Flashcards in SBO - Thoracic cage Deck (86):
Structure of the thoracic cage
12 Thoracic vertebrae
12 Pairs of ribs & Costal Cartilages
Sternum (consisting of: Manubrium, Sternal body, & Xiphoid process)
What are the regional characteristics of the Thoracic Vertebrae
Vertebral body - Larger than cervical and heart shaped
Vertebral foramen - Circular
Spinous process - long, sharp, and projects inferiorly
Transverse process - have facets for the ribs (except T11 and 12)
Facet Orientation - superior facets directed posteriorly, inferior facets directed anteriorly.
Size - gradual increase in size from T1 to T12
Which are the typical thoracic vertebrae, and what are the typical components of a thoracic vertebrae.
Superior costal facets - large semicircle, articulates with the rib head of the same number.
Inferior costal facets - small semicircle, articulates with the rib head below
Transverse costal facets - articulate with the rib tubercle of the same number.
What are the atypical thoracic vertebrae
T1, T10, T11 and T12
What are the unique features of the atypical vertebrae T1
Superior costal facets, entire circular shape
Inferior costal demifacet
Transverse costal facet
What are the unique features of the atypical vertebrae T10
Singular costal facet, entire circular shape
Transverse costal facet
What are the unique features of the atypical vertebrae T11 and T12
Singular costal facet, entire circular shape, pedicle
No transverse costal facet
Which ribs are classified as typical ribs
Which ribs are classified as atypical ribs
Ribs 1, 2, 10, 11, 12
Which ribs are identified as the true ribs and what is the other name for true ribs
Ribs 1-7 Vertebrocostal
Which ribs are identified as the false ribs and what is the other name for false ribs
Ribs 8-10 Vertebrochondral
Which ribs are identified as the floating ribs and what is the other name for floating ribs
Ribs 11 and 12 Vertebral
What type of bone is a rib
What is the costal groove for
Protecting vessels and nerves
What tubercle is between the subclavian artery and vein on the 1st rib. And which muscle attaches here
What is the costal cartilage made from
What type of joint is Rib 1 connection to the Manubrium
What is the posterior portion of the rib called, and what shape is it?
What are the landmarks of the rib head?
Superior articular facet - articulates with the inferior costal demifacet of the vertebral body above.
Inferior articular facet - articulates with the superior costal demifacet of the same numbered vertebral body.
Crest of the head - lies between the two facets
Name the elements of the typical ribs
Rib shaft or body,
Describe the components of the rib tubercle
Articular part - smooth, articulates with the TP of the same vertebra
Non-articular part - rough, for attachment of the lateral costotransverse ligament.
Which ribs are considered atypical
T1, T2, T10, T11, T12
Identify the atypical features of rib 1
Very short and flattened superior-inferiorly - Rib shaft has superior and inferior surfaces.
Scalene tubercle is on superior surface.
Groove for subclavian vein - anterior to tubercle.
Groove for subclavian artery - posterior to tubercle.
Rib head has a single facet, articulates with T1
Rib tubercle is very prominent
No rib angle or costal groove
Identify the atypical features of rib 2
Short rib slightly flattened - external surface faces superiorlaterally, internal surface faces inferiomedially.
Costal groove is prominent posteriorly
Tuberosity for serratus anterior mm
Rib head has two facets like other ribs
Identify the atypical features of rib 10
The rib head has only one facet.
May or maynot have a rib tubercle with an articular facet.
Identify the atypical features of ribs 11 and 12
Short ribs with free anterior margins.
The rib head has only one facet.
There is no rib tubercle or rib neck.
Identify the components of the sternum
Identify the components of the Manubrium
Located at the level of T3-4
Identify the components of the Sternal body
Located at the level of T5-9
What is the vertebral level of the Xiphoid process
Located at the level of T10
Identify the joints of the sternal portion of the anterior thoracic cage
Manubriosternal (sternal angle)
Identify the joints of the ribs and costal cartilages of the anterior thoracic cage
Identify the joints of the posterior thoracic cage
What type of joint is the Manubriosternal joint?
