Anomalies of intestinal rotation and fixation

Anomalies

of Intestinal

Rotation

and Fixation J. RICHARD REES, M.D. AND S. FRANK

From the Department of Surgery,The New York HospitalCornell UnGtersityMedical Center, New York, New

REDO, M.D.,New York, New York

Early Embryonic &ye. By the fourth to fifth week of embryonic life the fetal alimentary tract may be divided into the foregut, midgut, and hindgut on the basis of body position and blood supply. The midgut, our area of concern, is supplied by the superior mesenteric artery and may be divided into the prearterial loop (duodenojejunal) and the postarterial loop (cecocolic). To understand normal intestinal rotation, consider the superior mesenteric artery as the rotational axis of the midgut loop and the vitello-intestinal duct as continuous with its apex. First Stage: Fourth to Tenth Week of Embryonic Life. The midgut is present in the embryonic sac and is rapidly elongating, as is its mesentery. At the same time it is rotating from a saggital to a horizontal plane. The preand postarterial segments each rotate 90 degrees counterclockwise with respect to the superior mesenteric artery axis. Second Stage: Tenth to Eleventh Week of Embryonic Life. The entire midgut loop returns to the celomic cavity, the prearterial loop preceding the postarterial loop and each loop rotating an additional 180 degrees counterclockwise with respect to the superior mesenteric artery axis. Thus, at the end of this stage, the duodenojejunal loop lies posterior to the cecocolic loop and under the superior mesenteric artery and the cecum occupies the right upper quadrant. Each loop has now rotated 270 degrees with respect to the starting point, at the same time elongating. Third Stage: Twelfth Week to Fifth Month of Embryonic Life. This is a stage of fixation of the intestine and fusion of the mesentery with descent of the cecum into the right lower quadrant. The mesentery of the small bowel be-

York.

of intestinal rotation and fixation ANora4LIEs are both uncommon and perplexing. Recent experience with three patients with such problems prompted an analysis of our records and a review of this subject. In a classical study in 1923 Dott [1] collected forty-eight cases from the literature and added five additional cases emphasizing their surgical significance. Haymond and Dragstedt [Z] in 1932 added thirty-three new cases to the accumulated experience, bringing the total number to one hundred. Ladd [3] in 1936 recommended the procedure that is still most often used in treating midgut anomalies. Since then numerous reviews dealing with cecal volvulus [4-7 J, malrotation [a-11 1, reversed rotation [12,13], rotational anomalies in adults [13-151, and paraduodenal hernia [16] have been published. EMBRYOLOGY

The study of normal intestinal rotation was initiated by Mall [17] in 1898. Frazer and Robbins [18] in 1915 arbitrarily divided the process into three stages. Recent studies by Snyder and Chaffin [19] have been significant in dispelling earlier concepts, and these authors contend that embryonic intestinal rotation does not lend itself to classification into stages [11]. Although agreeing that the process is dynamic, we believe that the principle of stages facilitates a clear understanding of intestinal rotation. The following is a brief synthesis of the events as described by many authors [8,9,15,19]. 834

The American

Jouvnal of Suvgevy

Intestinal

Rotation

comes fixed from the ligament of Trietz posteriorly and downward to the right lower quadrant. CLASSIFICATION

OF ANOMALIES

Obviously anomalies of fixation and rotation may be classified according to failures in various stages [15]. For practical purposes, however, we prefer a modification of the classification proposed by Bill and Grauman [8] as follows: 1. Nonrotation. This is a condition in which the entire bowel is supported on a dorsal mesentery. The small bowel occupies the right side of the abdomen and the large bowel, the left. There are no associated bands. This anomaly is often found in patients with omphalocele, hernias of the foramen of Bochdalek, or gastroschisis [I], but may be found alone. 2. Incomplete rotation. This is the classical form of malrotation, in which the cecum lies in the midline or the right upper quadrant and there are associated bands passing from the colon to the right abdominal side wall causing duodenal compression. The base of the small bowel mesentery is shortened and the entire bowel and ascending colon are supported on a slender stalk easily capable of volvulus. 3. &versed rotation. In this situation embryonic rotation has been clockwise and the postarterial segment lies posterior to the prearterial segment and the superior mesenteric artery. This condition is rare and we have found only one case in our records. 1. dnomnlous fixation or fusion of the mesenteries. Patients with this condition may have internal hernias through mesenteric defects or fusion of the posterior parietal peritoneum over the bowel resulting in the so-called paraduodenal hernias [16]. There may be failure of fixation of the ascending colon so that both it and the small bowel are suspended from a slender mesentery, or aberrant fixation, that is, congenital bands passing from the bowel to the pelvic sidewall. Anomalies of fixation and fusion are often found in patients with incomplete rotation [15]. CLINICAL

MATERIAL

From 1932 to 1967 forty patients with anomalous rotation and fixation of the midgut were encountered at The New York HospitalCornell University Medical Center. Excluded Vol.

llfi.

