Clinically, “thoracic outlet syndrome” is used to describe symptoms resulting from abnormal compression of the brachial plexus of nerves as it passes over the first rib and through the axillary inlet into the upper limb. The anterior ramus of T1 passes superiorly out of the superior thoracic aperture to join and become part of the brachial plexus. The cervical band from a cervical rib is one cause of thoracic outlet syndrome by putting upward stresses on the lower parts of the brachial plexus as they pass over the cervical band and related cervical rib.
In the clinic
Collection of sternal bone marrow
The subcutaneous position of the sternum makes it possible to place a needle through the hard outer cortex into the internal (or medullary) cavity containing bone marrow. Once the needle is in this position, bone marrow can be aspirated. Evaluation of this material under the microscope helps clinicians diagnose certain blood diseases such as leukemia.
In the clinic
Single rib fractures are of little consequence, though extremely painful.
After severe trauma, ribs may be broken in two or more places. If enough ribs are broken, a loose segment of chest wall, a flail segment (flail chest), is produced. When the patient takes a deep inspiration, the flail segment moves in the opposite direction to the chest wall, preventing full lung expansion and creating a paradoxically moving segment. If a large enough segment of chest wall is affected, ventilation may be impaired and assisted ventilation may be required until the ribs have healed.
In the clinic
Surgical access to the chest
A surgical access is potentially more challenging in the chest given the rigid nature of the thoracic cage. Moreover, access is also dependent upon the organ that is operated upon and its relationships to subdiaphragmatic structures and structures in the neck.
The most common approaches are a median sternotomy and a lateral thoracotomy.
A median sternotomy involves making a vertical incision in the sternum from just below the sternal notch to the distal end of the xiphoid process. Care must be taken not to cause injury to the vessels, in particular to the brachiocephalic veins. Bleeding from the branches of the internal thoracic artery can occur and needs to be controlled. Opening the sternum causes traction on the upper ribs and may lead to rib fractures. Sometimes partial sternotomy is performed with the incision involving only the upper part of the sternum and ending at the level of manubriosternal junction or just below. A median sternotomy allows access to the heart, including coronary arteries and valves, pericardium, great vessels, anterior mediastinum, and thymus, as well as to the lower trachea. It can also be used for removal of retrosternal goiter or during esophagectomy. The incision can be extended laterally into the supraclavicular region, giving access to the subclavian and carotid arteries.
A lateral thoracotomy gives access to the ipsilateral hemithorax and its contents including the lung, mediastinum, esophagus, and heart (left lateral thoracotomy) (Fig. 3.33).
However, it involves division of muscles of the thoracic wall which leads to significant postoperative pain that needs to be well controlled to avoid restricted lung function. The incision starts at the anterior axillary line and then passes below the tip of the scapula and is extended superiorly between the posterior midline and medial border of the scapula. The pleural cavity is entered through an intercostal space. In older patients and those with osteoporosis, a short segment of rib is often resected to minimize the risk of a rib fracture.
Minimally invasive thoracic surgery (video-assisted thoracic surgery [VATS]) involves making small (1-cm) incisions in the intercostal spaces, placing a small camera on a telescope, and manipulating other instruments through additional small incisions. A number of procedures can be performed in this manner, including lobectomy, lung biopsy, and esophagectomy.
In the clinic