Thorax 1 Flashcards
3 structural features of the clavicle
and
2 bones the clavicle articulates with
Long
Slender
S-shaped bone (concavity and convexity)
Articulates medially with the manubrium and laterally with the acromion of the scapula
True ribs, false ribs and floating ribs
- True ribs: 1 - 7
- False ribs: 8 – 10
- Floating ribs: 11, 12
- All ribs articulate posteriorly with the
thoracic vertebrae
3 organs positioned under the diaphragm
Liver on the right and stomach and spleen on the left under the diaphragm
what is the pectoral girdle
Pectoral girdle: the clavicle and scapula work together to keep the upper limb out of the way of the trunk
Palpation of ribs
Palpate MS jointIf the fingers are moved laterally, the attachment point for the second pair of ribs should be felt
We can then count down ribs and the spaces between them; this is important for different clinical procedures such as auscultations for heart/chest sounds to inserting a chest drain
Boundaries of the superior thoracic aperture
anterior - jugular notch
posterior - T1
lateral - medial border of rib 1 and CC
6 important structures passing out of the superior thoracic aperture
Subclavian artery
Subclavian vein
Common carotid artery
Internal jugular vein
Trachea
Esophagus
Boundaries of the ITA
closed off by diaphragm
anterior - xiphisternal joint
posterior - T12
lateral - costal margin curve 7-10
What is thoracic outlet syndrome
there is a pronounced bend in brachial plexus/ and or subclavian vessels going to and from the upper limb; potential for these vessels and nerves to become compressed
nerves = c5-t1
label everything you can on the thoracic vertebrae
where does head of rib articulate with vertebral body
on vertebral body, there is 2 demi facets.
superior demi facet = articulates with inferior head border of rib above
inferior demi facet = articulates with superior border on the head of the rib below (corresponding)
what is Costochondral junction
Junction between the costal cartilage and the bony part of the rib
label and define costovertebral joint & costotransverse joint
cv - head of rib articulates with demifacet on vertebral body
ct - The point of articulation between the tubercle of a rib and the transverse process of a vertebra
costosternal joint and disease associated with it
junction between CC and sternum
disease = costochondritis, inflammation between the sternum and CC, causing pain
what are the 5 atypical ribs
1, 2, 10, 11 + 12
label and define costovertebral joint & costotransverse joint
cv - head of rib articulates with demifacet on vertebral body
ct - The point of articulation between the tubercle of a rib and the transverse process of a vertebra
which muscle attaches to scalene tubercle on superior surface of rib 1
scalenus anterior
VMA (vein, muscle, artery)
which thoracic vertebrae does rib 4 articulate with?
T3 and T4 (itself and one above)
features of rib 11 and 12
No tubercle as no articulation with transverse process of thoracic vertebrae
No neck
clinical relevance of first rib
Close relationship to lower nerves of the brachial plexus and main vessels of arm
Nerves of the brachial plexus C5,6,7 and T1 (supply upper limb); the way they travel through the aperture in relation to the first rib means they are vulnerable to compression
The nerves can become compressed between the clavicle and the first rib; causes pain in the forearm, hand and wrist
Can also compromise circulation in the upper limb because of the blood vessels
where do rib fractures commonly occur
Occur at the weakest point; angle
This is where the fibres are the most curved, so they are lest stable
4-10 most likely to be fractured
what is this?
cervical rib
A rib arising from anterior tubercle of TP of
C7
* Can cause pressure on lower brachial plexus
or subclavian artery
Not common (0.5%) - may have a free anterior end or connected to the first rib via fibrous band
Additional issue in terms of compression of nerves and vessels - thoracic outlet syndrome
Deltoid function and attachments
Deltoid fibres attach to the clavicle anteriorly and to the scapula posteriorly
Split into three muscle components
Abductor: moves the arm from the midline of the body
Clavicular fibres assist in arm flexion
Posterior fibres assist in arm extension
What is the deltopectoral groove and what runs in it?
Deltoid muscle separated from the muscle of the chest wall by the deltopectoral groove
cephalic vein runs through it
coracoid process is most easily palpatable
pec. major origins and insertion
O- Medial aspect of the clavicle
Lateral border of the manubrium and body of the sternum and to the costal cartilages 1-7
Rectus sheath (anterior layer)
I- Narrows and converges to insert into the bicipital groove of the humerus
function of pec. major
Adducts arm - towards trunk
Medial rotation of humerus
Extends flexed arm
Accessory muscle of inspiration when upper limb is fixed
Pec. minor origin and insertion
O - Attaches to ribs 3, 4 and 5
I - Inserts onto the coracoid process (The coracoid process is a hook-shaped bone structure that projects anterolaterally from the superior aspect of the scapular neck) the scapula (beak-like bony prominence)
Lateral thoracic vessels course along lateral border
Pec. minor function
Depresses the scapula (pull it down)
Shoulder abduction (part of the action of depressing the scapula)
serratus anterior origin and insertion
O- Serrated in appearance
Passes around the posterior aspect of the chest
I- Inserts posteriorly onto the medial border of the scapula
serratus anterior function and innervation
Draws the scapula round and important in movement of the upper limb (think of boxing motion; rotation of the scapula)
punching, protraction and rotation of scapula
LONG THORACIC
innermost intercostal muscle origin and insertion
Incomplete muscle layer - doesn’t run between every set of ribs
*Sometimes can span 2 or more intercostal spaces at a time
*Subdivided into different portions which are separate to one another:
- subcostalis (posterior)
- transverse thoracic (anterior)
summarise the intercostal muscles fibre direction and when they become membrane
external: inferomedial - costochondral junction to tubercle of rib
internal: superomedial - sternum to angle of rib
innermost: subcostalis (p) and transverse thoracis (a)
How is intercostal nerve related to the blood vessels?
