Bio

Publications


2016

Aseta, FB, Mwachaka PM, Odula PO, Malek A.  2016.  Histomorphological changes in the cornea of the rat following monocular eyelid closure. Anatomy, an international journal of experimental and clinical anatomy . 10(2):87-93.cornea.pdf

2015

Pulei, AN, Odula P, Malek A, Ogeng'o JA.  2015.  Distribution of elastic fibres in the human abdominal linea alba. Anatomy journal of Africa . 4(1):476-480.pulei_hla_aja.pdf.pdf
Loyal, PK, Ongeti K, Mandela P, Odula P.  2015.  Functional adaptability of the tunica media of the atriopulmonary junction.. Austin J of . 2(2):1034.poonamjeet_atj_austin.pdf
Kanyata, D, Odula P, Nyamai L, Nduati P.  2015.  Morphology and location of surface landmarks of foramen ovale in Kenyans. Int. J. Morphol. 33(2):471-475.kanyata_fo.pdf
Mwachaka, PM, Saidi H, Odula P, Mandela P.  2015.  Effects of monocular deprivation on rabbit neural cell densities.. J. Ophthalmic & vision research . 4(2):555-562.mwachaka_neural_cell_densities.pdf
Odula, PO, Hassanali J, Kiama SG.  2015.  Regional variation in the histomorphology and tensile strength of the ventral rectus sheath in the male goat (Capra hircus). Austin Journal of Anatomy . 2(2):1036. Abstractodula_vrs_austin.pdf

The ventral rectus sheath (VRS) plays a key role in the stabilization of the ventral abdominal wall. This sheath has to be particularly strong in ruminants to accommodate the viscera and the large quantities of forage in their stomach. This study was conducted to establish the structural and the mechanical properties of the ventral rectus sheath in the goat, a browser, in order to elucidate its function. The ventral rectus sheath was formed by supercial and deep lamina consisting of obliquely aligned collagen bers derived from the external and internal oblique abdominal aponeuroses respectively. Closely apposed and intimately held to the super cial lamina was a layer of longitudinally aligned elastic bers, the ttunica ava abdominis or modi ed deep fascia. This tunica flava abdominis progressively increased in thickness from the epigastrium to the hypogastrium. On tensiometry, the epigastric ventral rectus sheath withstood about half the load (50N/mm2) required to reach yield point compared to the umbilical ventral rectus sheath (94.5N/mm2). Furthermore, the Youngs modulus showed that the umbilical ventral rectus sheath was the stiffest at 669 (SD 22.2) N/mm2 while the epigastric ventral rectus sheath was the weakest at 554 (SD 29) N/mm2 respectively when exposed to longitudinal traction. In conclusion, the progressively thickening of the tunica ava abdominis and the super cial lamina from the epigastrium to the hypogastrium may confer reversible stretch ability and strength to the ventral rectus sheath and is therefore well suited for longitudinal load strength needed to support the compound stomach during browzing.

Odula, PO, Hassanali J, Kiama SG.  2015.  Regional variation in the histomorphology and tensile strength of the linea alba in the male goat (Capra hircus). Anatomy journal of Africa. 4(2):555-62. Abstractodula_la_aja.pdf

The linea alba (LA), a midline tendinous structure formed by the interlocking anterior abdominal wall aponeurotic fibers, acts as a passive tensile band that prevents sagging of the lower abdomen. The microstructure and the strength of these fibres would thus be expected to reflect on the forces that act on the linea alba. This study was undertaken to establish the histomorphology, morphometry and tensiometric characteristics of the linea alba of the goat so as to elucidate on the elements that are responsible for maintaining the integrity of the wall. Tissues resected from the linea alba in six male goats and prepared for routine light microscopy and stained with Weigert resorcin–fuchsin stain revealed three distinct laminae namely a superficial, intermediate and deep. The superficial lamina of goat epigastric linea alba, which was closely apposed to the overlying elastic tunica flava abdominis (deep fascia), was made up of predominantly obliquely aligned collagen bundles, an intermediate lamina comprising longitudinally aligned collagen bundles and a deep lamina consisting of transversely oriented collagen fibres. When exposed to longitudinal traction, the epigastric LA on average was the stiffest at 35 N/mm2 with an elastic coefficient 350 N/mm2 while the hypogastric LA was the weakest at 26.5 N/mm2 with an elastic coefficient 217 N/mm2 respectively. In conclusion, the epigastric LA was well suited for longitudinal load strength to support the compound stomach during grazing while the relatively elastic hypogastric LA was most suited for allowing a degree of midline sagging during browzing. The variations noted in tensiometry suggest that the hypogastric linea alba is more compliant to stretch but more predisposed to tearing than the epigastric line alba especially when exposed to sudden violent force or trauma.

