Skeletal System
Study Guide

1) The Skeletal System
Functions
Main Functions of the Skeletal System
1 Protection (ex: skull/vertebral column)
2 Movement (Leverage/force of motion)
3 Support (ex: femur supports upper body)
4 Storage of minerals (calcium) and lipids (yellow marrow)
5 Blood cell production (in red bone marrow)

2) Classification of Bones
1.
Long bones
2.
Flat bones *RIB & SKULL Bones
3.
Sutural bones
4.
Irregular bones
5.
Short bones
6.
Sesamoid bones

3) Two Divisions of the Skeletal System
Axial
 Total Bones: 80
 Includes the longitudinal axis of the body
 Skull ( 29 Bones)
 Vertebral Column ( 26
Bones)
 Bony Thorax ( 25
Bones)
Appendicular
 Total Bones: 126
 Upper Limbs ( 60
Bones)
 Lower Limbs ( 60
Bones)
 Pectoral Girdle ( 4
Bones)
 Pelvic Girdle ( 2 Bones)

4) Total Bones in Skeletal System
Axial
 Total Bones: 80
 Includes the longitudinal axis of the body
 Skull ( 29 Bones)
 Vertebral Column ( 26
Bones)
 Bony Thorax ( 25
Bones)
Appendicular
 Total Bones: 126
 Upper Limbs ( 60
Bones)
 Lower Limbs ( 60
Bones)
 Pectoral Girdle ( 4
Bones)
 Pelvic Girdle ( 2 Bones)
GRAND TOTAL: 206

5) Long Bone Structure
Diaphysis - the shaft
Epiphysis - wide part at each end of bones

6) Long Bone Structure
Diaphysis -compact bone
Epiphysis -spongy bone
At ends of bones there is articular cartilage, which is hyaline cartilage

7) Long Bone Structure
Ossification is bone formation
Epiphyseal Plate: where bone is actively growing
Babies have more cartilage than bone.
Babies have more bones than adults because as they grow up, some of the bones fuse together to form one bone.

8) Only movable bone of skull
 The mandible is the only freely movable bone of the skull.

9) Axial skeleton
Axial
 Includes the longitudinal axis of the body
 Skull
 Vertebral Column
 Thorax

10) Bones of thoracic cage
Thoracic cage
Ribs (both true & false ribs)
Sternum

11) Bones of pectoral girdle
Pectoral girdle
Clavicle
Scapula

12) Types of RIBS
TRUE RIBS  1-7
Are attached to the sternum by cartilage
FALSE RIBS  8 - 12
Attached indirectly to sternum by cartilage or not at all

13) Sacrum
 Sacrum is NOT part of the appendicular skeleton
 Sacrum is part of the axial skeleton

14) Lateral forearm bone
 The RADIUS is “rad” and is on the thumb side – LATERAL in anatomical position

15) Phalanges of hand
 There are 14 phalanges in the hand.

16) Bone that articulates with coxal bone of pelvic girdle
 The head of the FEMUR articulates with the coxal bone.

17) Fractures
 A fracture is any break in a bone.

18) Scoliosis
 Scoliosis – lateral curvature in lumbar region of vertebral column.