Ch. 24 Thoracic Wall Flashcards
The function of the _____ is to form a protective cavity for the heart and lungs and for the organs of the superior aspect of the abdomen
Thoracic wall
Flat bone located at the anterior aspect of the thorax in the midline
Sternum
The sternum is divided into three parts:
Manubrium, Body, Xiphoid process
Superior portion of the sternum
Manubrium
The jugular notch is found on the superior border of the ____
manubrium
The manubrium articulates with the ___ and the ____
clavicles and the first two pairs of costal cartilages. (hyaline cartilage between ribs and sternum)
Middle portion of the sternum
Body
The body is ___, ___, and ___ than the manubrium
long, narrow, and thinner
The body articulates with the costal cartilages of ribs ___ through ___
2-7
The junction of the manubrium and body.
sternal angle
Important palpable landmark for counting ribs
sternal angle
Smallest, most variable and inferior portion of the sternum
xyphoid process
a depression on the anterior aspect of the diploid profess; palpable and often is visible
epigastric fossa (pit of stomach)
Found between the xiphoid process and the body at the superior aspect of the epigastric fossa
xiphisternal joint
12 pairs of flat bones from most of the thoracic wall
ribs
Humans have ___ ribs on each side of the body
12
Variations of ribs include cervical ribs at ___ and lumbar ribs at ___
CV7 and LV1
The elongated flattened bones of the rib course ___ and ___ from the thoracic vertebrae
anteriorly and inferiorly
Portion of each rib articulates with the bodies of the thoracic vertebrae
head
Constricted portion of the rib lateral to the head
neck
posterior projection lateral to the neck of the rib
tubercle
the tubercle articulates with the _____ of its respective thoracic vetebrae
transverse process
Shaft of the rib
body
point of the rib where the curve of the rib is the sharpest
angle
the anterior end of the rib articulates with the _____
costal cartilage
ridge that lies on the inferior surface of the shaft of the rib
costal groove
IN the costal groove lies _____ (from superior to anterior)
intercostal vein, artery and nerve
The length of the rib increases the ___ to the ___ rib and then decreases to the ___ rib
1st-7th; 12th
The first seven ribs are ___
true
true ribs are directly connected to the sternum via their ____
costal cartilages
The last five ribs (8-12)
false
Each costal cartilage of ribs 8, 9, and 10 joins its ________
respective supra adjacent costal cartilage
The costal cartilages of ribs 11 and 12 end blindly in muscle with no _____
anterior articulation
ribs 11 and 12 are classified as
floating
The costal margin is formed by the costal cartilages of ribs ____, which course medially to superiorly
7-10,
The infrasternal angle is formed by the intersection of the ______ at the ______
costal margins; xiphisternal joint
The superior thoracic aperture is bounded by the ________
upper border of the sternum and by the first ribs
Opening through which the greater vessels and visceral tubes ascend or descent between the thorax and the neck
superior thoracic aperture
the inferior thoracic aperture is normally closed by the ____
diaphragm
Three major openings are found in the diaphragm which allow for the passage of the ___, ___ and ___
inferior vena cava, esophagus and aorta
The muscles of the thorax are arranged into three layers:
External layer: external intercostal muscles
Middle layer: Internal intercostal msucles
Internal layer: Innermost intercostal muscles
Origin of external intercostal muscles
lower margin of the rib above
insertion of external intercostal muscles
upper margin of the rib below
Action of external intercostal muscles
elevation of the ribs during inspiration
Innervation of external intercostal muscles
Intercostal nerve T1 through T6
Thoracoabdominal nerves t7 through T11
There are how many external intercostal muscles
11
From their point of origin, the fibers of the external intercostal muscles pass ___ and ___ to their point of insertion
medially and inferiorly
In the intercostal spaces, the external intercostal muscles extend from the ____ posteriorly to the region of the _____ anteriorly
tubercle of the rib; costochondral junction
The external intercostal muscles thin out at the
chostochondral junction
When the external intercostal muscles thin out and become membranous
external intercostal membrane
Origin of the internal intercostal muscle
upper margin of the rib below and its costal cartilage
Insertion of the internal intercostal muscle
lower margin of the rib above and its costal cartilage
action of the internal intercostal muscle
depression of the ribs during expiration
innervation of the internal intercostal muscle
intercostal nerves t1-t6
thoracoabdominal nerves t7-t11
how many internal intercostal muscles are there
11
From their point of origin, the internal intercostal muscles pass ___ and ___ to their point of insertion
medially and superiorly
In the intercostal spaces, the internal intercostal muscles extend from the ___ anteriorly to the ____ posteriorly to become the internal intercostal membrane.
sternum; angles of the ribs
where the internal intercostal muscles thin out and become membranous
internal intercostal membrane
How many innermost intercostal muscles are there?
11
The innermost intercostal muscles have the same origin, insertion, action and innervation as the
internal intercostal muscles
The innermost intercostal muscles are separated from the internal intercostals by the _____ and ___.
intercostal vessels and nerve.
The area between the internal and innermost intercostal muscles
neuromuscular plane
Other muscles associated with the thoracic wall
transversus thracis
subcostales
How many thoracic spinal nerves are there?
12
All of the thoracic spinal nerves traverse an ________ and divide into a ____ and a ___
intervertebral foramen; dorsal and ventral ramus
course posteriorly and divide into medial and lateral branches
dorsal fami
larger branches of the spinal nerves that course forward into the intercostal spaces.
ventral rami
The ventral rami have regional names:
T1-T6 – Intercostal nerves
T7-T11 – Thoracoabdominal nerves
T12 – Subcostal nerve
A typical intercostal nerve has the following course and distribution:
Passes below the neck of the rib corresponding to it
Courses between the innermost intercostal and the internal intercostal muscles in the neuromuscular plane
Passes forward in the costal groove on the lower surface of the rib where it courses inferior to the intercostal vein and artery
Gives off lateral cutaneous branch which divides into anterior and posterior branches
At the anterior end of the intercostal space it gives off a anterior cutaneous branch.
Intercostal nerve T4 courses inferior to the
fourth thoracic rib
The lateral cutaneous branch pierces the:
internal intercostal, external intercostal and serrates anterior muscles
the anterior and posterior branches of the lateral cutaneous branch supply the
skin of the chest wall
At the anterior end of the intercostal space, the intercostal nerve turns forward through the:
internal intercostal muscle and the external intercostal membrane and the pec major
anteriorly, the intercostal nerve is distributed as the ____ to the ____
anterior cutaneous branch; skin in front of the heat.