Decembev

1968

and Fixation from this report are cases of nonrotntion associated with diaphragmatic hernia, omphalocele, and gastroschisis [8] in infants as 1~11 as CeCd volvulus and paraduodenal hernia ~II adults [151. We have divided our cases into three groups according to the patient’s age: group I includes patients from birth to one year of age (Table I); group II, those from one to eighteen years of age (Table II) ; and group III. those eighteen years of age and over (Table III;. Group I. These patients have been subdivided into two subgroups: group 1.1, those with gastrointestinal tract symptoms, and group IB, those in whom anomalies of rotation and fixation were ancillary findings noted at autopsy. Our experience with nineteen patients in group IA is similar to that reported in the literature [g-11]. There were fifteen male and four female patients. The usual presenting complaint was bile-stained vomiting. Sixteen of the patients exhibited abdominal distention and three had a history of bloody stools. A flat plate of the abdomen was interpreted as compatible with duodenal obstruction in one third, showed small bowel obstruction in another third, and revealed small and large bowel obstruction in two; this study was not obtained in two patients. One flat plate demonstrated free intraperitoneal air. Referring to our classification of anomalies of rotation and fixation, two patients had nonrotation. One of these had duodenal atresia and multiple ileal atresias and the other had nonrotation with small bowel volvulus and gangrene. Of thirteen patients with incomplete rotation, eleven had duodenal bands, four had simple volvulus, one had volvulus with gangrene, and another had volvulus with gastric perforation. *Another patient with incomplete rotation had an internal hernia and still another an associated aganglionic rectosigmoid. Two patients had internal hernias alone. Both were complicated by gangrene and perforation, which occurred in one patient antenatally. One of these patients was later found to have cystic fibrosis. One patient presented with volvulus and gangrene secondary to a congenital band passing from the transverse colon to the right gutter. Finally one patient cxhibited reversed rotation. Two of the patients in group IA had anomalies of other systems, one having mongolism and the other having multiple anomalies of the

Rees and Redo

SUMMARY OF DATA IX PATIENTS

CaSS

(&I.)

Birth Age and Sex

Weight (gm.)

onsetof Symptoms

Clinical

ONE YEAR OF AGE OR YOUNGER

Manifestations

Radiographic

2,480

Birth

Bile-stained vomit; meconium passed

6 wk., F

3,200

5% wk.

5 days, M

3,540

Birth

Bile-stained meconium Bile-stained meconium

6 mo., F

1,480

6 mo.

Bile-stained vomit 7 days after genitourinary surgery; distention

Small

3 wk., M

3,200

5 days

Bile-stained

Bile-stained vomit; bloody stools Bile-stained vomit; meconium passed

Upper gastrointestinal series; incomplete rotation High small bowel ohstruction Free air under diaphragm

vomit; passed vomit; passed

vomit;

no distention;

Duodenal

obstruction

no distention;

Duodenal

obstruction

no distention;

NOIX

no distention

(&R.)

11. (B.H.) 12. (B.J.) 13. (F.S.) 14. (SK.) 15. (R.A.) 16. (C.H.) 17. (B.B.)

18. (B.C.) 19. (B.F )

5 days, M

3,400

15 hr.

4 days,

M

3.300

2 days

7 days,

M

3,200

7 days

Projectile bile-stained distention

2 days, M

1,880

Birth

Bile-stained

vomit;

1 day, M

2,790

Birth

Bile-stained

vomit;

3. (B. D.) 4. (D. R.)

distention;

Duodenal

obstruction

no distention

Duodenal

obstruction

no distention

Duodenal

obstruction

obstruction

vomit;

no

4 days, M

3,530

Birth

Bile-stained

vomit;

no distention

Duodenal

3,530

Birth

vomit;

bloody

2 days,

3,200

Birth

Bile-stained distention Bile-stained

vomit;

distention

Distention of large and small bowel Distention of large and small bowel

17 days, M

Not

12 days

Bile-stained

vomit;

no distention

Small

bowel obstruction

3 mo., M

recorded 2,800

Birth

recurrent

Small

bowel obstruction

3,490

3 days

vomit;

bloody

Small

bowel obstruction

1 day, M

3,590

Birth

Bile-stained tention Bile-stained distention Distention

vomit;

