1. Chapter 7E Skeletal System
Anatomy and Physiology

2. Vertebral Column
The vertebral column extends from the skull to the pelvis. It is made of many vertebrae separated by fibrocartilage called intervertebral discs.
The vertebral column supports the head and the trunk of the body. It is flexible to allow movement like bending forward, backward, or to the side. It also protects the spinal cord.
An infant has 33 separate bones but some of them fuse to eventually have 26 bones in an adult.

3. Normally the vertebral column has 4 curvatures
Normally the vertebral column has 4 curvatures. The curves are named based on the region they are located. The thoracic and sacral curvatures and primary curves. The cervical curve in the neck and lumbar curvature is in the lower back.

4. A Typical Vertebra
Vertebrae can have different features based on where they are located but they have some general features.
A typical vertebra has a drum-shaped body. The intervertebral discs are between the vertebra. They cushion and soften forces made by movements by walking and jumping.
Projecting from each vertebral body are 2 short stalks called pedicels. 2 plates called laminae fuse in the back to become the spinous process. Together the pedicles and laminae becomes the vertebral arch.

5. The transverse process allows ligaments and muscles to attach.
Superior and inferior articular processes have cartilage-covered facets that join the vertebrae together.
The intervertebral foramina provide passageways for spinal nerves.

6. Cervical Vertebrae
7 cervical vertebrae made the bony axis of the neck. These are the smallest vertebrae, but the bone tissue is denser than other areas.
They have transverse foramina which allow arteries to go to the brain. Also they have a forked vertebrae for muscle attachment.
The first vertebra, or atlas, supports the head. It is a bony ring. The second cervical vertebra, or axis, has a toothlike structure on its body. This allows the head to rotate.

7. Thoracic Vertebrae
There are 12 thoracic vertebrae. These vertebrae increase in size to help with increasing loads of body weight.

8. Lumbar Vertebrae
5 lumbar vertebrae are in the small of the back. These support more weight and larger, stronger bodies.

9. Sacrum
The sacrum is a triangular structure at the base of the vertebral column. It is made of 5 vertebrae that fuse together between ages
The sacrum is between the hip bones of the pelvis.

10. Coccyx
This is the tailbone, it is the lowest part of the vertebral column. It is made of 4 vertebrae that fuse together between ages The coccyx acts like a shock absorber. It also attaches muscles of the pelvic floor.

11. Thoracic Cage
The thoracic cage includes the ribs, the thoracic vertebrae, the sternum, and the costal cartilages that attach the ribs to the sternum.
These bones support the pectoral girdle and upper limbs, they protect internal organs in the thoracic and upper abdominal cavities, and are important in breathing.

12. Ribs
The usual number of ribs is 24 - one pair attached to each of the 12 thoracic vertebrae.
The first 7 pairs of ribs are called true ribs and join the sternum directly. The remaining 5 pairs are called false pairs because the ribs to do not reach the sternum directly.
The lower 2 pairs of ribs are called floating ribs.
A typical rib has a long, slender shaft that curves around the chest. On one end is an enlarged head . The neck of the rib is flattened and ligaments attach there.
Costal cartilages are made of hyline cartilage.

13. Sternum
The sternum or breastbone, is located along the midline anterior portion of the thoracic cage. It is a flat, elongated bone that develops in 3 parts - the upper manubrium, a middle body, and a lower xiphoid process.
The manubrium is where costal cartilages attach. The clavicles also connect to this area.

14. Pectoral Girdle
The pectoral girdle, shoulder girdle, made of 2 clavicles (collarbones) and 2 scapulae (shoulder blades).
The pectoral girdle supports the upper limbs and is an attachment for several muscles that move them.

15. Clavicles
These are slender, rod like bones that have an S shape. They are located at the base of the neck.
The clavicles hold the shoulders in place. They provide attachments for muscles of the upper limbs, chest, and back.

16. Scapulae
The scapulae are broad, triangular bones that are on either side of the upper back. They are flat. They are divided into portions by the spine. The supraspinous fossa and infraspinous fossa.
The scapula has 3 borders. The superior border is on the superior edge. The axillary or lateral border is toward the upper limb, and the vertebral, or medial border is closest to the vertebral column.