Abdominal region and muscles

Question 1

What is the purpose of abdominal muscles

Answer 1

Give the body a base of support for the upper limbs to work from and for UL muscle to attach onto

Question 2

What is the inferior and superior boundary of abdominal region

Answer 2

Inferior boundary= pelvic floor

Superior boundary= diaphragm

Question 3

How many abdominal regions are there

Answer 3

9

Question 4

What are the trans-planes of abdominal region

Answer 4

Trans-pyloric plane= halfway b/w supra-sternal and pubic symphysis (about 10th costal cartilage level=L1)
Trans-umbilical plane= umbilicus= L3-4 level
Trans-tubercular plane= tubercles of iliac crest= L5
Subcostal plane= inferior points of costal margin= approx L3

Question 5

Define the abdominal walls

Answer 5

Anterior wall= RA and obliques
Posteriorly= Lx vertebrae column and muscles (quad lam)
Laterally= 3 abdominal muscles (EO, IO, TA= comibine to form rectus sheath)

Question 6

What is the linea alba

Answer 6

Linea alba= white line formed from excess cross over of 3 connective tissue layers from abdominal muscles

Question 7

What is the rectus sheath

Answer 7

sheath of connective tissue that encloses the rectus abdominis and pyramidalis muscle

Question 8

How is the rectus sheath formed

Answer 8

Made up of 3 antero-lateral muscle aponeurosis:
External obliques–> goes anterior to RA
Internal Obliques–> splits, and goes front and behind RA (encapsulates RA), under umbilical, IQ only goes in front of RA
Transverse abdominis–> goes posterior to RA
All 3 muscles blend from muscle belly to connective tissue/tendon at the semilunar line
These connective tissues attach at the midline, creating a crossing over/doubling up of connective tissue forming a dense line of connective tissue=linea alba

Question 9

How does the rectus sheath change below the umbilicus

Answer 9

Approx halfway between umbilicus and pubis, all aponeurosis pass anterior to RA
TA and IQ aponeurosis merge and pass superifcially to rectus muscle

Question 10

What is the arcuate line

Answer 10

The line where TA and IQ pass anteriorly to RA below umbilicus, creates a thick connective tissue called arcuate line
It is halfway between umbilicus and pubis
Above arcuate line= RA has rectus sheath anteriorly and posteriorly
Below arcuate line= all muscles at front, RA resting on transversalis fascia

Question 11

Why is the arcuate line important

Answer 11

Site of entry of the inferior epigastric artery into rectus sheath
Site of weakness-> site of spigelian hernia

Question 12

What are the rectus sheath borders

Answer 12

Lateral borders= mid-clavicular line

Anterior and posterior= decussation of fibres

Question 13

What is the proximal and distal attachments, nerve innervation and action/function of pyramidalis

Answer 13

Origin= pubis and anterior pubic ligament
Insertion= linea alba (approx halfway b/w umbilicus and pubis)
Innervation= subcostal nerve (ventral rami T12 spinal nerve)
Action/function= tension of linea alba

Question 14

What is the inguinal canal

Answer 14

short passage that extends inferiorly and medially through the inferior part of the abdominal wall
Superior and parallel to the inguinal ligament
Canal serves as a pathway by which structures can pass from the abdominal wall to external genitalia

Question 15

What is the clinical relevance of the inguinal canal

Answer 15

point of potential weakness in the abdominal wall and hence a common site of herniation
During increased intra-abdominal pressure, abdominal viscera are pushed into the posterior wall of inguinal canal to prevent herniation of viscera into the canal, the muscles of anterior and posterior wall contract and ‘clamp down’ on the canal

Question 16

What are the boundaries of the inguinal canal

Answer 16

Anterior wall= aponeurosis of external oblique, reinforced by internal oblique muscle laterally
Posterior wall= transversalis fascia and conjoint tendon
Roof= transversalis fascia, internal oblique and TA arching fibres
Floor= Inguinal ligament, thickened medially by lacunar ligament

Question 17

How is the inguinal ligament formed

Answer 17

it is a ‘rolled up’ portion of the EQ aponeurosis

Question 18

What are the openings of the inguinal canal

Answer 18

2 openings of inguinal canal= deep and superficial ring

Question 19

Describe the deep ring of inguinal canal

Answer 19

Deep (internal) ring: found above midpoint of inguinal ligament–> which is lateral to epigastric vessels; rig created by the transversalis fascia which invaginates (actions of being turned inside out) to form a covering of the contents of inguinal canal

Question 20

Describe the superficial ring of inguinal canal

Answer 20

Superficial/external ring
Marks end of inguinal canal, lies just superior to pubic tubercle
Triangle shaped opening–> formed by envagination (process of turning outward/inside out) of EQ which forms another covering of the inguinal canal contents
Opening contains intercrural fibres which run perpendicular to aponeurosis to EQ and prevent ring from widening= herniation

Question 21

What are the contents of the inguinal canal in a male

Answer 21

Spermatic cord–> supples and drains the testies
Testicular descent–> brings arteries, veins, nerves, lymphatics and excretory ducts through spermatic cord
2 Stages:
7-12 weeks of fetal life, descents into inguinal canal
7-9 months descents into scrotum
Males are at the greater risk of hernias then females due to the spermatic cord through the canal, hence increasing weakness

Question 22

What are the contents of the inguinal canal in females

Answer 22

Smaller, round ligament around uterus–> on its way to labia majora
Walls are usually collapsed around their contents, preventing other structures from potentially entering the canal

Question 23

What is the conjoint tendon

Answer 23

Medial fibres of IQ aponeurosis uniting with deeper fibres of TA aponeruosis
Conjoint tendon then turns inferiorly and attaches onto pubic crest and pectin pubis
Forms part of the posterior wall of inguinal canal

Question 24

What are the effects of abdominal proturberance

Answer 24

Abdominal laxity produces protuberance
When increased abdominal protuberance is greater than abdominal strength it creates anterior pelvic tilt
t/f increased lordosis
t/f increased potential ‘unstable’ L5-S1 joint
t/f thoracic kyphosis increased (to balance Lx lordosis)
t/f anterior cervical convexity increases (to put head above sacrum)
t/f vertebral body compresssions/disc compressions
chnages in biomechanics
changes in wt distribution through vertebral column
changes in trabeculae pattern
Hence abdominal laxity creates proturerance creates changes in posture

Question 25

What is diastasis

Answer 25

diastasis recti
separation of rectus abdominis muscles–> separation of linea alba
Common during pregnancy–. increasing size/abdominal pressure+ relaxin+connective tissue
Can also occur in obese
Connective tissue is not able to withstand force/pressure hence linea alba separates and no longer holds the stomach ‘in’

Question 26

What is osteitis pubis

Answer 26

Basically unstable/upset symphysis pubis
From unstable SIJ t/f microtrauma- sheering forces
Muscle imbalances
Abdominals and adductors decussation at pubic symphysis- pulling on the articular surface t/f sclerotic changes on x-ray

Question 27

What is inguinal hernia

Answer 27

footballers hernia
Posterior inguinal wall weakness
may or may not require surgery