Chapter 3 Part 3 - The Skeletal System

Created by Daniellebelith 

Upgrade to
remove ads

The Appendicular Skeleton is Composed of

pectoral (fore) limbs
pelvic (hind) limb
shoulder and pelvic girdles

Pectoral Limb

no bony connection to the trunk, only attached by muscles

The Bones of the Forelimb are:

clavicle
scapula
humerus
radius and ulna

Clavicle

absent in dogs, sheep, horses, cows, pigs
present in cats

Scapula

shoulder blade

Humerus

long bone forming the upper formlimb

Carpus

composed of 7 short bones
carpal bones - two rows
8 bones - cow, sheep, horses, pigs

Metacarpus

composed of five small long bones (metacarpal bones) - dogs/cats
2nd and 5th gone on cow
5th gone on horse
3rd and 4th fused on cow

Horse

one large metacarpal - cannon bone
two small metacarpal bones - splint bones

Digits

composed of the phalanges - long bones
each digit has three phalanges, except digit 1, the dew claw, which has only two

Sesamoid Bones

pairs of small sesamoid bones
proximal sesamoid bones - junction of the metacarpal and proximal phalanx
distal sesamoid bone - junction of the middle and distal phalanges
Horse - navicular bone

Bone of Hindlimb: Pelvis

how the hindlimb connects to the body
it consists of two hip bones or ossa coxarum which are joined together at the pubic symphysis

Pelvis Articulates With

the sacrum at the sacroiliac joint

Each Hip Bone Consists of:

3 bones
ischium
illium
pubis
frouped around the acetabulum (socket of the hip joint)

Femur

long bone - forms the thigh
proximal femur head - articulates with the acetabulum

Tibia and Fibula

long bones - forms the lower leg
lie parallel to eachother
Tibia (more medial) - much larger of the two
Tibia articulates with the femur

Tarsus

seven short bones (tarsal bones)
three rows
two bones - proximal row (talus and calcaneus [ankle])
calcaneus (fibular tarsal bone) - has a large caudal projection - tuber calcis which forms the 'point' of the hock

Metatarsus

four metatarsal bones
some dog breeds - may lack the first digit (dew claw)
digits - called phalanges

Joints or Arthrosis

when one bone connects to another they form an articulation

Anthrology

the study of articulations between bones (joints)

Joints Allow:

variable degrees of movement and are categorized into three groups:
fibrous joints
cartilaginous joints
synovial joints (knee)

Fibrous Joints

immovable joints
bones that form them are united by dense fibrous connective tissue (skull - sutures)
fibrous joints are also classed as synarthroses (joint that permits little or no movement)

Sutures also Associated with

the teeth - where join to bony socket of jaw

Cartilaginous Joints

allow limited movement or no movement

United by cartilage

Synarthroses joints
ex. pubis symphsysis - connects the two hip bones
mandibular symphysis - joining the two halves of the mandible

Amphiarthroses Joints

allow some degree of movement between the bones
ex. between the vertebrae (limited flexibility)
between fibs and sternum

Synovial Joints or Diarthroses

allow a wide range of movement

Joint Cavity

the bones are seperated by a space filled with synovial fluid
a joint capsule surrounds the whole joint

Synovial Joints outer layer

consists of fibrous tissue that serves as protection

Synovial Joints cavity

is lined by the synovial membrane - secretes synovial fluid
lubriates the joints
provide nutrition for the hyaline articular cartilage

Some Synovial Joints Can Have Additional Stabilization

from ligaments within the fibers of the joint capsule (either side of joint - collateral ligaments)

Some Synovial Joints Can Have Stabilizing Ligaments

attached to the articulating bones within the joint (intracapsular ligaments)
cruciate ligaments within the stifle joint

Some Synovial Joints Can Possess One or More

intra-articular fibrocartilaginous discs or menisci within the joint cavity
1. increase the range of movement
2. act as 'shock absorbers' - reducing wear and tear
3. ex. stifle joints - two crescent shaped menisci

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set