Dilator pupillae

Dilator pupillae

They are involuntary  muscle fibers of the iris , which running radially from papillary margin to periphery .

It is supplied by sympathetic nerves from the superior cervical ganglion. It is widening the pupil and allowing for more light to pass through the eye.

Some condition like carcinoma of the lung, thyroid or oesophagus or metastatic lymph nodes may involve sympathetic trunk and give rise Horner’s syndrome,. One of the  characteristic feature of Horner’s syndrome is  slight constriction of pupil because dilator papillae muscle  losses it innervations  so fail to dilate pupil .  

Sphincter pupillae

Sphincter pupillae

Pupil is the central small aperture situated within the iris of eye. The size of it control by two muscles one is sphincter papillae and dilator papillae. So through pupil only the appropriate amount of light enters the eye .

    They are involuntary muscle fibers of the iris, which arranged circularly.

It is only present in papillary margin of iris. It is supplied by parasympathetic fibers from Edinger-westphal nucleus of oculomotor nerve.

Function: constrictor of the pupil in response to bright light. Failure of pupil to respond to light is an important clinical sign of the lack of nerve or brain function.

Erb's paralysis : brief and easy handout

Erb’s paralysis : it is also known as upper trunk plexus injury.

Cause of injury:  Upper trunk is ruptured due to forceful widening of the angle between the head and shoulder . traction of the arm during child birth and or by fall on the shoulder causes widening of angle between the head and shoulder. The root value of upper trunk is C5,6 .

In this paralysis, nerve roots involved: Mainly C5 and partly C6.

Muscles paralysed: Mainly biceps, deltoid,brachilais and brachioradialis.Partly supraspinatus, infraspinatus and supinator

Deformity: The deformity is known as "Policeman's tip hand" or "Porter's tip hand".

Loss of function:

Motor loss:

Arm: Hangs by the side, it is adducted due to paralysis of deltoid muscle. It is also medially rotated due to paralysis of supraspinatus, infraspinatus  and teres minor muscles

Forearm: Extended and pronated due to paralysis of biceps brachii.

Sensory loss:

The sensory loss of this clinical condition is minimal, only along the outer aspect of arm due to involvement of roots of C6 spinal nerve.

Moderator band / septomarginal trabeculum

Moderator band: (septomarginal trabeculum)

It is the unique features of the right ventricle , a thick muscular ridge extending from the ventricular septum to the base of the anterior papillary muscle.

 It conveys the right branch of the atrioventricular bundle (bundle of His) , a part of conducting system of the heart .

Function of the moderator band: it prevents the over distension of right ventricle. 

Easy handout of left ventricle of the heart

left ventricle:

 The wall of the left ventricle is thicker than the atrium and also  it is thicker than the right ventricle.

It contains two orifices

1.     Left  atrioventricular orifice: by this orifice oxygenated blood of left atrium enters into the left ventricle

2.      aortic orifice : by this orifice it sends it oxygenated blood to whole body via aorta.

Externally it forms some part of  the sternocostal surface and 2/3 of diaphragmatic surface. It also form apex, left border. It is separated from left atrium by atrioventricular sulcus /groove or coronary sulcus. It also separated from right ventricle by two groove anterior and posterior inter-ventricular groove. 

Internally it has two part inflowing rough part due to trabeculae carneae ( muscular ridges of the heart ) and outflowing smooth part also known as infundibulum. 

The cavity of the left ventricle is circular shape in cross section because the interventricular septum makes a bulge toward the right ventricle.

Trabeculae carneae of ventricles:

Three types of muscular projections are present in trabeculae carneae of left ventricle.

They are

1.     Ridges : fixed muscular elevations

2.     Bridges : two ends are fixed with central free portion

3.     Papillary muscles : in left ventricle it is two in number : anterior and posterior

Easy handout of right ventricle of the heart

Right ventricle of the heart:

The heart consists of four chambers:

·        Right and left atrium both are separated by interatrial septum

·        Right and left ventricle both are separated by interventricular septum

Right ventricle:

 The wall of the right ventricle is thicker than the atrium but it is less thick than the left ventricle.

It contains two orifices

1.     Right atrioventricular orifice: by this orifice deoxygenated blood of right atrium enters into the right ventricle

2.     Pulmonary orifice : by this orifice it sends it deoxygenated blood to the lung via pulmonary trunk for oxygenation.  

Externally it forms most the sternocostal surface and 1/3 of diaphragmatic surface. It also form inferior border. It is separated from right atrium by atrioventricular sulcus /groove or coronary sulcus. It also separated from left ventricle by two groove anterior and posterior interventricular groove . 

Internally it has two part inflowing rough part due to trabeculae carneae ( muscular ridges of the heart ) and outflowing smooth part also known as infundibulum. The two part are separated by a muscular ridge known as supraventricular crest.

The cavity of the right ventricle is crescent shape in cross section because  the interventricular septum make a bulge toward the right ventricle.

Moderator band: (septomarginal trabeculum)

it is the unique features of the right ventricle , a thick muscular ridge extending from the ventricular septum to the base of the anterior papillary muscle. It conveys the right branch of the atrioventricular bundle (bundle of His) , a part of conducting system of the heart .

function of the moderator band: it prevents the overdistension of right ventricle. 

Trabeculae carneae of right ventricle:

Three types of muscular projections are present in trabeculae carneae of right  ventricle.

They are

1.     Ridges : fixed muscular elevations

2.     Bridges : two ends are fixed with central free portion

3.     Papillary muscles of  right ventricle: are  three in number : anterior , posterior and septal. 

Interior of right ventricle of heart

Interior of right ventricle:

Internally it has two parts

1.     inflowing rough part due to trabeculae carneae  ( muscular ridges of the heart ) and

2.      outflowing smooth part also known as infundibulum. The two part are separated by a muscular ridge known as supraventricular crest.

The cavity of the right ventricle is crescent shape in cross section because the interventricular septum make a bulge toward the right ventricle.

Moderator band: (septomarginal trabeculum)

it is the unique features of the right ventricle , a thick muscular ridge extending from the ventricular septum to the base of the anterior papillary muscle. It conveys the right branch of the atrioventricular bundle (bundle of His) , a part of conducting system of the heart . 

Function : it prevent overdistension of heart 

Trabeculae carneae of right ventricle:

Three types of muscular projections are present in trabeculae carneae of right  ventricle.

They are

1.     Ridges : fixed muscular elevations

2.     Bridges : two ends are fixed with central free portion

3.     Papillary muscles of  right ventricle: are  three in number : anterior , posterior and septal.