2014

Ominde, BS, Odula P, Olabu BO, Ogeng'o JA.  2014.  Regional differences in the diameter of the coronary sinus among black Kenyans.. Anatomy and Physiology. 4(3):141.
Mwachaka, P, Saidi H, Odula P, Mandela P.  2014.  Effects of monocular deprivation on dendritic features of retinal ganglion cells. Int. J. Morphol. 32(4):1144-1151.mwachaka_retina_dendritic.pdf

2013

Munguti, J, Odula P, Awori K, Ogeng'o J, Sammy M.  2013.  Variant anatomy of the right portal vein in a black Kenyan population. Abstractkirsteen_awori.pdf

Surface mapping of the liver before invasive procedures depends on a proper understanding of its segmental vasculature. The right portal vein ramification and lengths show marked variations and these mostly involve its right posterior sectoral branch. Their incidence is variable among populations and altogether undocumented among Africans. One hundred livers obtained during autopsies and dissections at the Department of Human anatomy, University of Nairobi, were used in this study. Gross dissection was done to reveal and determine the branching pattern of the right portal vein and the origin of the right posterior sector branch. The lengths of the right portal vein were also measured and recorded. When present, the right portal vein terminated by bifurcation in 61% of the cases, trifurcated in 20.8% and quadrifircated in 18.2%. Its length was between 0.5cm and 4cm. The right posterior sector vein was given off the main portal vein in 34 cases, the common left portal vein trunk in 15 cases, and the right portal vein in 42 cases. In 9 cases, it was not observed at the porta hepatis. We report significant different incidences of the variant anatomy of the right portal vein compared to those found in previous studies and this should be borne in mind when doing surgical interventions

2012

El-Busaid, H, Hassan S, Odula P, Ogeng'o J, Ndung'u B.  2012.  Sex variations in the structure of human atrioventricular annuli. Abstract

Atrioventricular annuli are important in haemodynamic flexibility, competence, and support for tricuspid and mitral valves. The anatomical features of the annuli, such as circumference, organisation of connective tissue fibres, myocardium, and cellularity, may predispose to annular insufficiency and valvular incompetence. These pathologies occur more commonly in females, although the anatomical basis for this disparity is unclear. Sex variation in the structure of the annuli is important in providing a morphological basis for the patterns of these diseases. This study therefore aimed to determine the sex variations in the structure of human atrioventricular annuli. One hundred and one hearts (48 males, 53 females) obtained from the Department of Human Anatomy of the University of Nairobi were studied. Annular circumferences were measured using a flexible ruler and corrected for heart weight. Results were analysed using SPSS version 17.0 and sex differences determined using student's t-test. A p-value of less than 0.05 was considered significant. For light microscopy, specimens were harvested within 48 hours post-mortem, processed, sectioned, and stained with Masson's trichrome and Weigert's elastic stain with van Gieson counterstaining. Females had significantly larger annular circumferences than males after correcting for heart weight (p ≤ 0.05). Histologically, myocardium was consistently present in all male annuli while this was absent in females except in one specimen. The annuli were more elastic and cellular in males especially in the annulo-myocardial and annulo-valvular zones, respectively. The corrected larger annular circumference in females may limit heart valve coaptation during cardiac cycle and may be a risk factor for valvular insufficiency. The predominance of myocardium, annular cellularity, and elasticity may be more protective against heart valve incompetence in males than in females

El-busaidy, H, Saidi H, Odula P, Ogeng’o J, Hassanali J.  2012.  Age changes in the structure of human atrioventricular annuli. AbstractWebsite

