mm of thorax og abdomen Flashcards
mm of thorax
- intercostal mm
- subcostal mm
- transversus thoracis m
- diaprhagm
NS: intercostal nn fyrir alla nema phrenic n fyrir diaphragm
intercostal mm
3 flat mm
milli ribs in each intercostal space
external intercostal mm
11 pairs
-muscle fibers pass obliquely
ventrocaudally
-ext from tubercles of ribs to costal cartilages
-absent ventrally en continue as
external intercostal membrane
F: active in inspiration
external intercostal mm
11 pairs
-muscle fibers pass obliquely
ventrocaudally
-ext from tubercles of ribs to costal cartilages
-absent ventrally en continue as
external intercostal membrane
F: active in inspiration
internal intercostal mm
11 pairs
-muscle fibers pass dorsocaudally
-ext from parasternal regions, from adj. costal cartilages, to angle of ribs posteriorly
-absent dorsally
-cont. as internal intercostal membr
F: active in expiration
internal intercostal mm
11 pairs
-muscle fibers pass dorsocaudally
-ext from parasternal regions, from adj. costal cartilages, to angle of ribs posteriorly
-absent dorsally
-cont. as internal intercostal membr
F: active in expiration
innermost intercostal mm
11 pairs
-same orientation as internal intercostal mm
F: act w internal intercostal in expiration
*neurovascular bundles
(intercostal v, a, n) run in costal grooves–>
in plane milli innermost og internal intercostal mm
subcostal mm
in same plane as innermost intercostals
-span multiple ribs (2-3)
-more numerous in lower regions of post. thoracic wall
-same orientation as internal intercostals
F: depress ribs, act in expiration
transversus thoracis
deep surf of ant. thoracic wall in same plane as the innermost intercostals
-ext from post. xiphoid process + inferior body of sternum to lower borders of costal cartilages of ribs 3-6
*the muscle lies deep to the internal thoracic vessels
F: depresses costal cartilages
acts in forced expiration
diaphragm
musculotendinous structure
-fills the inf. thoracic aperture og sep thoracic cav from abd. cav.
O:
1) sternal p: xiphoid proc
2) costal p: lower 6 ribs (7-12)
3) lumbar p: upper l.v.bra (1-3)
I: central tendon of diaphragm
F: contracts in inspiration and relaxes in expiration
ns: phrenic n (cervical plx)
diaphragm
inspiration:
it contracts–> draws inferiorly and flattens.
At same time ext. intercostals draw the ribs up–> thoracic cav volume enlarges
expiration:
diaphragm elevates shape of dome (cupola)—> thoracic volume decreases
hiccups
involuntary contr. of diaphragm
+ sudden closure of vocal folds
(usually due to irritation, eating to much, carbonated drinks, emotional stress)
*hiccups more than 48 hours–> damaged nerve, cns or metabolic disorders
diaphragm openings
structures travelling milli thorax + abd
*opening for IVC
*esophageal hiatus: esophagus
og vagus nerve (vagal trunk)
*aortic hiatus: aorta + thoracic duct
*azygos + hemiazygos veins may also pass thru aortic hitatus or thru the crura
*right phrenic n. passes thru central tendon or the caval aperture
*left phrenic n. passes thru muscular p. of diaphragm, anterior to the central tendon
mm of abdomen
forming anterolateral abd wall
- obliqus externus abdominis m
- obliqus internus abdominis m
- transversus abdominis m
- rectus abdominis m
- pyramidalis m
NS: anterior rami of spinal nerves
(T7-T12/L1)
anterolateral mm function
1) flexion:
rectus abdominis
and bilateral contraction of obliqus abdominis internus/externus
3) lateral duction:
obliqus abdominis ext/int
4) rotation: obliqus abdominis ext/int
og transversus abdominis
together they are critical for many funct:
-firm/flexible wall that keeps og protects organs
-expiration (quiet og forced)
-coughing + vomiting
-defication
-mictuation
-partuation
(diastesis recti)
obliqus ext. abdominis
O: lower 8 ribs (5-12)
I: iliac + pubic crests
og by large aponeurosis to linea alba
*m.fibers inferomedial direction
*in midline the aponeuorosis from both sides intertwined and form linea alba
(from xiphoid proc to pubic symphysis)
INGUINAL LIGG:
lower thickened margin of aponeurosis, stretched milli ant.sup.iliac spine of pubic tubercle
obliquus internus abdominis
O: thoracolumbar fascia
iliac crest
inguinal ligg
I: pubic crest
by large aponeurosis to linea alba
Fibers go superomedially
transversus abdominis
O: lower 6 ribs
thoracolumbar fascia
iliac crest
inguinal ligg
I: pubic crest
og aponeurosis to linea alba
fibers transverse direction
rectus abdominis
O: xiphoid process og costal cartilages
I: pubic bone
*its a paired muscle, sep. by linea alba in the midline
*intersected by 3-4 transverse fibrous bands
–> tendinous intersections
pyramidalis
small triangular muscle
may be absent
-anterior to rectus abdominis
O: pubic bone
I: linea alba
f: tenses linea alba
the rectus sheath - aponeurotic tendinous sheath
- anterior layer:
-aponeurosis of obliqus externus
+ half of apon. of obliqus internus - posterior layer:
-other hafl of apon. of obliq. internus
+ aponeurosis transv. abdominis
rectus sheath
-upper 3/4 of rectus abdominis
(above arcuate line) —>
completely enclosed by anterior og posterior layer of rectus sheath
-lower quarter of rectus abdominis
(below arcuate line)
all of the aponeurosis move anteriorly to the rectus abdominis
–> at this point rectus abdominis is in direct contact with transversalis fascia
inguinal canal
narrow canal in ant. abd wall
-directly above inguinal ligg
-mediocaudal direction
WALLS:
inf: inguinal ligg
sup: muscle fibers of obliqus abd. internus og transv. abdominis
ventral: aponeurosis of obliqus abd externus
dorsal: transversalis fascia (very thin and weak wall!)
deep inguinal ring
-internally (beginning of inguinal canal)
-an aperture in transverse fascia
*location: a point midway milli
ant sup. iliac spine og pubic symphysis
above inguinal ligg
relations: inf. epigastric vessels
spf inguinal ring
-externally (end of inguinal canal)
-triangular opening in aponeurosis of obliqus abd. externus
-superior to pubic tubercle
-lateral + medial crus att. to pubic tubercle og pubic symphysis
content inguinal canal
men: spermatic cord
women: round ligg. uterus
-genital br. of genitofemoral nerve
–> they enter thru deep ing. ring and exit thru spf. ing ring
*ilioinguinal nerve:
enters abd. wall posteriorly, by piercing internal surf of transversus abdominis
OG internal oblique muscle
–> enters inguinal canal and cont. down to exit thru spf inguinal canal
