Muscles in abdomen and thorax Flashcards
What is the function of the rectus abdominas
acts in opposition to erector spinae muscles to produce flexion of the lumbar spine and to keep it straight
What happens when all 3 muscles in the abdomen contract together
they raise the pressure in the abdominal cavity so when they airway is open the diaphragm is pushed up, causing air to leave the lungs.
What do flat muscles do when the larynx is closed
provides pressure needed to expel contents of rectum, bladder and uterus.
What does contraction of each flat muscle do
plays a part in lateral flexion of the lumbar spine and rotation of thoracic spine.
They protect the viscera.
Contraction is useful in throwing up and coughing.
What are the muscles of the thorax
pectoralis major, deltoid, pectoralis minor, serratus anterior
Where is the inguinal ligament located
along the anterior superior iliac spine to the pubic tubercle
Describe the location and origin of the rectus abdominas
originates on pubic symphysis and inserts along the costal margin and xiphoid process. It arises from 5th, 6th and 7th costal cartilages and inserts on the pubic crest.
What is the function of pyramidalis
it attaches pubis inferior to linea alba
What forms the inguinal ligament
the inferior margin of aponeurosis of the external oblique
What forms the linea alba
fusion of external oblique aponeurosis, transversus aponeurosis and overlying internal oblique aponeurotic layer
The layers of which muscle join at the linea alba
The anterior and posterior layers of the rectus abdominas
What is aponeurosis
flat tendonous sheets
What are the linea semilunaris
the white line on the left and right of the linea alba
What are tendonous intersections
the lines that go left to right on a six pack, it separates the rectus abdominas.
What covers the top 3/4 of the rectus abdominas
the rectus sheath
The anterior layer of the rectus sheath
. The anterior layer extends from the costal margin to pubis and is firmly attached to tendonous intersections
What does the arcuate line mark
the lower border of the posterior rectus sheath
What does the rectus sheath contain
rectus abdominis, super/inferior epigastric vessels, thoracoabdominal nerves (anterior rami of T7-T12 spinal nerves
What does the bottom 1/4 of the rectus abdominas have
a loose fascia between the back of the rectus and peritoneum
Anterior and posterior layers of the rectus sheath superior to the arcuate line
anterior: external oblique and one layer on internal oblique.
Posterior: one layer of internal oblique and transversus abdominas
Anterior and posterior layers of the rectus sheath inferior to the arcuate line
anterior: external oblique, internal oblique, transversus abdominis
posterior: transversalis fascia
Where does the transversus abdominis originate from
. It originates on the iliac crest and on the lateral parts of the inguinal ligament and is attached to the costal cartilages
Where does the transversus abdominis inferiorly insert
the pubic crest
What ribs does the transversus abdominis arise from
ribs 6-12 and from rib 12 to the ilium it arises from the edge of the thoracolumbar fascia
What is the lower border of the transversus abdominis like
has a short, free lower border
Where do the fibers of the transversus abdominis arise from
a thickening on the iliopsoas fascia
Direction of fibers of the transversus abdominis
The fibres run in a transverse direction, except the bottom fibres which run obliquely downwards
Where does the internal oblique originate from
originates on the iliac crest and the lateral part of the inguinal ligament on the thoracolumbar fascia
What ribs is the internal oblique associated with
ribs 9-12
Where do the lowest fibers of the internal oblique arise from
thickness of the iliopsoas fascia
How does the internal oblique end
It ends in internal oblique aponeurosis which fuses on the underside with the transversus aponeurosis. Also joined on its outer aspect by external oblique aponeurosis (cut edge of external oblique)
What are the direction of the internal oblique fibers
The fibres at the top pass superiorly medially (up + in), the middle fibres are less steep, then they become transverse then at the inguinal ligament they run downwards
What ribs is the external oblique associated with
ribs 5 -12, with the posterior part arising from ribs 10-12 and the anterior part arising from ribs 9-6
Where does the external oblique insert
on the outer iliac crest, lineal aba and xiphoid process
What is the line of origin for the serratus anterior and external oblique
a zig zag
How does the external oblique end
The anterior part ends in the external oblique aponeurosis which fuses with the other 2 to form the rectus sheath
What is the anterior border of the external oblique
It has a long free border from the anterior superior iliac sine to the pubic tubercle.
What is the posterior border of the external oblique
fleshy and inserts along anterior half od iliac crest and has a short border between rib 12 and iliac crest
Describe the direction of the fibres of the external oblique
The fibres at the side are down and in direction and at the front the fibres run in a down and medial direction.
which is more superior the deep inguinal ring or the superficial inguinal ring
deep inguinal ring
What are the layers of the inguinal canal
peritoneum, testis, transversalis fascia, transversus abdominus, internal oblique, external oblique, Scarpa’s fascia, skin
What are the layers of the spermatic cord from inside to outside
tunica vaginalis (parietal and visceral), internal spermatic fascia, cremaster muscle and fascia, external spermatic fascia, deep fascia
What is the spermatic cord surrounded by
fascial covering from each of the anterior abdominal layers: external spermatic fascia (external oblique fascia), cremasteric muscle and fascia (fascial around internal oblique), internal spermatic fascia (transversalis fascia)
What are the contents of the spermatic cord
ductus (vas) deferens, testicular artery, artery of ductus deferens, pampiniform venous plexus, cremasteric artery, sympathetic nerve fibers, genital branch of genitofemoral nerve, lymphatics
What is inside the inguinal canal in females
the round ligament
