Lecture 4 thorax Flashcards
Structure common to all 3 parts of the mediastinum
Esophagus
Cranial Third of mediastinum
Dorsal structures
Ventral structures
Dorsal structures
- Seen
- Trachea
- +/- esophagus
- Not Seen
- Vessels: cranial vena cava, vagosympathetic trunk
- Cranial mediastinal lymph nodes
- +/- esophagus
Ventral structures
- Seen:
- Mediastinal reflection
- +/- internal thoracic arteries, veins, thymus
- Not seen:
- Sternal lymph nodes
Esophageal gas common in ….. over…..
Left later rads over the heart base
Middle mediastinum
Dorsal structures
Ventral structures
Dorsal structures
- Seen
- Trachea
- +/- esophagus
- Not seen
- +/- esophagus
- vagus
- lymphatics
- azygous vein
- intercostal vasculature
Ventral
- Seen
- Cardiac silhouette
- No seen
- individual chambers (border effacement)
Caudal mediastinum structures
Dorsal
Ventral
Dorsal
- Seen
- trachea
- +/- esophagous
- Not seen
- +/- esophagus
- vagus
- lymphatics
- azygous vein
Ventral structures
- Seen
- Caudal venal cava
- Not seen
- Phrenic nerve
The 2 mediastinal reflections
A portion of one lung lobe that extends from one side of the thorax to the other
Cranioventral mediastinal reflections
1.
2.
- Formed by the right cranial lung lobe extending from right side of the thorax to the left
- Left cranial lung lobe extends lateral and cranial to the right cranial lung lobe in some dogs
* Lingula
Caudoventral mediastinal reflections
1.
2.
- Represents the left lateral most extent of accessory lung lobe
- Appears to originate at the base of the heart
Accessory lung lobe originates on the …… and extends to the ……
Originates on right
Extends to left
Thymus
Four populations of lymph nodes in thorax
- Cranial mediastinal
- Tracheobronchial
- Pulmonary
- Sternal
…
PRAA
Persistent right aortic arch
Most common congenital ring anomaly
Causes segmental dilation of the esophagus
Esophagus (segmental dilation)
(Vascular ring anomaly)
aspiration pneumonia common
we see an unstructured pulmonary pattern here
Megaesophagus
Trachea and cardiac silhouette displaced ventrally
Alveolar pulmonary pattern in right middle lung lobe
Tracheo-esophageal strip sign
- esophageal abnormality
Sign of a mega esophagus
Traceal stripe sign
- Gas outlining tracheal serosa
Due to pneumomediastinum
- gas usually from a neck wound
Outlines vasculature of the cranial thorax
Most common cause of a pneumoretroperitoneum…..
Pneumomediastinum
- Pneumothorax can form secondary to a pneumomediastinum
- Pneumothorax WILL NOT lead to a pneumomediastinum
Most common tracheal problem
Intratracheal and extra tracheal collapse
- extra thoracic collapse on inspiration
- intra thoracic collapse on expiration
Abnormality with tracheal rings
- Yorkies, small breed dogs
Tracheal hypoplasia
Measure ratio of (thoracic inlet)/(width of trachea)
Common in bracheocephalic dogs
Thymoma
- associated with a myasthena gravis paraneoplastic syndrome and megaesophagus
Ventral deviation of trachea
Sternal lymph nodes….
Drain the abdomen
Difficult to see in cats?!
Tracheal bronchial lymph nodes…
3 types
Drain the Pulmonary Parenchyma
Right tracheal bronchial L.N.
- between the R cranial lung lobe bronchus and R lateral border of trachea
Left tracheal bronchial L.N.
- between L lateral border of trachea and L cranial lung lobe bronchus
Central tracheal bronchial L.N.
- Lives between R and L caudal bronchi
Cowboy sign and
Tracheal bronchial lymphadenopathy
vs
L. atrial enlargement
- Ventral displacement of caudal airways on lateral view
- Enlarged central tracheal bronchial L.N.
Enlarged L atrium
Mitral valve degenerative dz
marked inlarged L auricle
Trachea displaced dorsally
Moderate to severe
Three most common locations of an esophageal foreign body
Associated dz proc…
Thoracic inlet
Over heart base
At esophageal hiatus
Usually causes aspiration pneumonia
Esophageal foreign body
Air bronchograms
- Consistent with alveolar pulmonary pattern secondary to aspiration pneumonia from esophageal foreign body
Hiatal hernia about….
Stomach through esophageal hiatus
Through esophageal hiatus
More commonly seen on L lateral
Opacity
- Soft Tissue
- Gas
- Food
HIatal Hernia
Main mediastinal abnormalities
- Lymph Nodes
- Trachea
- Esophagus
Most common heart base mass
chemodectoma
