Intramuscular spaces in scapular region/ axillary spaces / spaces in shoulder region

Intramuscular spaces in scapular region

There are three spaces present in scapular region .

it is also known as axillary spaces or spaces in shoulder region 
. 

<script data-ad-client="ca-pub-3738618711723990" async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>

Quadrangular Space

o   Boundary:

medial: long head of triceps

lateral: humeral shaft

superior: teres minor

inferior: teres major

o   Contents

·         axillary nerve: passes through the quadrilateral space on its path to innervate the teres minor and deltoid and provide sensation to the lateral arm

·         posterior humeral circumflex artery

superior triangular space

• Boundary
• inferior: teres major
• lateral: long head of triceps
• superior: lower border of teres minor
• Contents

  Scapular circumflex artery

Inferior triangular space

Boundary

o    superior: teres major

o    lateral: lateral head of the triceps or the humerus

o    medial: long head of the triceps

·         Contents

o    profunda brachii artery

radial nerve 

 

Pre-axial (cranial) and post-axial border of upper and lower limb

Pre-axial (cranial) and post-axial border of upper and lower limb

•         It demarcates portion of the limb bud that lies cranial to the axis of the limb e.g radial aspect of upper limb and tibial aspect of lower limb. It marked out by the cephalic vein in the upper limb, and the great saphenous vein in the lower limb

•         clinical relevance: pre-axial polydactyly involves first digit of the hand (radial side) or first digit of the foot (big toe)

<script data-ad-client="ca-pub-3738618711723990" async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>

Post-axial (caudal) border
it demarcates portion of the limb bud that lies caudal to the axis of the limb e.g. ulnar aspect of upper limb and fibular aspect of lower limb. It marked out by the basilic vein in the upper limb, and the small saphenous vein in the lower limb

•         clinical relevance: post-axial polydactyly refers to an additional digit on the ulnar side of the hand, or lateral to the 5th toe

Upper limb

It extends from middle of the clavicle, Distally along the front of the shoulder joint, In the line of the cephalic vein, Lateral border of arm ,forearm and hand to lateral border of the thumb

It extends from middle of the axilla Along the medial side of arm along  the line of  basilic vein Medial side of forearm and hand Medial border of the little finger

Cleavage in first week of development

Cleavage

It is a series of mitotic divisions of the zygote.

Cytoplasm of zygote is successively cleavage (partitioned  ) to form a blastula consisting of increasingly smaller blastomeres (2-cell, 4-cell, 8-cell and so on)

Blastomeres are considered totipotent (capable of forming a complete embryo) upto the 4-8 cell stage (important when considering monozygotic twinning )

Blastomeres form a morula by undergoing compaction that is tight junctions are formed between the cells in the outer cell mass , thereby sealing off the inner cell mass . uvomorulin a glycoprotein found on the surface of blastomeres is involved in compaction

<script data-ad-client="ca-pub-3738618711723990" async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>

The diaphragms in the body

The diaphragms in the body are
1. diaphragma sellae
2. oral diaphragm (mylohyoid muscle)
3.supra pleural membrane (sibson's fascia )
4.the diaphragm
5. pelvic diaphragm
6. urogenital diaphragm

<script data-ad-client="ca-pub-3738618711723990" async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>

Summary of pericardial sinuses both transverse sinus and oblique sinus

Sinuses of pericardium

Pericardial sinuses are potential space within the serous pericardiam .

There are two pericardial sinuses: transverse and oblique.

Oblique sinus

Definition :

It is the cul-de-sac behind the left atrium and is closed on all sides except below .

It is placed between parietal and visceral layer of pericardium

<script data-ad-client="ca-pub-3738618711723990" async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>

 Shape:

 Inverted ‘J’ shaped

Boundaries:

Anteriorly : left atrium and visceral layer of serous pericardium

Posteriorly :  parietal layer of pericardium and fibrous pericardium

Right side : right pair of pulmonary veins and inferior vena cava

Left side : left pair of pulmonary veins

Above : upper margin of left atrium

Inferiorly : open

Special note:

The roof of oblique sinus and floor of transverse sinus is separated by upper margin of

the left atrium only , along which a bilaminar fold of serous pericardium extends from the

upper right to the upper left pulmonary veins

Development:

It develops as an effect of absorption of 4 pulmonary veins into the left atrium.

Function of oblique sinus:

 The oblique sinus permits the distension of left atrium during return of oxygenated

blood in it from the lungs.

Transverse sinus

Definition :

It is a transverse passage between two tubular reflections of serous pericardium and is lined by visceral layer only. It is an inter-visceral space.

Boundaries :

In front : ascending aorta and pulmonary trunk enclosed in a single tube of serous pericardium because both are developed from the truncus arteriosus

Behind intra-pericardial part of superior vena cava and upper margin of left atrium

Above bifurcation of pulmonary trunk

Below upper surface of left atrium

Development:

it is developed after degeneration of the central cells of the dorsal mesocardium .

Summary of transverse sinus of pericardium with clinical anatomy

Transverse sinus

Definition :

It is a transverse passage between two tubular reflections of serous pericardium and is lined by visceral layer only. It is an inter-visceral space.

Boundaries :

In front : ascending aorta and pulmonary trunk enclosed in a single tube of serous pericardium because both are developed from the truncus arteriosus

<script data-ad-client="ca-pub-3738618711723990" async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>

Behind intra-pericardial part of superior vena cava and upper margin of left atrium

Above bifurcation of pulmonary trunk

Below upper surface of left atrium

Development:

it is developed after degeneration of the central cells of the dorsal mesocardium .