Anatomy Blue Boxes Exam 1

Question 1

Chest Pain

Answer 1

Patients who have had a heart attack describe the associated pain as being “crushing” (substernal) that does not disappear with rest.

Question 2

First Rib (position and consequences of fracture)

Answer 2

The first rib is short and broad, and is just posterolateral to the clavicle. This positioning means that it is difficult to fracture, but when it is fractured, (usually due to blunt trauma), integrity of such structures as the brachial plexus, and subclavian vessels are at risk.

Question 3

Middle and Lower Rib Fractures

Answer 3

Middle rib fractures: Most common fracture. Potential injury of internal organs held within the thoracic cage (i.e. spleen, lungs, etc.)
Lower rib fractures: Potential damage to the respiratory diaphragm. This has been known to cause a diaphragmatic hernia

Question 4

Weakest part of a rib

Answer 4

Just anterior to the angle of the rib

Question 5

Flail chest

Answer 5

Multiple rib fractures result in segments of the anterolateral thoracic wall to move abnormally (inwards during inspiration and outwards on expiration), resulting in restriction of respiration. This may be fixed by installation of plate or wire to fix the fractured thoracic segment in place.

Question 6

Thoracotomy

Answer 6

Surgical intervention intended to gain access to the pleural cavity via incision in the Thoracic wall.
Anterior Thoracotomy: H-shaped incision through the perichondrium of one or more costal cartilage segments to gain entrance to the thoracic cavity.
Posterolateral Thoracotomy: A better approach. The patient lies lateral recumbent with their ipsilateral arm facing up, move their arm into a fully flexed/abducted position (displaces the scapula superiorly and laterally, allowing for access as high as the 4th intercostal space in some circumstances).
This procedure inevitably involves “splitting through” intercostal muscle, even after rib retraction.

Question 7

Rib retraction

Answer 7

A procedural step in Thoracotomy requiring the excision of a segment of rib to gain better access to the Thoracic Cage. This is done especially to ensure minimal damage to the neurovascular bundle beneath each rib. This method is frequently employed during a Thoracotomy when removing a lung (pneumonectomy). The remnant periosteum may at least partially regenerate the excised rib.

Question 8

Supernumerary Ribs

Answer 8

Usually individuals have 12 ribs bilaterally. Occasionally however, and individual may have more than that if they possess cervical or lumbar ribs. Individuals may have less than that if the 12th rib fails to form. Cervical ribs have been known to cause Thoracic Outlet Syndrome (impingement of neurovascular structures that supply the upper limb). Furthermore, Supernumerary Ribs, even if benign, have been known to make identification of vertebral levels confusing when using diagnostic imaging.

Question 9

Costal Cartilage

Answer 9

In children: due to high degree of elasticity, chest compression can produce an injury of structures within the thoracic cage, even if there is no rib fracture.
In the elderly: lack of elasticity results in calcification, making costal cartilage both brittle and radiopaque. The lack of structural integrity means that performing CPR is more likely to result in fractured ribs.

Question 10

Ossified Xiphoid Process

Answer 10

Patients usually in their early 40s frequently confuse their now partly ossified xiphoid process for a tumor developing in the “pit of their stomach” (the epigastric fossa).

Question 11

Sternal Fractures

Answer 11

Sternal Fractures are not a common phenomenon. They usually occur as a result of blunt trauma such as during a MVA. These fractures usually present as a comminuted fracture (fracture resulting in several fractured segments), though displacement is very uncommon due to the presence of fascia and the attachments of pectoralis muscles. Most commonly in the elderly, a sternal fracture takes place about the manubriosternal joint, because this joint begins to fuse with advanced age.
Concern with sternal injuries is mainly over potential underlying visceral injury.

Question 12

Median Sternotomy

Answer 12

A surgical procedure designed to gain access to the Thoracic Cavity, but the mediastinum specifically. This usually involves splitting the sternum in the median plane, for something like coronary bypass grafting, or removal of tumors from the superior lobes of the lungs. This is done to spare the patient the pain of a Thoracotomy.

Question 13

Sternal Biopsy

Answer 13

Removal of vascular spongy bone in order to obtain specimens of bone marrow for treatment and diagnostics.

Question 14

Sternal Anomalies

Answer 14

Complete Sternal Cleft: an uncommon protrusion of the heart through the sternum (ectopia cordis), which can be repaired during infancy.
Sternal Foramen: a perforation in the sternal body because of incomplete fusion of the precartilage components of the Sternum.

Question 15

Dislocation of Ribs

Answer 15

Displacement of costal cartilage from the sternum (interchondral or sternocostal joints).

Question 16

Separation of Ribs

Answer 16

Dislocation of the costochondral junction (the point where bony rib meets it’s costal cartilage). This usually results in the tearing of the perichondrium and periosteum when ribs 3-10 separate. This can cause overlapping of ribs (with the rib just above).

Question 17

Paralysis of Diaphragm

Answer 17

The two halves of the diaphragm’s motor function are separately innervated by the right and left Phrenic nerves. Therefore, whenever one of these Phrenic nerves is damaged, the two halves of the diaphragm continue to operate independently of one another. During inspiration, the damaged half should move superiorly because the abdominal viscera are able to push up on the paralyzed half of the diaphragm in response to the descending movement of the functioning half of the diaphragm. In other words, the two halves of the diaphragm should move in opposite directions.