Thorax I Flashcards
1
Q
How many pairs of ribs are there?
A
12 Pairs
2
Q
What is the function of the rib cage?
A
Protects internal organs (heart, lungs, blood vessels) Facilitates respiration (breathing)
3
Q
What bones make up the ribcage?
A
3 bones of anterior aspect:
Manubrium
Sternum
Xyphoid process
4
Q
What are the clavicle’s articulations?
A
Sternoclavicularjoint (top part of manubrium) Acromioclavicular joint (acromion posteriorly)
5
Q
Describe the types of ribs
A
True ribs - 1-7
False ribs - 8-10 (all connected to the same cartilage)
Floating ribs - 11&12 (don’t articulate w/ cartilage)
6
Q
Where are the kidneys in relation to the ribs?
A
Kidneys sit just under floating ribs posteriorly
7
Q
What do ribs articulate w/?
A
Articulate to transverses processes on vertebrae
8
Q
How many of each type of vertebrae are there?
A
Cervical - 7
Thoracic - 12
Lumbar - 5
Breakfast at 7, lunch at 12 and dinner at 7
9
Q
Describe the boundaries of the superior thoracic aperture
A
Ant border - manubrium
Post border - T1 vertebrae
Lateral border - 1st pair of ribs and cartilage
10
Q
Anatomically the superior thoracic aperture is?
Clinically the thoracic aperture is?
A
Thoracic inlet
Thoracic outlet
11
Q
Boundaries of inferior thoracic aperture?
AKA?
A
Ant border - Xiphi-sternal junction
Post border - 12th thoracic vertebrae
Lateral border - 12th ribs and costal margins
AKA = thoracic outlet
12
Q
Thoracic outlet syndrome
A
Group of disorders
Pain and paresthesia in neck, shoulder. arms and hands
Caused by compression brachial plexus and or subclavian vessels as they pass through the thoracic outlet (anatomical thoracic inlet)
13
Q
Ribs in younger people are…
A
Stronger and more flexible .˙. fractures in children uncommon
14
Q
What is special about the first rib?
If injured what may it damage?
A
Rarely fractured - short and broad because it’s in a protected position
Cannot be palpated
May injure brachial plexus + subclavian vessels
15
Q
How may rib fractures occur?
Where is it most likely to occur?
What can it cause?
A
May follow a direct blow
Following crush? injuries (indirectly)
At the angle -> point where direction of bone changes most sharply and hence at it’s weakest
Can cause flail chest - patient have difficulty breathing in and out
16
Q
What can fracture of lower ribs cause?
A
Can cause lacerated spleen, kidneys or liver
BUT they rarely fracture because have more flexibility than upper and middle ribs
17
Q
Describe the atypical ribs
A
Ribs 1, 11, 12
Have no neck, no major tubercle (as don’t articulate w/ anything) and no costal groove (except 12)
18
Q
Describe the structures that go over the first rib
A
Anteriorly - vein
Posteriorly - artery (subclavian)
Muscle - anterior scalene (come from transverse processes of c spine - 3 heads? ant, middle and post)
Help divide brachial plexus (nerve supply) to upper limb and help with divisions between arterial and venous systems.
19
Q
Cervical rib
A
Extra rib
Elongation of transverse process on cervical vertebrae
can impinge on brachial plexus and structures surrounding
Patients present w/ tingling sensation/ parasthesia in fingertips (1%)
20
Q
Fractured rib
A
Can end up w/ flail chest if fractured along w/ pneumothorax
(entry of air in plural space)
21
Q
Ossified Xiphoid process
A
People early 40s detect xiphoid process partly ossified and consult GP about hard lump in pits of stomach (epigastric fossae/ upper epigastric region)
Patient may fear have tumour/stomach cancer
22
Q
Where is VAN on ribs?
A
In costal groove (protected by), along lower edge of ribs
Vein is most superior
Must be mindful when insert chest drain above rib (4th/5th intercostal space)
23
Q
Thoracic Anaesthesia
A
Local anaesthesia in intercostal space given by injecting local anaesthetic agent around intercostal nerves bet. paravertebral line
(corresponds to tips of the transverse process)
24
Q
Where does the nerve supply originate?
A
Within the spinal cord
roots come out and connect w/ rami and nerves coming alongside vertebral aspect, to the costal groove to supply ant. and post portion
25
Where do nerves go?
They pierce through fascia of muscles - posterior and anterior aspects fuse
Help supply all dermatome regions and skin distribution
26
What is the neurovascular bundle protected by?
```
Muscles:
External
Internal
Innermost
VAN then in costal groove in rib
```
27
What is a dermatome?
Area of skin supplied by a single spinal nerve root
28
List some areas and their dermatome levels
Nipple line - T4
| Umbilical area - T10
29
How can shingles present with respect to dermatomes?