7 days, F

1 day, M

2,900

Birth

Bile-stained

vomit;

Birth

Marked

M

3 days, F

3,380

Birth

ti3. L.) 2. (B. G.)

distention;

bowel obstruction

4 days, M

Age and Sex

Weight (gm.)

onset

stools;

disstools;

“Ground glass,” small bowel obstruction

Small

distention

distention

SUMMARY OF DATA IN PATIENTS

Case

Observations

3 days, M

(&G.)

(kG.) 10. (B.B.)

TABLE WITH

of Symptoms

bowel obstruction

None

ONE YEAR OF AGE OR YOUNGER

Clinical

Manifestations

TABLE WITH

Radiographs

1 day, F

1,930

Birth

Respiratory

failure

None

1 day, F

1,425

Birth

Failure

1 day, M

2.770

Birth

Cyanosis,

anasarca

NOtX

3 mo., F

3,300

No gastrointestinal symptoms

Cyanosis, ure

heart fail-

N0lle

to thrive

The American

None

Journal

of

Surgery

Intestinal

.\SO1IAl~lliS

OF

I\TESTINAL

R(lTATIOS

rntation.

Inc”m,rlelc Vl~l\~lllw, xritb gangrene of small bowel. duodenal hands Incomplete rotation, hands Incomplete rotation; duodenal handi, intwnal hernia through small howcl mesenteq in right uppei quadrant I nc<,mplet<~ rotation. duodenal bend.

r~ilvulu;

d”
Inc~~mpletc handi

rotation,

incomplete rotation, bands Incomplete I-otatio”; bands. volvulus, stomach Incomplete Irotation; atresia and hands

Ladd procedure and I-ewrtion cm. of small bowel

NO”e

Ladd

None

Exploratory adhesions

of 2.5

procedure laparotom,

an<1 l\.hiS of

duodenal

None

Ladd

procedure

Living

and well

duodenal perforated

None

Ladd procedure, <,f gastric perforation; gastr<,stom\

Living

and well

1st operatio”-gastrojejun~~atomy; 2nd operation-Ladd procedure

Recurrent obstruction after operation; living and well second procedure Died on tenth postoperative of recurrent obstruction Living and well

ven-

Tract

Ncmrotation. two duodenal atresias N<>“l-otation; dextroversio” r)f the stomach; accessory livel- on left

196X

raf ad

1st operation-duodenojejunostomq multiple ileostomies Ladd procedure and duodenojejunostomy

Li\.ing

and hell

Living

and

well

None

Ladd

procedure

Living

and well

N”“e

Ladd

procedwe

Living

and well

None

Ladd procedure colostomy

Living

and well

None

Ladd

Living

and well

Sane

i-Gone Ladd procedure resection None

Nnne

and

Reduction of volvulus of congenital band

None

Small bowel adhesions

FIXATION

Other

(GROUP

resection

small

bowel

Living Died

and resection

and

lysis

of

Living

Later

8 hr. after

symmetrical

loba

day

imbalance

hit-th

and well

found

Surgical Procedure

Anomalies

first after

and well

to have

cystic

fibrosis

IB)

Mongolism, transposition of great vessels; meningomyelocele Trisome 16-18 chromosome pail-. congenital heart disease; anomalies of hands Sane Cor hiloculare, tion of lungs

l
Oied of electrolyte plus

Sane

AND

sigmoid

procedure

N”“f2

ROTATION

Anomalies

and l\,is

closure

duodenal

OF INTESTINAL

l3er-rmbPr

S”“C2

procedure

Nlmt-otatilm

1 Ifi.

IA)

Ladd

duodenal

S<,nl-otation

l’ol.

