Banking (ICSE Class 10 Mathematics Project)

ANTERIOR ABDOMINAL WALL
RECTUS SHEATH UNDER THE FOLLOWING HEADINGS:FORMATIONS AT DIFFERENT LEVELS,CONTENTS, APPLIED ANATOMY(LE)


Rectus sheath is an aponeurotic sheath covering the rectus abdominis muscle
It has 2 walls- anterior and posterior.
Anterior wall- completely covers the muscle from end to end.
It is firmly adherent to tendinous intersections of the rectus muscle


Posterior wall – is incomplete, being deficient above the costal margin and below the                             arcuate line
  It is free from the rectus muscle





Formation
Above the costal margin:
Anterior wall- external oblique aponeurosis
Posterior wall- deficient, rectus muscle rests on 5th,6th, 7th costal cartilages.
Between the costal margin and arcuate line
Anterior wall- external oblique aponeurosis
                                           Anterior lamina of internal oblique aponeurosis


Posterior wall- posterior lamina of internal oblique aponeurosis
Aponeurosis of transverses muscle


Below the arcuate line
Anterior wall – aponeurosis of all the 3 flat muscles of abdomen
Posterior wall – deficient. The rectus muscle rests on fascia transversalis.

      
Content:
          Muscle,
Rectusabdominis,
 Pyramidalis




Arteries
Superior epigastric artery – terminal branch of internal thoracic artery
Inferior  epigastric artery- a branch of external iliac artery


Veins
Superior epigastric vena comitantes join the internal thoracic vein
Inferior epigastric vena comitantes join the external iliac vein


Nerves
     Terminal branches of lower six thoracic nerves


Functions
Checks bowing of rectus muscles during its contraction and thus increases the efficiency of the muscle
Maintains the strength of anterior abdominal wall.


New concept of rectus sheath formation
The aponeurosis of all the flat muscles of abdomen are bilaminar thus giving 6 laminae in all. Three layers form the anterior wall and three layers form the posterior wall of the rectus sheath.


















Clinical anatomy
Divarication of recti
Separation of two rectus muscles occurs in elderly multiparous women with weak     abdominal muscles. Hernia sac containing loops of intestine protrude forward     between the widely separated recti.


Hematoma of rectus sheath-
Superior and inferior epigastric arteries are unduly stretched during a severe     bout of coughing or in later months of pregnancy, which ruptures when subjected to trauma. Thus an hematoma is formed within the rectus sheath.


Epigastric hernia-
The lineaalba is formed by the interlacing of aponeurotic fibres of the three          abdominal muscles. It is wider above the umbilicus and narrow below it . The part     becomes weak in elderly multiparous women. Raised intra abdominal  causes a small     amount of extraperitoneal fat along with a small containing greater omentum to protrude through the upper part of linea alba epigastric hernia.




UMBILICUS(SE)


Umbilicus is the normal scar in the anterior abdominal wall formed by the remnants of root of umbilical cord.
Position
In healthy adults it lies  in the anterior median plane at the level of disc between L3 and L4 vertebra.
It is lower in infants and in persons with pendulous abdomen.


Anatomical significance
The level of umbilicus serves as watershed line for venous and lymphatic drainage.
 The venous blood and lymph flow upwards above the umbilicus and downwards below the umbilicus.
It indicates the level of T10 dermatome.
It is one of the important sites of portocaval anastomosis.


Embryological significance
It is the meeting point of four folds of embryonic plate.
In embryonic life , a defect exists in linea alba at this site called umbilical ring which provides passage to
Midgut loop which herniates into the umbilical cord during 10th – 12th weeks of intrauterine life.
Two endodermal loops- allantois and vitellointestinal duct
Umbilical vessels
















Clinical aspects
Congenital anomalies
Fecal fistula
Urinary fistula
Exomphalos
     Congenital umbilical hernia











 ANTERIOR ABDOMINAL WALL – BLOOD SUPPLY(SE)















Anterior abdominal wall is supplied by
Cutaneous arteries
Deep arteries


Cutaneous arteries
Cutaneous branches of superior and inferior epigastric arteries
Cutaneous branches of posterior intercostals arteries
Superficial branches of femoral artery- superficial external pudendal, superficial epigastric and  superficial circumflex iliac arteries


Cutaneous veins-





They accompany the arteries and drain as follows
Below the umbilicus- into the great saphenous vein – into inferior venacava
Above the umbilicus- into axillary vein – superior venacava.
Deep arteries
Superior epigastric  and musculophrenic arteries
inferior epigastricand deep circumflex iliac arteries
small branches of intercostals, subcostal and lumbar arteries.