- How is the neurovascular bundle protected?
- Between which muscles does the neurovascular bundle pass?
(VAN – vein, artery, nerve)
(by costal groove)
(internal and innermost)
intercostal muscle fibre direction
label everything u can
label everything you can
label
3 attachments of the diaphragm
*Has an attachment posteriorly to the lower 6 ribs and their costal cartilages
*Vertebral attachment via arcuate ligaments - right crus and left crus (right is longer)
*Attachment anteriorly to the posterior element of the xiphoid process
label everything
In which 3 locations do the thoracic ventral rami pass?
- 1-6 intercostal spaces
- 7-9 pass deep to CCs to enter anterior abdominal wall
- 10-11 pass directly to anterior abdominal wall
Name of T12 nerve
Subcostal nerve
3 features of T1 nerve
Joined to brachial plexus
No lateral cutaneous branch
Also no anterior cutaneous branch
label the branches of the intercostal nerve
Chest drains – if inflammatory fluid (pleural effusion) or blood (haemothorax) accumulates
within the chest a chest drain is inserted above a rib to avoid the neurovascular bundle.
Into which intercostal space are chest drains generally inserted?
5th,mid-axillary line
what is a dermatome?
How many dermatomes are there in the thorax?
A dermatome is an area of skin that is supplied by a single spinal root.
12
What are shingles (herpes zoster)?
Infection of a spinal nerve, presents in dermatomal
fashion.
Long thoracic nerve - What muscle does this nerve supply? and clinical relevance
Serratus anterior
When the serratus anterior muscle is paralysed due to damage to the long thoracic nerve the median bundle of the scapula moves laterally
Serratus anterior muscle supplied by long thoracic nerve, and can be damaged during surgery
= winged scapula
Medial and Lateral pectoral - What muscles do these nerves supply?
Pec. Major and minor
The intercostal spaces are supplied by intercostal arteries. Identify the intercostal arteries:
There are 11 posterior intercostal arteries.
Where do the lower 9 arise from? The upper 2?
There are 9 anterior intercostal arteries.
Where do the upper 6 arise from? The lower 3?
Are you able to identify and label these on the image below?
(aorta)
(supreme intercostal artery – branch
of costocervical trunk)
(internal thoracic)
(musculophrenic)
What is a hiatus hernia?
How does this differ from congenital diaphragmatic hernia?
A hiatal hernia is a protrusion of the abdominal contents into the
thorax through an enlarged esophageal hiatus caused by a weakness or opening in the
diaphragm. Usually the upper part of the stomach but can also be part of the small intestine.
Failure of closure of the diaphragm during fetal development, meaning abdominal contents mush into the thorax. This reduces space for the developing lungs. The lungs will be smaller than expected (pulmonary hypoplasia), and will have less developed
blood vessels. This causes high blood pressure in the lungs (pulmonary hypertension)
phrenic nerve
travels anteriorly to lung root - supplies diaphragm
from C3,4,5
What is the function of platysma
The actions of the platysma muscle include pulling down
the mandible, which opens the mouth, and pulling the corners of the lips out to the side and down, which forms a frown. Additionally, the platysma muscle can form wrinkles in the neck as a person ages and their skin becomes less elastic and starts to sag
anterior intercostal veins drain into?
posterior intercostal veins drain into?
Anterior intercostal veins drain into the internal thoracic and musculophrenic veins
* Eventually into the subclavian and then the SVC
Posterior intercostal veins drain into the azygous and hemi-azygous systems
- Main azygous vein on right, and superior (accessory - superior) and inferior hemiazygous (proper - inferior) on left
- Important anastomotic pathway for venous return if IVC becomes blocked
- Azygous formed by union of right ascending lumbar and right subcostal veins
- Inferior hemiazygous formed by union of left ascending lumbar and left subcostal veins
label
Right venous posterior intercostal drainage
Superior receives 2+3 and goes into azygous
Supreme intercostal vein goes straight to BCV + receives 1
Left venous posterior drainage
Left superior goes straight to BCV
Supreme goes straight to BCV
what is the Retromammary space
Loose areola tissue that separates the pec. major and breast
label what u can
what are Lactiferous ducts
lactiferous ducts give rise to buds that form 15-20 lobules of glandular tissue, which constitute the gland. The ducts converge toward the nipple like the spokes of a bicycle wheel.
Arterial supply to the breast
Venous supply of the breast
Circular venous plexus are found at the base of nipple.
Veins of this plexus drain into thoracoacromial vein, lateral thoracic, & internal thoracic veins.
Arrangement of lymph nodes in the breast - label and whats their function?
Arranged into 5 groups which lie in the axillary fat:
1. Pectoral (Anterior) group: which lies on Pectoralis Minor along lateral thoracic vessels
2. Subscapular (Posterior) group: which lies on posterior wall of axilla on lower border of subscapularis along subscapular vessels
3. Brachial (Lateral) group: lies on lateral wall of axilla along the axillary vessels
4. Central group: lies in at the Center (base of axilla)
5. Apical group: lies at apex of axilla
Paralysis of Diaphragm
Paralysis of half of the diaphragm (hemi-diaphragm) due to an injury to its motor supply from the phrenic nerve does not affect the other half because each dome has a separate nerve supply. On X-rays the paralyzed dome appears higher)
- Instead of descending on inspiration, the paralyzed dome is pushed superiorly by the abdominal viscera that are being compressed by the active side. The diaphragm falls during expiration in response to the positive pressure in the lung
