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Some Discussion About Sternum Item

Mahamoda Mily Anatomy, MBBS Academia, Thorax


Item দেওয়ার আগে দুই বন্ধু একজন আরেক জনকে question করে দেখছিল, আসলে তাদের preparation টা কেমন হয়েছে।

সাদিয়া: আচ্ছা রিমা, item দিতে যেয়ে প্রথমে স্যার anatomical position এ sternum ধরতে বলবেন এবং anatomical points বলতে বলবেন। তুই তাহলে শুরু কর।

রিমা: ঠিক আছে।
Anatomical points of sternum:

  1. The quadrilateral shaped manubrium is directed upward.
  2. The triangular shaped xiphoid process is directed downward.
  3. Anterior surface of the body of the sternum is flat and its marked by 3 transverse ridge.
    আচ্ছা বলতো morphological type অনুযায়ী এটা কী type bone?

সাদিয়া: It is a long flat bone. বলতো কেনো flat bone বলা হয়?

রিমা: এটাতো পড়িনি।

সাদিয়া: শোন, এটাকে flat bone বলা হয় কারণ এটার histological structure হচ্ছে,
• Outer, inner compact and middle spongy layers
• It contain red bonemarrow throughout the life.
এবার বল sternum এর length কতো?

রিমা: About 17 cm long in males, less in females. তুই বল sternum এর part কয়টি?

সাদিয়া: 3 part.

  1. Manubrium.
  2. Body and
  3. Xiphoid process.
    তুই আমাকে manubrium টা describe কর? রিমা: Manubrium is quadrilateral in shape. It is the thickest and strongest part of the sternum. It has
    • 2 surfaces : anterior surface and posterior surface.
    • 4 borders: superior, inferior and two lateral border.
    [ a ] Anterior surface is convex from side to side and concave from above downwords.
    [ b] Posterior surface is concave and smooth.
    [ c] The superior border is thick, rounded and concave. It is marked by the suprasternal notch or jugular notch or interclavicular notch. Two clavicular notches are present on either side.
    [ d] The inferior border forms a secondary cartilaginous joint with the body of the sternum and forms an angle is called the sternal angle of Louis.
    [e ] The right and left lateral borders are marked by a small articular demifacet, which articulates with part of the second costal cartilage.
    তুই বল sternal angle কতো ডিগ্রি এবং sternal angle এর importance?
Sternum

সাদিয়া: Importance of sternal angle:

  1. An important landmark for counting of the ribs as second costal cartilage articulates at this level.
  2. Corresponds to the lower border of the body of the fourth thoracic vertebra.
  3. At this level, an imaginary line separate the superior and inferior mediastinum.
  4. Ascending aorta ends at this level.
  5. Arch of aorta begins and ends at this level.
  6. Descending thoracic aorta begins at this level.
  7. Bifurcation of trachea at this level.
  8. Corresponds to the arch of azygos vein.
    Sternal angle এর ডিগ্রি! এটাতো জানি না।

রিমা: 163°.

  1. It increase during inspiration.
  2. It Decrease during expiration.
    তুই আমাকে manubrium এর attachment বল?

সাদিয়া:
[ ] Anterior surface: gives origin to two muscle on each side:-

  1. Pectoralis major: arises from each side near the lateral border.
  2. Sternocleidomastoid (sternal head): arises from the upper end on either side of the median plane.
    [ ] Posterior surface: gives origin to 2 muscle on each side:-
  3. Sternohyoids – above
  4. Sternothyroids – below
    তুই posterior surface of the Manubrium এর relations বল?

রিমা:
[ ] Lower half:

  1. Arch of the aorta.
    [ ] Upper half from right to left:
  2. Left brachiocephalic vein.
  3. Brachiocephalic artery
  4. Left common carotid artery.
  5. Left subclavian artery.
    [ ] On either side :
  6. Lungs and pleurae.
    তুই আমাকে এখন body of the sternum describe কর?

