Chapter 8: The Appendicular Skeleton

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Chapter 8The Appendicular Skeleton
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The Appendicular Skeleton
Figure 81
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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 Pectoral Girdle
Figure 82a
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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 82b, c
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The Clavicles

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

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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

Figure 83a
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Structures of the Scapula

• Posterior surface

Figure 83c
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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
Figure 84
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The Humerus

• Also called the arm
• The long, upper armbone
• Articulates with the pectoral girdle

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The Forearm
Figure 85
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The Forearm

• Also called the antebrachium
• Consists of 2 long bones
• ulna (medial)
• radius (lateral)

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Ulna The Olecranon

• Superior end of ulna
• Point of elbow
• Superior lip of trochlear notch
• Articulates with trochlea of humerus

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The Wrist
Figure 86
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The Wrist

• 8 carpal bones
• 4 proximal carpal bones
• 4 distal carpal bones
• allow wrist to bend and twist

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Metacarpal Bones

• The 5 long bones of the hand
• Numbered IV from lateral (thumb) to medial
• Articulate with proximal phalanges

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Phalanges of the Hands

• Pollex (thumb)
• 2 phalanges (proximal, distal)
• Fingers
• 3 phalanges (proximal, middle, distal)

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The Pelvic Girdle
Figure 87
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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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Os Coxae

• Made up of 3 fused bones
• ilium (articulates with sacrum)
• ischium
• pubis

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The Acetabulum

• Also called the hip socket
• Is the meeting point of the ilium, ischium, and
  pubis
• Is on the lateral surface of the os coxae
• Articulates with head of the femur (lunate
  surface)

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The Pelvis
Figure 88
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The Pelvis

• Consists of 2 ossa coxae, the sacrum, and the
  coccyx
• Stabilized by ligaments of pelvic girdle, sacrum,
  and lumbar vertebrae

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Divisions of the Pelvis
Figure 89
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Divisions of the Pelvis

• True pelvis
• encloses pelvic cavity
• False pelvis
• blades of ilium above arcuate line

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The True Pelvis

• Pelvic brim
• upper edge of true pelvis
• encloses pelvic inlet

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Comparing the Male and Female Pelvis
Figure 810
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Comparing the Male and Female Pelvis

• Female pelvis
• smoother
• lighter
• less prominent muscle and ligament attachments

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Pelvis Modifications for Childbearing

• Enlarged pelvic outlet
• Broad pubic angle (gt 100)
• Less curvature of sacrum and coccyx
• Wide, circular pelvic inlet
• Broad, low pelvis
• Ilia project laterally, not upwards

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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 811
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The Patella
Figure 812
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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 813
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The Tibia

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

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The Fibula

• Attaches muscles of feet and toes
• Smaller than tibia
• Lateral to tibia

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The Ankle

• Also called the tarsus
• consists of 7 tarsal bones

Figure 814a
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Bones of the Ankle

• Talus
• carries weight from tibia across trochlea
• Calcaneus (heel bone)
• transfers weight from talus to ground
• attaches Achilles tendon
• Cuboid bone
• articulates with calcaneus

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Feet Metatarsal Bones

• 5 long bones of foot
• Numbered IV, medial to lateral
• Articulate with toes

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Feet Phalanges

• Phalanges
• bones of the toes
• Hallux
• big toe, 2 phalanges (distal, proximal)
• Other 4 toes
• 3 phalanges (distal, medial, proximal)

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Feet Arches

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

Figure 814b
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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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Male and Female Skeletons
Table 81