An axial slice at the level of the xiphoid process anteriorly and the body of T9 posteriorly indicates the level of:
1- superior border of the liver
2- inferior border of the heart
3- the central diaphragmic tendon
marks the superior level of the pericardium and the superior limit of the pulmonary trunk
Sternal angle
Shows the level of the beginning and end of the arch of aorta
Sternal angle
is the level at which the trachea bifurcates into R and L main bronchi
Sternal angle
Sternal angle
An axial slice through the sternal angle:
ant: sternal angle
pst: T4-T5 intervertebral discs
List 4 of the structures marked/shown by an axial slice through the sternal angle anteriorly and the T4/T5 intervertebral disc posteriorly:
1- sup level of pericardium
2- sup limit of the pul. trunk
3- arch of aorta begins and ends
4- trachea divides into R/L main bronchi
5- rib II articl8 w/ sternum
Protection of intercostal vasculatures
The intercostal vein and artery lie in costal groove and are protected by bone. The intercostal nerve is not typically protected by bone.
Costal groove
The ribs shaft has a groove on the inf. margin of its internal surface. Intercostal aa and vv lie in this groove.
Crest of the head
the head of a typical rib is wedge-shaped and is divided into two facets by the crest of the head.
The tubercle for serratus anterior is located on its superior surface.
Rib II
It has a singular articular facet on its head for articulation with T1
Rib 1
Ant. scalene muscle inserts into this rib
Rib I (Scalene tubercle)
Short ribs without a neck or tubercle
11 and 12
Ribs with one facets on their heads ( articulation with single vertebrae)
1 and 10-12
Demifacets on each side of the vertebral body articulate with —— while transverse costal facets articulate with the —– of the ribs.
head, tubercles
Has a complete superior costal facet instead of a demifacet.
T1
Vertebra T1 has a complete superior costal facet instead of a demifacet. The head of rib 1 does not articulate with vertebra C7.
a single complete costal facet for articulation with the same-numbered rib.
vertebrae T10-12
lack transverse costal facets on their transverse processes.
Vertebrae T11 & T12
Vertebrae T11 and T12 lack transverse costal facets on their transverse processes. Ribs 11 and 12 do not articulate with the transverse processes.
Joints of costal articulation
1- Costochondral joints
2- Sternocostal joints
3- Costotransverse joints
4- Costovertebral joints (joint of head of rib)
Costovertebral and costotransverse joints are
synovial joint
Costovertebral joint
The head of a typical rib articulates with the superior demifacet of the same-numbered vertebra and the inferior demifacet of the vertebra above it to form a joint of head of rib (synovial joint).
Costotransverse joint
The tubercle of the rib articulates with the transverse process of the same-numbered vertebra to form a costotransverse joint (synovial joint).
The types of the sternocostal joints
Rib I- Synchondrosis (fibrocartilaginous)
Ribs II- VII- Synovial
Costochondral joints
The bodies of ribs articulate with their costal cartilages at fibrocartilaginous joints known as costochondral joints.
Sternocostal joints
The costal cartilages of the 7 true ribs articulate with the sternum at sternocostal joints.
Interchondral joints
The costal cartilages of ribs 7-10 articulate with the cartilage above at synovial joints known as interchondral joints.
The contents of intercostal space (general)
intercostal muscles (3 layers) intercostal nn and bv
From the costochondral junctions to the sternum, the muscles are replaced by
external intercostal membrane
External intercostal membrane
orientation: forward and down
replaced by external intercostal membrane starting from costochondral junctions
Internal intercostal membrane
“backward & down”
Posterior and medial to the angles of the ribs, the muscles are replaced by the internal intercostal membrane
innermost intercostal muscle
similar to the internal intercostal muscle
innervation of the intercostal muscles
intercostal nn.
T12 n is subcostal n
subcostal n.
T12 n. is subcostal
Transversus thoracis m.
Subcostal m.
Also innervated by
intercostal nn.
