Osteology of thoracic cage

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OSTEOLOGY OF THORACIC

CAGEBY

DR. ABDUL WAHEED ANSARI CHAIRPERSON & PROF. ANATOMY

RAK COMS.

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A 55 year old male is brought into your trauma bay c/o of severe central chest pain that is reproducible on palpation and movement , post being involved in a rear ended MVA at 60kph.

Seat belt sign with sternal fracture

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Sternum

• The sternum (breastbone) located in the anterior midline of the body is a flat bone approximately 15 cm long consisting of three regions.

• The manubrium (the superior portion) articulates with the clavicles laterally and with the first two pairs of ribs.

• The body (which forms the bulk of the sternum) bears notches that articulate with the costal cartilages of the third to seventh pairs of ribs.

• At the inferior end of the sternum is the small, variably-shaped xiphoid process, which although formed of hyaline cartilage in youth, is usually ossified in adults.

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Sternal foramen• A sternal foramen is a round or ovoid

congenital bony defect that results from incomplete fusion of the sternal ossification centres. The estimated prevalence is 4.5%.

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Accessory ribs

• Cervical ribs at C7. Plain antero-posterior radiographs demonstrate C7 vertebra bearing a pair of ribs, left larger than right, which cannot be considered thoracic because they do not articulate with the manubrium.

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Ribs fractures

Flail chest is the most common serious injury to the ribs. It occurs when three or more ribs are broken in at least two places, front and back.The injured area of ribcage sinks in when the person inhales instead of lifting outwards.( Paradoxical movement).

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The ribcage consists of 24 curved ribs arranged in 12 pairs.

• The next three pairs of ribs aren’t connected to the sternum. Instead, costal cartilage attaches these ‘false ribs’ to the last pair of true ribs.

• The remaining two pairs aren’t attached at the front of the body at all and are known as ‘floating ribs’.

• Each pair is attached to a vertebra in the spine.

• At the front of the body, the first seven pairs of ribs are attached directly to the sternum (breastbone) by cartilage known as costal cartilage.

• These ribs are often called ‘true ribs’.

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11th & 12th ribs (6, 5)

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11th and 12th ribs are related to both kidneys

Abdominal CT, spleen lacerationCommon causes of splenic lacerations include MVA( Motor vehicle accident) or other high speed deceleration injuries. These produce lower rib fractures which can lacerate the spleen or liver. The patient may present with LUQ pain and referred pain to the shoulder secondary to phrenic nerve irritation (Kehr’s sign).

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Splenic rupture due to rib fractures on left side (9th+10th+11th ribs)

• A father brings his 15-year-old son to the emergency department because the son has a large bruise over his lower left ribs. This resulted from being struck by a car accident. In addition to complaining of pain in the upper portion of his left abdomen, the patient also has pain in his left shoulder, which seems to be aggravated with movement.

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Thoracic vertebrae

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Costal facets on transverse process and demi-facets on upper and lower borders of the body/centrum

• Unique thoracic features:Demi facets for articulation with rib head, seen from side (except for 11th and 12th.), • Articular facets on transverse

processes (for rib tubercle) and • long delicate spinous processes

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Cervical vertebrae

Unique cervical features: • Transverse foramina in the

transverse processes• Bifurcated spinous process• Typical are 3-6th • Atypical are 1st , 2nd and 7th.

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Lumbar vertebra features

• Heavy centrum • Broad heavy spinous process• Transverse process lacks facets

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Sacrum

• Unique features are• 5 pieces are conjoint together• Triangular piece at the tail end

of vertebral column.• Below it is the degenerating

part of back bone, the coccyx.• It consists of three to five

vertebrae. It is roughly triangular, with the tip of the triangle pointing down.

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Rib & vertebra articulation

• 1. Articular Facet of Rib• 2. Interarticular Crest• 3. Neck• 4. Articular Portion of Tubercle• 5. Nonarticular Portion of Tubercle• 6. Angle of Rib• 7. Costal Groove• 8. Body of Rib• 9. Articular Facet of Transverse Process• 10. Transverse Process• 11. Spinous Process• 12. Lamina• 13. Vertebral Foramen

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Normal curvatures of back bone

• When looking from the side, the spine has normal curvatures.

• In the neck (cervical spine) and low back (lumbar spine) there is normally an inward curvature. Convex anteriorly and concave dorsally.

• In the thoracic spine there is an outward curvature. Concave anteriorly and convex posteriorly.

• The fetal curvature is universally concave anteriorly and convex dorsally.

• The cervical and lumbar curvature develops after a child develops balancing his head over his neck and lumbar curvature develops after the child starts walking.

• The thoracic and sacral curvature remains concave even in adult life, anteriorly.

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Radiology of thoracic vertebrae

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Resources

• https://www.spinemd.com/conditions-diagnoses/cervical-kyphosis-reston-va.php

• https://home.comcast.net/~wnor/thoraxbones.htm

• http://web.uni-plovdiv.bg/stu1104541018/docs/res/skandalakis'%20surgical%20anatomy%20-%202004/Chapter%2002_%20Thoracic%20Wall%20and%20Pleurae.htm

• http://radiopaedia.org/articles/lumbar-rib

• http://www.wjgnet.com/2218-5836/full/v2/i2/WJO-2-13-g002.htm

• http://www.davidicke.com/forum/showthread.php?t=23140

• http://www.radpod.org/2008/04/08/sternal-foramen/

• http://radiologypics.files.wordpress.com/2013/03/thoracic-spine-lateral.jpg

• http://www.aaronswansonpt.com/breathing-part-i-anatomy-mechanics/

• http://www.coccyx.org/whatisit/normal.htm

• Essential Clinical anatomy-4th edition- Keith Moore ( pages 48-55).