Atrioventricular annuli are important in hemodynamic stability and support to tricuspid and mitral valves. Anatomical features of the annuli such as circumference, organization of connective tissue fibers, myocardium and cellularity may predispose to annular insufficiency and valvular incompetence. These pathologies increase with age and are more common in females, although the anatomical basis for this disparity remains unclear. This study therefore aimed to investigate age-related changes in the structure of human atrioventricular annuli. One hundred and one hearts (48males, 53 females) from subjects (15 to 60 years) were studied in three age groups (≤ 20 yrs, 21-39 yrs and 40-60 yrs). Annular circumferences were measured and corrected for heart weight. Routine histology was carried out on 21 hearts. Differences in annular circumference between the age groups were determined using one-way ANOVA while gender differences were determined using independent Students’t-test. Overall, females had significantly larger annular circumference than males after correcting for heart weight (p ≤0.05). The annular circumference generally increased with age however there was a significant increase in the 21-39 year age group (p ≤0.05). Microscopically, myocardium was consistently present in males but absent in females except in one specimen. The collagen fiber density increased with age in both gender as the fibers became more irregular. The annular cellularity, elasticity and myocardial content also declined with increasing age. The significantly wider annular circumference in the 21-39 year age group is clinically important as wider circumference is associated with decreased heart valve co-aptation and valvular incompetence. This may suggest an earlier predisposition to this pathology in the study population. The age-related decrease in annular cellularity, elasticity and myocardial content may explain the higher incidence of valvular incompetence with increasing age.

2010

Mwachaka, P. M.; Saidi, OPO'; KHS; W.  2010.  Locating the arcuate line of Douglas: is it of surgical relevance?
OCHIENG', DRODULAPAUL.  2010.  Anatomy and prevalence of atlas bridges in a Kenyan population: An osteological study. Journal of Clinical Anatomy. 23(6):649-653. : Karau P.B, Ogeng
OCHIENG', DRODULAPAUL.  2010.  The histomorphological organization of the hepato-caval interface in the human. J. Morphol.Sci, 27(3-4): 148-351. : Karau P.B, Ogeng
P.K, BUNDI, JA O'o, J HASSANALI, P O.  2010.  Morphometry and variations of bony ponticles of the atlas vertebrae (C1) in a Kenyans. Int. J. Morphol., 28(4): 1019-1024. : Int. J. Morphol., 28(4): 1019-1024 Abstract

Atlas bridges, the bony outgrowths over the third segment of the vertebral artery are associated with compression of the artery and nerves. There are limited studies comparing morphometry of the complete atlas bridges and that of the ipsilateral transverse foramen. Bilateral and gender differences in the morphometry of the complete bridges remain relatively unexplored. One hundred and two atlas vertebrae (49 male and 53 female) obtained from the Osteology Department of the National Museums of Kenya were used for this study. The presence of complete posterior atlas bridge (retroarticular canal) and lateral bridge (supratransverse foramen)
was noted. Measurements were taken for the diameters of foramina, and the ipsilateral transverse foramina and their areas calculated. Complete posterior bridges occurred in 14.6% and 13.6% on the right and left sides respectively. The lateral bridge was found in 3.9% of the cases on the right side only. The complete posterior bridges had a cross-sectional area of 23.44mm2 on the right and 24.98mm2 on the left side. The lateral bridges had a mean cross-sectional area of 27.30mm2. The right and left transverse foramina had mean crosssectional
area of 36.30mm2 and 37.20mm2 respectively, which was significantly larger than that of the ipsilateral complete and posterior bridges. The smaller dimensions of the complete atlas bridges compared to the ipsilateral transverse foramen suggest that they may predispose to vertebrobasilar insufficiency, Barre-Lieou and cervicogenic syndromes due to compression of the contents in the foramina.

KIRSTEEN, DRAWORI, OCHIENG' DRODULAPAUL.  2010.  The suprascapula notch: Its morphology and distance from the glenoid cavityin a Kenyan population. Folia morphol 2010; 69:241-5. : Folio Morphol

2009

Odula, PO.  2009.  Regional variations in the microscopic organization of the human rectus sheath. Abstract

The pattern of formation of the rectus sheath from the aponeuroses of external oblique, internal oblique, and transversus abdominis muscles shows regional variations. These variations may influence the microscopic organisation of the rectus sheath. Specimens were collected during autopsies from thirty one subjects (16 male, 15 female) aged 18-70 years old. The rectus sheath was exposed through gentle dissection of the superficial fascia of the anterior abdominal wall. Five millimeter thick sections were harvested and processed for light microscopy. Both walls of the rectus sheath were made up of three distinct zones: superficial, intermediate, and deep. The superficial and deep zones were fibroelastic while the intermediate zones comprised compact bundles of collagen fibres. In the anterior wall of the rectus sheath, these bundles above and below the arcuate line, respectively, were obliquely and transversely disposed. The bundles of the posterior wall of the rectus sheath were, however, transversely aligned. In conclusion, the microscopic organisation of the rectus sheath is determined by its pattern of formation. This sheath is mainly formed by the aponeuroses of the internal oblique and transversus abdominis.

