Thoracic wall and diaphragm (anat) Flashcards
Components of the STA
1st thoracic vertebra
1st pair of ribs and their costal cartilages
Superior border of manubrium
Components of ITA
12th thoracic vertebra
Lower 6 costal cartilages
Xiphisternal joint
What is a thoracotomy?
Surgical procedure for opening the thoracic wall in order to access the lungs, esophagus and trachea
What are the structures that pass through the STA/thoracic inlet?
Trachea, esophagus, apex of lungs and it’s pleura
Nerves -> phrenic, vagus, recurrent laryngeal, sympathetic trunks
Blood vessels -> brachiocephalic trunk, left common carotid artery, left subclavian artery, internal thoracic (mammary) arteries, brachiocephalic veins
Lymphatics -> thoracic duct
What is the thoracic outlet?
Space btw the clavicle and first rib
What is thoracic outlet syndrome (TOS)?
Group of disorders that occur when blood vessels/nerves in the space btw the clavicle and first rib (thoracic outlet) are compressed, causing pain in shoulders and neck and numbness in fingers
What is the sternum?
Flat, long, elongated bone in anterior part of the thoracic skeleton/cage
Where is the sternal notch located?
In btw the 2 clavicles
What is the 3 parts of the sternum and where they are located?
Manubrium
- piece above the sternal angle
Body of sternum
- middle piece below sternal angle
Xiphoid process
- small triangle below the body of the sternum
Alternative name for sternal angle
Angle of Louis
Where is the angle of Louis located?
At the level of the 2nd sternocostal joint -> corresponds to T4/T5 vertebra
- indicates 2nd rib
Where is CPR conducted over?
Center of sternum
Describe the shape of ribs
Curved and flat bones
Features of ribs
Light weight and highly resistant
Contains hemopoietic tissue -> form blood cells
Types of ribs and which ribs are which
Typical
- 3 to 9
Atypical
- 1 and 2
- 10 to 12
- (first 2 and last 3)
Components of typical rib
Head (2 facets) -> wedged shape
- located posteriorly
Neck -> lateral to the head of the rib
- subsequent portion
Tubercle -> see at jn of neck and shaft
Shaft -> curved portion of rib
- curves at costal angle
- thin and flat
Where is the costal/subcostal groove located?
On the internal surface of typical rib
Fn of costal groove
Protects the intercostal vein, artery and nerve (neurovascular bundle)
Describe the articular facets on the head of the rib
Smooth
Correspond w/ transverse process of vertebra
Where is the non-articular surface of rib located?
On the tubercle
Describe the non-articular surface of the rib
Rough
Attached to ligament
Characteristic of atypical ribs
Dissimilar
Describe the 1st rib
Broadest and shortest
Most sharply curved of the 7 true ribs
2 grooves crossing superior surface for subclavian vessels
- separated by scalene tubercle and ridge
Only 1 facet
Describe the 2nd rib
Thinner, less curved and much longer than the 1st rib
Describe the 10th-12th rib
Only 1 facet on their heads
11th and 12th ribs are short and have no neck/tubercles
Where are the costal facets of the thoracic vertebrae located?
On their bodies -> articulate w/ heads of ribs
Transverse processes -> articulate w/ tubercles of ribs
Which thoracic vertebrae have no costal facets on their transverse porcesses?
T11 and 12
Diff btw synovial, cartilaginous and fibrous joints
Synovial joints allow more movement than cartilaginous joints
Fibrous joints are usually fixed and immovable and have no joint cavity
Where are the synovial joints of the thoracic wall?
Btw ribs and vertebrae -> costovertebral and costotransverse joints
Btw sternum and clavicles -> sternoclavicular joints
Features of external intercostal muscle (EICM)
Run downwards and forwards
- drn is like placing hand in pocket
Elevate the ribs due to contraction of muscles
Muscles for inspiration
Features of internal intercostal muscles (IICM)
Deep to EICM
Run downwards and backwards -> perpendicular to EICM
Depress the ribs due to contraction of muscle
Muscle for expiration
How many pairs of thoracic spinal nerves does the thoracic wall have?
12
What are the branches of intercostal nerves?
Anterior cutaneous
- sensory
Lateral cutaneous
- sensory
Muscular
- motor
Collateral
- motor nerves
- run along upper border of rib
Which nerve supplies the back muscles (located posteriorly)?
Dorsal pri rami
What happens when spinal nerve leave the intervertebral foramina?
Divide into ventral pri rami and dorsal pri rami
Is the ventral pri rami an intercostal nerve?
Yes
- runs along extent of intercostal space
- anterior rami
What is general somatic efferent (GSE)?
Nerve -> motor to skeletal
- ventral horns (anterior) contain the cell bodies of motor neurons which innervate skeletal muscle
What is general somatic afferent (GSA)?
Nerve -> sensory from skin
- dorsal horns contain the cell bodies of sensory neurons where many afferent (sensory) fibres terminate
- convey sensation from skin to dorsal horn
Where does the intercostal vessels and nerves run?
