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AAMJ
ISSN: 2395-4159
Case Report
Anveshana Ayurveda Medical Journal
Variation in Pattern of Rectus Sheath and Rectus Abdominis
muscle w.s.r. to Diastasis Recti
Teena Jain
1
Sunil Kumar Yadav 2
Abstract
In modern anatomy muscles are studied as a separate branch ‘Myology’. The name
muscle was given on the basis of the shape i.e. ‘Mouse-like’. Acharya Sushruta said
that 500 Peśi in the human male body and 520 in the female body. Out of 500 nearly 400 are present in the Śākha, 66 in the Koshtha and 34 in the Śiras. Rectus
abdominis is the muscle of anterior abdominal wall and covered into the rectus
sheath. Rectus sheath formed from the aponeurosis of antero-lateral group of abdominal muscles and this sheath fused in mid line and forms linea alba. Medial border of these two muscles close to median plane. But in this case some variation found
during dissection.
Key Words: Peśi, rectus abdominis muscle, rectus sheath, linea alba.
Ph.D Scholar, 2 Assistant Professor, Dept.of Sharir Rachana, National Institute of Ayurveda,
Jaipur, Rajasthan.
1
CORRESPONDING AUTHOR
Dr. TEENA JAIN
Ph.D. Scholar, Dept.of Sharir Rachana,
National Institute of Ayurveda,
Jaipur, Rajasthan
Email: [email protected]
AAMJ / Vol. 2 / Issue 4 / July – August 2016
Teena & Sunil : Variation in Pattern of Rectus Sheath and Rectus Abdominis muscle w.s.r. to Diastasis Recti
INTRODUCTION
wall. It is widest in the upper abdomen and lies just to
the side of the midline. The paired recti are separated
in the midline by the linea alba.
M
yology is the study of muscles. More than 600
skeletal muscles make up the muscular system,
and technically each one is an organ—it is
composed of skeletal muscle tissue, connective tissue,
and nervous tissue. Each muscle also has a particular
function, such as moving a finger or blinking an eyelid.
Collectively, the skeletal muscles account for approximately 40% of the body weight.
The muscle fibres of rectus abdominis are interrupted by
three fibrous bands or tendinous intersections. One is
usually situated at the level of the umbilicus, another
opposite the free end of the xiphoid process and a third
about midway between the other two. They usually fuse
with the fibres of the anterior lamina of the sheath of the
muscle.
According to Acharya Charaka Śarir (body) consists of
the following parts; the two arms, the two legs, the
head and neck, and the trunk. These make up the hexa
partite body[i].
The medial border of rectus abdominis is closely related
to the linea alba. Its lateral border may be visible on
the surface of the anterior abdominal wall as a curved
groove, the linea semilunaris, which extends from the
tip of the ninth costal cartilage to the pubic tubercle.
Same, according to Acharya Sushruta the human body
is composed of six main parts, namely the four extremities, the middle body and the head.[ii]



Attachments –
Rectus abdominis arises by two tendons. The larger,
lateral tendon is attached to the crest of the pubis and
may extend beyond the pubic tubercle to the pectineal
line. The medial tendon interlaces with the contralateral
muscle and blends with the ligamentous fibres covering
the front of the symphysis pubis. Additional fibres may
arise from the lower part of the linea alba.
Śākha- denotes to extremities.
Madhya Śarir or Antarādhi is the trunk which inturn
includes thorax and abdomen.
Śir and Grīva is head and neck. Head also includes face in it.
According to Acharya Sushruta there are 500 Peśi in
the human male body and 520 in the female body. Out
of 500 nearly 400 present in the Śākha, 66 in the
Kośtha and 34 in the Śiras.[iii] Muscle of abdomen &
thorax are nicely described by Sushruta. Sushruta has
described that 5 Peśi are present in the
Udara(abdominal) region.[iv]
Superiorly, rectus abdominis is attached by three slips
of muscle to the fifth, sixth and seventh costal cartilages.