Secondary cartilaginous joint (symphysis)
What type of joint is the Xiphisternal joint?
Primary cartilaginous joint (synchondrosis)
What level is the sternal angle or manubriosternal joint located at?
Where are the Sternochondral joints located, and what is the classification of the joint?
The articulation between the costal cartilages of ribs 1-7 and the costal notches of the sternum.
Except for the articulation between CC and R1, which is a synchrondrosis (Primary cartilaginous).
What type of joint is the sternoclavicular joint (SC).
Synovial saddle joint
What are the features of the Interchondral joints
Articulation between costal cartilages of two adjacent ribs R6-9.
Usually synovial plane joints.
Interchondral joint b/w CCs of rib 9 & 10 is usually fibrous.
What is the joint classification of the Costovertebral joint
Synovial joint between rib head and vertebral body
Features of the posterior thoracic cage joints for Ribs 2-9
Rib head articulates with two adjacent vertebral bodies and the IVD between them.
Supported by two ligaments: Intra-articular ligament and radiate ligament.
Features of the posterior thoracic cage joints for Ribs 1, 10, 11, & 12
Articulates with the corresponding vertebral body.
No intra-articular ligament.
Does have a radiate ligament.
What are the features of the costotransverse joint
Synovial joint between costal facet of TP and tubercle of corresponding rib.
Ribs R1-10 only.
Describe the attachments of the medial costotransverse ligament.
From posterior aspect of the rib neck, to the anterior aspect of the corresponding transverse process
Describe the attachments of the lateral costotransverse ligament.
From non-articular part of the rib tubercle (posterior aspect of the rib) to the tip of the corresponding TP.
Describe the attachments of the superior costotransverse ligament
From superior aspect of the rib neck, to inferior aspect of the TP of the vertebra above.
Describe the boundaries of the Superior Thoracic Aperture or Thoracic Inlet
T1, 1st ribs and costal cartilages, superior border of the manubrium.
Describe the boundaries of the Inferior Thoracic Aperture or Thoracic Outlet
T12, 11th and 12th ribs, costal cartilages and xiphisternal joint.
Separates the thorax and the abdominal cavities.
What is the Primary Muscle of Respiration
What are the Internal Cage Muscles
What are the Intercostal Space Muscles?
What are the External Cage Muscles?
Serratus posterior superior
Serratus posterior inferior
Describe the thoracic diaphragm
Skeletal muscle between the thorax and abdomen.
Has two dome shaped halves called hemi-diaphragms.
Has a central tendon, trifoliate in shape (like a cloverleaf).
Note: the central tendon does not have any bony attachments.
What are the general functions of the thoracic diaphragm
Primary muscle of respiration (Inspiration).
Two domes support the right and left lungs.
Central tendon supports the heart.
Muscle of abdominal straining.
Weight lifting muscle
Identify the origins of the Diaphragm
Sternal origins: two muscular slips to xiphoid process.
Costal origins: internal surface of inferior six costal cartilages and ribs bilaterally.
Lumbar origins: "crura" of the diaphragm - musculotendinous bundles that arise from lumbar vertebrae, IVD, ALL, as well as arcuate ligaments.
Right crus is larger and longer than left crus. Right crus arises from L1-4; Left crus L1-3.
What is the insertion of the diaphragm?
Fibres of the diaphragm run superiomedially.
Fibres converge and insert into the central tendon.
What are the actions of the diaphragm?
Only the central tendon moves, the periphery of the muscle (origins) are fixed.
Contraction of the diaphragm pulls the central tendon (domes) inferiorly, increasing the vertical diameter of the thorax.
What is the nerve supply of the diaphragm?
Right and Left phrenic nerves from the Cx plexus (C3, 4, 5) provide it with motor supply as well as sensory supply to the central portion.
