Thoracic Wall and Muscles of Respiration Flashcards
pectoralis major
primarily acts on the shoulder joint
innervated by both the medial and lateral pectoral nerves
because it attaches to the ribs /can elevate ribs- it assists in forced inspiration.
pectoralis minor
muscle deep to the pec. major and acts indirectly on the shoulder joint by helping stabilize it
innervated by the medial pectoral nerve
proximal and distal attachments of pectoralis major
proximal
1. clavicular head - medial 1/2 of clavicle
2. sternocostal head-anterior surface of sternum costal cartilages 1-6
Distal
1. lateral lip of the intertubercular (biciptal groove) of the humerus
serratus anterior
major muscle of UE accessory in respiration proximal attachment - external surfaces of ribs 1-8 distal attachment -anterior surface of the medial border of the scapula
external intercostal muscles
anteriorly, fibers directed from superolateral to inferiormedial
tubercle of rib to costochondral junction
external intercostal membrane
anterior to internal intercostal muscles and replaces the external intercostal muscles anteriorly
subclavius
proximal attachment
-1st rib
distal attachment
-clavicle middle 1/3
internal intercostal muscles
anteriorly, fibers are directed superomedial to inferolateral
angle of ribs to sternum
innermost intercostal muscles
tend to run in sam direction as the internal inercostal muscles
only present laterally
subcostal muscles
muscles usually cross intercostal spaces but are variable
transversus thoracic muscles
internal surface of the anterior thoracic wall
inferior attachment
-on sternum
extend superiorly to attch onto costal cartilages 3-6
internal thoracic artery and vein
course vertically on the internal surface of the thoracic cage, lateral to the sternum
internal thoracic artery
branch of subclavian
supplies chest wall as well as the breasts
internal thoracic vein
empties into the brachiocephalic vein
intercostal vein, artey, and nerves
each intercostal space has all three
travel between the internal and innermost intercostal muscles
travel within the costal groove
intercostal nerves
T1-T11 (T12 is cubcostal )
intercostal arteries
posterior - arise from aorta
anterior- arise from the internal thoracic artery
intercostal veins
posterior- empty into azygous venous system
anterior - empty into the internal thoracic veins
diaphragm
major muscle of respiration
innervated by the phrenic nerve (C3,4,5 keeps you alive)
separates the thoracic and abdominal cavities
dorsal body cavities
cranial and vertebral
ventral body cavities
thoracic, abdominal, and pelvic
what separates the abdominal cavity from thoracic?
diaphragm
T/F the abdominal and pelvic cavities are not physicall separated
TRUE - they are not
division of thoracic cavity
THREE
- (2) pulmonary cavities - lungs
- mediastinum - further subdivided into 1. superior and 2. inferior (anterior, middle-heart, and posterior)
what does the thoracic cage (bony structure of thorax) include and functions?
12 thoracic vertebrae and discs 12 pairs of ribs and costal cartilage sternum functions: protects the heart, serves as an ATTACHMENT site for muscles (including muscles of respiration), and costal cartilages and joints contributing to the flexibility of the cage
vertebrae structure (number and curvature posteriorly)
7 cervical, concave - lordosis 12 thoracic, convex- kyphosis 5 lumbar, concave- 5 sacral, convex- 4 coccygeal (fused)
normal curvature of the spine
anteroposterior
intervertebral disc structure
annulus fibrosus - outer fibrocartilaginous rings
nucleus pulposa - inner gelatinous material
type of joint between the bony vertebra and intervertebral disc
symphysis
bones united by fibrous cartilage
which curves are primary curves?
thoracic and sacral
secondary curves in spine
cervical and lumbar curves - concave posterior
scoliosis
lateral curvature to the spine
this term always indicates an abnormal curvature
the body, pedicle, transverse process, lamina, spinous process, articulating processes (superior and inferior),
articular facets are components of what?
specific vertebral components
details on articular facets
flat surface where bones articulate (vertebra, and ribs)
these are synovial joints
facets have hyaline cartilage
superior and inferior articular processes form zygapophysial joints, but called facet joints
trend of size of intervertebral foramen
get smaller as go more caudal
lumbar openings not as large
major points of difference between lumbar vs. thoracic vertebra
- Body -upper thoracic smaller than lumbar body
- Spinous process- in thoracic it is large and points inferior. Lumbar process is short and stuby - indicating more ability to move in lumbar region
- Articular/costal facets-THORACIC VERTEBRAE HAVE A TRANSVERSE COSTAL FACET off of the transverse process and SUPERIOR AND INFERIOR COSTAL FACETS - on the body
components of a typical rib
Head - 2 FACETS Neck Tubercle - transverse process of the corresponding vertebrae Angle Costal groove
head of thoracic rib
two facets that articulate with the vertebral body at the same level and the body that is superior to it
Neck of thoracic rib
neck is between the head and the tubercle
Tubercle of thoracic rib
tubercle has articulating facets for the transverse process of the vertebral body at same level
angle of rib
rib turns anterolateral
flattens out as come around (more bulky in the posterior where contacting with the vertebral body)
costal groove of rib
location of intercostal nerve, artery, and vein
costo-transverse joint
transverse process of vertebra of same number as rib and the tubercle of rib
costovertebral joints
head of rib - body of rib superior to rib and body of rib at same level at the costal facets on body
*intervertebral disc positioned between the two bodies
example.. 7th rib will articulate with?