The most lateral fibres are usually attached to the anterior end of the fifth rib. The most medial fibres are occasionally connected to the costoxiphoid ligaments and
the side of the xiphoid process.
Vascular supply-
Anterior Abdominal Wall[v]
The abdomen is roughly cylindrical chambers extending
from inferior margin of thorax to superior margin of
pelvis & the lower limb. The wall consists partly of bone
but mainly of muscles. The skeletal element of wall is
formed by various muscles. There are five muscles in
anterior abdominal wall or anteriolateral group. Three
flat muscles whose fibers begin postero-laterally pass
anteriorly & are replaced by aponeurosis as the muscles
continuous towards the midline by external oblique,
internal oblique & transverse abdominis muscles. Two
vertical muscles i.e. rectus abdominis muscle and
pyramidalis near the midlines which are enclosed within a tendinous sheath formed by aponeurosis of flat
muscles.
Mainly by the superior and inferior epigastric
arteries.

Partially from small terminal branches from the
lower three posterior intercostal arteries, the
subcostal artery, the posterior lumbar arteries
and the deep circumflex artery.
InnervationRectus abdominis is innervated by the terminal branches
of the ventral rami of the lower six or seven thoracic
spinal nerves via the lower intercostal and subcostal
nerves.
ActionsThe recti contribute to the flexion of the trunk. They also
contribute to the maintenance of abdominal wall tone
required during straining.
Rectus abdominis muscle
Rectus abdominis is a long, strap-like muscle that extends along the entire length of the anterior abdominal
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Teena & Sunil : Variation in Pattern of Rectus Sheath and Rectus Abdominis muscle w.s.r. to Diastasis Recti
Rectus sheath
Rectus abdominis on each side is enclosed by a fibrous
sheath. The rectus sheath is formed from decussating
fibres from all three lateral abdominal muscles. External
oblique, internal oblique and transversus abdominis
each forms a bilaminar aponeurosis at their medial
borders. Rectus sheath is divided into anterior and posterior laminae.
The arrangement of the layers has important variations
at different locations in the body.
Above costal margin - The anterior rectus sheath is
formed from aponeurosis of external oblique muscle. In
posterior side the sheath is deficient, so muscle is directly attached to the ribs.
Fig. No. 1 Normal Rectus Sheath and Rectus Abdominis
Muscle.
Between costal margin and arcuate line - The anterior
rectus sheath is composed of both leaves of the
aponeurosis of external oblique and the anterior leaf of
the aponeurosis of internal oblique fused together. The
posterior rectus sheath is composed of the posterior leaf
of the aponeurosis of internal oblique and both leaves
of the aponeurosis transversus abdominis.
CASE REPORT
During routine gross anatomy dissection of anterior abdominal wall in National Institute of Ayurveda, Jaipur
we observe a rare case of variation of left side of rectus
abdominis muscle and rectus sheath. Generally right
and left side of rectus abdominis muscle covers in rectus
sheath and this sheath fused in mid line and forms linea
alba. Medial border of these two muscles close to median plane. But in this case the medial border of left
side rectus abdominis muscle is away from median
plane and the space between two recti is formed. In this
space some defect is present i.e. hernia.
Below arcuate line - The anterior rectus sheath is composed of all three muscles. The posterior rectus sheath is
composed of only fascia transversalis.
Linea alba
The linea alba is a tendinous raphe extending from the
xiphoid process to the symphysis pubis and pubic crest.
It lies between the two recti and is formed by the interlacing and decussating aponeurotic fibres of external
oblique, internal oblique and transversus abdominis. It
is visible only in the lean and muscular, as a slight
groove in the anterior abdominal wall. A fibrous cicatrix, the umbilicus, lies a little below the midpoint of the
linea alba, and is covered by an adherent area of skin.
Below the umbilicus, the linea alba narrows progressively as the rectus muscles lie closer together. Above
the umbilicus, the rectus muscles diverge from one other
and the linea alba is correspondingly broader.
Materials and MethodologyMaterials
1. Available literature regarding rectus abdominis
muscle and rectus sheath from Modern texts.
