Download Subtle Accents

Osteology of the Thoracic Wall
28/1/2014
Alex Hondsmerk
[email protected]
Objectives
Describe the osteology of the thoracic wall
- Ribs
- Sternum
- Clavicle
- Costal Cartilages
- Thoracic vertebrae
Clinical relevance
Objectives
Describe the osteology of the thoracic wall
- Ribs
- Sternum
- Clavicle
- Costal Cartilages
- Thoracic vertebrae
Clinical relevance
Thoracic Wall
Anterior – sternum
Lateral – 12 ribs
Posterior – 12 thoracic vertebrae
Objectives
Describe the osteology of the thoracic wall
- Sternum
- Ribs
- Costal Cartilages
- Clavicle
- Thoracic vertebrae
Clinical relevance
Sternum
Flattened bone forming middle of
anterior thoracic wall
From Greek στέρνον, sternos – 'chest'
3 parts:

Manubrium Articulates clavicle, rib 1 and half of rib
2
Body Articulates half of rib 2, ribs 3-6 and half
of rib 7

Xiphoid process (xiphisternum) Articulates half of rib 7

Sternal Angle
Also known as Angle of Louis (after Antoine
Louis – invented guillotine!)
Level of T4/T5 and second costal
cartilage – easily palpable - important
landmark
Thoracic plane:
Divides superior and inferior mediastinum
- Tracheal bifurcation
- Arch of the aorta (start and end)
- Ligamentum arteriosum
- Loop of recurrent laryngeal nerve
- Rib 2
Needle thoracostomy – pneumothorax
2nd intercostal space, mid-clavicular line
Jugular Notch
Also known as suprasternal notch
Between manubrium of sternum and
heads of clavicles
Palpating the trachea – in suprasternal
notch, one finger on each side.
Deviation = ? pneumothorax
Clinical Relevance
Pectus carinatum – Latin, 'keel chest'
'pigeon chest' - protruding sternum; can cause
difficulty breathing. Treated surgically or with
bracing
Pectus excavatum – Latin, 'hollowed chest'
More side effects than carinatum – displaced heart
and lungs, +/- mitral valve prolapse. Treated
surgically
Sternal fracture – high-energy impacts,
pathological fracture; associated with mediastinum
injures
Objectives
Describe the osteology of the thoracic wall
- Sternum
- Ribs
- Costal Cartilages
- Clavicle
- Thoracic vertebrae
Clinical relevance
Ribs
12 pairs of ribs in humans
I-VII are vertebrosternal – articulate
directly with sternum
VIII-X are vertebrochondral and
articulate with the costal cartilages
XI-XII are floating ribs – no anterior
connection
I-VII = true ribs, VIII-XII = false ribs
Costal margin – costal cartilages VII-X +
xiphisternum
Typical Ribs
Head, neck, tubercle, angle, shaft,
costal cartilage
Anteriorly – continuous with costal
cartilage
Posteriorly – articulates with vertebra
2 articular facets on head of rib, 1 on
tubercle – 3 per rib
Shaft bends at the angle
Superior surface of shaft is rounded,
inferior edge is sharp
Costal groove – contains intercostal
neurovascular bundle
Atypical Ribs
First rib – flat and horizontal, only one
articular surface on head (for body of T1)
No angle or costal groove. Scalene
tubercle separates grooves for
subclavian vein (anterior) and artery
(posterior)
Second rib – flat like rib I, but articulates
normally
Ribs X, XI and XII have only one
articulation with the vertebral body
XI and XII have no neck or tubercle and
articulate only with the body; short, little
curvature, point anteriorly
Clinical Relevance
Cervical ribs – extra rib on C7 – 1/500
people. Can cause thoracic outlet syndrome –
brachial plexus and / or subclavian artery
compression
Rib fractures – mostly middle ribs; # ribs I, II
can cause brachial plexus damage; generally
just anterior to angle. Painful but not
generally dangerous
Flail segment – multiple adjacent ribs broken
in multiple places, major chest trauma – freefloating portion of chest wall. Paradoxical
motion. Invariably associated with pulmonary
contusion +/- pneumothorax; 10-25%
mortality!
Objectives
Describe the osteology of the thoracic wall
- Sternum
- Ribs
- Costal Cartilages
- Clavicle
- Thoracic vertebrae
Clinical relevance
Clavicle
From Latin clavicula, 'little key'
Connects manubrium of sternum and
acromion of scapula – only bony
connection between arm and body!
Gently S-shaped; medial end articulates
with clavicular notch on manubrium.
Lateral end is flatter, articulates acromion.
Shaft attaches sternocleidomastoid,
pectoralis major, deltoid and trapezius
muscles
Trapezoid line, conoid tubercle
Objectives
Describe the osteology of the thoracic wall
- Sternum
- Ribs
- Costal Cartilages
- Clavicle
- Thoracic vertebrae
Clinical relevance
Vertebrae
12 thoracic vertebrae (7 cervical, 12 thoracic, 5 lumbar, 5 sacral, 3-5 coccygeal)
1 for each rib pair
3 articular surfaces – transverse costal facet, and superior and inferior
demifacets
Parts of
vertebra:
Body
Pedicles
Foramen
Spinous
process
Transverse
processes
Articular facets
Rib Articulation
Costovertebral joint: synovial joints;
- superior facet articulates with its own rib (i.e. superior costal facet of
T6 articulates with the head of rib 6)
- inferior facet articulates with head of rib below (i.e. inferior facet of T5
articulates with the head of rib 6)
Rib Articulation
Costotransverse joint: synovial joints;
- between tubercle of rib and transverse process of related vertebra
- stabilised by superior, lateral and costotransverse ligaments
Rib Articulation
Sternocostal joints;
- between costal cartilages 1-7
and sternum
- I fibrocartilage, II-VII synovial
Interchondral joints;
- VII-X
- indirect anchorage to
sternum
T1, T10-12 have only a single facet as they articulate only with their
own vertebra
T11 and T12 have no transverse costal facet
Thank you!
Any questions?
[email protected]