Shingles (Herpes zoster) - infiltrates along the dermatome line = v. painful
Usually only along 1 dermatome line
12 thoracic dermatomes
30
Why does complete loss of sensation usually not occur across dermatomes?
As any area of skin usually receives innervation from 2 adjacent nerves - considerable overlapping of contiguous dermatomes occurs
.˙. complete loss of sensation doesn't occur unless >2 intercostal nerves are anaesthetised
31
Which nerves supply the thoracic wall?
Medial and lateral pectoral nerves - branches of brachial plexus (C5-T1)
Help supply the muscles - pec. major
Lateral spreads out more
Long thoracic nerve - muscle = serratus anterior
Damage of nerve during chest surgery (breast) can cause paralysis of muscle + loss of shoulder movement + winged scapula
32
Other muscles in area
Subcostalis - below clavicle
Tenderline sheaths - underneath pec. major
Help protect vessels
33
What is the mid-axillary line and what is it significant for?
Line passes vertically down from apex of axilla
Important for drainage points from breast?
Safe point for insertion of drainage/chest drains
34
Important vertebral levels
T4/5 - Sternal angle
T3 - Manubriosternal joint
T9 - Xiphisternal jn - important for checking if ant and post are in line w/ each other.
35
Describe the orientation external intercostal muscles
Orientation = down and forward
| Anteriorly become continuous with and is replaced by anterior intercostal membrane
36
What is the origin and insertion of the external intercostal muscles?
```
Origin = inf. border of rib above
Insertion = sup. border of rib below
```
37
What are the actions of the external intercostal muscles?
Elevates during forced inspiration
| Supports intercostal spaces and thoracic cage
38
What is the innervation and blood supply of the external intercostal muscles?
Nerves = Intercostal nerves
| Blood supply = Anterior and posterior aspect of the intercostal arteries
39
Describe the orientation of the internal intercostal muscles
Down and backward
| Continuous with posterior intercostal membrane
40
What is the origin and insertion of the internal intercostal muscles?
```
Origin = costal groove of the rib above
Insertion = superior border of rib below
```
41
What is the action of the internal intercostal muscles?
Help relax the thoracic cage
| Depress ribs during forced expiration
42
What is the innervation and blood supply of the internal intercostal muscles?
Nerves = intercostal nerves
Blood supply = ant. and post. intercostal arteries
Internal thoracic and musculophrenic arteries
Costocervical trunk
43
Describe the innermost muscles
```
Origin = costal groove
Insertion = supero-posterior border of the rib below
Action = supports both external and internal intercostal muscles
Innervation = intercostal nerves, blood supply = same as internal
```
44
How are the innermost muscles separated from the internal intercostals?
By a neurovascular bundle containing intercostal nerves and blood vessels
45
What are the anterior and posterior continuations of the innermost intercostal muscles?
Anteriorly continued by transversus thoracis (sternocostalis) -> runs from posterior lower sternum to inner costal cartilage (rib 2-6)
Posteriorly - subcostalis muscles near angle of rib
46
What side of the body is the arterial and venous system?
Left hand side = arterial, runs down
| Right hand side = venous, runs up
47
Which arteries make up the blood supply to the thoracic cage?
Internal thoracic artery
Have branches from subclavian artery
Descending/thoracic aorta (posteriorly) - terminates by branching
gives a post and ant distribution
48
Where does the supreme intercostal artery come off?
The costocervical trunk of the subclavian artery - gives rise to 1st and 2nd posterior intercostal arteries - supply corresponding intercostal space
49
How many posterior intercostal arteries are there in total?
11
50
Where do the posterior intercostals branch from?
Thoracic aorta
intercostal spaces 3 - 11
Are small collateral branches along the superior border of the rib (costal groove)
51
Where do the posterior intercostal arteries run?
Between innermost and internal intercostal muscles
| terminal branches anastomose with anterior intercostals
52
How many anterior intercostal arteries are there?
9
53
Where do the anterior intercostal arteries originate?
| What do they supply?
From the subclavian, branches of internal thoracic artery
Supply upper 6 intercostal spaces
Branch at the 6th space into superior epigastric and musculophrenic (supplies the diaphragm)
ICS 7-9 supplied by branches from musculophrenic (lower 9)
54
Describe the pectoralis major muscle
Has clavicular head - attaches to medial half of clavicle
(top area)
Sternocostal head - anterior surface of the sternum, costal cartilages 1-6
55
Where does the pec. major insert?
Crest of the greater tubercle of the humerus
56
What is the action of pec. major?
Arm adduction, internal rotation, flexion (clavicular head), arm extension (sternocostal head)
Accessory muscle of inspiration when upper limb fixed
57
What is the innervation and blood supply of pec. major?
