Thoracic Wall Flashcards
What are the roles of the Thorax
- rigidity and elasticity
- respiration
- movement , provides attachment for muscles
- haematopoiesis
- connections with the neck upper limbs and abdomen
what makes up the thoracic cage
sternum 12 pairs of ribs their costal cartilages 12 thoracic vertebrae intervertebrae
what makes up the thoracic wall
thoracic cage skin subcutaneous tissue thoracic muscles + fascia 3 layers of muscles extending between ribs mammary glands/breast tissue
features of thoracic vertebrae
inferior and superior articular processes are vertical
articular facets face slightly medially to allow some rotation but no flexion
what are true ribs
1-7 and attach directly to the sternum through costal cartilage
false ribs
8-10 attach sternum indirectly through costal cartilage of 7th rib
floating ribs
11-12 and do not articulate with the sternum
structure of typical ribs 2-10
neck head tubercle body costal angle
structure of atypical ribs - rib 1
- scalene tubercle attachment for anterior scalene muscle
groove for subclavian vein - groove for subclavian artery and inferior trunk (c8 and t1) fo brachial plexus
No costal groove
atypical rib - floating ribs structure
- no attachment to sternum
- heads articulate only with corresponding vertebra
do not articulate with the transverse processes
three parts of the sternum
manubrium
body
xiphoid process
why is the sternal angle an important land mark
the second cc is at this le vet so can be used to count the ribs
this is at the level of the intervertebral disc between the T4 AND T5 vertebrae
the proximal and distal boundaries of the aortic arch are at this level
the bifurcation of the trachea
superior limit of the pulmonary trunk
azygous vein opening SVC
Ligamentium arteriosum
site of bone marrow aspiration
sternum
COSTOVERTEBRAL JOINT
each rib (exculding 1, 11, 12) articulates with the superior costal facet on its corresponding vertebrae and the inferior costal facet of the vertebrae above
this is a SYNOVIAL joint and is supported by a capsule with ligaments
facets of T1
1 and a half costal facets on its body
facets of T2 - T9
2 half costal facets
facets of T10
1 half costal facet
facets of T11 + T12
1 Oval costal facet each
costotransverse joint
the joint between the tubercle of the rib (except 11 and 12) and the transverse process of its corresponding vertebrae
costotransverse joints 1-7 structure
curved facets allowing rotary movement
costotransverse joints 8,9,10
flat facets allowing a gliding movement
COSTOCHONDRAL / COSTOSTERNAL JOINTS
All ribs articulate anteriorly with a costal cartilage (CC) via a primary cartilaginous joint
CC ribs 1-7 articulate directly with the sternum via synovial joints to allow movement (not rib 1)\
CC ribs 8-10 articulate with costal cartilage above and indirectly with the sternum
what is thoracic inlet bound by
T1 vertebrae, 1st rib and CC + manubrium
structure of thoracic inlet
slopes anteriorly inferiorly, the apex of the lung extends 2-3 cm above the anterior part of the 1st rib and clavicle
Structures that pass between the thorax and the neck
- Vessels that supply and drain the head and neck
- Trachea
- Oesophagus
- Vagus + recurrent laryngeal nerves
- Phrenic nerves
Structures that pass between the thorax and the upper limb lie on the first rib
- Subclavian vein
- Subclavian artery
- (Inferior trunk of the brachial plexus)
what is the thoracic outlet bound by
T12 vertebra, 11th and 12th ribs, CC of ribs 7-10 and xiphoid process
closed incompletely by the diaphragm
THORACIC OUTLET SYNDROME
Thoracic outlet syndrome is a group of disorders that occur when blood vessels or nerves in the space between your collarbone and your first rib (thoracic intlet) are compressed
what composes the breast
mammary glands, skin and connective tissues
15-25 lobes and ducts surrounded by fat and well developed connective tissue
what are Montgomery tubercles
they are visible portions of areolar glands on the skin surface within the areola
what are Montgomery glands
sebaceous glands in the breast
where is the base of the breast located
In adult females, base of it is located between the levels of 2nd – 6th (7th) ribs
where is the breast found anatomically
between the superficial and deep layers of superficial fascia
they sit on pec. major, serratus anterior and external oblique miscues
where is the deer pectorlis fascia
between the superficial fascia and the muscle
coopers ligaments
connective tissue condenses to form ligaments which support the breast and connect the deep fascia to the dermis of the skin
The retromammary space
a layer of loose connective tissue between the deep layer of superficial fascia and the deep fascia, provides a good degree of movement over underlying structures
what are the two main arteries that supply the breast and their branches
internal thoracic artery - mammary branches and
anterior intercostal arteries
axillary artery - lateral thoracic artery and the thoracic-acromial artery
where do the veins in the breast drain
they follow the arteries and drain mainly to the axillary and internal thoracic veins
where do the areola and lateral quadrants drain to
axillary lymph nodes
where does the medial quadrant drain to
parasternal lymph nodes and often the opposite breast
where do the inferior breast quadrants drain to
