Trunk Wall and Inguinal Region Flashcards
The mammary gland overlies what two muscles
pectoralis major and serratus anterior
The nipple lies where
at about the 4th intercostal space
the nipple is _____ and the ____ ____ opens onto it
fissured; lactiferous duct
What allows the nipple to become erect?
circularly arranged smooth muscle
What is the pigmented area around the nipple
areola
The areola exhibits ____ and what is there purpose
small bumps or sebaceous glands; secrete oil during pregnancy to lubricate and protect while lactating
How does the appearance of the areola differ in women who have not had children vs women who have
before children it is a pinkish color, after having children it changes permanently to brown (allows the baby to see it better for breast feeding)
Does the mammary gland have capsule?
No
The mammary gland is a modified what
sweat gland
Location of the mammary gland
lies in the superficial fascia, its deep aspect separated from the underlying
musculature by deep fascia (epimysium)
What is the retromammary space?
thin area between the gland and deep fascia that contains no fat; allows free movement of the gland over the muscle
How is the mammary gland attached?
firmly attached to the overlying skin by suspensory ligaments
that extend down to the posterior mammary fascia
What happens to the lactiferous ducts during puberty?
they branch and fat is deposited around
The mammary gland is predominantly what
fat, which gives the breasts their shape
During pregnancy, the ____ ____ within the fat increase in size
secretory lobules
What are secretory lobules composed of?
milk-secreting cells arranged into groups or alveoli at the ends of the lactiferous ducts
What are alveoli of the lactiferous ducts?
groups of milk secreting cells
What is the lactiferous sinus?
a swelling just before the ducts open onto the surface of the nipple where milk is stored
When do woman start secreting milk?
after child birth
When can secrete ____ which is what?
colostrum, a creamy pre-milk fluid, may be expressed during the last trimester of pregnancy
Mammary glands innervation
lateral and cutaneous branches of intercostal nerves 2 through 6; they receive sensory and sympathetic innervation
Arterial supply of the mammary glands
- perforating br. of the internal thoracic a.
- lateral thoracic a. from the axillary a.
- lateral and anterior br. of the intercostal aa.
Venous drainage of the mammary glands
similar to arterial supply, but axillary drainage is the most important
What is the axillary tail of the mammary gland
a tail of fatty tissue that extends back into the axilla region
Why is lymphatic drainage important?
due to the frequency of carcinoma of the breast
About __% of lumphatic drainage flows via the ___ ___ to the ___ ___
75%; axillary tail; axillary nodes
The remaining __% pass toward the ___ ___ or to the ___ ___
25%; parasternal nodes; opposite breast
Where are carcinomas most frequent in the breast?
supero-lateral quadrant (upper outer quadrant)
Why are carcinomas frequent in the supero-lateral quadrant?
since 75% of lymph passes through this region
Characteristics of carcinoma in the breast
- less mobile as the breast is anchored to the deep fascia
- dimpled, orange peel appearance due to the suspensory ligaments
What are the accessory muscles of respiration
pectoralis major and minor, external oblique, and serratus anterior
How do these muscles aide in respiration?
by fixing the pectoral girdles (scapula and clavicle) so
these muscles then act on the rib cage
Muscles of the thorax proper
- serratus posterior supeior
- serratus posterior inferior
- levator costarum
- intercostals
- external
- internal
- innermost
- transversus thoracis
- subcostals
Muscles of the back of the thorax proper
serratus posterior superior and inferior, and levator costarum
Serratus posterior superior attachment
from the vertebrae to the ribs R2-R4/5
Serratus posterior superior action
elevates the upper 4 ribs to increase thoracic diameter
Serratus posterior inferior attachment
inferior 3 or 4 ribs near the angle and is direct supero-laterally
Action of serratus posterior inferior
will pull (depress) the ribs preventing the diaphragm from pulling them up
Muscles of the thoracic wall
intercostal muscles, are organized in to 3 layers
First layer of intercostal muscles
external intercostals
External intercostals attachment
extend from the posterior aspect around to the costochondral junction where they become a membrane
Membrane by the external intercostals meeting the costchondral junction
anterior intercostal membrane
how are the fibers of the external intercostals directed?
inferomedially (like putting your hands into your pockets).
What are the external intercostal fibers continuous with?
the fibers of the external oblique mm. of the anterior abdominal wall
Second layer of the muscles of the thoracic wall
internal intercostals
Internal intercostals attachment
extend from the sternum around to the angle of the ribs where they
become a membrane
The internal intercostals become what membrane
internal intercostal membrane
How are the fibers of the internal intercostals directed?
run at right angles to those in the external layer - inferoposterior in direction
What are the internal intercostal fibers continues with?
internal oblique mm. of the anterior abdominal wall
Third layer of muscles of the thoracic wall
composed of 3 muscles linked in a membrane
- transversus thoracis
- innermost intercostals
- subcostals
Transversus thoracis attachment
attach to the back of the sternum and xiphoid process
-continuous with the transversus adbominis mm. of the anterior abdominal wall
Innermost intercostals attachment
found along the mid-axillary line; similar indirection to the internal intercostals and may be considered a subset of them, separated by the intercostal neurovascular bundle
Subcostals attachment
found posteriorly near the angle of the ribs; characteristically
cross one rib before reattaching
Function of the third layer of muscles of the thoracic wall
elevate the ribs, expanding the thoracic diameter and keeping the
intercostal spaces rigid to prevent the lungs pushing the muscle outward
Innervation of the muscles of the intercostal spaces
innervated segment-ally by the anterior rami of the spinal nerves which from T1-T12 are referred to as inter- costal nerves