1. Skeleton of the Equine The Fore and Hind Limbs
Gerard Laverty A.W.C.F.

2. The Skeletal System The Bones:
Cartilages: Form the major portion of the embryonic skeleton and part of the skeleton in the adult
Ligaments: Connect the articular ends of the bones, binding them together and facilitating or limiting movement
Connect cartilage and other structures
Serve to support or attach fascia or muscles
Gerard Laverty

3. The Function of Bones A framework to support the horses body
Protection of internal organs
Plays an important role in the formation of blood cells, in the Medullary Canal
Provide elevation
Part of the propulsion mechanism, articulation
A reservoir of minerals, Calcium and Phosphorous
For example the ribs, skull, spine.
Elevation, long bones of the legs
Combined with the muscles produce movement.
The bones act as levers
Gerard Laverty

4. Important Points
Bone is not static – bone cells are being replaced and remodeled constantly
Remodeling may be due to
Conditioning
Diet
Conformation
Disease
Age
Gerard Laverty

5. Positive Change Increase in thickness Increase in density
Gerard Laverty

6. Negative changes
Loss of bone quality or quantity, rarefaction or degeneration – for example Osteoporosis
Extra bone deposits, exostosis – for example a “splint”
May be caused by “Endogenous” or “exogenous” factors
Gerard Laverty

7. The Composition of Bone
The organic component, cells and matrix
Organic – from living tissue
The inorganic component, the minerals
Inorganic – not derived from living tissue
Gerard Laverty

8. Regions of the Part The Limb: All the bones of the structure
The Leg: The bones from the knee or hock to the ground
The Digit: The bones from the fetlock to the ground
Gerard Laverty

9. The Parts of a Bone
Epiphysis: The ends of the bone, may include articular surface
The Physis: The area of growth
The Diaphysis: The shaft of the bone
Periosteum: Skin covering the bone except at the articular surface and P.3.
Compact or cortical bone: The outer dense, hard, layer of bone tissue
Medullary Canal: A narrow space or cavity throughout the length of the diaphysis
Bone marrow: Soft material filling the canal
Cancellous or spongy bone: The network of spongy bone tissue that makes up the majority of the bone
Gerard Laverty

10. Gerard Laverty

11. Bones of the Fore Limb Scapula: The shoulder blade
Humerus: Point of shoulder to elbow
Ulna: Forms the point of the elbow
Radius: The area from the elbow to the knee
The Carpal bones: 7 bones in 2 rows, lowest joint does not open
The Metacarpal bones
The Sesamoids, proximal
First Phalange
Second Phalange
Third Phalange
Distal Sesamoid
Gerard Laverty

12. Bones of the Fore Limb Scapula Humerus Ulna Radius Carpals Metacarpals
What will happen to this.
Carpals
Metacarpals
Sesamoids
1st 2nd 3rd.Phalanges
Distal Sesamoid
Gerard Laverty

13. Bones of the Hind Limb The Pelvis The Femur, hip to stifle Patella
Fibula, Tibia
Tarsal bones, 6, main movement between the Tibia and the Tibia - Tarsal
Metatarsal bones, 3
Same as the fore leg and digit
Gerard Laverty

14. Pelvis Pelvis Femur Patella Fibula, Tibia Tarsals Metatarsals, 2,3,4
Proximal
Sessamoid
Phalange 1,2,3.
Distal Sessamoid
Gerard Laverty

15. The Metacarpals
Large Metacarpal: M. 3. Long bone, large head forms part of the knee joint. Tapered shaft, with large Foramina on the posterior face.
Large distal end, articular surface divided by Median Ridge, articulates with P. 1. and Proximal Sessamoids
Small Metacarpals: M. 2 and M. 4.
Large head, fine tapering shaft, rounded distal end. Forms part of the knee joint. M. 2 has two articular faces and is slightly larger than M. 4. They form a groove on the posterior aspect of M. 3 for ligament and tendons.
Gerard Laverty

16. Proximal Sesamoids Located on the posterior distal end of M. 3.
Articulate with M. 3
Triangular in shape
Increase the articular surface of the fetlock joint
Act as fulcrum point for ligaments and tendons
Gerard Laverty

17. First Phalange
Located between distal end of M. 3 and proximal end of P. 2
Large articular head with Median Groove matching the Median Ridge of M. 3
Forms part of the fetlock joint
Tapered shaft
Large distal end forms part of Pastern Joint
Gerard Laverty

18. Second Phalange Cube shaped
Proximal articular face forms part of Pastern joint
Distal end forms part of the Coffin joint
Distal end of the bone is within the hoof
Gerard Laverty

19. Distal Sesamoid Small boat shaped
Located on distal posterior aspect of P. 2
Forms part of the Coffin joint
Acts as a fulcrum for tendon to pass over
Gerard Laverty

20. Distal Phalange, P.3. Modified bone Very porous No Periosteum Corium
Fore digit, P. 3 is rounded on it’s lower perimeter
Hind is more pointed, palmar surface more concave
Gerard Laverty

21. Parts of P.3. Pyramidal or Extensor Process
Distal perimeter rounded on fore, pointed on hind
The Wings, divided by the Pre – Plantar Groove
Semi – Lunar Crest
Palmar/plantar Foramina
Corium in place of Periosteum
Very Porous, concave solar surface
Articular surface divided by a median ridge
Gerard Laverty

22. Self Test
The skeletal system is made up of how many parts, what are they?
A major portion of the embryonic skeleton is composed of ……………
Ligaments connect bones together, T/F
List four functions of bones
Bone is constantly being replaced, T/F
Three causes of bone change,
A negative change of bone would be called……., for example …………
The term for an extra bone deposit is ………..
Bone change brought on by external factors is said to be “Exogenous”, T/F
Bone has an organic and inorganic makeup, the organic part is the bone cell or matrix. What is the inorganic part?
Using the forelimb as an example what part is the leg and what part the digit?
Any bone can be separated into different areas, the ends are called …….
The area of growth in a young bone is called the ……….
The shaft is called the ………..
All the bones of the limb except one are covered by a thin skin called the ……….
If you cut through a bone the outer layer is very dense that is the “cortical bone” T/F
The inner layer of bone is “Cancellous bone” T/F
The cavity in the centre of long bones is called the ………………
The acronym SHUR stands for Scapula, ………., ……….., ………..
Below the knee of hock there are, 7, 8, 9, or 11 bones?
The scapula is attached to the spine with a shoulder joint as in humans, T/F
The small bones of the knee are called, ………………?
The correct term for the cannon bone of the fore leg is …………?
The correct term for the navicular bone is ………..?
The hind leg differs from the fore because it has a boney joint to the spine T/F?
Bones have holes for blood vessels to pass through, they are called ……….?
Gerard Laverty