সাদিয়া: Body of the sternum is flat. It is the longer, narrower and thinner than the manubrium. It lies opposite the 5th to 9th thoracic vertebrae. Anterior surface presents 3 transverse ridge which indicate fusion of the 4 sternebrae.
Parts:

  1. Two surfaces: anterior and posterior.
  2. Two ends: upper and lower.
  3. Two lateral borders.
    তুই muscle attachment বল?

রিমা:
[ ] Anterior surface gives origin to: pectoralis major.
[ ] Posterior surface gives origin to: sternocostalis.
সাদিয়া, তুই এটার relation বল?

সাদিয়া: Relations of the posterior surface :
• Right of the median plane:
1. pleura
2. Anterior border of right lung.
• Upper left half of the median plane:
1. Left pleura
2. Left lung
• Lower left half of the median plane:
1. Pericardium
তুই এখন xiphoid process টা বল?

রিমা:
• The xiphoid process is the smallest part of the sternum.
• It is triangular in shape. It is thin, pointed, bifid, perforated.
• It is located in the epigastrium.
[ ] It has two surfaces (anterior and posterior), two lateral borders and two ends ( superior and inferior)
আমার এটার attachment টা মনে থাকে না। তুই একটু সহজ করে বলতো?

সাদিয়া: ঠিক আছে, শোন।
Anterior surface gives insertion to:

  1. Recuts abdominis
  2. Aponeurosis of external and internal obliques.
    Posterior surface gives origin to:
  3. The diaphragm
  4. Linea alba
    আর এটার relation এ থাকবে anterior surface of the left lobe of the liver.
    তুই কি ossification পড়েছিস?

রিমা: Process of bone formation is called ossification.
[ ] Sternum is of cartilaginous ossification. It has 6 ossification centre. Ossification starts at intra uterine life and completes 25 years.
তুই এটার Development বল?

সাদিয়া: somatopleuric layer of lateral plate mesoderm.

Sternum


Developmental anomalies:

  1. Funnel chest: sternum is depressed from normal position.
  2. Pigeon chest: sternum is elevated from normal position.
    Clinically sternum এর importance বলতো? রিমা: clinically এটার importance অনেক বেশি।
    [ ] sternal puncture. Bone marrow aspiration for haematological examination.
    [ ] It is done upper half of the manubrium.
    বলতো কেনো upper half এ puncture করা হয়?

সাদিয়া: কারণ lower half এর relation এ arch of aorta থাকে। এটা যাতে injured না হয় এই জন্য upper half এ করা হয়। আরো importance আছে।
[ ] Open heart surgery te mid sternotomy করা হয়।
আচ্ছা বলতো cleft sternum কখন হয়?

রিমা: Sternum formation হয় two sternal buds থেকে। যদি sternal buds fuse না হয়, তখন cleft sternum হয়।
Examples:
• Cleft sternum
• Bifid sternum
• Perforated sternum.
একটা topic কিন্তু আমাদের বলা হয়নি। বলতো সেটা কী?

সাদিয়া: কী? সবকিছু তো বলা হলো। আর কী বাকি আছে। মনে পড়ছে না তো! তুই বল?

রিমা: joints name and types.

সাদিয়া: ওহ ঠিকতো। এটা আমি বলবো এটা আমি পারি।

  1. Sternoclavicular joint: saddle type of synovial joint
  2. Manubriosternal joint: secondary cartilaginous joint.
  3. Xiphisternal joint: primary cartilaginous joint
  4. 1st condrosternal joint: primary Cartilaginous joint
  5. (2nd to 7th) condrosternal joint: plane type of synovial joint

রিমা: তুইতো অনেক ভালো preparation নিয়েছিস। Best of luck.

সাদিয়া: তুই ও।Item টা দুই জনেরই clear হয়ে যাক এই দোয়া করি।

Reference:

  1. BD Chaurasia’s (7th addition)
  2. Essential of Human Anatomy by A.K Datta

Platform Academic Wings/
Sahina Akter Suma
International Medical College
Session: 2018-2019

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