The document summarizes the skeletal system, which consists of two main sections: the axial skeleton and appendicular skeleton. The axial skeleton includes bones like the skull, vertebrae, ribs, and sternum that protect internal organs. The appendicular skeleton includes the bones of the limbs that allow for movement. There is variation in bone number between species and sometimes within species. The document then describes the individual bones that make up these two sections of the skeletal system.

1. SKELETAL SYSTEMS

2. Two Major Sections of the Skeleton
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 Axial Skeleton
 Used to protect fragile tissue that is held
underneath
 Vertebrae, ribs, skull sternum
 Appendicular Skeleton
 These bones allow for movement
 Bones of the limbs

3. Variations of Bones
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 Total number of bones vary by species and
even within a species
 Example:
 Horse – 205 bones
 Dog – average - 320 bones
 Some dogs are born with short tails and others have
long tails which change the number of vertebrate
present
 Dewclaws  some are born with some are born
without changing the number of digits present

4. Bones of the Axial Skeleton
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 Cranium
 Made mostly of flat bones (50 bones in a dog)
 Shape varies between species and breed
 Used for protection of the brain and other
sense organs (taste, smell, hearing, sight,)
 Lower jaw – mandible, is moveable allowing
an animal to obtain and chew food

5. Bones of the Axial Skeleton
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 The Vertebral Column
 Extends the length of the body from the skull
 Protects the spinal cord and allows for
movement
 Anatomy of the Vertebral Disk
 Covered with bony arch - protects spinal cord
 Intervertebral disks can be found between
vertebrae. add cushion between the disks (not
found between C1 and C2)

6. Bones of the Axial Skeleton
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 The Vertebral Column
 Broken down into anatomical divisions
 Cervical(7)
 Thoratic (13)
 Lumbar (7)
 Sacrum (3)
 Coccygeal (14-23)

7. Bones of the Axial Skeleton
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 The Vertebral Column
 Cervical Vertebrae – neck
 Mammals have 7 Cervical Vertebrae
 C1 – Atlas – allows for up and down movement of
head
 C2 – Axis – allows for side to side movement
 Thoracic Vertebrae – have attached ribs
 Help to protect the heart and lungs, allow for
respiration

8. Bones of the Axial Skeleton
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 The Vertebral Column
 Lumbar Vertebrae – lower back between thoracic
vertebra and pelvis
 Flexes and extends as an animal moves
 Provide support for organs in the abdomen
 Sacrum Vertebrae
 Fuse with the pelvis allowing support of the hind end
of the animal

9. Bones of the Axial Skeleton
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 The Vertebral Column
 Coccygeal Vertebrae – Tail
 Vary by species and within the species
 Dogs typically have 20 Coccygeal vertebrae but can
range from 6-23!

10. Bones of the Axial Skeleton
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10/13/10

11. Create it!
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 Congrats…you have graduated from the
school of vertebral engineering! Lets put
that education to good use!

12. Bone of the Axial Skeleton
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 Cranial – PECTORAL LIMBS
 Scapula
 Humerus
 Radius
 Ulna
 Carpus
 Metacarpal
 Phlanges

13. Bones of the Appendicular
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 Scapula
 Joins the humerus through a shallow ball and
socket joint.
 Flat bone with a spine to attach tendons and
ligaments

14. Bones of the Appendicular
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 Humerus
 Upperbone of the forelimb.
 Connects scapula to the elbow

15. Bones of the Appendicular
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 Radius and Ulna - Forearm
 Ulna runs to the point of the elbow and
accepts the end of the humerus.
 Radius closely connects to the ulna and forms
the remainder of the elbow joint.
 The elbow joint is a hinge joint and the reason
that we can twist our forearm is because of the
movement between the radius and ulna, not the
elbow joint.

16. Bones of the Appendicular
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 Carpus - Wrist
 Radiusand ulna continue to the carpus.
 Group of bones arranged in two rows.
 Number of bones vary among species.
 Dog –7
 Ruminants – 6
 Horse – 7 or 8

17. Bones of the Appendicular
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 Metacarpus - Hand
 Long Bones
 Lots of differences in species.
 Dogs and cats have four long and one much
smaller one (dewclaw)
 Horses have only one major bone, corresponds to
the third one in other species, but has two smaller
ones as well.
 Ruminants only have one very large metacarpal
bone. As the ruminant embryo develops, the third
and fourth one fuse together.

18. Bones of the Appendicular
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 Phalanges – fingers and toes
 Number of toes corresponds to the number of
metacarpal bones.
 Singular form is phalanx.
 The last phalanx is covered by the nail or
hoof.

19. Bones of the Appendicular
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 Caudal End – PELVIC LIMBS:
 Pelvis
 Femur
 Tibia
 Fibula
 Tarsus
 Metatarsus
 Phalanges

20. Bones of the Appendicular
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 Pelvis
 3 fused bones.
 Pubis
 Ischium
 Ilium
 Sacrum supports the pelvis.
 Connection can be damaged, and may split away.
 Pelvis is made of two halves.
 Each half divides into regions: ilium, ischium, pubis.
 Ilium joins to the sacrum.

21. Pelvis
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22. Bones of the Appendicular
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 Femur – Leg Bone
 Ball
and socket joint to the pelvis.
 Goes to the knee.

23. Bones of the Appendicular
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 Patella – Knee Cap

24. Bones of the Appendicular
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 Tibia and Fibula
 Similar to Ulna and Radius in forearm

25. Bones of the Appendicular
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 Tarsus - Ankle

26. Bones of the Appendicular
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 Metatarsus – Top of foot

27. Bones of the Appendicular
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 Phalanges - Toes