Contents of intercostal space (specific)
Posterior intercostal Vein
Posterior intercostal Artery
From thoracic aorta
Intercostal Nerve
Anterior intercostal artery
From internal thoracic artery
Form the VAN
Orientation of intercostal a and v
intercostal v is sup to a.
Both V and A are protected by the costal groove.
Orientation of the intercostal n
Inf. to the intercostal a.
The location of intercostal VAN
lies b/w the internal and innermost intercostal muscles.
Intercostal nn
Ant ramus of a thoracic spinal nerve.
Gives off lateral and anterior cutaneous branches
The arterial supply to the thoracic wall comes from the:
Thoracic aorta
Subclavian a
Axillary a
Thoracic aorta supplies the thoracic wall via
the pst. intercostal and subcostal aa.
Subclavian a. supply the thoracic wall via
internal thoracic and supreme intercostal aa.
Axillary a. supply the thoracic wall via
sup. and lat. thoracic aa.
The posterior intercostal arteries give rise to —–.
The posterior intercostal arteries give rise to branches that accompany the posterior rami of the spinal nerves and the lateral cutaneous branches of the intercostal nerves.
The posterior intercostal arteries of intercostal spaces 3-11 (and the subcostal arteries) arise —–.
The posterior intercostal arteries of intercostal spaces 3-11 (and the subcostal arteries) arise posteriorly from the thoracic aorta.
The posterior intercostal arteries of intercostal spaces 1 and 2 arise from —–.
The posterior intercostal arteries of intercostal spaces 1 and 2 arise from the supreme (superior) intercostal artery, a branch of the costocervical trunk.
The internal thoracic arteries terminate in the sixth intercostal space by dividing into the —– and —–arteries.
Superior epigastric and musculophrenic arteries.
The internal thoracic arteries arise in the root of the neck from the —–surfaces of the —– arteries.
From the inferior surfaces of the subclavian arteries.
The internal thoracic arteries descend on the —– surface of the thorax —– to the sternum and —– to the clavicle and upper six costal cartilages.
internal surface
lateral to the sternum
posterior to the clavicle
Spaces without anterior intercostal aa.
Intercostal spaces 10-11
The anterior intercostal arteries of intercostal spaces 1-6 arise from the —–.
internal thoracic aa.
The anterior intercostal arteries of spaces 7-9 arise from —–.
musculophrenic aa.
The anterior and posterior intercostal arteries have —–and —– branches that anastomose with each other.
terminal and collateral
The intercostal veins accompany the intercostal arteries and nerves and lie most superior in the —–.
costal grooves
The posterior intercostal veins anastomose with the —– veins.
anterior intercostal
Most posterior intercostal veins drain into the —– , while the anterior intercostal veins drain into the —–.
pst- azygos system of veins
ant- internal thoracic veins
The internal thoracic veins accompany the —–.
internal thoracic arteries
The breast
Breast tissue is typically found overlying the pectoralis major m.
Overlies ribs 2-6 from sternum to midaxillary line
location of the nipple will vary according to the size and shape of the breast
The nipple contains the openings of the 15-20 lactiferous ducts
The mammary glands are enclosed in
superficial fascia/ subcutaneous connective tissue.
suspensory ligament
variable amt of fat and bands of fibrous CT
retromammary space
separates the breast from deep fascia over pectoralis major by loose CT.
It also allows some movement over the chest wall.
Allows minor movement of the breast over chest wall
retromammary space
The axillary tail
breast tissue extend into axilla.
Significant during breast examination
Blood supply of the breast
Mainly from mammary branches of:
internal thoracic artery
lateral thoracic artery
posterior intercostal arteries
Venous drainage of the breast
Has a venous drainage roughly mirroring its arterial supply:
tributaries of the posterior intercostal veins may carry cancer cells to the vertebral venous plexus.
lymphatic drainage of the breast
60-75% of lymph from the breast drains into the axillary nodes
Very important in understanding the mechanisms of metastasis of breast cancer