(GROUP

C3.7

Ladd procedul-e hesions

.Sonwtation; volvulus and gangrene I,f small bowel Inter-nal hrrnia and volvulus thrlmgh defect in small bowel mrsrntery and antenatal periorati
(>a~trointestinal

FIXATIOS

and Fixation

Congenital obstruction of bladder neck: tricular septal defect and pulmonary stenosis; common urogenital sinus; chordee Nl,“e

Sonrotation, duodenal atresia. multiole ileal atresias Incomplete rotation, right upper <,uadt-ant cecum. duodenal atrwia Incomplete rotation, duodenal band? Incomplete rotation, duodenal bands. v~,lvulus Incomplete rotation. duodenal band\, volvulus: microcolon isigmoid) Incomplete rotation: duodenal hands, midgut volvulus lievci-red I-otation

ANOMAI.IES

AND

Rotation

liesults

None

I)ied

6 hr. afta

None

I)ied

1 hr. after- birth

None

I)ied

Sane

1)ied in cardiac at :i mr,.

birth

of hyda-opq fetali failure

Rees and Redo

838

II

TABLE SUMMARY

OF DATA

ANOMALIES

IN PATIENTS OF INTESTINAL

FROM

ONE

TO EIGHTEEN AND

ROTATION

YEARS

FIXATION

OF AGE

(GROUP

WITH

II)

Age

(r*.) and Sex

Case

Past

7, M &S.,

2. (C. B.)

3. (A.

2%,

5, M M.1

15,

5. (J. 6.

G.)

(J.

M.1

10 yrs.

5 yrs.

7. (I.

M

H.)

M

History

Omphalocele at birth; “celiac disease” at 11 mo.; gastrointestinal bleeding at 2 yr.; gastrointestinal bleeding and abdominal pain at 7 yr. Bouts of severe abdominal pain and three massive episodes of gastrointestinal bleeding

Anomalies of Other Systems

Tract Surgical

Results

Living

and

well

None

Incomplete rotation; volvulus; duplication of stomach and esophagus; peptic ulcer; neuroenteric cyst Incomplete rotation; duodenal bands: multiple ileoileal intussusceptions

Ladd procedure at 4 yr.; thoracoabdomiaal resection of duplication at 5 yr.

Living

and

well

Fused ribs; vertebral

Ladd procedure and reduction of intussusception

Living

and

well

“Prune belly syndrome,’ multiple genitourinary procedures; at age 2 yr., laporatomy performed for small bowel obstruction

Incomplete duodenal 1”S

rotation; bands;

Ladd procedure of adhesions

Living

and

well

“Cyclic vomiting” since birth Recurrent abdominal pains for 6 yr.; occasional nausea and vomiting “Cyclic vomiting” and severe abdominal pains

Incomplete duodenal Incomplete duodenal

rotation; bands rotation; bands

Incomplete duodenal

rotation; bands

at

Incomplete rotation; volvulus; duplication distal ileum and Meckel’s diverticulum

Procedure

Ladd procedure and small bowel resection

M Imperforate anus birth; “temper tantrums”

K.)

4. (I.

5. F

Medical

Gastrointestinal Anomalies

genitourinary tract and a ventricular septal defect with pulmonic stenosis. Fifteen patients underwent a single operation and two patients had two or more. Three patients required resection of the small bowel because of gangrene. Other findings requiring repair at surgery included one instance of duodenal and multiple ileal atresias, one of duodenal atresia alone, one of gastric perforation, and one of an aganglionic rectosigmoid initially treated by loop colostomy. The Ladd procedure [3] was the one of choice. The patients requiring multiple operative procedures for gastrointestinal tract symptoms were usually those in whom the original problem had not been understood. Two patients were not subjected to operation. One of these, our only example of reversed rotation, was thought to have celiac syndrome, and died of inanition before proper therapy could be instituted. Gross [9] has called attention to the error of making a diag-

of

volvu-

*00m*

lies

Ladd

procedure

Living

and

well

Absent right kidney: hyop&sia of bones of right f&arm Multiple genitourinary anomalies; absent right testicle None

Ladd

procedure

Living

and

well

None

Ladd

procedure

Living

and

well

None

and

lysis

nosis of celiac syndrome without a full gastrointestinal contrast evaluation. The other patient suffered an antenatal perforation and died shortly after birth while undergoing diagnostic studies. Two patients died during the postoperative period because of persistent obstruction followed by perforation. One of these deaths probably occurred because of confusion about the entity encountered at surgery. Patients in group IB were characterized by having multiple congenital anomalies and no obvious gastrointestinal tract symptoms. The autopsy findings in these patients are included for completeness. Group II. The patients in group II are all interesting from the standpoint of how they presented clinically. Two of them had associated duplications of the gastrointestinal tract that caused massive hemorrhage requiring surgery. One of these patients had a neuroenteric The American

Journal

of Surgery

Intestinal Rotation and Fixation

S3Cl

‘GABLE III SUSIMARY OF DATA IN PATIENTS INTESTINAL

i2. F

Autopsy- (metastic carcinoma of breast)

a.

til, F Surgeq i&f. n- 1 21, F Autopsy (patient 3. died after (J. F 1 cardiac

surgery)

.5!4. M Barium enem2~ (‘I\‘. Al.1 28. M Barium enema .‘,. (I<. A 1

4.