Innervation = Medial and lateral pectoral nerves (C5-T1)
ie. entirety of brachial plexus
Blood supply = thoracoacromial artery and internal thoracic artery
58
Describe pec. minor - origin, insertion, innervation, blood supply, action
Origin - anterior surface, costal cartilage of ribs 3-5
Inserts - coracoid process
Innervation - medial and lateral pectoral nerves (C5-T1)
Blood supply - thoracoacromial, superior and lateral thoracic artery (runs along lateral border of muscle)
Action - helps stabilise scapulothoracic joint, for stability in upper arm
59
What else does pec. minor do?
It divides axillary artery into 3 parts - 1st, 2nd and 3rd branch
60
Transversus thoracis - what is it and where does it originate?
Thin muscle in butterfly effect
Combo from sternal ends of costal cartilage of ribs 4-7
Fibres diverge superolaterally
61
Describe serratus anterior
Innervation
Blood supply
Action
Dagger like projections coming off the ribcage
Innervation - Supplied by long thoracic nerve (C5-C7)
(SALT)
Blood supply - thoracodorsal and lateral thoracic arteries
Action - help rotate the scapula anterolaterally
Ends up merging with external oblique (lower down abdominal muscles)
62
Describe the subclavius and the clavipectoral fascia
| What is the function of the two?
Subclavius = Small triangular muscle - located between clavicle and the 1st rib
Clavipectoral fascia = located under cover of clavicular head of pectoralis major (between pec. minor and subclavius)
Both used to protect underlying brachial plexus and subclavian vessels from damage by a broken clavicle
63
Platysma
Muscle that controls facial expressions
| Bottom lip and lower corners of mouth
64
Describe the diaphragm
| Action
Tendoni sheath = muscular with a central tendon
Action = breathing - inspiration, expiration, both quiet and explosive
during exercise it's going to expand and cause ribcage to contract more?
65
How is the innervation of the diaphragm acquired?
Originates in the cervical area and moves down
As it descends (differential growth) past C3,C4,C5, tendon picks up parts of myotomes and innervation from these levels
Supplied by the phrenic nerve
66
What are the accessory muscles of the diaphragm?
Scalene, SCM (from back of ear to sternum)
| chronic smokers have gasp for breath, help facilitate expansion of ribs and open lungs
67
How does the diaphragm carry out its fn?
Increases capacity in thorax
breathing in = contracts and goes flat (increase inter-thoracic size)
breathing out = relaxes and resumes dome shape (internal intercostal muscles help)
68
Describe pump and bucket handle movements
Pump handle - when breathing in causes cage to expand outwards
Bucket handle - causes angle of rib to move up and down, raises and expands cage to allow lungs to open up
69
Hiatus Hernia
Portion of stomach penetrates through weakness or tear in oesophageal hiatus in diaphragm
Congenital diaphragmatic hernia = defect in diaphragm
get a hole .˙. abdominal organs (eg. intestine, stomach and liver) move through and upwards into baby's chest
70
Say what you know about paralysis of the diaphragm
Hemidiaphragm - ˙.˙ injury to motor supply from phrenic nerve, doesn't affect the other half as each dome has separate nerve supply
On X-ray paralysed dome appears higher
Instead of descending on inspiration, paralysed dome pushed superiorly by abdominal viscera that is being compressed by the active diaphragm
Falls during expiration in response to positive pressure in the lungs.
71
Internal thoracic arteries and veins accompany arteries as...
...Venae comitantes
It refers to a vein that is usually paired, with both veins lying on the sides of an artery. They are found in close proximity to arteries so that the pulsations of the artery aid venous return.
72
Where does the thoraco-acromial artery come off?
Comes off the second part of the axillary artery
Pectoralis major and minor muscles, the anterior part of the deltoid muscle, and dermal sensation overlying the clavipectoral fascia
73
Where does the lateral thoracic artery come off?
Second part of the axillary artery
| Supplies the serratus anterior muscle
74
What is the positioning of the breast?
Overlies 2nd - 6th rib
2/3 rests on pec.major, 1/3 rests on serratus anterior
Also on ribs, pec.minor, chest wall
Extends from lateral margin sternum to midaxillary line
Lies in superficial fascia front chest
Lower medial edge overlaps upper part rectus sheath - because rectus sheath attaches lower potion of costal angle where everything fuses together
75
What type of gland is the breast?
Mammary gland: simple and complex mammary gland
76
Describe the simple and complex mammary gland
```
Simple = consists all milk-secreting tissue leading to single lactiferous duct
Complex = consists all simple mammary glands, serving one nipple
```
77
What is the shape of the breast?
Conical shape
78
What is the structure of the breast?
Has a base, apex, tail (axillary tail)
| Has no capsule
79
What is the important of the tail of the breast?
Where feel during examination for lymph nodes as main site for lymph tissue drainage/drainage of breast tissue
80
Do males have breasts?
