Anatomy - Pectoral Region and Thoracic Cage Flashcards
1
Q
To what vessel is the cannula attached on the cadaver to perfuse the cadaver?
A
Carotid artery
2
Q
What does superficial fascia include?
A
- Fat 2. Fibrous connective tissue3. Cutaneous vessels and nerves All coming from the thoracic wall, the axilla, and the neck 4. Breasts in females
3
Q
What verifies that the skin reflection is at the appropriate plane to separate it from the superficial fascia?
A
Dimpling on the undersurface of the skin
4
Q
Why are the areola and nipple hard to identify on a cadaver?
A
Because there is loss of pigmentation
5
Q
Which muscles do breasts overlie?
A
Pectoralis major muscles
6
Q
Between what ribs do breasts lie?
A
2 and 6 (normally)
7
Q
Why do boobs sag?
A
Loss of tensile strength of ligaments of Cooper
8
Q
How many lactiferous sinuses?
A
15-20
9
Q
What are the pectoralis major and minor and the subclavius muscles enveloped by? What does it attach to?
A
Clavipectoral fascia (type of deep fascia)Attaches to clavicle above and floor of axilla below
10
Q
What is the pectoral region?
A
Region external to the anterior thoracic wall that anchors upper limbs to trunk
11
Q
What kind of modified glands are the breasts?
A
Modified sweat glands
12
Q
What are the suspensory ligaments of Cooper continuous with?
A
Dermis of skin
13
Q
What is the predominant component of breasts in nonlactating women?
A
Fat
14
Q
What separates the breast from the clavipectoral fascia?
A
Retromammary space = layer of loose connective tissue
15
Q
Transverse breast borders?
A
Midaxillary line and sternum
16
Q
Can breast cancer occur in men?
A
Yes
17
Q
How far can the axillary process of the breast extend? How?
A
As far as the apex of the axilla by perforating deep fascia
18
Q
Innervation of the breast?
A
Anterior and lateral cutaneous branches of the 2nd to 6th intercostal nerves
19
Q
Innervation of the nipple?
A
Lateral cutaneous branch of 4th intercostal nerve
20
Q
Largest muscle of pectoral region?
A
Pectoralis major
21
Q
Pectoralis major:1. Origin2. Insertion3. Innervation4. Function
A
- Medial half of clavicle, anterior surface of sternum, first 7 costal cartilages, aponeuris of external oblique2. Lateral lip of intertubercular sulcus of humerus3. Medial and lateral pectoral nerves4. Adduction, medial rotation, and flexion of the humerus at the shoulder joint
22
Q
What is the deltopectoral triangle?
A
Area between the 2 muscles NOT covered by muscle
23
Q
What 2 vessels are found in the deltopectoral triangle?
A
- Cephalic vein2. Thoracoacromial artery
24
Q
How to tell difference between arteries and nerves?
A
Nerves are FLAT
25
Pectoralis minor:1. Origin2. Insertion3. Innervation4. Function
1. Anterior surfaces of the 3rd, 4th, and 5th ribs and deep fascia overlying the related intercostal spaces2. Coracoid process of scapula3. Medial pectoral nerve4. Depresses tip of shoulder and protracts the scapula
26
Subclavius: 1. Origin2. Insertion3. Innervation4. Function
1. Rib 1 at junction between rib and costal cartilage2. Groove on inferior surface of middle 3rd of clavicle3. Nerve to subclavius4. Pulls clavicle medially to stabilize sternoclavicular joint, and depresses the tip of the shoulder
27
Serratus anterior: 1. Origin2. Insertion3. Innervation4. Function
1. Lateral surfaces of upper 8-9 ribs and deep fascia of related intercostal spaces2. Costal surface of medial border of scapula 3. Long thoracic nerve (on external surface)4. Protraction and rotation of the scapula around the rib cage, keeps medial border and inferior angle of scapula opposed to thoracic wall
28
What is the boxers' muscle?
Serratus anterior
29
What would damage to the long thoracic nerve due to breast cancer surgery cause?
1. "Winging" of the scapula when pushing forward with the arm because the medial border and inferior angle of the scapula will elevate away from the thoracic wall2. Normal elevation of the arm is no longer possible
30
Where do nerves, lymphatics, and vessels pass from the axilla to the pectoral region?
