Muscles of Respiration, G1.21, Anatomy, Thorax, Thoracic Wall

Quiet Breathing:

1. Inspiration
1. Diaphragm
2. Tonic contraction of the external intercostals and intracondral portion of the internal intercostals to resist negative pressure
2. Expiration
1. Passive or elastic recoil
2. Tonic contraction of muscles of the anteriolateral abdominal walls to antagonise the diaphragm

Active (Forced).

1. Inspiration
1. Diaphragm
2. Tonic contraction of the external intercostals and intracondral portion of the internal intercostals to resist negative pressure
3. Sternocleidomastoid, Descending (superior ) Trapezius, Pectoralis Minor and Scalenes
4. Subcostales, Levatores Costarum and Serratus Posterior Superior to Elevate Ribs  
2. Expiration
1. Passive or elastic recoil
2. Tonic contraction of muscles of the anteriolateral abdominal walls to antagonise the diaphragm
3. Rectus abdominis, External and Internal Obliques, and Transverse Abdominis
4. Internal Intercostals and Serratus Posterior to depress ribs

Internal aspect of anterior thoracic wall, G1.20, Anatomy, Thorax, Thoracic Wall

Internal aspect of anterior thoracic wall, G1.20, Anatomy, Thorax, Thoracic Wall

Muscles:

1. Sternohyoid and Sternothyroid muscles

Nothing else notable

External aspect of thoracic wall, G1.19, Anatomy, Thorax, Thoracic Wall

External aspect of thoracic wall, G1.19, Anatomy, Thorax, Thoracic Wall:

1. Muscles
1. Sternothyroid
2. Sternohyoid
3. Scalene - Anterior, Middle and Posterior
2. Parasternal Lymph nodes
3. Subclavian Vessels between the Subclavius Muscle and 1st Rib

Muscles of the Thoracic Wall, G1.19, Anatomy, Thorax, Thoracic Wall

Muscles of the Thoracic Wall, G1.19, Anatomy, Thorax, Thoracic Wall:

1. Serratus posterior superior
2. Serratus posterior inferior
3. Levatores costarum

Contents of the intercostal space, transverse section, G1.18, Anatomy, Thorax, Thoracic Wall

Contents of the intercostal space, transverse section, G1.18, Anatomy, Thorax, Thoracic Wall:

• Musculocutaneous layers:
1. External Intercostal Muscle and Membrane
2. Internal Intercostal Muscle and Membrane
3. Innermost Intercostal Muscle, Transverse Thoracis muscle and membrane
• Nerves
1. Anterior Rami of T1 to T11 are the Intercostal Nerves. T12 is the Subcostal Nerve.
2. Posterior Rami innervate the deep muscle of the back and skin adjacent to the vertebral column

Anterior ends of inferior intercostal spaces, G1.17, Anatomy, Thorax, Thoracic Wall

Anterior ends of inferior intercostal spaces, G1.17, Anatomy, Thorax, Thoracic Wall:

• External Intercostal and External Oblique muscle fibers run inferomedially
• Internal Intercostal and Internal Oblique Muscles are continuous
• The Intercostal nerves run parallel to the ribs and cartilages. On reaching the abdominal wall:
• T7 and T8 continue superiorly
• T9 continue horizontally
• T10 continue inferomedially towards the umbilicus

Vertebral Ends of external aspect of inferior intercostal spaces, G1.16, Anatomy, Thorax, Thoracic Wall

Vertebral Ends of external aspect of inferior intercostal spaces, G1.16, Anatomy, Thorax, Thoracic Wall:

Nerves:

• Posterior ramus of thoracic nerve
• Collateral Branch of intercostal Nerve
• The Intercostal Nerve is most inferior of the VAN - Important when doing a plural tap - but high enough to avoid the collaterals

Muscles: 

1. Semispinalis Muscle 
2. Longissimus Muscle
3. Illiocostalis Muscle
4. Levatores Costarum Muscle
5. External Intercostal Muscle
6. Internal Intercostal Muscle - is continuous with the internal intercostal membrane
7. Innermost Intercostal Muscle

Ligaments:

• Internal Intercostal Membrane
• Lateral costotransverse ligament

Vertebral Ends of internal aspect of intercostal spaces, G1.15, Anatomy, Thorax, Thoracic Wall

Vertebral Ends of internal aspect of intercostal spaces, G1.15, Anatomy, Thorax, Thoracic Wall:

• Posterior Intercostal Vein, Artery and Nerve - VAN
• Collateral Branches of intercostal vessels and nerve
• Nerves:
• Communication from the the sympathetic trunk via Rami Communicates 
• Anterior Ramus runs anterior to the costotransverse ligament and 
• the Posterior Ramus of the Thoracic Nerve runs posterior to the Costotransverse Ligament
• Visualise the spinal ganglion
• Splanchnic Nerve is a visceral branch of the Sympathetic Trunk
• Ligaments:
• Radiate Ligaments of the head of the Rib
• Superior Costotransverse Ligaments
• Internal Intercostal Membrane is continuous with the superior costotransverse ligament
• Anterior Longitudinal Ligament
• Muscles:
• Innermost intercostal Muscle
• Subcostales Muscle
• External Intercostal Muscle