Thorax, Snell Flashcards
3 parts of sternum
1) Manubrium
2) Body
3) Xiphoid process
Manubrium articulates with
1) Body of sternum
2) Clavicles
3) First costal cartilage
4) Upper part of 2nd costal cartilage
Landmark formed by articulation of manubrium with body of sternum
Sternal angle of Louis
5 structures at the level of sternal angle of Louis
1) 2nd costal cartilage
2) Junction of superior and inferior mediastinum
3) Bifurcation of trachea
4) Junction of ascending aorta and aortic arch and aortic arch and descending aorta
5) IV disc between T4 and T5
Body of sternum articulates with on each side with
2nd to 7th costal cartilages
T/F Xiphoid process is ossified at birth
No, plate of cartilage that becomes ossified at proximal end during adult life
T/F No ribs or costal cartilages are attached to the xiphoid process
T
T/F Sternum possesses red hemopoietic marrow throughout life
T
Ribs, #
12
Categories of ribs
1) True
2) False
3) Floating
True ribs
Attached to the sternum by their costal cartilages (1st-7th)
False ribs
Attached anteriorly to each other and to the 7th rib by their costal cartilages and small synovial joints (8th-10th)
Floating ribs
No anterior attachment (11th-12th)
Atypical rib
1st rib
Superior vs inferior: Costal groove
Inferior
Costal groove accomodates
Intercostal vessels and nerves
Typical rib: Parts
1) Head
2) Neck
3) Tubercle
4) Shaft
5) Angle
Head of rib: How many facets
2
Head of rib: Superior facet articulates with
Vertebra immediately above it
Head of rib: Inferior facet articulates with
Numerically corresponding vertebral body
Tubercle of rib: How many facets
1
Tubercle of rib: Facet articulates with
Transverse process of the numerically corresponding vertebra
Part of rib where the shaft bends forward sharply
Angle
Important structures related to the first rib (2)
1) Brachial plexus
2) Subclavian artery and vein
T/F The first rib is flattened anteroposteriorly
F, superoinferiorly
First rib: Muscle attached to its upper surface and inner border
Scalenus anterior
Crosses first rib anterior to the scalenus anterior
Subclavian vein
Lie in contact with 1st rib posterior to the scalenus anterior attachment
1) Subclavian artery
2) Brachial plexus
A cervical rib occurs in ~ ___% of persons
0.5
Cervical rib: Arises from
Transverse process of C7
Cervical rib: Possible anterior attachments
1) Free
2) Connected to first rib by fibrous band
3) Articulate with 1st rib
Thoracic outlet syndrome is brought about by compression of what structures by the cervical rib
1) Brachial plexus
2) Subclavian artery
T/F Costal cartilages of eighth, ninth, and tenth ribs connect to the cartilage immediately above them
T
T/F 11th and 12th ribs do not have costal cartilages
F, cartilages of the eleventh and twelfth ribs end in the abdominal musculature
Rib #s: Head articulates by a synovial joint with the corresponding vertebral body and that of the vertebra above it
2nd-9th
Rib #s: Heads have a simple synovial joint with the corresponding vertebral body
1st, 10th-12th
Type of joint: Manubriosternal joint
Cartilaginous
Type of joint: Xiphisternal joint
Cartilaginous
Type of joint: Costovertebral joint
Synovial
Articulation of rib tubercle with transverse process of corresponding vertebra is absent in which ribs
11th-12th
Type of joint: Costochondral
Cartilaginous
Movement in the costochondral joint
NONE
Type of joint: Articulation of first costal cartilage with manubrium
Cartilaginous
Articulation of first costal cartilage with manubrium: Movement
NONE
Type of joint: Articulation of second to the seventh costal cartilages articulate with the lateral border of the sternum
Synovial joints
Type of joint: Articulation of sixth, seventh, eighth, ninth, and tenth costal cartilages with one another