They pass through the clavipectoral fascia between the subclavius and the pectoralis minor OR under the inferior margins of the pectoralis major and minor
31
Where is the serratus anterior muscle located in relation to the pectoralis minor?
Deep to it
32
External intercostal:1. Superior attachment 2. Inferior attachment 3. Innervation4. Function
1. Inferior margin of above rib2. Superior margin of below rib3. Intercostal nerves 4. Inspiration to move rib superiorly and supports intercostal space
33
Internal intercostal: 1. Superior attachment 2. Inferior attachment 3. Innervation4. Function
1. Lateral edge of costal groove of above rib2. Superior margin of below rib deep to the attachment of the related external intercostal3. Intercostal nerves4. Expiration to move ribs inferiorly and supports intercostal space
34
Innermost intercostal: 1. Superior attachment 2. Inferior attachment 3. Innervation4. Function
1. Medial edge of costal groove of above rib2. Internal aspect of superior margin of below rib3. Intercostal nerves4. Probably elevate the ribs
35
What are the 4 types of intrinsic thoracic muscles? List from superficial to deep
1. External intercostals2. Internal intercostals3. Innermost intercostals4. Transversus thoracis muscles (same plane as innermost intercostals)
36
Describe the orientation of external intercostal muscles.
From superior lateral to inferior medial (until reaching the external intercostal membrane) in an oblique manner
37
Function of external intercostal muscles? How?
Elevate ribs during inhalationFirst rib is fixed by scalene muscles that anchor it to the bones of the neck
38
How many intercostal muscles?
11 of each 3 types
39
Describe the orientation of internal intercostal muscles.
Perpendicular to the external intercostals (until reaching the internal intercostal membrane)
40
Function of internal intercostal muscles? How?
Depress ribs during forceful expiration 12th rib is fixed by the quadratus lumborum to the vertebrae
41
Are intercostal muscles continuous around the chest?
NOPE, membranous layers help complete the spaces left unfilled by the muscles
42
Where do the nerves and vessels (artery + vein) of the intrinsic thoracic muscles travel? How are they arranged? What is the clinical significance of this?
Between the internal and innermost intercostal muscles underneath each ribSuperior to inferior: V, A, N During a pleural tap, the needle is inserted on the upper border of the rib so as to minimize potential damage to nerves
43
Function of innermost intercostal muscles?
Probably elevate the ribs
44
Describe the orientation of innermost intercostal muscles.
Same as internal intercostal muscles
45
Which of the nerves and vessels (artery + vein) of the intrinsic thoracic muscles are most likely to be injured during an intercostal injury? Why?
Nerve because least protected by rib costal groove (most inferior)
46
How to tell the difference between rib bone and rib cartilage?
Difference in color between the two because there is no blood flow to cartilage
47
Are there external intercostals between costal cartilages?
Nope, the external intercostal membrane is there
48
What is the most anterior component of the superior mediastinum lying immediately posterior to the manubrium of the sternum?
Thymus
49
Describe the shape of the thymus.
Asymmetrical bilobed structure
50
Upper and lower borders of thymus?
Upper: can extend up in the neck to the thyroid glandLower: anterior mediastinum over pericardial sac
51
Size of thymus?
Large in childAtrophies after puberty Considerable size variation in the adult Barely identifiable in elderly, consisting mainly of fat
52
Blood supply to thymus?
Small branches from right and left internal thoracic arteries
53
Venous drainage of thymus?
Into left brachiocephalic vein and internal thoracic veins
54
Why do we sometimes find ectopic parathyroid glands on the thymus?
Because they both develop from the third pharyngeal pouch so the thymus is sometimes the site for ectopic parathyroid hormone production
55
Lymphatic drainage of thymus?
1. Parasternal nodes2. Tracheobronchial nodes3. Nodes in root of neck
56
Other name for internal thoracic arteries?
Mammary arteries
57
From what arteries do the internal thoracic arteries branch?
Right and left subclavian arteries
58
Blood supply of thoracic wall?
Anterior and posterior intercostal arteries
59
From what arteries do the anterior and posterior intercostal arteries branch?
