Lab 4: Fetal Skull, Vertebral Column, Sternum, and Ribs

What are fontanelles?

Soft spots in the fetal skull that allow compression during birth and accommodate brain growth.

What are the four major fontanelles?

Anterior fontanelle, Posterior fontanelle, Sphenoid fontanelle, Mastoid fontanelle.

Where is the anterior fontanelle located?

Front/top of the fetal skull; it is the largest fontanelle.

Where is the posterior fontanelle located?

Back of the fetal skull.

Where is the sphenoid fontanelle located?

Side/front of the skull near the temples.

Where is the mastoid fontanelle located?

Side/back of the skull near the mastoid region.

How do the bones of the skull develop?

Through intramembranous ossification.

How many vertebrae are in the cervical region?

7 vertebrae.

How many vertebrae are in the thoracic region?

12 vertebrae.

How many vertebrae are in the lumbar region?

5 vertebrae.

How many vertebrae are in the sacral region?

5 fused vertebrae.

How many vertebrae are in the coccygeal region?

Usually 4 fused vertebrae.

Which spinal curves are posteriorly concave?

Cervical and lumbar curves.

Which spinal curves are posteriorly convex?

Thoracic and sacral curves.

What is the significance of the spinal curves?

They increase flexibility, absorb shock, and help maintain balance.

What are the anterior and posterior longitudinal ligaments?

Ligaments that hold the vertebrae together.

What are intervertebral discs?

Cartilage pads located between vertebrae.

What are the functions of intervertebral discs?

They act as shock absorbers between vertebrae.

What are the two parts of an intervertebral disc?

Nucleus pulposus and annulus fibrosus.

What is the nucleus pulposus?

The inner gelatinous layer of an intervertebral disc.

What is the annulus fibrosus?

The strong outer layer surrounding the nucleus pulposus.

What is the body (centrum) of a vertebra?

The major weight

What is the vertebral arch?

The posterior portion of a vertebra that helps bear weight.

What structures make up the vertebral arch?

Pedicles and laminae.

What is a laminectomy?

Surgical removal of a vertebral lamina to relieve symptoms of a ruptured disc.

What passes through the vertebral foramen?

The spinal cord.

What are intervertebral foramina?

Openings through which spinal nerves pass.

What are transverse foramina?

Openings along the sides of the vertebral column through which spinal nerves pass.

What is the spinous process?

The posterior projection of a vertebra.

How many transverse processes does a vertebra have?

Two.

What are articular processes?

Superior and inferior projections that articulate with neighboring vertebrae.

Where are cervical vertebrae located?

In the neck region.

What are the characteristics of cervical vertebrae?

They are the smallest vertebrae and have bifid spinous processes.

What is the atlas?

The first cervical vertebra (C1).

What is unique about the atlas?

It lacks a spinous process.

What does the atlas articulate with?

The occipital condyles of the skull.

What movement does the atlas allow?

Head nodding ("yes" movement).

What is the axis?

The second cervical vertebra (C2).

What is the dens (odontoid process)?

A projection on the axis that serves as a pivot point for skull rotation.

What movement does the axis allow?

Head rotation ("no" movement).

Where are thoracic vertebrae located?

In the chest region.

Which thoracic vertebrae articulate with ribs?

T1 through T10.

What shape is the vertebral foramen of thoracic vertebrae?

Circular.

What is the orientation of thoracic spinous processes?

Sharp and directed downward.

Where are lumbar vertebrae located?

In the lower back.

What are the characteristics of lumbar vertebrae?

They are the largest vertebrae and are specialized for weight

What shape is the vertebral foramen of lumbar vertebrae?

Triangular.

What is the sacrum?

A triangular bone formed by the fusion of five vertebrae.

What are sacral foramina?

Openings through which nerves and blood vessels pass.

What is the sacral canal?

A continuation of the vertebral canal through the sacrum.

What is the coccyx?

The tailbone.

What is the function of the coccyx?

It serves as an attachment site for a few muscles.

From what embryonic structure does the vertebral column develop?

The notochord.

What is the notochord?

A mesodermal structure found in all chordates that gives rise to the vertebral column.

What are the three major regions of the sternum?

Manubrium, Body, Xiphoid Process.

What is the manubrium?

The superior portion of the sternum.

What attaches to the manubrium?

The clavicles at the clavicular notches.

What is the jugular notch?

A notch at the superior portion of the manubrium.

What is another name for the jugular notch?

Suprasternal notch.

What is the body of the sternum?

The middle portion of the sternum.

Which ribs attach to the body of the sternum?

Ribs 2 through 7.

What is the xiphoid process?

The inferior portion of the sternum.

What happens to the xiphoid process with age?

It becomes ossified.

What attaches to the xiphoid process?

Abdominal muscles.

Why is the xiphoid process clinically important?

It serves as a landmark for CPR.

How many pairs of ribs does a human have?

12 pairs.

What are true ribs?

Ribs whose cartilage attaches directly to the sternum.

Which ribs are true ribs?

Ribs 1 through 7.

What are false ribs?

Ribs whose cartilage does not attach directly to the sternum.

Which ribs are false ribs?

Ribs 8 through 12.

What are floating ribs?

Ribs that do not attach to the sternum at all.

Which ribs are floating ribs?

Ribs 11 and 12.

What is the head of a rib?

The portion that attaches to the vertebrae.

What is the neck of a rib?

The region located near the head of the rib.

What is the shaft of a rib?

The main length of the rib.

What is the costal groove?

A groove in the shaft of a rib that contains nerves and blood vessels.

What is the tubercle of a rib?

A projection that articulates with thoracic vertebrae.

What does the tubercle attach to?

The costal facets of thoracic vertebrae.