Thoracic Wall MCQs

The intercostal nerve is a branch of ventral rami (anterior) of thoracic spinal nerves. Intercostal nerves are distributed primarily to the thoracic and abdominal walls: The 1st thoracic nerve with a variable proportion of the 2nd passes into the brachial plexus. The 3rd, 4th, 5th, 6th supply only the thoracic wall, The 7th, 8th, 9th, 10th, and 11th supply both thoracic and abdominal walls. Reference: Textbook of Gray's Anatomy for students, 3rd Edition, Thorax, Page number - 180

The blood flow to the lower limb is maintained by intercostal and superior epigastric arteries. In the post-ductal coarctation of the aorta, an extensive collateral circulation develops from the following sources: Axillary artery - The branches involved are: Thoraco-acromial Lateral thoracic Subscapular Subclavian artery - The enlarged branches are: Suprascapular Costocervical trunk (1st and 2nd posterior intercostals) Internal thoracic arteries Costocervical trunk Posterior intercostal arteries Inferior epigastric arteries Reference: Textbook of Gray's Anatomy for students, 3rd Edition, Thorax, Page number - 162

Rib notching occurs along the inferior margin of the third to the eighth ribs; it is caused by pulsation of dilated intercostal arteries. The major pathways of collateral flow include the following: Subclavian artery to the internal mammary artery to the intercostal arteries. And Rib notching is prominent on the inferior margins of the posterior third to sixth ribs, bilaterally. Therefore, option B is wrong choice here. Reference: Textbook of Gray's Anatomy for students, 3rd Edition, Thorax, Page number - 162

Posterior intercostal arteries are not branches of the internal thoracic artery, hence there would be no decrease in blood supply through these arteries. Branches of the internal thoracic artery: Terminal branches at the level of the 6th intercostal space: Superior epigastric artery Musculophrenic artery Sternal branches to: Transversus thoracis muscle Periosteum of the posterior sternal surface Sternal red bone marrow Anterior intercostal arteries for the first 6 intercostal spaces. Perforating branches that pierce and supply pectoralis major and then become direct cutaneous vessels that supply the skin. Reference: Textbook of Gray's Anatomy for students, 3rd Edition, Thorax, Page number - 162

The VAN triad of an intercostal vein, artery, and nerve run along the bottom of a rib, in the costal groove. To avoid hitting any of these important structures, it is important to remember to always place a tube or needle above the margin of a rib (or,if you prefer to think about it this way, at the bottom of an intercostal space). Reference- Textbook of Gray's Anatomy for students, 3rd Edition, Thorax, Page number - 162

The internal intercostal muscles are the muscles of expiration. The device shown in the image is an incentive spirometer. It is a device used to help your lungs recover after surgery or a lung illness. Reference : Textbook of Gray's Anatomy for students, 3rd Edition, Thorax, Page number - 126

The structure marked A is the intercostal nerve. It doesn't lie between external and internal intercostal muscles, but lies between the internal and innermost intercostal muscles. Typical intercostal nerves are those that only supply only the thoracic wall, e.g, 3rd to 6th intercostal nerves. Reference: Textbook of Gray's Anatomy for students, 3rd Edition, Thorax, Page number - 180

The thoracic splanchnic nerves lie on the anterior surfaces of the vertebral bodies. Remember, the splanchnic nerves lie medial to the sympathetic trunk, which is lying on the heads of the ribs. The vagus nerve lies in the anterior chest and eventually forms the esophageal plexus, covering the esophagus. The phrenic nerve innervates the diaphragm--it is not near the posterior wall of the thorax. Intercostal nerves run in the intercostal groove at the posterior border of the rib--they are not near the vertebral bodies. Reference: Textbook of Gray's Anatomy for students, 3rd Edition, Thorax, Page number - 162