the inferior phrenic lymph nodes
how many intercostal spaces are there
11 pairs each filled with three layers of muscles and membranes
external intercostal muscles - structure and what is their role
extend from the inferior edge of the rib above to the superior edge of the rib below
however anteriorly they are replaced by the intercostal membrane
they raise the ribs during inspiration, as there origin (superior attachment) is more proximal to the vertebral column
internal intercostal muscles
extends from the lateral edge of the costal groove of the rib above, to the superior edge of the rib below
posteriorly the muscle fibres are replaced by internal intercostal membrane
prevent undraping during inspiration and aids in the elastic recoil by moving the ribs inferiorly in expiration
innermost intercostal muscles
act with intercostal muscles and their deep surface is covered with endothoracic fascia
transverse thoracis
lies posterior to the sternum
runs from the internal aspect of the ribs and costal cartilages 3-6, to the sternum, xiphisternum and costal margin
subcostalis
lies on the posterior wall
runs from the lower internal surface near the angle down to the inner surface of 2 to 3 ribs below
intervertebral foramen
run between the pedicle, articular processes, vertebral body and IV disc
what puts the spinal intercostal nerve at risk
compression by arthritis, fracture or disc prolapse
intercostal nerves
Intercostal nerves, together with the intercostal vein and artery (the order is VAN) lie in the costal groove at the inferior edge of the rib, between the internal and innermost intercostal muscles
intercostal nerves journey
- gives of lateral cutaneous branch
- travels in the costal groove
- becomes superficial parasternally, named after anterior cutaneous branch
nerve supply to the thoracic wall
- Supraclavicular nerves (C3-4) descend over the clavicle as far as the 2nd costal cartilage
T1 nerve
has no cutaneous distribution over the anterior thoracic wall
- Joins the brachial plexus, supplying the medial arm and forearm
T2 nerve
gives a large lateral cutaneous branch (THE INTERCOSTOBRANCHIAL NERVE) that supplies the thorax wall in axilla and upper, medial part of upper limb (at risk in breast surgery)
T7-12
Supply the skin and muscles of the abdominal wall as well
Ventral rami of T2 – T11
provide motor fibres to intercostal muscles, abdominal
muscles
– sensory supply to the skin and parietal pleura
The ventral ramus of T1 joins the Brachial Plexus (inferior
trunk) to supply
– the small muscles of the hand
– the skin of the medial aspect of the arm and forearm – muscles of the 1st intercostal space
arterial supply of the thoracic wall
Subclavian artery ✓ vertebral artery ✓ thyrocervical trunk ✓ costocervical trunk ✓ Internal thoracic artery Thoracic aorta ✓ Anterior intercostal arteries
✓ Internal thoracic artery
– Lies along the margins of the sternum
– Terminates as the superior epigastric and musculophrenic arteries
Thoracic aorta (between T4/5 - T12)
✓ Parietal branches:
– 3rd - 11th posterior intercostal arteries
– Subcostal artery (inferior to 12th rib, supply posterior abdominal wall)
– Superior phrenic artery (diaphragm)
✓ Anterior intercostal arteries
– 2 per space in spaces 1-6
– 7th -10th Anterior intercostal arteries are branches of the musculophrenic artery
– 11th intercostal space and subcostal area have no anterior supply
Other supplies to arterial
✓ 1st-2nd posterior intercostal arteries (from supreme intercostal branch of costocervical trunk)
✓ 3rd-11th posterior intercostal arteries (from Thoracic aorta)
– 2 per space
✓ Anterior and posterior intercostals anastomose.
– This anastomosis may form a collateral circulation in Coarctation of the Aorta
venous drainage of the thoracic wall
✓ Anterior intercostal veins drain to the internal thoracic vein →brachiocephalic vein
✓ Posterior intercostal veins drain either to the brachiocephalic vein or to the superior vena cava via azygos system
AZYGOS SYSTEM
✓ Drains the posterior wall of the thorax and part of the posterior abdominal wall
✓ Begins from lumbar and subcostal veins and/or direct branch of the inferior vena cava
✓ Passes behind the diaphragm, with the aorta and thoracic duct
✓ Ascends in the posterior mediastinum, passes posterior to the right lung hilum, arches and opens into the superior vena cava
− Connects superior and inferior vena cava
HEMIAZYGOS
✓ =Inferior hemiazygos vein
✓ Has connections with the left renal vein
✓ Passes through or behind the left crus of the diaphragm
✓ Crosses to the right at approximately T9 and joins the azygos
ACCESSORY HEMIAZYGOS
✓ =Superior hemiazygos ✓ Descends from 4th intercostal space, crosses to the right at approximately T8 ✓ Can open into • Azygos • Hemiazygos • Both
anterior lymph drainage of the thoracic wall
→parasternal nodes
– alongside internal thoracic (mammary) artery
→bronchomediastinal trunks
posterior lymph drainage of the thoracic wall
→intercostal nodes
→thoracic duct (inferiorly) or bronchomediastinal trunks (superiorly)
rib fractures
✓ most frequently occur between ribs 3 and 10.
✓ Little can be done to assist the healing of broken ribs other than binding them tightly to limit movement.
✓ Can cause hemothorax, pneumothorax with or without pulmonary injury, splenic injury
