Thoracic cage

1
??? ???? ?????? ??????
2
Thoracic cage
3
Thoracic inlet
4
(No Transcript)
5
Thoracic Cage

• - The thoracic cage consists of the sternum, the
  ribs, and the thoracic vertebrae.
• - It has a narrow inlet and a wide outlet.
• I. Thoracic inlet (the upper opening of the
  thoracic cage)
• Boundaries
• a. Anterior -------------- Supra-sternal notch of
  the manubrium sterni.
• b. On each side --------- First rib.
• c. Posterior -------------- First thoracic
  vertebra.

6
II. Thoracic outlet

• It is the lower opening of the thoracic cage.
• Boundaries
• a. Anterior -------------- Xiphoid process.
• b. On each side --------- Lower six costal
  cartilages Last two ribs.
• c. Posterior -------------- Last thoracic
  vertebra.
• - It is closed by the diaphragm which separates
  it from the abdominal cavity.

7
Ribs

• Classification of ribs according to their
  attachments to the sternum
• - There are twelve ribs on each side classified
  as
• A True ribs --------- Upper seven ribs (their
  anterior end is attached to the sternum).
• B False ribs --------- Lower five ribs (they are
  not attached anteriorly to the sternum).
• - The lower two ribs are called the floating ribs
  because they are free anteriorly.
•  
• Classification of ribs according to their
  structure
• A Typical ----------- 3rd - 9th ribs.
• B Atypical ---------- 1st, 2nd, 10th, 11th, and
  12th ribs. (first two and last 3) ribs)

8
Typical rib
9

• A Posterior end, formed by
• 1. Head, contains
• - Small upper demifacet for articulation with
  the small lower demifacet on the side of the
  vertebra above it.
• - Large lower demifacet for articulation with
  the large upper demifacet on the side of the
  vertebra of the same number.
• - Between both demifacets there is the crest
  of the head.
• 2. Neck
• - It is the flattened constriction next to
  the head.
• 3. Tubercle, formed by
• - Articular part (medial part), which
  articulates with the circular facet on the tip of
  the transverse process of the vertebra of the
  same number.
• -Non articular part (lateral part), which is
  attached to the lateral costo-transverse ligament
  .

10
Atypical ribsFirst rib (general features)
11
First rib Structures related
12
(No Transcript)
13
The neck of the first rib
The neck is related anteriorly from medial to
lateral to a. Stellate ganglion. b.
Superior intercostal artery. c. Ventral
ramus of the 1st thoracic nerve.  
14
Second rib
15
(No Transcript)
16
Tenth rib
a. Single articular facet on the head.
17
Eleventh rib
a. Single articular facet on the head. b. No
tubercle.
18
Twelveth rib
a. Single articular facet on the head. b. No
tubercle. c. No neck. d. No costal groove. e.
Large head. f. Tapering anterior end.
19
Sternum(Parts)
20
Sternum(General features)
21
Thoracic vertebrae

• Classification of thoracic vertebrae
• - There are twelve thoracic vertebrae classified
  as
• A Typical ------ 2nd 8th vertebrae.
• B Atypical ----- 1st, 9th, 10th, 11th, and 12th
  vertebrae (first one and last 4 vertebrae).

22
Characteristics of a typical thoracic vertebra

• 1. The body is characterized by
• - Small in size and heart shaped.
• - Its side contains two demifacets
• a. Large upper demifacet for
  articulation with the head of the rib of the
• corresponding number.?
• b. Small lower demifacet for
  articulation with the head of the rib below it. ?
• 2. The tip of the transverse process contains
  circular facet for articulation with the
• tubercle of the rib of the corresponding
  number. ?
• 3. The spine is long, tapering, and directed
  downwards and backwards.
• 4. The vertebral foramen is circular and small. ?
• 5. The superior articular process faces
  backwards, while the inferior articular

23
Typical thoracic vertebra
Lateral surface
Superior surface
24
First thoracic vertebra
1. The body is small . 2. The vertebral foramen
is wide and triangular. 3. The body carries
complete circular articular facet for
articulation with the head of the first rib. 4.
The spine is horizontal.
25
The ninth tenth thoracic vertebrae
Ninth vertebra
Tenth vertebra
26
The eleventh twelveth thoracic vertebrae
Eleventh vertebra
Twelveth vertebra
27
(No Transcript)
28
Thank You
Prof. Dr. Wafaa Abdel-Rahman