EXTERNAL OBLIQUE MUSCLE(SE)
External oblique muscle is one of the three flat muscles of the abdomen,
Origin
Arises from eight fleshy slips from the outer surface ( middle of shaft) of lower eight ribs.













Insertion
The fibres run downward , forward and medially
Most of the posterior fibres pass vertically downwards to be inserted on the     anterior 2/3 of outer lip of iliac crest. Posterior border of muscle is free
The remaining fibres end in a aponeurosis which is inserted into linea alba extending from xiphoid process to pubic symphysis.


The upper border of aponeurosis is free and is overlapped by pectoralis major     muscle.
The lower border of aponeursis is free, thickened and rolled inwards to form the inguinal ligament
Just above the pubic crest the aponeurosis presents a triangular aperture called     superficial inguinal ring.
Nerve supply
Lower six thoracic nerves


Actions
Supports and protects the abdominal viscera
Compresses the abdominal viscera as in expulsive acts like micturition, defecation, vomiting
Forceful expiratory acts like coughing , sneezing .
Movements of the trunk- lateral flexion and rotation.


RECTUS ABDOMINIS(SE)
Rectus abdominis is a long , flat strap muscle extending vertically upwards along the     linea alba from pubic symphysis below to the costal margin above.
Origin
The muscle arises by two twotendinous heads
Lateral head from lateral part of pubic crest.
Medial head from anterior pubic ligament









Insertion
By four fleshy slips  along a horizontal line passing laterally from xiphoid process to     5th,6th and 7th costal cartilages


The muscle presents three tendinous intersections
Opposite to umbilicus
Opposite to free end of xiphoid process
Midway between the above two


The muscle is enclosed in aaponeurotic sheath derived from the three flat muscles of the abdomen.
Each tendinous intersection is attached to the anterior wall of rectus sheath and they     divide the long muscle column into shorter segments to provide more strength.


Nerve supply
Lower six thoracic nerves




Action
1. Flexion of the trunk at the lumbar region
2. It tenses the linea alba


















CONJOINT TENDON(SE)
Spermatic cord

Conjoint tendon ( falxinguinalis) is formed by the fusion of lower aponeurotic fibres of internal oblique and transverses abdominis muscles which arches over the spermatic cord and is attached to the pubic crest and medial part of pectin pubis.


It forms the medial half of the posterior wall of inguinal canal and strengthens the anterior abdominal wall opposite the superficial inguinal ring.
Medially it blends with the anterior wall of rectus sheath.
Laterally it may extend upto the interfoveolarligament( thickening in fascia transversalis along the medial border of deep inguinal ring) .


The weakening of Conjoint tendon due to old age or injury to iliohypogastric or ilioinguinal nerves predisposes the occurrence of direct inguinal hernia.


RECTUS SHEATH- FORMATIONS , CONTENTS AND APPLIED ANATOMY(SE)
Rectus sheath is an aponeurotic sheath covering the rectus abdominis muscle
It has 2 walls- anterior and posterior.
Anterior wall- completely covers the muscle from end to end.
It is firmly adherent to tendinous intersections of the rectus muscle


           Posterior wall – is incomplete, being deficient above the costal margin and below the arcuate                 line
It is free from the rectus muscle
Formation
Above the costal margin:
Anterior wall- external oblique aponeurosis
Posterior wall- deficient, rectus muscle rests on 5th,6th, 7th costal cartilages.


Between the costal margin and arcuate line
Anterior wall- external oblique aponeurosis
                                            Anterior lamina of internal oblique aponeurosis
Posterior wall- posterior lamina of internal oblique aponeurosis
           Aponeurosis of transverses muscle


Below the arcuate line
Anterior wall – aponeurosis of all the 3 flat muscles of abdomen
Posterior wall – deficient.the rectus muscle rests on fascia transversalis.







