Thorax

Aorta

Posterior intercostal artery
Lateral cutaneous branch
Internal thoracic artery
Anterior intercostal branch

Eleven pairs of intercostal nerves course between adjacent ribs, and the subcostal nerves course below each 12th rib. These nerves are the continuation of the ventral primary rami of thoracic segments of the spinal cord. The intercostal nerves travel just inferior to the inferior margin of the rib, in the costal groove.

Each intercostal nerve contains somatic sensory and motor axons as well as sympathetic axons that innervate sweat glands, arrector pili muscles , and vascular smooth muscle. Each intercostal nerve innervates deep structures, such as the intercostal muscles, the lateral rim of the diaphragm, and the parietal pleura, and has cutaneous branches innervating the skin and superficial fasciae..


The first intercostal nerve contribute mostly to the Brachial plexus & what remains is a small branch, the 2nd & some times the 3rd give lateral cutaneous branch called intercostobrachial nerve which anastomose with the medial cutaneous nerve of the arm. Intercostal nerves 7 to 12 continue inferomedially to innervate the abdominal wall

Intercostal Nerve Block

Costal angle (mostly) Posterior axillary line Anterior axillary line Fracture site Parasternal line

Intercostal Nerve Block

Sternal origin

Costal origin
Lumbar origin
Central tendon

Sternocostal triangle

Lumbocostal triangle


3 Hiatus Vena cava foramen: inferior vena cava ( vertebrae VIII & IX) Esophageal hiatus: esophagus, vagus nerve (vertebrae X ) Aortic hiatus: aorta, thoracic duct, azygos vein, hemiazygos vein (vertebrae XII )

aorta

esophagus
Inferior vena cava

thoracic aorta

Esophagus hiatus
Vena caval foramen

Esophageal Hiatus Hernia

Diaphragmatic Hernia

Blood Vessels

Superior Surface: Pericardiophrenic artery Musculophrenic artery superior phrenic arteries Inferior Surface: Inferior phrenic arteries Veins Correspond to the arteries
Internal thoracic artery Thoracic Aorta
Abdominal aorta
Superior & inferior vena cava

Lymphatic Drainage & Innervation

Phrenic lymph nodes
Parasternal & posterior mediastinal lymph nodes
Phrenic nerves
Cervical plexus ( C3-C5 )