OCHIENG', DRODULAPAUL.  2009.  Anatomic position of the asterion in Kenyans for posterolateral surgical approaches to cranial cavity. Journal of Clinical Anatomy.23 (1): 30-33. : Mwachaka P, Hassanali,J and P. Odula
OCHIENG', DRODULAPAUL.  2009.  Regional histomorphomery of the hepatic inferior vena cava: a possible sphincteric mechanism. Int. J. Morphol., 27(3): 849-854. : Bundi P.K, Ogeng Abstract
Regional histomorphomery of the hepatic inferior vena cava: a possible sphincteric mechanism
OCHIENG', DRODULAPAUL.  2009.  Regional variations in the microscopic organization of the human rectus sheath. :. Journal of Morphological Sciences. 26(2). : Mwachaka P.M, Odula P, Awori K.A and W. Kaisha. Abstract
The pattern of formation of the rectus sheath from the aponeuroses of external oblique, internal oblique, and transversus abdominis muscles shows regional variations. These variations may influence the microscopic organisation of the rectus sheath. Specimens were collected during autopsies from thirty one subjects (16 male, 15 female) aged 18-70 years old. The rectus sheath was exposed through gentle dissection of the superficial fascia of the anterior abdominal wall. Five millimeter thick sections were harvested and processed for light microscopy. Both walls of the rectus sheath were made up of three distinct zones: superficial, intermediate, and deep. The superficial and deep zones were fibroelastic while the intermediate zones comprised compact bundles of collagen fibres. In the anterior wall of the rectus sheath, these bundles above and below the arcuate line, respectively, were obliquely and transversely disposed. The bundles of the posterior wall of the rectus sheath were, however, transversely aligned. In conclusion, the microscopic organisation of the rectus sheath is determined by its pattern of formation. This sheath is mainly formed by the aponeuroses of the internal oblique and transversus abdominis.
OCHIENG', DRODULAPAUL.  2009.  Locating the arcuate line of Douglas: Is it of surgical relevance? Journal of Clinical Anatomy.23 (1): 84-86. : Mwachaka, P, Saidi H.S, Odula P, Awori K and W. Kaisha
OCHIENG', DRODULAPAUL.  2009.  Variations in the pattern of formation of the abdominis rectus muscle sheath among Kenyans. Int. J. Morphol., 27(4): 1025-1029. : Mwachaka, P, Odula P, Awori K. and W. Kaisha Abstract
 The pattern of formation of the human rectus sheath exhibits variations, it is not clear if these variations are population specific. This study aimed at describing the pattern of formation of the rectus sheath in a select Kenyan population. Formation of the rectus sheath was analyzed in eighty subjects (47 male, 33 female) during autopsies and cadaveric dissection. The anterior wall of the rectus sheath in all cases was aponeurotic and firmly attached to rectus abdominis muscle. The posterior wall of the rectus sheath was aponeurotic in 71 (88.5%) cases, the rest were musculoaponeurotic and only seen in males. In all cases the aponeurosis of internal obliqueabdominis split into two lamina; a deep lamina that fused with the aponeurosis of transverses abdominis at the lateral border of rectus abdominis and a superficial lamina that fused with aponeurosis of external oblique abdominis mid-way between the medial and lateral borders of rectus abdominis muscle. The pattern of formation of the rectus sheath among Kenyans shows some variations which have not been reported by previous workers. Knowledge of these variations is important in surgery as this sheath is always incised when making most aabdominal incisions.
OCHIENG', DRODULAPAUL.  2009.  Sex variation in occurrence of myocardium in human mitral valve cusps.. Int. J. Morphol., 27(4): 1217-1222. : Gatonga P, Odula P, Saidi H.S and P. Mandela.
OCHIENG', DRODULAPAUL.  2009.  The sutural morphology of the pterion and asterion among Kenyan adults.. Braz. J. Morphol. Sci., 2009, vol. 26, no. 1, p. 4-7.. : Mwachaka, P; Hassanali,J and P. Odula. Abstract
The pterion and asterion are points of sutural confluence seen in the norma lateralis of the skull. Their patterns of formation exhibit population-based variations. Data on the Kenyan population however remains scarce and yet the understanding of the sutural morphology of these points is important in surgical approaches to the cranial fossae. Ninety human skulls of known gender (51 male, 39 female) were examined on both sides. Four types of pteria were observed: sphenoparietal (66.7%), frontotemporal (15.5%), stellate (11.1%) and epipteric (6.7%). The epipteric type occurred more in females (10.5%) than in males (4.8%). Sutural bones were found at the asterion in 20% of the cases. Variations in the sutural morphology of the pterion and asterion in the Kenyan crania is similar to that of other populations.
OCHIENG', DRODULAPAUL.  2009.  The course of the hepatic inferior vena cava in a Kenyan population.. Journal of Clinical Anatomy.22 (5): 610-613.. : Karau P, Ogeng
OCHIENG', DRODULAPAUL.  2009.  Topography and distribution of ostia venae hepatica in the retrohepatic inferior vena cava.. The Annals of African Surgery.4: 13-17.. : Bundi P.K, Ogeng Abstract
Background : Openings of hepatic veins into the retrohepatic surface of the inferior vena cava (ostia venae hepatica) play a part in controlling hepatic circulation by acting as collateral channels in obstruction. Their topography and distribution must be taken into account during catheterization and liver transplantation. This anatomy is however little known among Kenyans.   Objectives: To study the position, number and distribution of ostia venae hepatica in a selected Kenyan population   Materials and methods: Eighty fresh postmortem liver specimens were obtained from the Chiromo Mortuary. The hepatic IVC was isolated from the lower border of caudate lobe to the diaphragmatic opening, with the liver in position. The vein was opened posteriorly by a vertical incision along its whole length and the lateral flaps reflected laterally. The topography of the ostia was studied using the Sahni model. The number and patterns of the ostia were also studied. The patterns of openings of the left, right and middle hepatic veins were studied as well as the distances between them.   Results : A total of 584 ostia were identified, an average of 7.3 per liver. The ostia were distributed on the lateral portions of the vein, with an avascular plane at the centre. Major veins terminated in the upper third of the hepatic inferior vena cava, with little extraparenchymal course. The mean distance between the right hepatic vein and middle hepaticvein was 1.7cm   Conclusion : The numerous ostia venae hepatica identified in these subjects offer collateral flow channels during hepatic venous obstructionin Budd-Chiari syndrome. The topography and patterns of distribution of the openings suggest the advantage of an avascular virtual plane, which is asafe dissecting path for hepatovascular surgeons.

