Thoracic anatomy Flashcards
Which 2 ribs does the manubrium articulate with?
1st and 2nd
The sternal angle marks the level of which costal cartilage?
2nd
The tip of the xiphisternum is located at which vertebral level?
T10
Name the 5 atypical ribs
1
2
10
11
12
Which muscle originates from rib 2?
Serratus anterior
Which muscle inserts onto rib 1?
Scalenus anterior
Which are the true ribs?
1-7
Where do true ribs attach to anteriorly?
The sternum
Which ribs are the false ribs?
8-10
Where do the false ribs attach to?
Costal cartilages superior to them
Which are the floating ribs?
Ribs 11 and 12
Where do the floating ribs terminate?
Do not have an anterior attachment - they end in the abdominal musculature
Which vertebra does the first rib articulate with?
T1
Which 3 muscles form the innermost layer of the thoracic wall?
Transversus thoracis (most superficial)
Innermost intercostals
Subcostals
Which muscles form the internal layer of the thoracic wall?
Internal intercostals
Which muscles form the external layer of the thoracic wall?
External intercostals
What is the innervation of the transversus thoracis?
Intercostal nerves T1-T11
The transversus thoracis is continuous with which muscle inferiorly?
Transversus abdominis
What separates the innermost intercostals from the internal intercostals?
Intercostal neuromuscular bundle
What is the innervation of the innermost intercostals?
Intercostal nerves
What is the function of the muscles in the innermost layer of the thoracic wall?
Depress the rib cage
What is the innervation of the subcostals?
Intercostal nerves
How many pairs of internal intercostal muscles are there?
11
The internal intercostals are continuous with which muscles?
Internal obliques
What is the innervation of the internal intercostals?
Intercostal nerves
What is the function of the internal intercostals?
Depress the rib cage (decrease thoracic volume)
How many pairs of external intercostals are there?
11
What are the external intercostal muscles continuous with?
The external obliques
What is the innervation of the external intercostals?
Intercostal nerves
What is the function of the external intercostals?
Elevate the ribcage (increase thoracic volume)
The central tendon of the diaphragm fuses with the inferior surface of which structure?
Fibrous pericardium
Which vertebral level is the caval hiatus at?
T8
Which vertebral level is the oesophageal hiatus at?
T10
Which vertebral level is the aortic hiatus at?
T12
Which structures pass through the caval hiatus?
IVC
Terminal branches of right phrenic nerve
Which structures pass through the oesophageal hiatus?
Oesophagus
Right and left vagus nerves
Oesophageal branches of left gastric artery + vein
Which structures pass through the aortic hiatus?
Aorta
Azygous vein
Thoracic duct
What is the motor innervation of the diaphragm?
C3-C5
What are the accessory muscles of inspiration?
What are the accessory muscles of expiration?
Describe the ‘pump-handle’ movement in inspiration.
Where ribs 2-6 cause the sternum to move up and out in the sagittal plane on inspiration.
Describe the ‘bucket-handle’ movement in inspiration.
Where the lateral portions of ribs 7-10 move up and out in the coronal (frontal) plane on inspiration.
What is the anterior border of the thoracic inlet?
Superior border of the manubrium and costal cartilage of 1st rib.
What is the lateral border of the thoracic inlet?
1st pair of ribs
What is the posterior border of the thoracic inlet?
T1
What are the superior relations of the thoracic inlet?
Root of neck
Brachial plexus (superolateral)
What are the anterior relations of the thoracic inlet?
Manubrium
What are the inferior relations of the thoracic inlet?
Superior mediastinum
Name the structures that pass through the thoracic inlet.
Trachea
Oesophagus
Thoracic duct
Lung apexes
Nerves (phrenic, vagus, recurrent laryngeal, sympathetic trunks)
Arteries (common carotid, subclavian)
Veins (internal jugular, brachiocephalic, subclavian)
Lymph nodes and lymphatic vessels
What causes thoracic outlet syndrome?
Compression of subclavian artery or C8/T1 nerves.
Give the causes of thoracic outlet syndrome.
Cervical rib
Enlarged C7 transverse process
Muscular abnormalities
Neck trauma
Tumours (pancoast)
Subclavian artery aneurysm
Thoracic outlet syndrome usually presents with a gradual onset of which features?
