Human Anatomy Vol 1

THORAX

4 The remains of the foramen oaale are occasionally
present. This is a small slit-like valvular opening
between the upper part of the fossa and the limbus. It
is normally occluded after birth, but may sometimes
persist.

till you reach the inferior border. Continue to incise

along the inferior border till the inferior end of anterior

interuentricular groove. Next cut along the infundibulum.

Now the anterior walFof right ventricle is reflected to

the left to study its interior.

Position

The right ventricle is a triangular chamber which
receives blood from the right atrium and pumps it to
the lungs through the pulmonary trunk and pulmonary
arteries. It forms the inferior border and a large part of
the sternocostal surface of the heart (Fig. 18.7).

Exlelnol Feolules

1. Externally, the right ventricle has two surfaces-
   anterior or sternocostal and inferior or diaphrag-
   matic.


2. The interior has two parts:

a. The inflowing part is rough due to the presence of

muscular ridges called trabeculae carneae. It

develops from the proximal part of bulbus cordis

of the heart tube.

b. The outflowing part or infundibulurn is smooth

and forms the upper conical part of the right

ventricle which gives rise to the pulmonary trunk.

It develops from the mid portion of the bulbus

cordis.

The two parts are separated by a muscular ridge called

the supraaentricular crest or infundibulo-ventriculat crest

situated between the tricuspid and pulmonary orifices.

lnternol Feoiures

1 The interior shows two orifices:

a The right atrioventricular or tricuspid orifice,

guarded by the tricuspid valve.

b. The pulmonary orifice guarded by the pulmonary

valve (Fig. 1.8.12).

2 The interior of the inflowing part shows trabeculae

carneae or muscular ridges of three types:

a. Ridges or fixed elevations

b. Bridges

c. Pillars or papillary muscles with one end attached

to the ventricular wall, and the other end

connected to the cusps of the tricuspid valve by

chordae tendinae (Latin strings to stretch). There

are three papillary muscles in the right ventricle,

anterior, posterior and septal. The anterior muscle

Superior vena cava

Supraventricular crest

Anterior cusp of tricuspid valve

lnferior vena cava

Chorda tendinae

Anterior papillary muscle

Arch of aorta with three branches

Moderator band

Apex of heart

Fig. 18.12: lnterior of the right ventricle. Note the moderator band and the supraventricular crest