1. Aorta2. Internal thoracic arteries 3. Subclavian arteries
60
From what arteries do the posterior intercostal arteries branch?
1. Upper 2: supreme intercostal artery branching from the costocervical trunk of the subclavian artery2. Remaining 9: posterior surface of thoracic aorta
61
On which side of the vertebral column is the aorta?
Left side
62
Which vessels are longer: right of left posterior intercostal muscles for intercostal spaces 3-11? Why?
Right ones because they need to cross the midline as the aorta is on the left side of the vertebral column
63
Which arteries of the thoracic wall supply more superficial regions?
1. Anterior and posterior intercostal arteries2. Internal thoracic arteries
64
From what arteries do the anterior intercostal arteries branch?
1. Upper 6: directly or indirectly from internal thoracic arteries 2. Lower 5: from musculophrenic artery
65
Describe the position of the internal thoracic arteries.
1. From subclavian arteries they pass anteriorly over the cervical dome of the pleura2. Descend vertically through thoracic inlet and along deep aspect of anterior thoracic wall3. They lie posterior to the costal cartilages of the first 6 ribs and 1 cm from sternum
66
Describe the terminal branching of the internal thoracic arteries.
At about the 6th intercostal spaces, they branch into: 1. Superior epigastric artery continuing inferiorly into anterior abdominal wall2. Musculophrenic artery passing along the costal margin through the diaphragm and ending near the last intercostal space
67
Which are larger: anterior or posterior intercostal arteries?
Posterior intercostal arteries
68
Describe the venous drainage of the intercostal veins.
1. Centrally: into the azygos system or the internal thoracic vein to the brachiocephalic veins2. Left superiorly/posteriorly: left superior intercostal vein to left brachiocephalic vein3. Right superiorly/posteriorly: right superior intercostal vein to azygos vein
69
Function of transversus thoracis muscles?
Depress the ribs in midline + help attach vessels/veins to sternum and to the thoracic wall
70
Transversus thoracis:1. Superior attachment 2. Inferior attachment 3. Innervation4. Function
1. Inferior margins and internal surfaces of costal cartilages of 2nd to 6th ribs2. Inferior aspect of deep surface of body of sternum, xiphoid process, and costal cartilages or ribs 4-7 3. Intercostal nerves4. Depresses costal cartilages
71
Which nerve innervates both the pectoralis major and minor?
Medial pectoral nerve
72
Is the superior border of the lung at rib 1?
NOPE, actually goes into the neck
73
In which ICS is the nipple found in men?
5th
74
What is the skin fold from the axilla to below the nipple called?
Anterior axillary fold
75
What ARE intercostal nerves?
Ventral rami of the thoracic spinal nerves
76
3 extrinsic pectoral muscles?
1. Pectoralis major2. Pectoralis minor3. Serratus anterior
77
What is an alternate function of the pectoralis minor muscle? How does it do this? When is this function particularly important?
It's an accessory respiratory muscle that assists in elevating the ribs during forced inspiration, especially in patients with dypsneaWhen the pectoralis minor acts in this way, it acts from the coracoid process. Thus, its insertion acts as its origin
78
What gives shape to the breasts? Describe their location
The suspensory ligaments of Cooper Extend perpendicularly from the deep fascia superficial to the pectoralis major to the skin
79
Describe the pathway of milk in the breast.
Breast lobules produce milk => lactiferous ducts => lactiferous sinus => 12-15 ductal openings into the nipple
80
Are lactiferous ducts found in all women?
NOPE, they disappear after menopause because they depend on hormones
81
Role of areolar glands?
Sebaceous glands that enlarge during pregnancy to help lubricate the skin for breast feeding
82
When do the nipple and areola become more pigmented? How come? In which population is this exacerbated?
During the last trimester of the 1st pregnancyDue to increased amount of melaninIn African Americans
83
Where is the ONLY muscle of the mammary gland located? What kind? When does it contract?
The areola - smooth muscleContracts upon stimulation
84
What are the 5 arteries providing blood supply to the breasts?