Contents
Muscles
Rectus abdominis
Pyramidalis
Arteries
 Superior epigastric artery – terminal branch of internal thoracic artery
  Inferior  epigastric artery- a branch of external iliac artery


Veins
Superior epigastric vena comitantes join the internal thoracic vein
Inferior epigastric vena comitantes join the external iliac vein


Nerves
    Terminal branches of lower six thoracic nerves


Functions
Checks bowing of rectus muscles during its contraction and thus increases the efficiency of the muscle
Maintains the strength of anterior abdominal wall.


New concept of rectus sheath formation
     The aponeurosis of all the flat muscles of abdomen are bilaminar thus giving 6 laminae in     all.three layers form the anterior wall and three layers form the posterior wall of the rectus  sheath


.




PHYSIOLOGICAL UMBILICAL HERNIA(SA)


     During the 5th – 10th week of intrauterine life the midgut loop herniates into the extra-     embryonic part of coelomic cavity. Thus the midgut loop appears as a content of     physiological umbilical hernia. This loop  returns back to the abdominal cavity during the     10th- 12th week of intrauterine life.
Persistence of this  in new born is called exomphalos.


RASPBERRY TUMOUR(SA)


The vitellointestinal duct communicates the primitive midgut with the extra- embryonic     part of yolk sac.
In 98% cases the duct disappears.
When the distal part of the duct persists, it may discharge mucus at the surface     ,evaginating the surface at the umbilicus producing raspberry red tumour( cherry red     tumour).


TRANSPYLORIC PLANE AND STRUCTURES LIE ON IT(SA)
It is an imaginary horizontal plane.
Anteriorly – it passes through the tips of 9th costal cartilages and posteriorly through     the lower part of the body of L1 vertebra. This plane lies midway between the     suprasternal notch and pubic symphysis.
Structures lying at the level of this plane
Pylorus of stomach
Fundus of gall bladder
Hila of both kidneys


ILIOINGUINAL NERVE(SA)
It is the anterior primary ramus of L1 spinal nerve
It pierces the internal oblique muscle below and lateral to iliohypogastric nerve and     enters the inguinal canal.
The nerve runs along the inferolateral side of spermatic cord and comes out through the     superficial inguinal ring.
It has no lateral cutaneous branch.




INGUINAL LIGAMENT(SA)
 The inguinal ligament is formed by the lower border of external oblique aponeurosis which     is thickened and folded backwards on itself.
It extends from the anterior superior iliac spine to the pubic tubercle.
The lateral half of the ligament is rounded and oblique and the medial half is grooved     upwards and horizontal.


Lower border – attachment of fascia lata
Upper surface- lateral2/3rd  - internal oblique
• Lateral 1/3rd- transversus abdominis
                Middle part – cremaster muscle




CREMASTRIC REFLEX(SA)
Upon stroking the skin of the upper medial aspect of thigh, there is reflex contraction of     cremaster muscle leading to elevation of testis.
This reflex is more brisk in children.
Afferent limb- femoral branch of genitofemoral nerve
Efferent limb- Genital  branch of genitofemoral nerve
Reflex center- LI and L2 spinal segments


PYRAMIDALIS MUSCLE(SA)
It is a small triangular muscle lying anterior to the lower part of rectus abdominis     muscle.
This muscle lies within the rectus sheath.
Apex is directed above and medially and base lies in front of the pubis.
It is rudimentary in human beings.
Nerve supply – subcostal nerve
Action –It tenses the lineaalba


NERVE SUPPLY TO PYRAMIDALIS AND DARTOS MUSCLE(SA)
Pyramidalis
     It is supplied by subcostal (T12) nerve.
Dartos muscle
It is supplied by sympathetic fibres through genital branch of genitofemoral nerve.


RECTUS SHEATH- MUSCLES FORMING, CONTENTS(SA)
Contents
Muscles
Rectus abdominis
Pyramidalis
Arteries
Superior epigastric artery – terminal branch of internal thoracic artery
Inferior  epigastric artery- a branch of external iliac artery
Veins
Superior epigastric vena comitantes join the internal thoracic vein
          inferior epigastric vena comitantes join the external iliac vein
Nerves
Terminal branches of lower six thoracic nerves


MENTION THE LAYERS PRESENT IN THE ANTERIOR WALL OF RECTUS SHEATH AT DIFFERENT LEVELS(SA)
Above the costal margin:
Anterior wall- external oblique aponeurosis
Between the costal margin and arcuate line
Anterior wall- external oblique aponeurosis
                                      -Anterior lamina of internal oblique aponeurosis
Below the arcuate line
Anterior wall – aponeurosis of all the 3 flat muscles of abdomen








ARCUATE LINE(SA)
The posterior wall of the rectus sheath, at the level midway between the pubic symphysis     and umbilicus, ends in an arcuate line or lineasemicircularis( fold of douglas).
The line is concave downwards.
Below the level of arcuate line the anterior wall of rectus sheath is formed by the     aponeurosis of all three muscles of abdomen.