Small synovial joints
Movement that rotates the neck of rib around its own axis
Respiration
Brachial plexus, subclavian artery, and subclavian vein can be compressed between which bones
1) First rib
2) Clavicle
Muscles of respiration within intercostal spaces
1) External intercostal
2) Internal intercostal
3) Innermost intercostal
Thoracic muscles are lined internally by
Endothoracic fascia and parietal pleura
Intercostal nerves and blood vessels run between what muscles
1) Internal intercostal muscles
2) Innermost intercostal muscles
Intercostal nerves and blood vessels: Arrangement from superior to inferior
VAN
Intercostal vein
Intercostal artery
Intercostal nerve
Needle thoracostomy: Indications
1) Tension pneumothorax
2) Large hemothorax
Most important muscle of respiration
Diaphragm
Diaphragm: Insertion
Central tendon
Diaphragm: Nerve supply
Phrenic
Raise ribs during inspiration and lower ribs during expiration
External intercostals
Thoracic muscle: Elevate ribs
1) Levatores costarum
2) Serratus posterior superior
Thoracic muscle: Lowers ribs
Serratus posterior inferior
Diaphragm: Origins
1) Sternal
2) Costal
3) Vertebral
Diaphragm: Sternal part arises from
Posterior surface of xiphoid
Diaphragm: Costal part arises from
Deep surfaces of lower 6 ribs and their costal cartilages
Diaphragm: Vertebral part arises from
Crura and arcuate ligaments
Diaphragm: Encloses the esophagus
Right crus
Diaphragm: Right crus arises from
Bodies and IV discs of L1-3
Diaphragm: Left crus arises from
Sides and IV discs of L1-2
Diaphragm: Supports the heart
Central tendon
Weight-lifting muscle
Diaphragm
Thoracoabdominal pump
Diaphragm
As the thoracoabdominal pump, the diaphragm helps in
1) Return of blood to right atrium
2) Passage of lymph through thoracic duct
Diaphragm: Aortic opening, level
T12
Diaphragm: Aortic opening, transmits
1) Aorta
2) Azygos vein
3) Thoracic duct
Diaphragm: Esophageal opening, level
T10
Diaphragm: Esophageal opening, transmits
1) Esophagus
2) Right and left vagus
3) Esophageal branches of left gastric vessels
4) Lymphatic vessels from lower 3rd of esophagus
Diaphragm: Caval opening, level
T8
Diaphragm: Caval opening, through what part of diaphragm
Central tendon
Diaphragm: Caval opening, transmits
1) IVC
2) Terminal branches of right phrenic
Diaphragm: Sympathetic trunk passes posterior to
Medial arcuate ligament on each side
T/F Any penetrating wound to the chest below the level of the nipples should be suspected of causing damage to the diaphragm until proved otherwise
T
Diaphragm: Arching domes of diaphragm can reach level of ___ rib
5th, right dome can reach a higher level
Intercostal arteries per intercostal space, #: Posterior intercostal
1 large
Intercostal arteries per intercostal space, #: Anterior intercostal
2 small
Intercostal veins: Posterior drain into
Azygos or hemiazygos
Intercostal veins: Anterior drain into
Internal thoracic and musculophrenic veins
Posterior intercostal arteries: First 2 are branches of
Superior intercostal artery from costocervical trunk of subclavian artery
Posterior intercostal arteries: Lower 9 are branches of
Thoracic aorta
Anterior intercostal arteries: First 6 are branches of
Internal thoracic
Anterior intercostal arteries: Lower 3 are branches of
Musculophrenic from internal thoracic
Internal thoracic artery arises from
1st part of subclavian
Internal thoracic artery: Descends directly behind
1st 6 costal cartilages
Internal thoracic artery: ___ cm lateral to sternum
About a fingerbreadth
Internal thoracic artery: Terminates in the
6th ICS
Internal thoracic artery: Divides into
1) Superior epigastric
2) Musculophrenic
