GROSS ANATOMY OF SKELETAL SYSTEM, ARTICULATIONS AND MOVEMENTS

Lecture Notes

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I. Axial skeleton A. Skull bones (22) 1. Cranial bones (8) functions-to protect brain
a. Frontal -roof of eye orbit

b. Paired parietals - form superior and lateral cranial cavity(2)

c. Paired temporals (2) -external auditory meatus, surrounds auditory and balance receptors

d. Occipital (1) -articulates with cervical vertebrae

e. Sphenoid (1) -articulates with all cranial bones , forms posterior lateral and medial sides of orbit

f. Ethnoid (1) nasal passages, medial portion of orbit

2. Facial bones (14) a. Paired nasal -base of nose

b. Paired maxillae -upper jawbone

c. Paired zygomatics -cheekbones

d. Mandible -lower jaw

e. Paired lacrimals- tear duct, medial wall orbit
 

Demonstrate the positions of each facial and cranial bone. Diagram the bones of orbit in correct positions.

3. Paranasal sinuses
 hollows in bones lined with mucus making & moving epithelium

a. Locations
 frontal
 sphenoid
 maxillary

b. Function
 moisten and warm air, remove pathogens and debrs

4. Hyoid bone
 support larynx and oral swallowing

5. Fontanels
 areas not yet completed intramembranous ossification
 allow movement during birth to ease delivery, allows growth of skull for brain growth

Describe the functions and locations of the sinuses and fontanelles

B. Thorax (vertebrae, ribs and sternum) 1. Vertebral bones (33) a. Typical structure

 body
 vertebral foramen
 inferior & superior articular facets for vertebrae below & above
 transverse processes

b. Types
 cervical (7) support, move head (atlas, axis, c2,-c7)

ID transverse foramen through transverse processes for vertebral vessels & nerves only Thoracic (12) support, hold ribs ID have articular facets on transverse processes only thoracic

ID longest spines
 
 

 Lumbar (5) support ID very large body, blunt processes Sacral (5) articulates with pelvic girdle ID fused triangle Coccyx ID fused tail remnant
Diagram the differences between the different types of vertebrae.

2. Ribs - articulate with thoracic vertebrae via hyaline cartilage

 True ribs-              #1-7 articulate directly with sternum via hyaline cartilage

  False ribs                #8-12 articulate indirectly with sternum via cartilage

  Floating ribs           #11-12 do not articulate with sternum

3. Sternum - articulates with ribs 1-10II. Appendicular skeleton A. Pectoral girdle (shoulders) 2 bones freely movable,  not strong articulations, susceptible to damage. 1. Clavicle (collarbone)
 long bones, s-shaped
 articulates with sternum and acromium of scapula

2. Scapula (shoulder blades)
 flat bone - major attachment site for shoulder muscles

B. Upper appendages (~60 bones) 1. Arm bone (humerus)
u articulates proximally with scapula & distally with forearm bones (radius & ulna)

2. Forearm

a. Radius (lateral thumb)  round near humerus

b. Ulna (medial)  near to humerus

3. Wrist, palm, fingers
List in sequence, proximal to distal, all of the bones of the upper extremity. C. Pelvic girdle - larger & much stronger than pectoral

gender differences
pubic arch -greater in female
pelvic inlet -greater in female
greater sciatic notch-greater in female
Shape -wider in female

Coxal bones (2) superbone of three bones
 all bones articulate at acetabulum (fossa for head of femur)

a. Ilium (superior)
 articulate with sacral vertebrae

b. Pubis (anterior & inferior)
 articulate with each other

c. Ischium (posterior & inferior) major weight bearing bone when you are sitting

D. Lower appendages ~ 60 bones 1. Thigh (femur) bone
 largest, heaviest bone
 articulates with coxal as acetabulum proximally & distally with the tibia at knee

2. Leg (fibula & tibia) bones

a. Fibula (lateral)
 small bone that does not articulate with femur (not a weight-
bearing bone)

b. Tibia - large bone articulates with femur and talus (1 tarsal)

3. Tarsals, metatarsals, phalanges
 ankle (7), foot (5), toes (14)click on this image for an audio message with suggestions for learning bones
List in sequence, proximal to distal, all of the bones of the lower extremity. 

III. Articulation classifications
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A. Function (amount of movement) 1. No movement - synarthrotic

2. Some movement - amphiarthrotic

3. Freely moveable - diarthrotic

B. Structure 1. Fibrous - short or long ligaments between bones

2. Cartilaginous - cartilage pad between bones

3. Synovial -most common and most complex articulation

Articular cartilage pads between adjacent bones allow greater movement by reducing friction.
Synovial sac (a synovial membrane producing synovial fluid) between bones allows greater movement by providing cushioning) Synovial fluid also contains white blood cells that resist disease and promote repair.
Ligaments hold joint together and restrict movement
Tendons with skeletal muscle transmit force of contraction which stabilizes (and reduces movement of) joint.

C. Selected examples
1.Fibrous
a.. Between cranial and facial bones -short ligaments (synarthrotic)

b. Teeth in jaws -short ligaments (synarthrotic)

c. Distal Tibiofibular - longer ligaments (amphiarthrotic)

d. Interosseous ligaments between diaphysess of radius and ulnar bones - longer ligaments (amphiarthrotic)


2. Cartilaginous

a. Epiphyseal plates - hyaline cartilage (synarthrotic)

b. Intervertebral disk between bodies- fibrocartilage (amphiarthrotic)

c. pubic symphysis -fibrocartilage (amphiarthrotic during late stages of pregnancy)

3. Synovial

a. between long bones (diarthrotic )

b. between articular facets of vertebrae (diarthrotic )
Describe the three types of structural joints and the three types of functional joints. Give specific examples.
C. Special movements allowed by synovial joints 1) Gliding movement

2) Angular movements (usually pairs of opposing movements)

a) Flexion (decrease in angle), extension (increase in angle), hyperextension (too much increase)

b) Abduction - take away from midline, Adduction add to midline

c) Circumduction - circle of flexion, extension, abduction and adduction

3) Rotation - bone turning around on axis

4) Special movements (usually pairs of opposing movements)

a) Supination - move radius around ulna so palm up
Pronation - move radius around ulna so palm down

b) Inversion - sole turned medially
Eversion - sole turned laterally
   

c) Dorsiflexion – foot upwards
Plantarflexion – foot downwards

d) Elevation - lifting super
Depression - moving to original position

e) Protraction – away from body
Retraction – towards body
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Demostrate the movements at each diarthrotic articulation.  

D. Structural types of synovial joints (with associated movement) 1) Plane (flat on flat)
intervertebral between articular surfaces, intercarpal,
intertarsal, proximal ends of metatarsals & metacarpals
(gliding)

2) Hinge (U-shape outside barrel)
 ulna/radius and humerus, femur and tibia,
interphalangeal
(flexion, extension)
 TMJ
(protraction, retraction, elevation, depression)

3) Pivot (round with ring)
atlas-axis (rotation)
 radioulnar at proximal epiphyses (rotation allowing supination, pronation)

4) Condyloid (oval in concavity)
 occipital - atlas
 metacarpal - phalangeal
 metatarsal - phalangeal
(extension, flexion, adduction, abduction, circumduction)

5) Ball and socket
coxal - femur
scapula-humerus
(circumduction)

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Professor Thomas M. Lancraft
Human Anatomy and Physiology Courses
at St. Petersburg College
St. Petersburg/Gibbs Campus

6/2006