2008

OCHIENG', DRODULAPAUL, OCHIENG' DRODULAPAUL, OCHIENG' DRODULAPAUL.  2008.  Child maltreatment at a violence recovery centre in Kenya. Journal of Tropical Doctor. 38: 87-89.. : Saidi H, Odula P and K. Awori
OCHIENG', DRODULAPAUL.  2008.  Anatomic position of the pterion among Kenyans for lateral skull approaches.. Int. J. Morphol., 26(4): 931-933,. : Mwachaka P, Hassanali,J & Odula P Abstract
Anatomic position of the pterion among Kenyans for lateral skull approaches. 

2006

Mwachaka, P. M.; Saidi, OPO'; KHS; W.  2006.  Locating the arcuate line of Douglas: is it of surgical relevance?

2004

OCHIENG', DRODULAPAUL, OCHIENG' DRODULAPAUL, OCHIENG' DRODULAPAUL, OCHIENG' DRODULAPAUL, OCHIENG' DRODULAPAUL, OCHIENG' DRODULAPAUL, OCHIENG' DRODULAPAUL.  2004.  Femoral hernia surgery at Mulago Hospital.. East Central Afr J.Surg 9 (2):72-75.. : Odula P.O. and I. Kakande. Abstractodula_femoral_hernia.pdfodula_femoral_hernia.pdf

Objective: To determine the incidence, pattern and the immediate outcome of femoral hernia surgery in Mulago Hospital.
Methods: A hospital based descriptive study during which a questionnaire was drafted to study all consecutive patients operated for femoral hernia over a period of twelve months.
Results: There were 13 patients with 13 femoral hernias accounting for 6.3% of all groin hernias operated on in the same period. The age ranged from 42 years to 70 years old with a mean of 54.6 years old. All the patients were females with 12 of them (92.3%) being parous. Ten (76.9%) presented with strangulation. Three had wound complications and one had chest infection post-operatively. More than fifty percent of patients were discharged within the first three post-operative days. There was no mortality.
Conclusion: Though rare, femoral hernias have a high risk of strangulation and hence prone to adverse sequelae post-operatively. All medical officers should familiarize themselves with early diagnosis and operative intervention of this relatively rare but dangerous hernia.