7th rib head- articulating with Body of T6 and T7
7th rib tubercle articulating with transverse process w/ facet of same level vertebral body (T7)
atypical ribs
1st and 2nd rib and 10-12
typical ribs
3-9
what type of costal cartilage do ribs have?
hyaline cartilage
true ribs
1-7
false ribs
8-10
floating ribs
11-12
costochondral joints
ribs with the costal cartilage = synchondrosis
sternocostal joints
sternum with costal cartilage -1st rib=synchondrosis - rib with costal cartilage
2nd-7 ribs = plane synovial joint
interchondral joints
between costal cartilages - synovial (most)
synchondrosis unites what
bones united by hyaline cartilage
symphsis unites what
bones united by fibrous cartilage
components of the sternum
Manubrium (most superior)
Body
Xiphoid process
Manubrium
jugular notch = suprasternal notch
sternal angle
sternal angle and what joint
this is the manubriosternal joint which is a symphysis - bones connected by fibrous cartilage
at the inferior portion of the manubrium
this is at notch two
JUNCTION B/W THIS AND BODY
what to note on body of sternum
costal notches - articulation for the costal cartilages
xiphoid process and what joint
Xiphisternal joint which is a synchondrosis (bones connected by hyaline cartilage) at 7th notch
inferior portion of sternum
this joint will often fuse in older adults
Proximal and distal attachments of pectoralis major
proximal attachments
1. medial half of clavicular head of clavical
2. sternocostal head- anterior surface of sternum. costal cartilages 1-6
Distal
1. lateral lip of the intertubercular (bicipital) groove of the humerus
proximal and distal attachments of serratus anterior
distal : anterior surface of the medial border of the scapula
proximal: external surfaces of ribs 1-8 (lateral)
pectoralis minor
innervation and action
innervated by the medial pectoral nerve
accessory muscle of respiration (forced inspiration)
subclavius muscle innervation and action
n. to subclavius
accessory muscle of respiration (forced inspiration
ELEVATES first rib
attachments of pectoralis minor
proximal : external surfaces of ribs 3-5
- 1-8 = serratus anterior
distal: coracoid process of scapula
attachments of subclavius
proximal : 1st rib (makes sense because it lifts the 1st rib in function)
distal: clavicle (middle 1/3)
intercostal muscle divisoin
External intercostal muscles
Internal intercostal muscles
innermost intercostal muscles
External intercostal muscles
anteriorly- Fibers run like putting hands in pocket - superorlateral to inferior medial
go from tubercle of rib (transverse process of same level body vertebrae) to costochondral junction and replaced anteriorly by the external intercostal membrane
internal intercostal muscles
Anteriorly, fibers are directed from superiomedial to inferiolateral (opposite of external)
Go from angle of ribs to sternum
replaced posteriorly by internal intercostal membrane
innermost intercostal muscles
only present laterally and tend to run in same direction from superiormedial to inferior lateral like the internal intercostal muscles
muscles on the internal surface of the thoracic cage
subcostal muscles
transversus thoracic muscles
subcostal muscles
these muscles usually CROSS two intercostal spaces (variable though)
Transversus thoracis muscle
attachments and function
accessory muscles to respiration
4-5 muscle slips in internal aspect of thoracic cavity wall
attach from costal cartilages about 3-6 and pass towards inferior medial aspect of the lower body of the sternum and xiphoid process
components of intercostal space
each intercostal space has a vein, artery, and nerve (VAN)
where are the internal intercostal V,A, and N’s?
only between the internal intercostal muscles and the innermost intercostal muscles
travel within the costal groove of the rib
V- most superior N- most inferior
intercostal nerves
t1-t11 (t12 is subcostal)
intercostal arteries
Post/Ant portions
Posterior - arise from the aorta
Anterior - arise from the internal thoracic artery
(internal thoracic artery is a branch of the subclavian artery)
intercostal veins
Post/Ant portions
Posterior- empty into the azygous venous system - see medistinum lecture
Anterior - empty into the internal thoracic veins
Astemosis
anterior and posterior arteries will of intercostal will come together
Diaphragm
Function and innervation
what does it separate?
major muscle of respiration
innervated by the phrenic nerve (c3,4,5 keep you alive)
separates the thoracic and abdominal cavities
Attachments of diaphragm
Xiphoid process, lower ribs and costocartilages, upper lumbar vertebrae (L1-L3)
3 openings/ hiatus of diaphragm and level
- Caval (inferior vena cava) @ T8
- Esophogeal hiatus @T10
- Aortic hiatus @T12 - POSTERIOR to diaphragm - doesnt go through
‘I(IVC) ate(8) ten eggs (Esoph) at (aorta) twelve)
inspiration and expiration does what to the thoracic volume?
Inspiration? - expands thoracic volume (secondary to the other effects)
Expiration? - decreases thoracic volume
Inspiration…
Diaphragm CONTRACTS AND DESCENDS - increasing vertical height of thorax and compressing the abdominal viscera
CONTRACTION OF INTER-COSTAL MUSCLES - causes an increase in the anteroposterior (AP) dimension of the thorax via movement of the ribs and sternum
CONTRACTION OF INTERCOSTAL MUSCLES - increase in lateral dimensions of thorax via movement of the lateral aspect of the ribs
accessory muscles to inspiration
sternocleidomastoid
pec major and minor
serratus anterior
principle muscle of inspiration
external intercostal muscles
internal intercostals -interchondral part
primary muscle of respiration
diaphragm - increasing dimensions of thorax in multiple planes
muscles involved in forced expiration
internal intercostal
abdominal muscles
rectus abdominous
external oblique, internal oblique, transversus abdominus