B. ,S. K

)

7.

ix. 51.: 8. IF. 1%)

!I. (I<. S.l 10. (E. >.I

Surgery (colopexy)

CR N,l

1

Fixation and fusion anomaly with incomplete rotation; ascending colon in midline; duodenojejunal junction beneath ascending colon Nonrotation with larae bowel on left, small bowel on right Fixation and fusion anomaly with incomplete rotation; ascending colon suspended in midline suspended on a “arrow mesentery Nonrotation: large bowel on left, small bowel on right Nonrotation: large bowel in left lower quadrant. small bowel on right Fixation and fusion anomaly; large bowel suspended on 12 inch mid-abdominal mesentery

III

OF

1

None

Svmvtoms of obstructing peptic ulcer h-one

Hernia re pair None

5luriple cardiac anomalies; nhsent lest kidne? Kl)“e

1. Coloptq Cecopexv 3. Gastrectomy Appendectomy

So”e

Sane

Nlrnr

N”“C?

h-0°C

None

Ascending colon in midline on narrow mesentery; fixation and fusion anomaly plus incomplete rotation Konrotation

Symptoms of pancreatic carcinoma

Exploratory laporatomy for jaundice

Sane

Obstructing, ulcer

Partial gastrectomy

xone

Konrotation

Bleeding duodenal ulcer

Partial gastrectomy with vagectomy

None

Nonrotation: large bowel on left, small bowel on right

71, RI Autopsy (death secondary to metastatic carcinoma 54 F Barium enema

Incomplete bands

rotation;

Incomplete

rotation

51. M ITpper gastrointestinal series and surgery 5:; hl l‘pper gastrointestinal series and surgery

(GRWP

(:a5ttointestinal Tract Svmptoms

Findings

70 M Barium enema and surger\

61 M Autopsv and S”rgWy

11.

12. ix&‘.\\’

:18 F

YEARS OF AGE \VITH ASOMALIES

ROTATION AND FIXATIOS

Anatomic 1. II< K.’

OVER EIGHTEEN

duodenal

cyst [?O] and was explored three times because of exsanguinating hemorrhage before the duplication was found. The other patient had an ileal duplication associated with Meckel’s diverticulum containing gastric mucosa. One patient during presented with “temper tantrums” which he lay on his back, kicked his feet, and clutched his abdomen. In retrospect these episodes were probably attacks of severe abdominal pain. Two of the patients had been labelled as neurotic “cyclic vomiters,” a condition always meriting gastrointestinal contrast evaluation [9]. All of the patients in this group may be classified as having incomplete rotation with duodenal bands. All underwent a Ladd procedure and there were no postoperative deaths.

Recurrent bouts of gastrointestinal tract obstruction: symptoms of bleeding duodenal ulcer Symptoms due to sigmoid diverticulitis plus acti\.? duodenal ulcer Obstructive jaundice due to pancreatic carcinoma

hleedinp duodenal

2.

Group III. Patients in group III were studied in an effort to obtain information regarding the occurrence of symptoms in older patients with anomalies of rotation and fixation. In only one of these patients was surgery performed because of symptoms directly attributed to anomalies of rotation. It is of interest, however, that four patients had difficulty with acid-peptic disease and three of them ultimately required surgery because of complications. Wang and Welch [15] noted this association in 10 per cent of their adolescent and adult patients having anomalies of intestinal rotation and fixation. It could be postulated that these patients had partial duodenal obstruction leading to duodenal and antral stasis and hence ulceration. Five of

Rees and Redo those in this group had nonrotation, three had incomplete rotation, and four had anomalies primarily of fixation and fusion associated with incomplete rotation. COMMENTS

Anomalies of rotation and fixation, although rare, tax surgical judgement. Symptoms associated with these conditions may present in any age group. Series of adult patients and adolescents [l3-151 appear in the literature. Although anomalies of rotation and fixation are not the leading causes of intestinal obstruction [21,22] in the neonate they occur frequently enough [23] to merit consideration in the differential diagnosis of gastrointestinal obstruction. In evaluating the infant who presents with a history of bile-stained vomiting it is essential to: (1) determine if meconium or blood has been passed, (2) observe for other congenital anomalies, and (3) obtain base-line blood chemistries and a flat plate of the abdomen. If superior radiographic facilities are available, a barium enema may be useful. This, however, is not absolutely essential, and under less than ideal circumstances valuable time may be lost awaiting completion of the procedure. Older children with a history of cyclic vomiting, recurrent attacks of abdominal pain, or those considered to have celiac syndrome merit a complete gastrointestinal contrast evaluation

PI.

