Lecture 16: Thoracic wall, Pleura, and Lungs

Protect the vital organs

Pressure equalization

Attachment site for upper limbs

Origin for many muscles

What are the functions of the Thorax?

Sternum

12 pairs of ribs

12 thoracic vertebrae

What are the skeleton components of the thorax?

Intervertebral discs

Costovertebral joints

Sternocostal joints

Sternoclavicular joints

costochondral

interchondral

What are the joint components of the thorax?

Intercostal vein

Artery

nerve (VAN) aka neurovascular bundle

What do the intercostal spaces contain?

True ribs

1-7

Attach to the sternum

False ribs

8th, 9th, and usually 10th

\-Attach to rib above them

Floating ribs

11th, 12th, and sometimes 10th

\-End in the musculature

Inspiration

Diaphragm and intercostal contract, ==Abdominal viscera are compressed==, intrathoracic ==volume increases== in both AP and transverse dimension

Expiration

Diaphragm and intercostals relax, abdominal viscera decompressed, intrathoracic volume decreases.

Flail Chest

A segment of ribs that are free floating due to trauma

Pectoralis major

Pectoralis minor

Inferior serratus anterior

scalene muscles

What muscles have a secondary role in respiration?

External/Internal intercostals

Innermost intercostals

Subcostal

Transverse Thoracis

serratus posterior superior/inferior

Levatores csotarum

What are the true muscles of the Thoracic wall?

Serratus posterior Superior

Main action: proprioception

Innervation: 2-5 intercostal nerves

Serratus Posterior inferior

Main action: Proprioception

Innervation: Anterior rami to thoracic nerves

Levator costarum

A: Elevate ribs

I: Posterior rami

External Intercostal

A: Elevate ribs

I: Intercostal nerves

\-The most superficial layer

\-Fibers are directed downward and forward (==hands in pockets_==

Internal Intercostal

A: Elevate and depress ribs during forces inspiration

I: Intercostal Nerves

\-Forms the intermediate layer

\-Fibers are directed downward and backward from the subcostal groove of the rib above to the upper border of the rib below.

* Hand on hips

Innermost Intercostals

A: Elevate and depress ribs during forced inspiration

I: Intercostal Nerves

\-Forms the deepest layer and corresponds to the transverse abdominis muscle in the anterior abdominal wall.

\-IS an incomplete muscle layer and crosses more than one intercostal space within the ribs.

Subcostal

A: Elevate and depress ribs during forced inspiration

I: Intercostal Nerves

Transverse Thoracis

A: Weakly depress ribs

I: Intercostal Nerves