Equine Skeletal SystemBy Jess and Keara

What bones are made of?

Periosteum fibrous membrane rich in blood vessels

that envelopes the bone, except at the articular surfaces; it contributes especially to the bone’s growth in thickness.

*(articular surface= the surface of a joint at which the ends of the joint meet)

Compact Bone dense bone tissue composed of osteons, which resist pressure and shocks and protect the spongy tissue; it forms especially the diaphysis of the long bones.

Haversian Canal

Elementary cylindrical structure of the compact bone made up of four to 20 concentric bone plates that surround the Haversian canal.

Lengthwise central canal of the osteon. It encloses blood vessels and nerves.

Osteon

Spongy Bone Tissue made of bony compartments

separated by cavities filled with bone marrow, blood vessels and nerves

This structure gives bones their lightness.

Medullary Cavity Cylindrical central cavity of the bone

containing the bone marrow Encloses lipid-rich yellow bone marrow

Soft substance contained in bone cavities, producing blood cells; marrow is yellow in the long bones of

adults.

Bone Marrow

Volkmann’s Canal Transverse canals of the compact bone

enclosing blood vessels and nerves; Connect the Haversian canals with each other

and with the medullary cavity and the periosteum

Blood Vessel Channel in the bone through which the blood

circulates, carrying the nutrients and mineral salts the bone requires

Articular Cartilage Smooth resistant elastic tissue

covering the terminal part of the bone where it articulates with another bone

it facilitates movement and absorbs shocks

Connective Tissue

Ligaments

Link bones Sheets of strong, fibrous connective

tissue Identical to tendons in muscular

system Only difference is there function Ligaments attach bone to bone and tendons attach muscle to bone

Cushioning… Cartilage Smooth resistant elastic tissue

covering the terminal part of the bone where it articulates with another bone

it facilitates movement and absorbs shocks

Synovial Fluid› Small membranous sacks that

contain fluid and rest between bones of a joint, i.e., above coffin bone

› Helps to cushion and absorb shock

Joints

Types Fibrous

Cartilagenous

Synovial

Fibrous Immoveable!

Ex, plates in skull

Cartilagenous Partially moveable

Connected by cartilage

Ex, joints between vertebrae

Synovial Completely moveable Hinge

› Joint between 3rd metacarpal and long pastern

Ball and Socket› Joint between ilium and femur (hip joint)

Can you name the bones?

We’ll see…

Skull

What makes up the mouth…

Premaxilla (incisive bone)› Holds alveoli for upper incisive teeth

Maxilla› Holds alveoli for molar and premolar teeth

Mandible (lower jaw)› Holds alveoli for all teeth of lower jaw

And all the rest….

Bones of the Middle Ear

Malleus ~ Hammer

Incus ~ Anvil

Stapes ~ Stirrup

Spine1. Cervical vertebrae2. Thoracic vertebrae3. Lumbar vertebrae4. Sacrum5. Coccygeal/ caudal vertebrae

Cervical Vertebrae Make up the neck of the horse 1st cervical vertebrae = Atlas 2nd cervical vertebrae = Axis

› Allows neck to flex and rotate

Thoracic Vertebrae 18 Characteristically have high spines 3rd and 4th form the withers

Lumbar Vertebrae 6 Characteristically long and flat

Sacrum

Coccyx

Made up of 6 sacral vertebrae fused together(*not mentioned in video but comes right after lumbar vertebrae and before the caudal)

Made up of 15-21 coccygeal Vertebrae. (More commonly known as the Caudal Vertebrae.)

Ribs and Sternum 18 pairs of ribs First 8 pairs connect to the sternum Sternum ~ breast bone

› Made up of 6-8 sternebrae and cartilage

Foreleg

Shoulder bones connected to the….

Scapula

Humerus

Radius

Ulna (not functional in a horse)

From the wrist distally… Carpus

› Forms what is commonly called the knee in a horse

Metacarpus› 3rd metacarpal, or cannon bone, is the

only functional metacarpal Splint bones – 2nd and 4th metacarpal

› Small bones running parallel to the cannon bone on either side

*** splints is a condition when a splint bone sustains a fraction

Fingers???

Technically referred to as phalanges 1st Phalange ~ Proximal Phalanx ~

Long Pastern 2nd Phalange ~ Middle Phalanx ~ Short

Pastern 3rd Phalange ~ Distal Phalanx ~ Coffin

Bone

Can you name them?

Hind Leg

Pelvic Girdle Os Coxae ~ half of the pelvic girdle

› 3 bones Ilium Ischium Pubis

Hip bone’s connected to the …

Femur Patella ~ knee cap Crus = Fibula + Tibia

› Fibula isn’t functional; fuses along the length of the tibia

Now you know the bones…

…Can you name all 205-210 of them?

While you were learning all about the bones of a horse, did you notice any similarities between a horse’s

skeleton and a humans?

Here are just a few… We have almost the exact number of

bones as horses Horses’ forelegs are almost identical to

our arms in position, the only real difference being the elongation of the bones that make up our wrist, hand and fingers in the horses’ knee, lower leg (cannon), ankle and hoof

Differences The main differences between a horse’s skeleton

and a human’s skeleton come from a horse being a quadraped while humans are bipeds

This changes the angle of the limbs in relation to the spine, the length of the neck, and the shape of the head

Horses’ being prey animals and humans predators also affects the skull; a horse’s orbits are laterally positioned because they are monocular, and their jaw is longer to provide for the powerful molars they use to chew their fibrous diet

theend

OH MY BONES!!!!!!!!!!

………XD

Sources http://visual.merriam-webster.com/hum

an-being/anatomy/skeleton/structure-long-bone.php

http://www.besthealth.com/besthealth/bodyguide/reftext/html/skel_sys_fin.html#joints

http://www.teachpe.com/anatomy/joints.php

http://www.yourveterinaryclinic.com/page7/page8/skeleton-horse.html