The Skeleton Flashcards
As a horse-owner, why is it important to have some knowledge of the equine skeleton?
- To have awareness of bony areas so we don’t hurt the horse/damage them.
- To identify the area (eg. where a wound is found).
What is the purpose of the skeleton?
It is the framework of the body. It gives shape, protects vital organs, and is a solid base for ligaments/muscles/tendons.
How many bones are there in an adult horse’s body?
Approx. 205 (plus cartilage and ligaments).
What is the equine skeleton split into?
Two sections:
- Axial (Skull, spine, sternum, ribs)
- Appendicular (Fore and hind limbs)
Name the main 8 parts of the skull.
- Occipital bone
- Cranium
- Zygomatic process
- Orbit
- Facial bones
- Nasal bone
- Maxilla
- Mandible
What is the occipital bone?
At the back of the skull, it forms a joint with the top part of the neck.
What is the cranium?
The bone which surrounds the brain.
What is the zygomatic proccess?
An arch of strong, prominent bone below the eye, which gives further protection.
What is the orbit?
The cavity the eye lies in, in the skull.
What is the maxilla?
The upper jaw. Together with the mandible, it contains the teeth.
What is the mandible?
The lower jaw. It’s hinged between the ear and eye to provide motion for chewing. It is one of the larger bones in the body.
What are the five sections of the spine, and the numbers of vertebrae in each?
The cervical (7), thoracic (18), lumbar (6), sacral (5), coccygeal (15-20: 18 average).
How many ribs does a horse have?
18 pairs, each pair connected to a thoracic vertebrae.
What are the first two bones in the cervical veterbrae?
1) The atlas, which supports the skull and allows for the nodding movements of the head.
2) The axis, which allows rotational movement.
Describe the structure of the lumbar vertebrae.
The 6 vertebrae are large and rigid to cope with the transfer of thrust from the horse’s hind limbs.
What is the sternum?
A flat, boat-shaped bone which forms the lower part of the rib cage.
Describe the structure of the sacral vertebrae.
The 5 vertebrae are fused and joined together to form part of the hip girdle.
Describe the general structure of a singular vertebrae.
- Most vertebrae are shaped like a cross.
- The vertebral body forms an arch called the neural arch.
- Above this is a bony projection called the dorsal spinous process, which provides an attachment for the supraspinous ligament. This is one of a group of ligaments and muscles that hold the vertebrae together.
- The spinous processes also act as anchorage for muscles which hold other bones in place (eg. the muscle which overlies the scapula).
- On each side of the vertebra are the transverse processes.
What is the sternum?
A flat, boat-shaped bone which forms the lower part of the rib cage.
Describe the differences between different spinal vertebrae.
- In different parts of the spine, the vertebrae vary in shape and size because each section has a different function and is subject to different stresses.
- Both the dorsal spinous and transverse processes vary in size and length.
- The processes of the cervical vertebrae are much smaller to allow for greater movement in this area.
- The dorsal spinous processes are longest in the wither region of the thoracic section to provide more anchorage for the muscles.
- The transverse processes are long and wide in the lumbar region.
What is between each vertebrae?
An inter-vertebral disc: a flat shaped piece of cartilage which is slightly compressible.
What is the hole within each vertebra called?
The spinal or vertebral canal.
What are the main functions of the spine?
- It connects the head and limbs, and provides strength to support the weight of the body.
- It holds in place and protects the spinal cord. The cord passes through the vertebral canal, and contains the nerves running from the brain to all parts of the body.
- Neves emerge from the cord, and pass between the vertebrae at intervals and onto various parts of the body.
Describe the structure of the ribs.
- The ribs curve round and protect the heart and lung area. They are thin flat bones.
- There are 8 pairs of ‘true’ ribs, which connect directly to the sternum.
- There are 10 pairs of ‘false’ ribs which are connected to the sternum by strips of cartilage only.
- The ribs are able to move slightly, in and out, to allow expansion and contraction of the lungs when breathing.