Thoracic Wall 1 Flashcards
What organs are protected by the thorax?
Heart + great vessels, lungs and major airways Liver Stomach Spleen Kidneys
How does the thorax assist resp?
Resists negative intra thoracic pressure
Works in partnership w the diaphragm + abdo muscles
Does haematopoiesis occur in the thorax?
ye
How many ribs are there in the thoracic cage?
12 pairs
What makes up the thoracic wall?
✓Thoracic cage
✓ Skin
✓Subcutaneous tissue ✓Thoracic muscles + fascia
✓3 layers of muscles extending between ribs [i.e. intercostal space]
✓Mammary gland/breast tissue
How to identify thoracic vertebra?
Inferior and superior articular processes are vertical and articular facets face slightly medially that allow some rotation but no flexion
Also they kinda look like a giraffe in lateral view
(Lumbar is moose, cervical is Sid the sloth)
What is the latin term for ribs and why isn’t helpful to know?
L. costae, cause things that are rib related are referred to as costal; re: costal cartilage
What are true ribs?
Attach to sternum directly through costal cartilage
What are false ribs?
Attach to sternum indirectly through costal cartilage of 7th rib (SEVENTH RIB)
What are the floating ribs?
Floating ribs (11-12) do not articulate with sternum
What ribs are true ribs?
pairs 1-7
What ribs are false ribs?
pairs 8-10
What ribs are floating ribs?
pairs 11-12
What are the different rib categories by sternal articulation and what ribs fall into these categorisations?
✓ True ribs (1-7) attach sternum directly through costal cartilage
✓ False ribs (8-10) attach sternum indirectly through costal cartilage of 7th rib
✓ Floating ribs (11-12) do not articulate with sternum
What ribs are ‘typical ribs’ in terms of structure?
Ribs #2(3)-9(10)
What structures are found on a typical rib?
Head, Neck, Tubercle, Body (shaft) + Costal angle
Where is the costal groove on a typical rib?
Costal groove on the inner surface and close to the inferior border for the intercostal nerves and vessels
What is different about the first rib?
✓Scalene tubercle attachment for anterior scalene muscle
✓Groove for subclavian vein
✓Groove for subclavian artery
and the inferior trunk (C8 and T1) of the brachial plexus
✓Single facet on head to articulate with T1 vertebra only
✓No costal groove
What are atypical about the floating ribs?
• Are not attached to the sternum
• Heads articulate only with corresponding vertebra
• Do not articulate with the transverse processes
Rib #12 is related to pleura (watch out in kidney surgery)
What structures make up the sternum?
Manubrium, body and xiphoid process (xiphisternum)
what is the sternal angle?
The point of the manubriums articulation with the body of the sternum
What is found at the level of the sternal angle?
− 2nd Costal Cartilage (CC)
− Intervertebral disc between T4 and T5 vertebra
− The proximal and distal boundaries of the aortic arch
− The bifurcation of the trachea
− Superior limit of the pulmonary trunk
− Azygos vein opening to SVC
− Ligamentum arteriosum
Describe the costovertebral joints?
The joints are synovial, supported by a capsule with ligaments
Ribs will articulate with the superior costal facet of its corresponding vertebra and the inferior costal facet of the vertebra above
What ribs don’t take part in a costovertebral joint?
1, 11 and 12, the rest articulate with the superior costal facet of its corresponding vertebra and the inferior costal facet of the vertebra above
Describe the facets of the costovertebral joints in descending order of the thoracic vertebra
✓ T1 vertebra has 1 and one half costal facet on its body
✓ T2 – T9* vertebrae have 2 half costal facets
✓ T10* has 1 half costal facet
✓ T11 and T12 have 1 oval costal facet each
* Variations occur
What is the costotransverse joint?
The joint between the tubercle of rib (except 11 and 12) and the transverse process of its corresponding vertebra
E.g. Rib #6 • articulates with the bodies of T6 and T5 • transverse process of T6 • Therefore its neck lies slightly obliquely
What are costochondral joints?
A joint in all ribs where they articulate with a costal cartilage (chondrum) via a primary cartilaginous (hyaline) joint
Describe how each rib articulates at their costochondral joints
✓ CC of ribs #1 – 7 articulate directly with the sternum via synovial joints to allow movement (except CC1)
✓ CC of ribs #8 – 10 articulates with the costal cartilage above and, indirectly with the sternum
What is the other name anatomists will use for the superior thoracic aperture?