DESCRIBE INGUINAL CANAL UNDER FOLLOWING HEADINGS  (a)LOCATION & EXTENT 
 (b)BOUNDARIES (c) CONTENTS (d) APPLIED ANATOMY. ADD A NOTE ON INGUINAL HERNIAS. MENTION FACTORS PREVENTING INGUINAL HERNIAS(LE)      
         Inguinal canal is a musculoaponeurotic canal
Location & Extent
             It is located in the lower part of anterior abdominal wall, just above the medial half of inguinal     ligament.
          It extends from deep inguinal ring to superficial ingunal ring.
                                                  



Boundaries
                         



                                   

Deep inguinal ring:
It is an oval gap in fascia transversalis situated about 1.25 cm above the midinguinal point &     lateral to stem of inferior epigastric artery.
Superficial inguinal ring:
It is a triangular gap in external oblique aponeurosis
Anterior wall: from outwards to inwards
             Skin
             Superficial fascia
             External oblique aponeurosis
             Internal oblique muscle (only in lateral 1/3)
Posterior wall: from inwards to outwards
             Parietal peritoneum
             Extraperitoneal fat
             Fascia transversalis
             Internal oblique muscle (only in medial 2/3)
             Conjoint tendon (only in medial ¼)
         Roof:
             Arching fibres of
             Internal oblique muscle
             Transversus abdominis
          Floor:
             Inguinal ligament’s grooved upper surface
             Lacunar ligament (at medial end)


   Contents
     Spermatic cord in males or Round ligament of uterus in females
     Ilioinguinal nerve
  Applied anatomy
          Inguinal hernia:
              Protrusion of any of the abdominal contents through the inguinal wall or inguinal canal is called     inguinal   


         
 Hernia
          Types of inguinal hernia:
Direct inguinal hernia
           Indirect inguinal hernia

		Direct inguinal hernia	Indirect inguinal hernia
1.	Congenital / Acquired	Acquired	Congenital Acquired
2.	Etiology	Weakness of Abdominal wall muscles	Persistence of patent processus vaginalis
3.	Age	Old	Children ,Young age
4.	Unilateral / bilateral	Bilateral	Unilateral / bilateral
5.	Relation to inferior epigastric artery	Medial	Lateral
6.	Enters inguinal canal  through	Inguinal triangle	Deep inguinal ring





 Factors preventing inguinal hernias:
Obliquity of inguinal canal- since the inguinal canal is oblique, the anterior & posterior walls are
       approximated like flap valve when the intra abdominal pressure is raised.
Superficial inguinal ring is guarded from behind by conjoint tendon
Deep inguinal ring is guarded from front by internal oblique muscle
Shutter mechanism of internal oblique muscle
Contraction of cremaster pulls the testis upwards & superficial inguinal ring is plugged by     spermatic cord (ball valve mechanism)
Contraction of external oblique results in approximation of 2 crura of superficial inguinal ring (slit mechanism)
INGUINAL CANAL – BOUNDARIES AND CONTENTS(SE)           
Inguinal canal is a musculoaponeurotic canal, which is located in the lower part of anterior     abdominal wall, just above the medial half of inguinal ligament.
It extends from deep inguinal ring to superficial ingunal ring.
It is about 4 cm long
                                                    



Boundaries
                                                  
                       



                               



  Deep inguinal ring:
It is an oval gap in fascia transversalis situated about 1.25 cm above the midinguinal point &     lateral to 
 stem of inferior epigastric artery
Superficial inguinal ring:
It is a triangular gap in external oblique aponeurosis
Base is formed by pubic crest
2 sides of triangle are called as medial & lateral crura














