Continuing down the thorax we have now reached the fifth rib. As far as physical description is concerned, the fifth rib is not markedly different than the fourth rib aside from being slightly larger. As a true rib the fifth rib presents fairly free movement characteristics and can have a multitude of lesions (for the sake of simplicity the classes of lesions will either be an inhalation or exhalation lesion).
The muscular attachments to the fifth rib are: serratus anterior, serratus posterior superior, pectoralis minor (dependent on the person), iliocostalis cervicis, iliocostalis thoracis, internal intercostal, and external intercostal. As with every rib from the second downward, the pleura attaches to the internal portion of the fifth rib.
The nerves related to the fifth rib are: the anterior and posterior divisions of the fifth thoracic nerve, the sympathetic chain ganglia, the fifth thoracic sympathetic ganglion, the fifth intercostal nerve, and the recurrent meningeal nerve.
The circulatory structures related to the fifth rib are: the intercostal artery and vein, the azygos and accessory hemiazygos vein, the mediastinal arteries, posterior intercostal arteries, internal thoracic arteries, the thoracic lymphatic duct, and the bronchomediastinal lymphatic ducts. As with the fourth rib this is by no means a definitively exhaustive list so if you have more to add help me “dig on”.
The conditions associated with a lesion of the fifth rib are essentially the exact same as those of the fourth rib and are differentiated dependent on the side of the lesion. If the right fifth rib is in lesion there will be bronchial, pleural, and lung disorders. If there is a lesion of the left fifth rib there will be nervous, circulatory, and mechanical effects connected to disorders of the heart. The important difference is that the fifth rib is the most often fractured rib due to its position as being the most exposed rib.
Considering that the musculature attached to the fifth rib is the same as the fourth rib the same correction options are available to the Operator. Using the arm as a long lever is a very attractive option as it will allow the Operator to move between the thoracic spine and the costo-vertebral joints by changing the fixed point if done appropriately. Understanding Fryette mechanics will also allow for smooth corrections of ribs in the seated position if the Operator appropriately couples side-bending and rotation. It is also of note that the ribs themselves have the ability to act as handles that connect the sternum and the associated thoracic vertebrae allowing for correction to the ribs as well as anything they connect to. As always it takes a proper understanding of anatomy and physiology for the operator to know the hows, whens, and whys of corrections.