2. What to learn?
โข Introduction
โข Surface landmarks
โข Superficial fascia
โข Deep fascia
โข Muscles of pectoral region
3. Introduction
โข Location: Front of chest
โข Essential consist of structure which connects the upper
limb to the anterolateral chest wall
โข i.e. bones and muscles
โข Additionally Mammary gland
7. Superficial fascia
โข Band
โข Contains: moderate amount of fat, mammary
gland, fibrous septa
๏ถContents
1) Cutaneous nerves
2) Cutaneous vessels
3) The platysma
4) The breast
8. Cutaneous Nerves
โข Branches of the cervical plexus (C3, C4):(medial,
intermediate and lateral supraclavicular nerves)
โข skin over the upper half of the deltoid and from the
clavicle down to the second rib.
โข The anterior and lateral cutaneous branches of the second
to sixth intercostal nerves : skin below the level of the
second rib.
โข The intercostobrachial nerve T2 : skin of the floor of the
axilla and the upper half of the medial side of the arm.
9.
10. โข Pulled away: The area supplied by spinal nerves
C3 and C4 directly meets the area supplied by
spinal nerves T2 and T3. This is because of the
fact that the intervening nerves (C5, C6, C7, C8
and T1) have been 'pulled away' to supply the
upper limb.
11. Cutaneous Vessels
โข The cutaneous vessels are very small.
โข The anterior cutaneous nerves are accompanied
by the perforating branches of the internal
thoracic artery.
โข The second, third and fourth of these branches
are large in females for supplying the breast.
โข The lateral cutaneous nerves are accompanied by
the lateral cutaneous branches of the posterior
intercostals arteries.
12. The Platysma
โข Thin, broad sheet of subcutaneous muscle.
โข Muscle of face
โข Supplied by the facial nerve.
โข When the angle of the mouth is pulled down, the muscle
contracts and wrinkles the skin of the neck.
โข The platysma may protect the external jugular vein
(which underlies the muscle) from external pressure.
14. ๏ Modified sweat gland- modified apocrine gland
๏ Made up of 15โ20 lobules of glandular tissue
embedded in fat.
๏ Fat accounts for its smooth contour and most of its
bulk.
๏ These lobules are separated by fibrous septa
running from the subcutaneous tissues to the
fascia of the chest wall (the ligaments of
Cooper/ Astley Cooper fibers/ suspensory
ligaments)
๏ Between the capsule and the fascia over pectoralis
major is the loose connective tissue of the
retromammary space.
15. ๏ Each lobule drains by its lactiferous
duct on to the nipple, which is
surrounded by the pigmented areola.
๏ This area is lubricated by the areolar
glands of Montgomery
โฆ large,
โฆ modified sebaceous glands โmay form
sebaceous cysts โ may infected.
17. Naming the quadrants for the
purpose of describing a lump๏ Or
1. Upper medial
quadrant
2. Upper lateral
quadrant
3. Lower medial
quadrant
4. Lower lateral
quadrant
18. Position & extent
๏
๏
๏
2/3 rests on
pectoralis major,
1/3 on serratus
anterior,
while its lower
medial edge just
overlaps the upper
part of the rectus
sheath.
23. ๏ Axillary artery โ
โฆ Lateral thoracic (mainly)
โฆ Acromiothoracic branches.
๏ Internal thoracic (internal mammary) artery
โperforating branches; these pierce the 1st โ 4th
intercostal spaces, then traverse pectoralis major
to reach the breast along its medial edge. The 1st
& 2nd perforators are the largest of these
branches.
๏ Intercostal arteries โ lateral perforating
branches- relatively unimportant source.
25. Venous drainage
๏ Sub areolar venous plexus
๏ Posterior intercostal veins communicate
with internal vertebral venous plexus
veins - therefore cancers can spread to
vertebra- may cause back pain
28. ๏ Follows the pathway of its blood supply
๏ along tributaries of the
1. axillary vessels โ axillary lymph
nodes;
2. internal thoracic vessels โ piercing
pectoralis major โ to traverse each
intercostal space โ to lymph nodes along
the internal mammary chain; these also
receive lymphatics penetrating along the
lateral perforating branches of the
intercostal vessels.