1. Internal thoracic artery branches (perforating anterior chest wall to 2-4th intercostals) to anteromedial portions2. Lateral thoracic artery branches 3. Thoracodorsal artery (from subscapular artery)4. Intercostal artery (perforators)5. Thoracoacromial artery
85
Is the breast affected by coronary bypass surgery in females in which the internal thoracic artery is harvested? Why/Why not?
NOPE, because of the extensive and redundant blood supply of the breast
86
Describe the venous drainage of breasts.
Follows the same tracts as the arteries to axillary, internal thoracic, and intercostal veins
87
What are the 4 types of lymph nodes that drain the breast? Which one is responsible for the majority of the lymphatic drainage?
1. Axillary lymph nodes*** (75% of drainage)2. Supraclavicular lymph nodes3. Internal mammary lymph nodes 4. Abdominal lymph nodes (25% of drainage)
88
What is another name for internal mammary lymph nodes?
Parasternal lymph nodes
89
Which breast lymph nodes are at greater risk for cancer metastases?
Supraclavicular lymph nodes
90
How can breast cancer move from one breast to the other?
Via internal mammary lymph nodes through the pectoral major fascia
91
What artery does the lateral thoracic artery branch from?
Axillary artery
92
What artery does the internal thoracic artery branch from?
Subclavian artery
93
Why can cancer spread easily from the breasts to the vertebral column/brain?
Because there are no valves between the intercostal veins and the vertebral veins
94
Where do most breast cancers occur? In what lymph nodes do these drain?
Superior lateral quadrantsDrain into axillary lymph nodes
95
What are 5 explanations for felt breast lumps? List in order of %
1. Fibrocystic changes2. No disease3. Miscellaneous benign4. Cancer5. Fibroadenoma
96
Incidence of lifetime breast cancer in women?
1:7 by age 90(most common visceral cancer in women)
97
When does breast examination indicate breast cancer? Explain each symptom.
1. Skin dimpling because the cancer cells are attacking the suspensory ligaments of Cooper and shortening them 2. Prominent vascular patterns because a fast-growing tumor will have a large vascular demand and will cause dilation of superficial veins 3. Skin edema due to lymph accumulation in the skin (orange peel appearance) because the cancer is attacking the subcutaneous lymphatics 4. Nipple retraction due to shortening of lactiferous ducts5. Cancer en cuirasse: hard, woody texture to skin (rare manifestation)
98
What are breasts ultrasounds used for?
To distinguish fluid-filled cysts (light) from solid masses (dark)
99
What are breasts MRI used for?
To evaluate how extensive the breast cancer is
100
What is fibroadenoma?
Benign neoplasm of glandular epithelium with significant increase in connective tissue
101
What color would a breast tumor appear as on a mammogram?
White
102
Which 2 nerves are very important to preserve during a masectomy?
1. Long thoracic nerve, which controls serratus anterior2. Thoracodorsal nerve which controls latissimus dorsa
103
How do surgeons performing masectomies or lumpectomies find the lymph nodes to remove?
Lymph mapping using an injection of dye in the breast where the tumor was which will travel to the proximal lymph nodes to the tumor
104
What are the 2 methods of surgical repair following a radical masectomy? Explain each. Which works best?
1. Transverse rectus abdominus myocutaneous (TRAM) flap surgery***: opposite rectus adbominus muscle is used to replace the mass lost and retains blood supply because it had both a superior and an inferior one2. Latissimum dorsi flap
105
What is a radical masectomy?
Masectomy involving the removal of the pectoralis major and minor due to metastasis
106
What are the 3 compartments of the thorax? What does each consist of?
1. Right and left lateral compartment: pleural sacs and their respective lung2. Central compartment: mediastinum and its contents
107
Are the right and left lateral thoracic compartments identical?
NOPE, the right side is wider and shorter than the left because of the liver pushing up on the right side and/or the heart pushing down on the left
108
How are rib 11 and 12 anchored to the thoracic wall?
By abdominal wall muscles
109
Can the extrinsic muscles be used for breathing?
YUP, but not main action
110
Function of extrinsic muscles?
Moving upper limbs
111
What are the 6 posterior extrinsic thoracic muscles?