Obliquely in btw internal and innermost intercostal muscle
Each intercostal space contains which intercostal arteries?
Posterior intercostal artery (PIA)
Anterior intercostal artery (AIA)
Where does AIA arise from?
From internal mammary artery (IMA) or its terminal branch (aka: musculophrenic artery)
Where does the PIAs of upper 2 spaces arise from?
Costocervical trunk -> branch of subclavian artery
Where does the PIAs of IC spaces 3-11 arise from?
Thoracic aorta
Location of subclavian artery
Superior to the lungs on both sides
What does the subclavian artery bifurcate into?
Superior epigastric artery and musculophrenic artery
Where is the superior epigastric and musculophrenic artery located?
At 6th intercostal space
What is the artery and vein that runs along the length of the lungs medially?
Internal mammary artery and vein
What are the diff intercostal veins?
Superior vena cava (SVC)
Azygos vein
Brachiocephalic vein
Anterior intercostal and internal mammary veins
Where do the anterior intercostal veins drain into?
Internal mammary veins
Where does the posterior intercostal veins drain into?
Azygos venous sys/brachiocephalic veins
Where does the azygos vein terminate?
SVC
Where is the azygos vein located?
On the right side of vertebral column (pt’s right)
Where is the right and left brachiocephailc vein located?
Neck region
- merge to form SVC
Where does the midsternal line run along?
Intersection of median plane w/ anterior chest wall
Where does the midclavicular line run along?
Pass through midpoints of clavicle (heart apex beat)
Where does the anterior axillary line run along?
Runs vertically along anterior axillary fold
- side of body anteriorly
Where does the posterior axillary line run along?
Runs vertically along posterior axillary fold
- side of body in the middle
Where does the midaxillary line run along?
Runs from apex of axilla, parallel to anterior axillary fold
- side of body posteriorly
What does the breast consist of?
Mammary gland tissue, fibrous tissue, ligaments, septa and fat
What are the arteries that supply the breast?
Internal mammary artery -> perforating branches
Anterior intercostal arteries
Lateral thoracic branch of axillary artery
What are the veins that supply the breast?
Internal mammary veins
Intercostal veins -> posterior and anterior
Axillary vein -> lateral thoracic tributary
What are the lymphatic of the breast?
Internal thoracic nodes
Axillary nodes
Innervation of the breast
2nd to 6th intercostal nerves
Innervation of the nipple
4th intercostal nerve
What are the mammary glands of the breast and where are they located?
Modified sweat glands
Subcutaneous tissue anterior to the pectoral muscles and the anterior thoracic wall
What does estrogen do?
Controls the growth of the ducts
What does progesterone do?
Controls the growth of the glandular buds
How is the base of the breast attached to the body?
Extends vertically from ribs 2 to 6 and transversely from sternum to midaxillary line
What does the retromammary space in the breast do?
Separates breast from deep fascia -> allows for movement of breast from chest wall
What are the suspensory ligaments of Cooper?
Fibrocollagenous connective tissue that provides support to the breast
Signs and symptoms of breast cancer
Breast lump/thickening that feels different from surrounding tissue
Change in size, shape/appearance of breast
Changes in skin over the breast
Newly inverted nipple
Peeling, scaling or crusting of pigmented area of skin surrounding the nipple/breast skin
Redness/pitting of skin over breast (like orange skin)
What is a mammogram?
Radiological examination of breast to screen breast cancer
Where do muscular fibers of diaphragm arise from?
Xiphoid process, lower ribs and upper lumbar vertebrae
Where do muscular fibers converge to?
Central tendon
Does each dome of the diaphragm have a separate nerve supply?
Yes
Where does phrenic nerve arise from?
Anterior rami of C3-C5 nerve roots
What does the phrenic nerve consist of?
Motor, sensory and sympathetic nerve fibers
What does the phrenic nerve do?
Provide complete motor innervation to the diaphragm
Provide sensory innervation to central part of diaphragm
Provide sympathetic innervation to blood vessels
What are the structures that pass through the openings in the diaphragm and which level they enter from?
Inferior vena cava (IVC) -> T8
Esophagus -> T10
Aorta -> T12
*except for aorta, no. of letters = spinal level it arises from
Structures passing through the diaphragm and spinal level it arises from
Vagus nerve -> T10
Thoracic duct -> T12
Azygos vein -> T12
Movement of thoracic wall during inspiration results in what changes to the diaphragm?
Increased vertical and transverse diameter
Why does thoracic cage widen during inspiration?
Ribs are elevated
Why does thoracic cage narrow during expiration?
Ribs are depressed
What is congenital diaphragmatic hernia (CDH)?
Condition resulting from a developmental defect in the diaphragm leading to protrusion of abdominal contents into thoracic cavity
Characteristics of babies w/ CDH and why
Have small, underdeveloped lungs and low blood O2 as movement of abdominal organs into fetus’ chest crowds its lungs