29. ๏ A subareolar plexus of lymphatics
below the nipple (the plexus of
Sappey)
๏ 75% โ axillary
๏ 15% โ internal mammary
๏ Upper โ can go to supraclavicular
๏ Lower 2 quadrants can go to
subdiapragmatic or abdominal nodes
32. Development and structure
๏ Begins to develop as early as the 4th week as a
downgrowth from a thickened mammary ridge
(milk line) of ectoderm along a line from the
axilla to the inguinal region.
๏ Supernumerary nipples or even glands proper
may form at lower levels on this line.
33. ๏ Lobule formation occurs only in the female
โข breast & does so after puberty.
๏ Each lactiferous duct is connected to a tree- like system
of ducts and lobules, intermingled & enclosed by
connective tissue to form a lobe of the gland.
34.
35. ๏ The resting (non-lactating) breast, however
consists mostly of fibrous & fatty tissue;
variations in size are due to variations in fat
content, not glandular tissue which is very
sparse.
36. ๏ During pregnancy alveoli bud off from the smaller ducts
& the organ usually enlarges significantly, & more so in
preparation for lactation.
๏ When lactation ceases there is involution of secretory
tissue.
๏ After menopause progressive atrophy of lobes & ducts
takes place.
37. The male breast
๏ Resembles the rudimentary female
breast
๏ has NO lobules or alveoli.
๏ The small nipple and areola lie over
the 4th intercostalspace.
38. Clinical anatomy
๏ง Amastia (Absence of breast)
๏ง Polymastia (Supernumerary breasts)
๏ง Athelia (Absence of nipple)
๏ง Polythelia (Supernumerary nipples)
๏ง Gynaecomastia (in Klinefelterโs syndrome)
๏ง Breast cancer
๏ง Breast abscess
39. Amastia of right breast
Polymastia
Polythelia
Nipple retraction
Athelia
Gynaecomastia
41. MUSCLES OF THE PECRORAL
REGION
โข 1. Pectoralis major
โข 2. Pectoralis minor
โข 3. subclavius
โข 4. Serratus
anterior
42. Pectoralis major
Origin:
1. Clavicular head; from the front of the
medial third of the clavicle
2. Sternocostal head; from the anterior aspect
of the sternum and the upper six costal
cartilages
Insertion: Lateral lip of bicipital groove of the
humerus
Action: 1. Adduction and medial rotation of
the arm
2. Flexion of the arm (clavicular
portion)
Nerve supply
1. Lateral pectoral nerve, C5, 6, 7
2. Medial pectoral nerve, C8, T1
43.
44. Pectoralis minor
Origin: 3rd , 4th and 5th ribs near
their cartilage.
Insertion: Medial aspect of
coracoid process of the scapula
Action:
โข Depresses point of shoulder; if
the scapula is fixed, it elevates
the ribs of origin
โข Nerve supply: medial pectoral
nerve, C8,T1
45. Subclavius muscle
โข Origin: First costal cartilage
โข Insertion: Lower surface of
clavicle (subclavius groove)
โข Action: Depresses the clavicle and
steadies this bone during
movements of the shoulder girdle
โข Nerve supply: Nerve to the
subclavius, from the roots of
brachial plexus C5,6
46. Serratus anterior muscle
โข Origin: From the outer surface of
upper 8 ribs
โข Insertion: costal aspect of medial
border and inferior angle of scapula
โข Action:
โข Draws the scapula forward around
the thoracic wall (protrusion); rotates
scapula
โข Nerve supply: long thoracic nerve,
C5,6,7
47. Clavipectoral Fascia
โข The clavipectoral fascia is a strong sheet of
connective tissue that is attached above to the
clavicle.
โข Below, it splits to enclose the
pectoralis minor
then continues
muscle and
downward as
the suspensory ligament of the
axilla and joins the fascial floor of
the armpit.