1. Trapezius2. Rhomboid major3. Rhomboid minor4. Latissimus dorsi5. Levator scapulae6. Posterior superior serratus
112
What is the collateral branch of the intercostal vein, artery, and nerve?
Much smaller branches located above each rib
113
What are the 2 types of breathing? 2 names for each
1. Quiet inspiration = eupnea2. Forced breathing = hypernea
114
Describe eupnea.
1. Inspiration by muscular contraction: diaphragm (deep breathing) or costal (shallow breathing) with external and innermost intercostals 2. Expiration is a passive process without muscle contraction
115
Describe hypernea.
Active inspiratory and expiratory movements: 1. Inspiration: diaphragm (deep breathing) or costal (shallow breathing)2. Expiration: transversus thoracic, internal intercostals, and abdominal muscles
116
Posterior surface projection of xiphisternal joint?
T9
117
Posterior surface projection of suprasternal notch?
T2/T3
118
Sensory/Dermatomal innervation of breasts?
1. Thoracic intercostal nerves from T3-T5 2. Supraclavicular nerves (upper and lateral breast) 3. Lateral cutaneous branch of T4 (nipple)
119
Are are the pectoralis major and minor used for respiration?
For inspiration with insertions acting as origins
120
What is thoracic outlet syndrome? Example of cause?
Refers to a collection of signs and symptoms that arise from compression of the subclavian artery and vein, and trunks of the brachial plexus by various structures in the area just above the first rib behind the clavicle, within the confined space of the CLINICAL thoracic outlet (different from anatomical)Possible cause: cervical ribs
121
What plane passes through the sternal angle?
Transverse thoracic plane
122
What is a portacath? What is it used for? How is it placed?
Subcutaneous reservoir from which a small catheter passes under the skin into the internal jugular vein Can be used for delivering chemotherapy following breast cancer (placed on contralateral side of breast cancer if there has been axillary dissection as lymphatics would not be available to drain possible infection due to placement of the portacath) Placement: use ultrasound to see axial image across root of neck to see common carotid artery and right internal jugular vein => identify the internal jugular vein: larger and demonstrates normal respiratory variation, compressibility and size dependent on position of patient => puncture => brachiocephalic vein => SVC
123
Risk of placing a portacath?
Common carotid artery puncture or lung apex puncture
124
Why is the portacath placed all the way in SVC?
To ensure proper mixing with blood because chemotherapeutic agents are severely toxic so this prevents thrombosis and vein wall irritation
125
What do axillary nodes drain to?
Subclavian trunks
126
What do parasternal nodes drain to?
Bronchomediastinal trunks
127
4 types of axillary lymph nodes? List from inferior to superior.
1. Pectoral 2. Lateral3. Central4. Apical
128
Breasts in men?
Small ducts composed of cords of cells that do not extend beyond the areola
129
Where does breast cancer develop? 3 locations.
1. Acini cells2. Lactiferous ducts3. Breast lobules
130
What does staging a breast cancer mean?
1. Size of primary tumor?2. Exact site of primary tumor?3. Number and sites of lymph node spread?4. Organs to which tumor has spread?
131
3 posterior thoracic muscles that can alter the position of ribs and sternum and help breathing?
1. Levatores costarum2. Serratus posterior superior3. Serratus posterior inferior
132
Lymphatic drainage of thoracic wall?
1. Parasternal nodes2. Intercostal nodes3. Diaphragmatic nodes
133
Where are diaphragmatic lymph nodes located?
Posterior to xiphoid and where diaphragm attaches to vertebral column
134
Where do intercostal nodes drain?
1. Upper thorax: bronchomediastinal trunks 2. Lower thorax: thoracic duct
135
What is the subcostal nerve?
Spinal nerve T12
136
What is the largest branch of an intercostal nerve?
Lateral cutaneous branch that pierces anterior wall and divides into an anterior and posterior branch
137
Other than innervating the thoracic wall, what else do intercostal nerves innervate?
1. Anterior rami of T1: brachial plexus2. Lateral cutaneous branch of 2nd intercostal: medial surface of arm3. Lower intercostals: muscles, skin and peritoneum of abdominal wall
138
What surgical procedures can be conducted without having to do a sternotomy?
1. Lobectomy2. Lung biopsy3. Esophagectomy