Neurological and vascular features
Describe vascular features of thoracic outlet syndrome.
Weak radial pulse
Low BP
Limb pallor on elevation
Raynaud’s
Adson’s sign positive
**All above happen on affected side
Describe some sensory features of thoracic outlet syndrome.
Pain or paraesthesia on ulnar border of hand or distal forearm
Sensory deficit (aggravated by exercise)
Describe some motor features of thoracic outlet syndrome.
Weakness or wasting corresponding to part of brachial plexus involved
Wasting of thenar muscles
Where does the trachea arise?
Lower border of cricoid cartilage (C6)
Where does the trachea bifurcate?
Sternal angle (carine = T5)
Which epithelium lines the conducting respiratory airways?
Ciliated pseudo stratified columnar epithelium (with interspersed goblet cells)
What are the 6 anterior relations of the trachea in the neck?
Isthmus of thyroid gland
Inferior thyroid veins
Thyroid ima artery (in 10%)
Sternohyoid
Sternothyroid
Cervical fascia
What are the 6 anterior relations of the trachea in the thorax?
Manubrium
Remains of thymus
Left brachiocephalic vein
Aortic arch
Brachiocephalic trunk
Left common carotid artery
What are the 2 posterior relations of the trachea in the neck?
Oesophagus
Vertebral column
What are the 2 posterior relations of the trachea in the thorax?
Oesophagus
Vertebral column
What are the 6 lateral relations of the trachea in the neck?
Common carotid arteries
Right and left lobes of thyroid
Recurrent laryngeal nerves
Internal jugular
External jugular
Omohydoid
What are the 4 lateral RHS relations of the trachea in the thorax?
Pleura
Right vagus nerve
Brachiocephalic trunk
Azygous vein
What are the 6 lateral LHS relations of the trachea in the thorax?
Pleura
Left recurrent laryngeal nerve
Aortic arch
Left common carotid artery
Left subclavian vein
Thoracic duct
What is the thymus?
A specialise primary lymphoid organ of the immune system where T cells mature.
Where is the thymus located?
Within superior mediastinum, posterior to manubrium.
Where is the cortex of the thymus located?
Peripherally within each follicle of the thymus.
What is the cortex of the thymus mainly composed of?
Lymphocytes supported by a network of branches of epithelial reticular cells.
Where is the medulla of the thymus located?
In the centre of each follicle
What cells are found within the medulla of the thymus?
Epithelial reticular cells
Reticulocytes (though fewer than in cortex)
Hassall’s corpuscles (remains of epithelial tubes)
The thymus is derived from which embryological structure?
3rd pharyngeal pouch
What happens to the thymus after pubity?
Decreases in size
What is divided for a median sternotomy to be performed?
Incision made to divide sternum.
No muscle layers involved.
Where is the incision for an anterolateral thoracotomy made?
Incision is made in 4th intercostal space extending from the sternal edge to the midaxillary or posterior axillary line.
Which muscle layers are divided for an anterolateral thoracotomy?
Pectoralis major
Pectoralis minor
Anterior parts of serratus anterior
Intercostal muscles
What happens to perform a clamshell thoracotomy?
Bilateral anterolateral thoracotomy where the sternum is also divided.
Which muscles are divided in a posterolateral thoracotomy?
Latissimus dorsi
Serratus anterior
Intercostal muscles
What are the 3 groups of lymph nodes which receive lymph from breast tissue?
Axillary (75%)
Parasternal (20%)
Posterior intercostal nodes (5%)
Where does lymph from the nipple and areola drain?
Subareolar lymphatic plexus
Where should chest drains be inserted?
The safe triangle
What are the 4 borders of the safe triangle?
Base of axilla
Lateral border of latissimus doors
Lateral border of pectorals major
5th intercostal space
Where should a large bore annul be inserted for a thoracocentesis in adults?
4th or 5th intercostal space in the mid-axillary line.
Where should a large bore annul be inserted for a thoracocentesis in children?
2nd intercostal space MCL
What type of thoracotomy is used as a resuscitative thoracotomy?
Anterolateral
When should a left sided resuscitative thoracotomy be used?
Traumatic cardiac arrest
Those with left sided injuries
When should a right sided resuscitative thoracotomy be used?
In patients who have not arrested but have profound hypotension and right sided chest injuries
