topic 3: The bones and joints of the thorax. The movements of respiration.

Question 1

bones of thorax

Answer 1

Sternum: Also known as the breastbone, the sternum is a flat bone located in the anterior midline of the chest. It consists of three main parts: the manubrium, body, and xiphoid process.

Ribs: There are 12 pairs of ribs in the human body, which attach posteriorly to the thoracic vertebrae and anteriorly to the sternum via costal cartilages. Ribs are classified into three types:

True Ribs (1-7): Directly attach to the sternum via their own costal cartilages.
False Ribs (8-10): Indirectly attach to the sternum via the costal cartilage of the rib above.
Floating Ribs (11-12): Do not attach to the sternum and terminate anteriorly within the musculature of the abdominal wall.

Thoracic Vertebrae: The 12 thoracic vertebrae (T1-T12) form the posterior part of the thoracic cage, providing attachment sites for the ribs.

Question 2

joints

Answer 2

1. Costovertebral Joints:
   -Type: Synovial, Plane (gliding) joints.
   -Articulating Facets: Head of the rib articulates with the vertebral body and the intervertebral disc.
   -Ligaments:
   Radiate Ligament(xtends from the crest of the head of the rib to the anterior and posterior surfaces of the intervertebral disc)
   Superior Costotransverse Ligament: (Connects the neck of the rib to the transverse process above.)
   -Movements: Allow slight gliding and rotation of the rib during respiration
2. Costotransverse Joints:
   -Type: Synovial, Plane (gliding) joints.
   -Articulating Facets: Tubercle of the rib articulates with the transverse process of the thoracic vertebra.
   -Ligaments:
   Costotransverse Ligament (extends from the neck of the rib to the transverse process of the thoracic vertebra)
   -Movements: Provide stability to the thoracic cage and limit excessive movement.

3. Costochondral Joints:
Type: Hyaline cartilage (primary cartilaginous) joints.
Articulating Facets: Rib cartilage attaches to the sternal end of the rib.
Ligament: None.
Movements: Allow slight movement during respiration and provide flexibility to the chest wall.

4. Sternocostal Joints:
Type: Synovial, Plane (gliding) joints.
Articulating Facets: Costal cartilage of the true ribs articulates with the sternum.
Ligaments:
-Anterior Sternocostal Ligament: Connects the anterior surface of the sternum to the costal cartilages.
-Posterior Sternocostal Ligament: Connects the posterior surface of the sternum to the costal cartilages.

Movements: Facilitate the elevation and depression of the ribs during respiration.

Question 3

insipiration

Answer 3

Inspiration: The process of inhalation involves the expansion of the thoracic cavity, which increases the volume of the lungs and allows air to flow in.

Key movements during inspiration include:

Elevation of the Ribs: Contraction of the external intercostal muscles lifts the ribs upward and outward.

Flattening of the Diaphragm:
Contraction of the diaphragm causes it to flatten, further increasing thoracic volume.

Question 4

expiration

Answer 4

Expiration: The process of exhalation involves the reduction of thoracic cavity volume, which compresses the lungs and expels air.

Key movements during expiration include:

Depression of the Ribs: Relaxation of the external intercostal muscles allows the ribs to return to their resting position.

Relaxation of the Diaphragm: Relaxation of the diaphragm causes it to return to its dome-shaped position, reducing thoracic volume.