Download rajiv gandhi university of health sciences, karnataka

RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES,
KARNATAKA, BANGALORE
ANNEXURE-II
6. BRIEF RESUME OF THE INTENDED WORK
6.1 NEED FOR STUDY: The word "jugular" refers to the throat or neck. It derives from the
Latin "jugulum" meaning throat or collarbone and the Latin "jugum" meaning yoke.
Veins of neck are superficial or deep to deep fascia, and are not entirely separate. The external
jugular vein forms part of the superficial venous system of the head and neck. With its tributaries
it drains the superficial structures of the face, scalp and posterolateral neck. The internal jugular
vein is part of the deep venous system of the head and neck.
Internal jugular vein is a large vein collecting blood from skull, brain, superficial parts of face
and much of neck. It begins at the cranial base, descends in the carotid sheath and terminates
posterior to the sternal end of clavicle by uniting with the subclavian vein to form
brachiocephalic vein. Its inferior bulb, dilatation near its end, is in the depression between the
sternal and clavicular heads of the sternocleidomastoid, the lesser supraclavicular fossa, where a
needle can be inserted with precision in the living subject.1
Various anomalies of the internal jugular vein have been reported. The studies have made
possible the correlation of these anomalies with disorders in the ontogenetic development of the
veins of the neck.2
In its course, it descends vertically applied to lateral side of internal and common carotid artery,
enclosed with them and vagus nerve in the carotid sheath. It may course lateral, in front of
(overriding) and rarely medial to common carotid artery.3
The vein may be rudimentary, its blood return taken over by the external jugular vein. The
external jugular vein crosses obliquely superficial to sternocleidomastoid, and ends in subclavian
vein.1 It has been proved that a large external jugular vein is associated with a small internal
jugular vein. The two veins may communicate directly in the upper neck or indirectly, via
emissary veins which link the superficial and deep systems. It is therefore feasible that blood that
normally passes through one system may be diverted through the other causing the diameters of
these vessels to vary inversely with each other.4
Rarely, the internal jugular vein receives tributaries like bronchial, vertebral, suprascapular and
transverse cervical veins. Rare anomalies like bilateral duplication of the internal jugular veins
have also been reported.5
Internal jugular vein is often chosen by clinicians and anesthetists for central venous access
because the landmarks are easily identifiable. It also offers higher success rate with fewer
complications, when done with a thorough knowledge of its anatomy, variations and anomalies.
Knowing all the morphological variants of the course of head and neck veins is of utmost
importance both for the surgeon operating at this level, for radiologists performing a
catheterization, and for the clinician in general.2 The internal jugular vein may be endangered
during removal of tuberculous or neoplastic lymph nodes.1 Their involvement in these different
procedures can lead to various acute complications such as accidental carotid arterial puncture,
irritation to the brachial plexus, pericardial tamponade, haemothorax, pneumothorax and
formation of a local haematoma compromising the upper airway.3
Not many dissection studies have been done on internal jugular vein and its variations in
Karnataka/ India. Hence this study becomes essential.
ANNEXURE-III
6.2 REVIEW OF LITERATURE:
1. Internal jugular vein is a large vein collecting blood from skull, brain, superficial parts of face
and much of neck. It begins at the cranial base, in the posterior compartment of jugular foramen,
where it is continuous with the sigmoid sinus. It ultimately terminates by uniting with the
subclavian vein, posterior to the sternal end of clavicle, to form the brachiocephalic vein, which
in turn empty into superior vena cava. As it descends in the carotid sheath, it is related to internal
and common carotid arteries on the medial side and the vagus nerve between vein and arteries,
but posterior to them. Superficially, it is overlapped by sternocleidomastoid muscle and the deep
cervical lymph nodes lie along its superficial aspect.
Tributaries received by the vein, during its course through the neck include: facial vein, lingual
vein, pharyngeal vein, superior and middle thyroid veins and occasionally occipital vein. The
thoracic duct opens near the union of left subclavian vein and internal jugular vein and right
lymphatic duct opens at the same site on right.
2. A study conducted on 60 human cadavers, observed the internal and external jugular veins
from the point of view of their origin, course and affluents. Following morphological
variabilities were observed in case of the jugular veinsExternal jugular vein that receives as affluents the facial and lingual veins and drains into
internal jugular veins, draining the latter’s territory – 3.33%
Internal jugular vein that receives the lingual, upper thyroid and facial veins, independent13.33%, via the linguofacial trunk- 50%, and via thyrolinguofacial trunk-33%.
The authors have correlated these anomalies with disorders in the ontogenetic development of
the veins of the neck. The superficial veins of the head and neck arise from the superficial
capillary plexus which eventually, will form the primary vein of the head. By the enlargement of
the individual capillaries, the confluence and regression of some of the veins in the area where
the blood flow was deviated, wide canals are formed. The factors controlling this are still largely
unknown. With the development of the cranium, the first vessel that can be identified is the
ventral pharyngeal vein, which drains most of the mandibular bone and the hyoid arch in the
common cardinal vein. Progressively, as the neck lengthens, its drainage level shifts towards the
cranial part of the precardial vein which later develops into the internal jugular vein.