A discussion of gastrointestinal tract hemorrhage in childhood is beyond the scope of this paper, but problems of this nature may complicate the picture in those patients with anomalies of fixation and rotation, as manifested in two of our reported patients. Adult patients [13-151 who are symptomatic because of midgut rotational anomalies have been reported but the exact incidence of those who are asymptomatic is hard to determine. The mere presence of such anomalies is certainly not an indication for surgical exploration [l5] but leads to the question of why gastrointestinal studies were obtained in such patients. SUMMARY

Clinical experience with forty cases of anomalies of rotation and fixation of the midgut loop and its mesentery is reported. Suggestions regarding a practical classification of such anomalies are made.

These abnormalities may cause symptoms in the neonatal period or the patient may remain asymptomatic into adulthood. The mere presence of such anomalies is not an indication for surgical exploration. REFERENCES 1. DOTT, N. M. Anomalies of intestinal rotation: their embryology and surgical aspects with report of 5 cases. Brit. J. Surg., 11: 251, 1923. 2. HAYXOND, H. E. and DRAGSTEDT, L. R. Anomalies of intestinal rotation. .Qurg. Gynec. b Obst., 53: 316, 1931. 3. LADD, W. E. Surgical diseases of the alimentary tract in infants. New England 1. Med., 215: ‘705, 1936. 4. DONHAUSER, T. L. and ATWELL, S. Volvulus of the cecum with a review of 100 cases in the literature and a report of 6 new cases. Arch. Surg., 58: 129, 1949. 5, FIGIEL, L. S. and FIGIEL, S. J. ~‘olvulus of the cecum and ascending colon. Radiology, 61: 496, 1953. 6. NELSON, T. G. and BOWERS, W. F. Volvulus of 72: cecum and sigmoid colon. Arch. Surg. 469, 1956. 7. SWEET, R. H. \‘olvulus of the caecum, acute and chronic, with reports of eight cases. New Englund J. Med., 213: 287, 1935. 8. BILL, A. H. and GRAUMAN, D. Rationale and technic for stabilization of the mesentery in cases of nonrotation of the midgut. J. Pediat. .%rg., 1: 127, 1966. 9. GROSS, R. E. The Surgery of Infancy and Childhood. Philadelphia, 1953. W. B. Saunders Co. 10. SNYDER, W. H., JR. and CHAFPIN, L. Embryology and pathology of the intestinal tract: presentation of 48 cases of malrotation. Ann. Surg.. 146: 368, 1954. 11. BENSON, C. D., MUSTARD, W. I,, RAVITCH, M. K., SYNDER, W. H., and WELCH, K. J, Pediatric Surgery. Chicago, 1962. Year Book Publishers, Inc. 12. DAVIES, O., JOHANSEN, R., and GOLDMAN, L. Reversed rotation of the bowel causing acute intestinal obstruction. Ann. Surg., 143: 875, 1955. 13. ESTRADA, R. L. Anomalies of Intestinal Rotation and Fixation. Springfield, Ill., 1958. Charles C Thomas, Inc. 14. FINDLAY, C. W. and HUMPHREYS, G. H. Congenital anomalies of intestinal rotation in adults. Surg. Gynec. & Obst., 103: 417, 1956. 15. WANG. C. and WELCH, C. E. Anomalies of intestinal rotation in adolescents and adults. Surgery, 54: 839, 1963. 16. ZIMMERMAN, L. M. and LAUPMAN, H. C. Intraabdominal hernias due to development and rotational anomalies. Ann. .Turg., 138: 82, 1953. 17. MALL, F. P. Development of the human intestine and its position in the adult. B&E. Johns Hopkins Hosp., 9: 197, 1898. 18. FRAZER, J. E. and ROBBINS, R. H. On facts concerned in causing rotation of the intestine in man. /. Amt., 50: 75, 1915. 19. SNYDER, W. H., JR. and CHAFFIN, L. An intermedi-

Intestinal

Vol.

116,

December 196X

Rotation

and Fixation

Ml