rib
and sternum
Symphyses--bones connected by broad, flat fibrocartilage
pad intervertebral joints, pubic symphasis
Synovial or Diarthrotic Joints
• freely movable
• Articulating bones separated by fluid filled joint
cavity
– Fluid reduces friction
• Examples:
– all limb joints;
– most joints of body
Reminders
• ID and describe bones and bone markings
presented in handout.
• Describe basic kinds of joints and give
examples.
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