3. A study was done on 104 consecutive uraemic patients undergoing creation of internal jugular
vein temporary angioaccess, focusing on the anatomical variation of internal jugular vein. The
internal jugular veins were classified according to their diameters and anatomical locations. The
internal jugular veins were divided into adequate sized (5mm diameter or more) and small sized
(less than 5mm) groups. An internal jugular vein was defined to be of normal location if it lay
superficially and laterally to the carotid artery with a distance less than 10mm between them. An
internal jugular vein located ≥ 10mm lateral to the carotid artery was defined to be far away from
the carotid artery. The reverse of carotid artery and internal jugular vein indicated that the
internal jugular vein was located medially to the carotid artery. The term ‘overriding’ was used
for an internal jugular vein located directly above the carotid artery.
This study found anatomical variations in 18.3% of the right and 16.4% of the left internal
jugular veins. Unilateral variations were found in 17.3% and bilateral variations were discovered
in 8.7%. A total of 26% had internal jugular vein anatomical variations that might contribute to
difficulty in external landmark guided internal jugular veins cannulation.
4. The relationship between internal jugular vein diameter as measured with an ultrasound
imaging machine and external jugular vein diameter was studied in 50 anesthetized patients
undergoing elective cardiac surgery. There was an inverse correlation between external jugular
vein diameter and internal jugular vein diameter (r=-0.47, p<0.001). 40% patients with an
external jugular vein diameter of 7mm or greater had an internal jugular vein diameter of less
than 15mm. No patient with an external jugular vein diameter of less than 7mm had an internal
jugular vein diameter of less than 20mm. No other patient dimension (height, weight, body mass
index, neck circumference) predicted internal jugular vein size. These results suggest that a large
external jugular vein (i.e. 7mm or greater in external diameter) may be associated with a small
internal jugular vein.
5. A rare bilateral duplication of the internal jugular vein was discovered during cadaveric
dissection. From each jugular foramen, a single internal jugular vein descended to the level of
the hyoid bone then divided into medial and lateral veins. The medial internal jugular veins
travelled in the carotid sheath; the lateral internal jugular veins coursed posterolateral to the
sheath across the lateral cervical region (posterior triangle) of the neck. On the right side, both
internal jugular veins entered the subclavian vein separately. On the left side, the medial internal
jugular vein drained into a large bulbous jugulovertebrosubclavian sinus. The lateral vein
diverged posterolaterally toward the border of trapezius muscle, then received transverse cervical
vein, and then turned sharply anteromedially to drain into the jugulovertebrosubclavian sinus.
The study also suggests that internal jugular vein duplication differs from fenestration
anatomically and potentially, developmentally. The mechanism of development and the clinical
significance of multiple internal jugular veins are also discussed.
ANNEXURE-IV
6.3 OBJECTIVES OF STUDY:
To find out:
1.
2.
3.
4.
5.
Location of internal jugular vein in relation to common carotid artery
Position of internal jugular vein in relation to heads of sternocleidomastoid
Mode of termination of internal jugular vein
Afferent vessels of internal jugular vein
Caliber: right and left internal and external jugular veins and common carotid arteries
at the level of cricoid cartilage
ANNEXURE-V
MATERIAL AND METHODS:
7.1 SOURCE OF DATA:
The preserved human cadavers from Department of Anatomy, Kempegowda Institute of Medical
Sciences and other Medical Colleges in and around Bangalore.
7.2 METHOD OF COLLECTION OF DATA:
Purposive sampling technique will be used. The study will be conducted on 50 adult human
cadavers irrespective of sex. Gross dissection will be done by following the guidelines of
Cunningham’s manual. The deep dissection of neck will be done. Carotid sheath will be exposed
and internal jugular vein will be identified on both sides. Relevant findings regarding its location
in relation to carotid artery, heads of sternocleidomastoid and termination of afferent vessels will
be noted. The caliber of the internal jugular vein, external jugular vein and common carotid
arteries will be measured using sliding calipers at the level of cricoid cartilage. Statistical
analysis will be done based on these measurements using descriptive statistics like percentage
and mean. Paired-t test will be used to compare the calibers of veins and arteries of both sides.
ANNEXURE-VII
LIST OF REFERENCES:
1. Williams P.L., Bannister L.H., Berry M.M., Collins P., Dyson M., Dussek J.E.et.al. Gray’s
anatomy, 39th Ed. Edinburgh: Elsevier Ltd., 2006. 552
2. Monica-Adriana Vaida., Niculescu V., Motoc A., Bolintineanu S., Izabella Sargan., Niculescu
M. C. 2006 “Correlations between anomalies of jugular veins and areas of vascular drainage of
head and neck.” Romanian Journal of Morphology and Embryology, 47(3): 287-90
3. Bing-Shi Lin., Chi-Woon Kong., Der-Cherng Tarng., Tung-Po Huang., Gau-Jun Tang. 1998
“Anatomical variation of the internal jugular vein and its impact on temporary haemodialysis
vascular access: an ultrasonographic survey in uraemic patients.” Nephrology Dialysis
Transplantation, 13: 134-38
4. Stickle B. R., McFarlane H. 1997 “Prediction of a small internal jugular vein by external
jugular vein diameter.” Anaesthesia, 52: 220-22
5. Downie S.A., Schalop L., Mazurek J.N., Savitch G., Lelonek G.J., Olson T.R. 2007 “Bilateral
duplicated internal jugular veins: case study and literature review.” Clinical Anatomy, 20(3):
260-6