The Skeletal System

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The Skeletal System

• Chapter 5

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Long bone
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Haversian System
Junqueira and Carneiro, Basic Histology, a text
and atlas, pp. 44 and 46, Figures 8-6 and 8-8.
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Bone growth
Epiphyseal plates
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Axial Skeleton

• 3 parts
• 1. Skull
• 2. vertebral column
• 3. bony thorax
• The skull consists of
• -cranium (around brain)
• -facial bones

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Cranium

• 8 bones
• Frontal (forehead)
• Parietal (paired laterally)
• Temporal (paired laterally)
• Occipital (posterior cranium)
• Sphenoid (butterfly shaped part of brain base
  and behind eye orbit)
• Ethmoid (roof of nasal cavity)

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Cranium

• Coronal suture where frontal and parietal bones
  meet
• Sagittal suture where parietal bones meet
• Squamous suture where temporal and parietal
  meet
• Lambdoidal suture junction of occipital with
  parietal bones

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Facial Bones
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Fetal skull

• Fontanels fibrous membranes connecting cranial
  bones soft spots
• For brain growth and skull compression during
  birth
• Converted to bone by 22-24 months

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Vertebral column
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Pectoral Girdle

• Clavicle collarbone
• Scapula shoulder blades
• Glenoid cavity of scapula is where humerus fits

Scapula
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Upper Limbs
Head of humerus (glenoid fossa)
Radial groove for nerve (seen on back
side) Deltoid tuberosity
humerus
capitulum
epicondyle
Radial tuberosity
radius
trochlea
ulna
ulna
(a)
(b)
Anterior view, left arm (a) anatomical
position (b) hand pronated
Image www.tpub.com/.../medical/14295/css/14295_23
.htm
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Image from Wikimedia
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The hand

• Carpals wrist
• Metacarpals palm
• Phalanges fingers

Distal end of radius is always on thumb side.
Image www.heumann.org/.../appendicular.skeleton.h
tml
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Pelvic Girdle

• Formed from 2 coxal (hip) bones
• Pelvis coxal bones sacrum coccyx
• Bears weight of upper body
• Protects reproductive, urinary organs, and
  intestines

False pelvis
True pelvis
Image www.heumann.org/.../appendicular.skeleton.h
tml
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Pelvis

• Female pelvis (vs. male)
• Shallower, thinner --shorter sacrum
• Ilia flare laterally --larger inlet of true
  pelvid
• Rounded pubic arch

Male female
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Lower limbs
Femur Slants medially to put knees in line with
center of gravity
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Lower limbs

• Tibia (shinbone)
• Larger then fibula
• Tibial tuberosity where ligaments of patella
  attach
• Medial malleolus inner ankle (on big toe side)
• Fibula
• Lateral malleolus outer ankle

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Foot
heel
ankle
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Joints (articulations)

• Hold bones together, yet provide for movement
• Functional classification
• Synarthroses immovable
• Amphiarthroses slightly movable
• Diarthroses freely movable
• Structural classification
• Fibrous (generally synarthroses)
• Cartilagenous (mostly amphiarthroses)
• Synovial (diarthroses)

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Structural Joints

• Fibrous
• In sutures of skull
• Bound by connective tissue fibers
• Cartilagenous
• Bone ends covered by cartilage
• Pubic symphysis, invertebral joints (slightly
  movable)
• Epiphyseal plates, between 1st ribs and sternum
  (immovable)

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Structural Joints

• Synovial
• Connected by joint cavity with synovial fluid
• 4 key features
• Hyaline cartilage at bone ends
• Capsule of fibrous connective tissue lined with
  synovial membrane
• Joint cavity with synovial fluid
• Reinforcing ligaments
• Bursae and tendon sheaths help reduce friction at
  muscles/ligaments/tendons

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Types of synovial joints
Mulitaxial, rotation
Rotating uniaxial
Uniaxial angular
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Types of synovial joints
Biaxial, side to side Back and forth
A.k.a. plane joint Flat w/ no rotation
Biaxial (like condyloid) movement
Image www.visualdictionaryonline.com
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