Anterior wall: from outwards to inwards
             Skin
             Superficial fascia
             External oblique aponeurosis
             Internal oblique muscle(only in lateral 1/3)
Posterior wall: from inwards to outwards
              Parietal peritoneum
               Extraperitoneal fat
             Fascia transversalis
              Internal oblique muscle (only in medial 2/3)
              Conjoint tendon (only in medial ¼)
         Roof:
         Arching fibres of
             Internal oblique muscle
             Transversus abdominis
          Floor:
             ligament’s grooved upper surface
 ligament (at medial end)      
     
  Contents
 Spermatic cord in males or Round ligament of uterus in females
 2Ilioinguinal nerve


SPERMATIC CORD – COVERINGS AND CONTENTS (SE)     
Coverings of spermatic cord :
  From within outwards,
       Internal spermatic fascia – derived from fascia transversalis
  Cremasteric fascia – derived from the internal oblique muscle
        External spermatic fascia – derived from external oblique aponeurosis
                          



Contents of spermatic cord:
Vas deferens
Artery to vas deferens & sympathetic plexus around it
Cremasteric artery
Testicular artery
Pampiniform plexus of veins
Lymphatics from testis
Genital branch of Genitofemoral nerve
Remains of processus vaginalis


                                                  





PROTECTIVE MECHANISM OF INGUINAL CANAL (SE)                  
     Obliquity of inguinal canal
        Superficial & Deep inguinal ring don’t lie opposite to each other
        When intra abdominal pressure rises, anterior & posterior walls of canal approximate with each     other like a flap valve & obliterates the passage
     Guarding of inguinal rings
         Superficial inguinal ring is guarded from behind by conjoint tendon
         Deep inguinal ring is guarded from front by internal oblique muscle
     Shutter mechanism of internal oblique muscle
        Tmuscle forms the anterior wall, roof, floor of inguinal canal
        When the muscle contracts, the roof approximates to the floor like a shutter
     Ball valve mechanism
        Contraction of cremaster pulls the testis upwards & superficial inguinal ring is plugged by spermatic cord
     Slit valve mechanism
        Contraction of external oblique results in approximation of  2 crura of superficial inguinal ring like a     slit valve












INGUINAL HERNIA – TYPES & COVERINGS                     
          Protrusion of any of the abdominal contents through the inguinal wall or inguinal canal is called inguinal Hernia
Types of inguinal hernia:
      Direct inguinal hernia
  Indirect inguinal herni
                                                 
                                      


		Direct inguinal hernia	Indirect inguinal hernia
1.	Definition	protrusion of abdominal contents occurs through the weak posterior wall of inguinal canal  (Hesselbach’s triangle)	protrusion of abdominal contents occurs through the deep inguinal ring
2.	Congenital / Acquired	Acquired	Congenital or Acquired
3.	Etiology	Weakness of Abdominal wall muscles, factors increasing intra abdominal pressure like chronic cough, constipation	Persistence of patent processus vaginalis
4.	Age	Old	Children ,Young age
5.	Unilateral / bilateral	Bilateral	Unilateral / bilateral
6.	Relation to inferior epigastric artery	Medial	Lateral
7.	Enters inguinal canal  through	Inguinal triangle	Deep inguinal ring
8.	Hernial sac neck	wider	Narrow
9.	Coverings	From within outwards, Peritoneum Extra peritoneal tissue Fascia transversalis Cremasteric fascia External spermatic fascia Skin	From within outwards, Peritoneum Extra peritoneal tissue Internal spermatic fascia Cremasteric muscle & fascia External spermatic fascia skin

                                                       
 Coverings of indirect inguinal hernia         
fascia
fascia
                                        

                                                        


Coverings of direct inguinal hernia
fascia
                                                         

        


   


6.INDIRECT INGUINAL HERNIA (SE)
Indirect inguinal hernia is protrusion of abdominal contents through the deep inguinal ring
may be congenital/ acquired
              congenital – due to patency of processus vaginalis
              acquired – due to increased intra abdominal pressure
occurs in children ,young adults
predisposing factor is partial or complete patency of processus vaginalis.
may be unilateral or bilateral
hernia sac neck is narrower
lies lateral to inferior epigastric artery
Coverings:
      From within outwards,
Peritoneum
Extra peritoneal tissue
Internal spermatic fascia
Cremasteric muscle & fascia
External spermatic fascia
skin
fascia
fascia
                                      