2. Research Journals or papers presented on the related topics.
3. Authentic Internet sources.

For cadaveric dissection Study:
1. Cadaver: Female
2. Dissection kit
The linea alba has two attachments at its lower end: its
superficial fibres are attached to the symphysis pubis,
and its deeper fibres form a triangular lamella that is
attached behind rectus abdominis to the posterior surface of the pubic crest on each side. This posterior attachment of linea alba is named the ‘adminiculum
lineae albae'. The linea alba is crossed from side to
side by a few minute vessels.
AAMJ / Vol. 2 / Issue 4 / July – August 2016
For literary study:
Methodology
811
Literature Study: All the information regarding rectus abdominis muscle and rectus sheath was collected from modern texts, research journals or pa-
Teena & Sunil : Variation in Pattern of Rectus Sheath and Rectus Abdominis muscle w.s.r. to Diastasis Recti

Diastasis recti - This is commonly defined as a gap of
pers presented on the related topics and authentic
internet sources.
Cadaveric Study: - Cadaveric dissection was done
in the dissection hall of department of Śarira
Rachana of NIA, Jaipur. While studying the dissected cadaver, photo images were taken with the
help of digital camera.
Dissection of the anterior abdominal wall was done
on cadaver by using dissection kit; Cunningham’s
manual of practical anatomy, Grant’s Dissector and
Frank H. Netter for understanding the variation of
rectus abdominis muscle and rectus sheath.
roughly 2.7 cm or greater between the two sides of the
rectus abdominis muscle. This condition has no associated morbidity and mortality. The distance between the
right and left rectus abdominis muscle is created by the
stretching of the linea alba. Diastasis of this muscle occurs principally in two populations; newborns and
pregnant women.
Women are more susceptible to develop diastasis recti
when over the age of 35, high birth weight of child,
multiple birth pregnancy, and multiple pregnancies.
Additional causes can be attributed to excessive abdominal exercise after the first trimester of pregnancy.
DISCUSSION
Diastasis recti may appear as a ridge running down the
midline of the abdomen, anywhere from the xiphoid
process to the umbilicus.
Rectus abdominis muscle is the vertical muscle of anterior abdominal wall. These are paired muscle and covered in rectus sheath. Rectus sheath is formed from
aponeurosis of external oblique, internal oblique and
transversus abdominis muscle. The right and left side of
rectus sheath fused in midline and formed linea alba.
When we dissected female cadaver we found that the
medial border of left side rectus abdominis muscle is
away from median plane and the space between two
recti is formed. This case represents the diastasis recti
also known as abdominal separation.
During dissection we found that some structures bulge
out below the umbilicus and the gap between two recti.
This structure may be abdominal viscera or the only
peritoneum. This bulging is not true herniation, because
all the layers of the abdominal wall in that region are
intact.
CONCLUSION
Rectus abdominis is the muscle of anterior abdominal
wall and covered in rectus sheath. In this case, a gap
present between two recti muscles and linea alba is not
clearly defined. Some structures may be abdominal viscera or membrane bulge out in this gap below the umbilicus. In this site where the bulging present, all the
layers of the abdominal wall are intact, so it is not true
hernia.
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Fig. 2 Abnormal Rectus Sheath and Rectus Abdominis
Muscle
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Teena & Sunil : Variation in Pattern of Rectus Sheath and Rectus Abdominis muscle w.s.r. to Diastasis Recti
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ii.
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iv.
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AAMJ / Vol. 2 / Issue 4 / July – August 2016
v.
Grey’s anatomy for students- byRichard L Drake, Wayne
Vogl, Adam W.M. Mitchell –Elsevier Churchil Philadelphia Edinburgh London 2005 international edition ISBN0808923064 –page no.-246-250.
Source of Support: Nil.
Conflict of Interest: None declared
How to cite this article: Teena & Sunil : Variation in Pattern
of Rectus Sheath and Rectus Abdominis muscle w.s.r. to
Diastasis Recti. AAMJ 2016; 4:809 – 813
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