Remember: C3, 4, 5 keeps the diaphragm alive!
Peripheral parts receive sensory supply from the inferior 6 intercostal nerves and subcostal nerves.
What are the 3 apertures of the diaphragm
Describe the features of the Caval opening.
At level of T8 body, opening in the central tendon.
Transmits the inferior vena cava, some branches of the right phrenic nerve and some lymphatic vessels.
Describe the features of the Oesophageal hiatus.
At level of T10 body, formed by the right crus.
Transmits the oesophagus, vagus nerves.
Describe the features of the Aortic hiatus.
At level of the T12 body.
The aorta passes posterior to the diaphragm, not through it, posterior to the median arcuate ligament.
With the thoracic duct and the azygous vein.
What are the arcuate ligaments of the diaphragm, and what do they each arch over?
Median arcuate ligament - arches over the aorta.
Medial arcuate ligament - arches over the psoas muscle.
Lateral arcuate ligament - arches over the quadratus lumborum muscle.
What are the accessory muscles of respiration?
And what do they help with?
Serratus anterior, and serratus posterior superior
Pectoralis major and minor.
Scalenes (anterior, middle, posterior)
Help expand the thoracic cavity when inspiration is deep and forceful.
Describe the features, muscle fibres and innervation of the external intercostal muscles
11 pairs of muscle
Run in an inferio-anterior direction (hands in front pockets, fingers down).
Extend posteriorly to anteriorly from the rib tubercle to the costochondral junction.
Are continuous inferiorly with the external oblique muscle of the anterolateral abdominal wall.Action: elevation of the ribs - inspiration.
Innervation: Corresponding intercostal nerves.
Describe the features, muscle fibres and innervation of the internal intercostal muscles
11 pairs of muscle
Run in an infero-posterior direction (hands in back pockets fingers down).
Are deep to and are at right angles to the external intercostals.
Extend from sternum in front, to rib angle behind.
Continuous with the internal oblique muscles of the anteriolateral abdominal wall.
Interosseous component: depress ribs.
Interchondral component: elevate ribs
Corresponding intercostal nerves.
Describe the features, muscle fibres and innervation of the innermost intercostal muscles
Deepest layer, may be incomplete.
Separated from the internal intercostals by the neurovascular bundle.
Considered to be part of the internal intercostal and has the same action.
Pass between the internal surfaces of adjacent ribs.
Located in the centre (between anterior and posterior ends) of the IC space.
Corresponding intercostal nerves.
Describes the features,
Muscle fibres, Action and Innervation of the subcostal muscles.
Variable in size and shape
Extend from the lower margin of the rib above.
To the upper margin of the rib located 2-3 ribs below.
Spanning 1-2 IC spaces.
Running in same direction as internal IC muscles (inferior-posterior).
Similar to internal intercostal muscles.
Corresponding intercostal nerves.
Describe the features of the Transverse thoracis or sternocostalis muscles.
4-5 slips of muscle, variable in size.
Arises from posterior surface of xiphoid and body of sternum.
Inserts onto the internal surface of 2-6 costal cartilages.
Is continuous inferiorly with the transversus abdominus muscle of the anterolateral abdominal wall.
Describe the features, superior and inferior attachments, action and nerve supply of the Serratus Posterior Superior.
Located at the junction of the neck and thorax.
Extends from the vertebrae to the ribs.
Fibres run inferior and lateral.
inferior part of the nuchal ligament, spinous processes C7-T3.
superior borders of ribs 2-4
elevates the upper ribs (muscle of inspiration).
intercostal nerves 2-5.
Describe the features, superior and inferior attachments, action and nerve supply of the Serratus Posterior Inferior.
Lies at the junction of thoracic and lumbar regions.
Also extend from vertebrae to ribs.
But fibres run in a different direction: superior and lateral.
Spinous processes of T11-L2
inferior borders of lower ribs (R8-12), near the angles.
Action: Depresses the inferior ribs.