The thoracic inlet
Describe the boundaries of the thoracic inlet/superior thoracic aperture
- Bound by T1 vertebra, 1st rib + costochondral joint and manubrium
- Slopes antero-inferiorly (to the level of T2/3) from the transverse plane
(Apex of lung extends 2 -3 cm above the anterior part of the 1st rib and clavicle)
What structures pass between the thorax and neck in the thoracic inlet/superior thoracic aperture?
- Vessels that supply and drain the head and neck
- Trachea
- Oesophagus
- Vagus + recurrent laryngeal nerves
- Phrenic nerves
Which ribs are not palpable?
1st Rib (Thoracic)
What rib has superior/inferior surfaces?
1st rib (Thoracic)
What is found on the superior surface of the first rib?
From A->I:
Groove for subclavian artery (and inferior trunk (c8t1) of brachial plexus)
Scalene tubercle
Groove for subclavian
What rib articulates with only one other vertebra?
Rib one (Thoracic)
What is found at the level of the xiphisternum?
Solar plexus region: T6 Dermatome
What is the benefit of some costotransverse joints having curved facets?
Allows rotary movement (significant in resp movements)
What is the benefit of some costotransverse joints having flat facets?
Allows gliding movement (significant in resp movements)
What costotransverse joints have flat/curved facets?
1 to 7 have curved facets
8-10 have flat facets
What is a costosternal joint?
The articulation between the costal cartilage and the sternum via synovial joints (other than the first costosternal joint which is primary cartilaginous joint)
What are the borders of the inferior thoracic aperture/thoracic outlet?
T12 vertebra,
11th + 12th Ribs,
costal cartilages of ribs 7-10 (Costal margin/costal arch),
Xiphiod process
Incompletely closed by the diaphragm
Why can the thoracic outlet be a confusing term for the inferior thoracic aperture
There is a disorder of the thoracic inlet/superior thoracic aperture known as the thoracic outlet syndrome
What is thoracic outlet syndrome?
As the brachial plexus, subclavian artery + vein pass between the 1st rib and clavicle on their way to the limbs they may be compressed
Common sites of compression are:
Skelene triangle
Costoclavicular space (between 1st rib and clavicle)
Subpectoral (pec minor + coracoid process)
What structures pass inferiorly to the clavicle?
Brachial plexus
subclavian artery + vein
What is the breast?
✓ Is an accessory gland consisting of mammary glands, skin and connective tissues
✓ Modified sweat gland
✓ Similar structure in males and pre-
pubertal females
Describe the visible structures of the breast
Breasts are reasonably uniform in males but vary greatly in females due to a vast swath of factors; thus defining the size and shape of the breast is difficult.
On all breasts however you will find a hyper pigmented area known as the areola, forming a circle, the centre of which is a glandular protrusion known as the nipple
What are the structures found on the areola?
✓ Montgomery tubercles are the visible portions of Areolar glands on the skin surface, within the areola
What are Areolar glands?
✓ Areolar glands (Montgomery glands): Sebaceous glands in the breast
What is the structure of the base of the breast?
✓ In adult females, base of it is located between the levels of 2nd – 6th (7th) ribs
✓ From the lateral border of the sternum to the mid-axillary line
✓ The upper lateral section may extend towards the axilla
– Axillary process (axillary tail of Spence)
– May perforate deep fascia and extend as far superiorly as the apex of the axilla
Where is the breast found in comparison to other structures?
between the superficial and deep layers of superficial fascia
Sits on pectoralis major, serratus anterior and external oblique muscles
Between the superficial fascia and the muscles is the deep (pectoralis) fascia
What histological structures make up the breast?
15-25 lobes comprising lobules and ducts, surrounded by fat and a well- developed, connective tissue stroma
In certain regions, connective tissue condenses to form Suspensory ligaments of the breast (Cooper’s ligaments)
What do suspensory ligaments of the breast (Cooper’s ligaments) do?
– Connect deep fascia to the dermis of the skin
– Support the breast
What is found in between the deep layer of the superficial fascia of the breast and the deep pectoralis fascia?
A potential space: the retromammary space
What is the retromammary space?
A layer of loose connective tissue between the deep layer of superficial fascia and the deep fascia
– Provides some degree of movement over underlying structures
What causes an orange peel like appearance in the breasts?
The action of the coopers ligaments against oedema or cancer (debated)
What are the four Ts associated with pathology of the anterior mediastinum?
Thymoma
Lower pole of Thyroid tumour
Terrible Lymphoma
Teratoma