Have rudimentary glands and nipples
Mammary glands functionless and consist of few small ducts
Usually little fat is present and glandular system doesn't develop
81
What are the lobules of the breast?
Main area where things produced physiologically
Each lobule breast drained by lactiferous
duct usually opens independently on nipple
Collection acini ducts from all lobules merge
82
What are the lactiferous ducts?
Gives rise to buds that form 15-20 lobules glandular tissue – which constitute the gland
Ducts converge toward nipple like spoke of bicycle wheel
83
What is the areola?
Dark pink/brownish circular area of skin surrounds nipple
Contains numerous sebaceous glands that enlarge during pregnancy and secrete an oily substance – provides lubricant for areola and nipple
Has hair follicles
Devoid of fat
84
What are the features of the nipple?
Conical/cylindrical prominences in centre of areolae
Emerges from anterior aspect of breast
Have no fat, hair or sweat glands
Contains smooth muscle fibres
Lies opposite 4th intercostal space
Carries narrow pores of lactiferous ducts
85
What are the fibrous septae?
Aka. suspensory ligaments
Keeps breast tissue attached to wall thorax
Made of connective tissue
Mammary gland firmly attached to dermis overlying skin by suspensory ligaments (of Cooper) of breast
Ligaments extend from retromammary fascia to skin and provide support
86
What occurs to the Cooper's ligaments?
Overtime degrade because not as elastic and firm .˙. breasts can droop as age
87
What is interspersed between lobes to keep the breast structure together?
Fatty tissue
88
What is the retromammary layer?
Thin, fatty tissue behind the breast
89
Describe the course of products made in the lobules
Made in lobule (in the acini), drain into duct from where it emerges in ampulla, goes to the nipple
From here it's expressed as milk or whatever pathological process that's occurring
90
What is the axillary tail and the clinical significance?
Small part of mammary gland extends along edge of pec.major toward axilla
If it enlarges during menstrual cycle, may be confused with enlarged lymph node
91
Where does the blood supply come from?
Has a high vascular supply from walls of ribs, pec. major and minor and suspensory ligaments
92
List the blood supply of the breast
1. thoracoacromial artery - from sup portion up to areolar portion
2. lateral mammary artery (branch of lateral thoracic)
3. medial mammary artery (branch of internal thoracic)
4. mammary branches of intercostal arteries
Thoracoacromial and lateral thoracic are branches of axillary artery
93
Describe the venous drainage of the breast
Follows blood supply
Circular venous plexus found at base nipple
Drain into subclavian and along middle border to go into SVC and axillary vein (+internal thoracic veins?)
94
How are the lymph vessels arranged in the breast?
Into 5 groups lay in axillary fat
95
What are the 5 groups of lymph vessels in the breast?
1. Pectoral (ant) - Lies on pec major along lateral thoracic vessels
2. Subscapular (post) - lies on posterior wall axilla on lower border subscapularis, along subscapular vessels
3. Brachial - lateral wall of axilla along axillary vessels
4. Central - lies in centre (base of axilla)
v. close to axillary and subclavian vein
drains into subclavian tail and goes medially + superiorly
5. Apical - lies at apex axilla - try to feel for in breast exam
60-70% drain in axillary tail/ lymph nodes
96
What is the significance of the central group?
Dangerous because everything converges there
Can be used as a sign to see if cancer spread elsewhere
v. close to axillary and subclavian vein
Must feel for it when doing axillary sweep
97
What is the subclavian lymph trunk?
Formed by union of efferent lymph vessels of apical group
| Usually opens in subclavian vein, on left side opens into thoracic duct
98
How can you remember the lymph nodes of the breast?
```
APICAL
A = anterior
P = posterior
I = infraclavicular
C = central
A = apical
L - lateral
```
99
Where do other lymph nodes drain?
Drain into parasternal lymph nodes/opposite breast - mostly from medial breast
100
Where can shingles present?
Can present directly underneath the breast
101
What is the innervation of the breast?
Ant and lateral cutaneous branches 4th - 6th intercostal nerves
sensory - skin, sympathetic - blood vessels/smooth muscle in skin over nipple
102
What is the significance of breast cancer?
1 in 8 women
103
In the case of breast cancer, how may the breasts change?
Interference of lymph drainage of chest by cancer may cause deviation of nipple and produce a leather like appearance of skin
104
Where can breast cancer metastasise to?
Lymph nodes, bone, pleura lungs, liver and skin
| This may occur in males also
105
What tends to happen in male breast cancer?
Tends to infiltrate into deep pectoral fascia, pec major and apical group of axillary lymph nodes
106
What is important if a mastectomy is to be done?
The pattern of blood supply must be understood to plan an incision for conservative breast surgery
Mastectomy need cauterisation/ligation w/ diatherapy major blood vessels to decrease blood loss