Trachea: Continuation of
Larynx
Trachea: Begins at
Lower border of cricoid, C6
Trachea: Divides into right and left main bronchi at level of
Sternal angle of Louis
Trachea: Length
~ 13cm
Trachea: Diameter in adults
2.5 cm
Trachea: Shape of supporting cartilage
U
Trachea: Posterior relations
1) Esophagus
2) Left recurrent laryngeal nerve
Levels of the airway
1) Trachea
2) Main bronchi
3) Lobar bronchi
4) Segmental bronchi
5) Terminal bronchiole
6) Respiratory bronchiole
7) Alveolar duct
8) Alveolar sac
9) Alveolus
Trachea, relations: Right
1) Azygos
2) Right vagus
3) Pleura
Trachea, relations: Left
1) Left vagus
2) Left phrenic
3) Pleura
4) Arch of aorta
5) Left common carotid
6) Left subclavian
Right vs left main bronchus: Wider, shorter, more vertical
Right
Right main bronchus: Branch given off before entering the hilum of right lung
Superior lobar bronchus
Right main bronchus: Branches given off upon entering the hilum of right lung
Middle and inferior lobar bronchi
Left main bronchus: Related structures
1) Aortic arch above
2) Esophagus behind
Left main bronchus: Branches given off on entering the hilum of left lung
Superior and inferior lobar bronchi
Foreign bodies that lodge into the right main bronchus usually pass into
Middle or lower lobar bronchus
2 parts of the pleura
1) Parietal
2) Visceral
Lowest area of the pleural cavity
Costodiaphragmatic recess
Parietal vs visceral pleura: Sensitive to pain, temperature, touch and pressure
Parietal pleura
Parietal pleura: Costal parietal pleura is supplied y
Intercostal nerves
Parietal pleura: Mediastinal parietal pleura is supplied by
Phrenic nerve
Parietal pleura: Diaphragmatic parietal pleura is supplied by
Phrenic nerve
Visceral pleura: Nerve supply
Autonomic from pulmonary plexus
Visceral pleura: Sensitive only to
Stretch
Thin layer of loose connective tissue that separates the parietal pleura from thoracic wall
Endothoracic fascia
Lower margins of pleural reflections
1) 8th rib MCL
2) 10th rib MAL
3) 12th rib paravertebral
Lower margins of lungs
1) 6th rib MCL
2) 8th rib MAL
3) 10th rib paravertebral
Intrapleural pressure
-4 mmHg
Visceral pleura is derived from
Visceral mesoderm
Parietal pleura is derived from
Somatic mesoderm
Lungs: Main function
Oxygenation of blood
of lobes: Right lung
3
of lobes: Left lung
2
Fissure/s: Right lung
Horizontal and oblique
Fissure/s: Left lung
Oblique
Right vs left lung: Larger and heavier
Right
Right vs left lung: Shorter and wider
Right
Lung: Apex extends ___ cm above ___
2.5 cm, clavicle
Where parietal and visceral pleura meet
Root of lung
Root of lung: Contents
1) Bronchi
2) Pulmonary artery and vein
3) Bronchial vessels
4) Lymph vessels
Right vs left lung: Hyparterial and eparterial bronchi
Right
Left lung: Hyparterial vs eparterial
Hyparterial
Largest subdivision of a lung lobe
Bronchopulmonary segment
Bronchopulmonary segment: Shape
Pyramidal
Bronchopulmonary segment: Apex directed towards
Lung root
Bronchopulmonary segment: Named according to
Segmental bronchus supplying it
Bronchopulmonary segment: Separated from adjacent segments by
Connective tissue
Bronchopulmonary segment: Has its own
1) Bronchus
2) Arterial supply
3) Venous drainage
4) Lymphatic drainage
Anatomic and surgical unit of the lung
Bronchopulmonary segment
Bronchopulmonary segment: Right lung
10
1) Superior lobe: Apical, anterior, posterior
2) Middle lobe: Lateral, medial
3) Inferior lobe: Superior, anterior basal, lateral basal, medial basal, posterior basal
IMAGE at DOWNLOADS
Bronchopulmonary segment: Left lung
10
1) Superior lobe: Apico-posterior, anterior, superior lingular, inferior lingular
2) Inferior lobe: Superior, anterior basal, lateral basal, medial basal, posterior basal
