• In the thorax there are 12 thoracic bones. These are divided into atypical and typical ribs.
- Thoracic vertebra have a spinous process and thing bodies as well as transverse
processes for the articulation with the ribs.
- Typical vertebra includes T2 -T8 as they have a superior and inferior costal
facet. In some cases they are called ‘demi-facets’ for each head of the rib.
- However atypical vertebrae are T1, T9,T10,T11,T12 and they only have a single
costal facet and this is more in the middle of the body and pedicel of the bone as
opposed to typical vertebra where they are more superior and inferior.
• The T1 articulates with the first rib
• Remember all the nerves are under the vertebrae
• There are also 12 pairs of ribs and costal cartilage.
There are also typical and atypical ribs.
• 7 pairs of ribs are directly attached to the sternum via their costal cartilage however ribs 8-10 are
indirectly attached to the sternum via directly attaching to the 7th costal cartilage first. Ribs 1-7
are called true ribs, 8-10 are false ribs.
• Ribs 11 and 12 are floating ribs as they do not have any costal cartilage and do not attach onto the
sternum instead they end floating in the abdominal and thoracic muscle body.
• The first rib is atypical as it is very flat due to it being close to the brachial plexus and
subclavian vessels. Ribs 1,2,11,12 are all atypical.
• Rib 1: due to its flat, wide and short appearance. Also only has one facet.
• Rib 2 : roughened area on its upper surface, where serratus anterior attaches.
• Ribs 11& 12 have no neck, and only contain one facet, which is for articulation with the
corresponding vertebrae.
• The first rib also has a rough area to with the scalene muscle articulate with
,• The articulation of the ribs with vertebra is as follows. Every vertebra T1-T12 articulate with 4
head of ribs (2 on each side)
• For typical vertebra (2 demi facets) the head of a rib will articulate with the inferior facet of
one vertebra and the superior facet of the vertebra below it.
• The articular part of the rib tubercle will then articulate with the transverse costal facet of the
vertebra with the superior demi facet that it is bound to.
• For the atypical vertebra they only articulate with one rib as they only have one costal facet for
the rib to articulate with?
,• The following joints of the body thorax are in the table below
JOINT JOINT TYPE ARTICULATION
Intervertebral Secondary cartilageous, synovial Between vertebrae
joint
Costovertebral Primary cartilagenous? synovial Between the head of the rib and the
plane joint costal facets of the vertebra
Costotransvers Synovial joint Between the neck/tubercle of the rib
and the transverse facet of the
vertebrae
Sternocostal 1st rib and sternum Secondary Between the costal cartilage and the
cartilagenous strenum
2nd-7th are synovial plane
Sternocalvicular Saddle joint Between the sternum and the clavical
Costochondral Primary cartilaginous for 1st rib. Between the rib and the costal
Synovial plane for the rest cartilage
Intercondral 5th-9th synovial plane joint These are the joints between the
9th-10th is fibrous tissue cartilage so from the 5th-10th rib
Manubriosternal Secondary cartilaginous Between the manubrium and the
strenum
Xiphisternum Secondary cartilageous Between the xyphoid process and
the sternum
,• This is the Costocondral joint. See ribs 5 to 10:
THORACIC NEUROVASCULATURE
• The thoracic neurovasculature runs in the intercostal groove. The neurovsculature contain the
intercostal nerve, vein and artery. The order from superior to inferior is VAN.
• The intercostal veins and arteries have an anterior and posterior side. The posterior sides join up
to the SVC and the aorta and the then joins up to the thoracic artery on the posterior side.
• The intercostal nerve is a somatic nerve
• Anteriorly it is derived from the anterior cutaneous branch and then on lateral side there is the
lateral cutaneous branch
• The sympathetic trunk lies lateral to the vertebral column and is comprised of ganglia known
as paravertebral ganglia.
• The sympathetic trunk travels from T1-L2
,CLINICAL ASPECTS: SHINGLES
• Shingles are caused by the human herpes virus -3 HHV3
• Primary infection usually occurs in children producing chicken pox (varicella)
• However the virus lies dormant in the dorsal root ganglia (sensory neurones)
• It may then flare up again during immunosupressants in a single dermatome
• In 56% of cases this will be on the chest wall.
THORACIC AND RESPIRATORY MUSCLES
• Thoracic muscles are comprised of respiratory muscles and then
accessory respiratory muscles:
• Respiratory muscles include (in the following superficial order)
- External intercostals (Pockets)
- Internal intercostals (TITS)
- Innermost intercostal
- Diaphragm
• Accessory muscles include:
- Trapezius
- Latissimus dorsi
- Quadratus lumborum
- Pectoralis major and minor
- Scalenes
, -Sternocleidomastoid
-Erector spinae
-Serratus anterior and posterior
• During quite breathing the main muscle of respiration is the diaphragm then followed by the
intercostal muscle. It is only during forceful or exercise when the accessory muscles re
involves in respiration.
LUNG PLEURA
• The pleura is a serous membrne mesothelial membrane the layers of the pleura are as follows
from superficial to deep:
- Parietal pleura
- Visceral pleura
• The pleural cavity between the two layers hols pleural fluid which is used to lubricate during
lung movement. The Pleura extend much further down than the lungs do to accommodate for
expansion
• Remember the phrenic nerve has no branches and can be seen along side the heart. The
vagus nerves is very branched and sits behind/within the heart.
• The parietal pleura is a shiny layer and has costal, diaphragmatic and mediastinal parts which
is innervated by somatic phrenic and intercostal nerves
• The visceral pleura however is adhered to the surface of the lungs and is innervated by
autonomic nerves
• The apex of the lungs and pleura extends 2cm above the clavicle
• The edge of the plural sacs meet at the midline behind the sternal angle T4/T5
• On the left side the pleura curves out laterally at the 4th costal cartilage around the heart.
The margin of the right plural descends down to the 6th rib then passes laterally (due to
the apex of the hearth)
• Both pleural sacs extend down to the 8th rib in the midclavicular line and the 10th rib of
the mixaxillary line. The pleura end at the 12th rib.
• The lower margin of the lungs lies 2 ribs above the pleural limit: 6th rib in midclavicular
line, 8th rib in the midaxillary line, 10th at the angle of the ribs.
• The oblique fissure runs from T4 to the 6th rib in the midclavicular line
• The horizontal fissure runs from the 5th rib in midaxilary line to the 4th costal cartilage
at the sternum
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