Small Animal Management – Anatomy
Objectives
Identify the points of external anatomy of animal species
Identify points of skeletal anatomy of animal species
Understand types of connective tissue and how they differ
Understand types of muscle and how they differ
Know the parts and functions of major body systems
Skeletal Anatomy
The skeleton is composed of various types of connective tissue that provide the
structure and form of the body and bind the parts of the body together. The alignment
of bones, especially in the legs, is vital to the functionality and longevity of the animal.
Skeletal structure is inherited, and structural defects can be passed to future generations.
The axial skeleton refers to the central skeleton that includes the skull, the
vertebral column, and the ribs; the appendicular skeleton refers to the limbs and
appendages of the body. Differences in skeletal anatomy of avian species and mammals
are relatively minor.
The following are terms that relate to both the axial and appendicular skeletons:
Bone – Bone is the hardest connective tissue, and provides structure and form to the
body. In birds, the bones are lighter weight and hollow, allowing some birds to fly.
Cartilage – This connective tissue is more flexible than bone, and can found either on
parts of the bone or independent of bone. Ears are examples of cartilage that are
independent of bone.
The following are types of cartilage:
Articular – covers the surface of the bone in some types of joints.
Meniscus – cartilage located between bone surfaces to cushion the surfaces
Joint – where bones come together. Bodies have a variety of types of joints.
The following are the different types of joints:
Arthroidal – a joint in which small oval-shaped bones fit into a depression in the
large (example, carpal joint)
Ball and socket – highly movable joints in which the end of one bone is shaped into
a ball that fits into a socket of the other bone in joint (example, hip)
Hinge – joint that allows movement in only one direction
Suture – an immovable joint where two bones join (example, the bones of the skull)
Symphysis – a type of joint where the two bones meet and work as a single bone,
are joined by cartilage, and have limited movement (example, pelvis)
Ligament – connective tissue that attaches bone to bone
Tendon – connective tissue that attaches muscle to bone
Axial Skeleton
The axial skeleton of avian species and mammals is very similar, so differences in
the axial skeleton will be noted with each particular bone. The following are the
components of the axial skeleton from the front of the body to the rear:
Skull – the skull is the bony structure that provides shape to the head. The following are
the bones and regions that make up the skull:
Cranium – the portion of the skull that surrounds and protects the brain
Nasal – the bone that creates the bridge of the nose
Nasal septum – the cartilage that divides the nasal cavity into two structures
Sinuses – spaces in the skull that are filled with air or fluid
Vertebral column – the column of bone also known as the backbone or the spine
The vertebral column is made up of many individual vertebrae. The plural form of
vertebra is vertebrae. Vertebrae are grouped based on their location in the vertebral
column, and are numbered from the head to the tail. The following list of vertebrae is in
order from the skull to the end of the spine.
Cervical – the vertebrae that constitute the neck
All mammals have seven cervical vertebrae, regardless of the length of their necks.
Cervical vertebrae are numbered C1 through C7, with C1 being nearest the skull.
Thoracic – the vertebrae next to the cervical
Thoracic vertebrae from the external part of the back, and are attached to the ribs.
Lumbar – the vertebrae following the thoracic
Lumbar vertebrae do not have ribs attached, and are supported by muscle only. The
lumbar region is also termed the loin.
Sacral – the vertebrae following the lumbar
These vertebrae make up the croup or rump, depending on specie
Coccygeal – also known as caudal vertebrae, the coccygeal vertebrae are the last in the
vertebral column, and make up the tail.
Ribs – the paired bones that attach on one side to the thoracic vertebrae and on the other
side to the sternum
The sternum is also known as the breastbone (or keel in avian species)