OCHIENG', DRODULAPAUL.  2004.  The immediate outcome of groin hernia surgery at Mulago Hospital.. East Central Afr J.Surg 2004;Vol. 9 No1 :48-52.. : Odula P.O. and Kakande I Abstractodula_groin_hernia.pdf

A prospective descriptive study based on 208 cases of groin hernia that had surgery at Mulago Hospital over a 12-months period beginning on 1st January 2000 was undertaken. There were more males than females. The mean age was 35.4 years with the mode and median of 40 and 33 years respectively. Patients under 15 years were 37 (17.8%) and had a peak incidence in the 1-3 years age group while in adults the peak was in the 24-34 years age group. Only 2 girls were seen in the under 15 years old group. Most females (86%) who presented
with groin hernias were aged above 34 years. There were 195 (93.7%) inguinal hernias of which 159 (81.5%) were indirect inguinal hernias and 34 (17.4%) were of the direct inguinal variety. Busoga hernias were diagnosed in only 4 (2.05%) of inguinal hernias. There were only 13 (6.2%) femoral hernias. Post-operative complications occurred in 41.8% of the cases. There was one death. (0.48% mortality)

1999

OCHIENG', DRODULAPAUL.  1999.  The immediate outcome of groin hernia surgery at Mulago hospital, Kampala. MMed.(Surg). Makerere University.. MMed.(Surg). Makerere University.. : Odula P.O. Abstract
A prospective descriptive study based on 208 cases of groin hernia that had surgery at Mulago Hospital over a 12-months period beginning on 1st January 2000 was undertaken. There were more males than females. The mean age was 35.4 years with the mode and median of 40 and 33 years respectively. Patients under 15 years were 37 (17.8%) and had a peak incidence in the 1-3 years age group while in adults the peak was in the 24-34 years age group. Only 2 girls were seen in the under 15 years old group. Most females (86%) who presented with groin hernias were aged above 34 years. There were 195 (93.7%) inguinal hernias of which 159 (81.5%) were indirect inguinal hernias and 34 (17.4%) were of the direct inguinal variety. Busoga hernias were diagnosed in only 4 (2.05%) of inguinal hernias. There were only 13 (6.2%) femoral hernias. Post-operative complications occurred in 41.8% of the cases. There was one death. (0.48% mortality)

1996

1990

OCHIENG', DRODULAPAUL.  1990.  The structural organisation of the syrinx in the domestic fowl and a few selected passerine birds, with special reference to the tympaniform membranes. B.Sc. (Anat). University of Nairobi.. B.Sc. (Anat). University of Nairobi.. : Odula P.O. Abstractsyrinx_09.08.16.pdf

This study addresses itself to the microscopic organization of the connective tissue system of the syrinx with respect to the specialized functions during avian vocalization .Light microscopy has revealed that the cranial and caudal ends of the syrinx in the domestic fowl consists of an expanded submucosa .The cranial and caudal ends of the intercartilagenous connection in the lateral tympaniform membranes were characterized by the high content of elastic tissues. In contrast with the other parts of the trachea and bronchi, the luminal epithelium of the syrinx had a compact stratified squamous appearance punctuated by a few epithelial pegs.

Electron microscopic revealed that the luminal epithelium in the tympaniform membranes of the domestic fowl and passerine bird consisted of numerous microvilli and various junctional complexes. The luminal tunica propria in the domestic fowl was characterized largely by mature elastic fibres, whereas the submucosa consisted of mainly microfibrils, immature elastic fibers and occasional blood vessels. The serosa was predominantly collagenous. The intercartilagenous connection, in the domestic fowl consisted of numerous fibroblast, collagen fibres and a few elastic fibres.

It is suggested here that, during avian vocalization, the membrane tension is determined by the amount and distribution of the fibroblasts, the collagen and elastic fibers. The presence of epithelial pegs, the various junctional complexes found in the luminal epithelium, the elastic fibres encountered at different stages of maturation, in the luminal tunica propria and the submucosa in the membrane may play a role in the accommodation of the vibrational and shearing stresses likely to be generated during avian vocalization . These forces are then transmitted to the intercartilagenous connection, which in turn conveys these stresses to the stronger, rigid cartilaginous frame work and ligaments of the syrinx.

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