         
  
RELATION OF INFERIOR EPIGASTRIC ARTERY TO DEEP INGUINAL RING (SE)
 Inferior epigastric artery is a branch of external iliac artery & arises just above the inguinal  ligament
  Deep inguinal ring lies lateral to stem of inferior epigastric artery
                                                                 





INGUINAL RINGS (SUPERFICIAL/DEEP) (SA)
   Deep inguinal ring:
Is an oval gap in fascia transversalis situated about 1.25 cm above the midinguinal point & lateral to 
 Stem of inferior epigastric artery
   Superficial inguinal ring:
Is a triangular gap in external oblique aponeurosis
Base is formed by pubic crest
2 sides of triangle are called as medial & lateral crura


MENTION THE CONTENTS OF INGUINAL CANAL    (SA)
   Spermatic cord in males or Round ligament of uterus in females (entire content)
   Ilioinguinal nerve (partial content )– enters canal by piercing internal oblique muscle about 2.5 cm      below  &  medial to anterior superior iliac spine. It is situated superficial to spermatic cord


  CONTENTS OF INGUINAL CANAL IN FEMALE     (SA)
    Round ligament of uterus (entire content)
    Ilioinguinal nerve (partial content )– enters canal by piercing internal oblique muscle about 2.5 cm below & medial to anterior superior iliac spine. It is situated superficial  round ligament


  INGUINAL TRIANGLE - BOUNDARIES    (SA)        
      Inguinal triangle is bounded
           Medially – lateral border of rectus abdominis
           Laterally – inferior epigastric artery
           Below – inguinal ligament
           Floor – peritoneum, extra peritoneal tissue, fascia transversalis






                                                

    It is divided into medial & lateral parts by obliterated umbilical artery/ medial umbilical ligament                                       












 HESSELBACH’S TRIANGLE (SA)




                                                    

     


Inguinal triangle is bounded
           Medially – lateral border of rectus abdominis
           Laterally – inferior epigastric artery
           Below – inguinal ligament
    It is divided into medial & lateral parts by obliterated umbilical artery/ medial umbilical ligament
    Direct inguinal hernia occurs through this triangle when there is weakness of abdominal wall


SPERMATIC CORD – COVERINGS, CONTENTS    (SA)
Coverings of spermatic cord:
  From within outwards,
  Internal spermatic fascia – derived from fascia transversalis
  Cremasteric fascia – derived from the internal oblique muscle
  External spermatic fascia – derived from external oblique aponeurosis


Contents of spermatic cord:
Vas deferens
Artery to vas deferens & sympathetic plexus around it
Cremasteric artery
Testicular artery
Pampiniform plexus of veins
Lymphatics from testis
Genital branch of Genitofemoral nerve
Remains of processus vaginalis


NAME THE STRUCTURES PROTECTING THE SUPERFICIAL & DEEP INGUINAL RING (SA)
         Superficial inguinal ring is guarded from behind by conjoint tendon & reflected part of inguinal 
          ligament
         Deep inguinal ring is guarded from front by internal oblique muscle








SITES OF HERNIA IN THE ABDOMEN (SA)
     External sites:
Epigastric region
Umbilicus
Paraumbilical region
Inguinal region
 Lumbar region
Incisional hernia
     Internal sites:
     Paraduodenal recess
Epiploic foramen
  
COVERINGS OF OBLIQUE INGUINAL HERNIA (SA)   
     From within outwards
      Peritoneum
      Extra peritoneal tissue
      Internal spermatic fascia
      Cremasteric muscle & fascia
      External spermatic fascia
      Skin.


THE DIFFERNCE BETWEEN DIRECT AND INDIRECT INGUINAL HERNIA (SA)



		INDIRECT INGUINAL HERNIA	DIRECT INGUINAL HERNIA
1	Aetiology	Preformed sac	Weakness of posterior wall of inguinal canal
2	Precipitating	-	Chronic bronchitis, enlarged prostate
3	On standing	Does not come out	Come out
4	Direction of the sac	Sac comes through the deep inguinal ring	It comes out of Hesselbachs triangle
5.	Obstruction	Common, as neck is narrow	Not common because neck is wide
6.	Internal ring occlusion test	Not seen	The swelling is seen