Nerve supply: ventral rami of spinal nerve T9-12.
Describe the features, superior and inferior attachments, action and nerve supply of levator costarum.
12 pairs of triangular (fan-shaped) muscles.
Fibres run inferior and lateral from the apex of TPs to fan onto the rib below.
Superior Attachment: tips of the C7-T11 TPs.
Inferior Attachment: subajacent ribs between tubercle and angle.
Elevates the rib below, muscles of inspiration (weak).
dorsal rami of C8-T11 spinal nerves.
What structures of the thoracic wall does the Posterior (dorsal) rami innervate?
Bones, joints, muscles and skin of the back.
What structures of the thoracic wall does the Anterior (ventral) rami innervate?
T1 ventral rami divide into two parts:
Large superior part - joins the brachial plexus
Small inferior part - forms the 1st
T2-T11 form 11 pairs of intercostal nns
T12 form 1 pair of subcostal nns
Describe the innervation of the thoracic walls
12 pairs of thoracic spinal nerves
Exit the intervertebral foramen and divide into anterior (ventral) and posterior (dorsal) rami.
Describe the features of the typical intercostal nerve
Runs the length of the intercostal space.
Runs between the lining of the lung (pleura) and the internal intercostal membrane.
Near the angle of the ribs
it passes between the innermost and internal intercostal muscles, entering the costal groove (superior part of the IC space)
Near the sternum
It passes between the costal cartilages as the anterior cutaneous branch to supply the skin of the anterior chest.
Name the Intercostal nerve branches
Arise near the angle of the ribs and travels between the innermost and internal intercostal muscles to supply skin over the lateral thoracic wall and abdominal walls.
Lateral cutaneous branches
Arise in the mid-axillary line, peirces the intercostal muscles to supply skin over the lateral thoracic wall and abdominal walls.
Anterior cutaneous branches
Peirce muscles in parasternal line, to supply the skin over the anterior thoracic wall & abdominal walls
Supply the corresponding 3 intercostal muscles, subcostal, transverse thoracis muscles and serratus posterior superior.
Describe the features of the Thoracic Dermatomes
Intercostal nerves supply the skin over the thoracic cage.
The area supplied by each thoracic level approximately corresponds to the underlying intercostal space.
Describe the features of the Posterior intercostal and subcostal arteries.
Branches from the thoracic aorta.
Passes between the internal and innermost intercostal muscles.
Runs with the intercostal vein and nerve in the costal groove.
Runs with IC nerve
Supplies back muscles and skin
Lateral cutaneous branch
Supplies skin of the lateral thorax
Describe the features of the internal thoracic artery.
Branch of the subclavian artery
Passes inferiorly behind the sternum
Gives rise to 6 anterior intercostal arteries
Pass between the internal and innermost intercostal muscles,
Anastomoses with the posterior intercostal arteries,
The internal thoracic artery divides into musculophrenic and superior epigastric arteries.
Anterior intercostal arteries 7-9 arise from the musculophrenic branch of the internal thoracic artery
No 10th or 11th anterior intercostal arteries.
Describe the venous drainage of the thoracic walls
Posterior intercostal veins
Anterior intercostal veins
Internal thoracic veins
These veins accompany the arteries of the same name
Anterior and posterior IC veins anastomose
Draining into the azygos venous system, then the superior vena cava.
What are the contents of the intercostal space, and the muscles traversing the intercostal spaces.
From superficial to deep.
External intercostal muscles
Internal intercostal muscles
Neurovascular bundle (Superior to inferior)
Intercostal Vein, Artery and Nerve (VAN).
Innermost intercostal muscles.
Transverse thoracic mm
What are the Primary Germ layers in embryology and which week do they form
What structures are formed by Ectoderm`
Epidermis of skin
What structures are formed by Mesoderm
Synovial joint membranes
Cartilage bone and other connective tissues
Skeletal, smooth and cardiac muscle
Blood and bone marrow