Thoracic Wall Flashcards
Bones of the thorax: demonstrate the main anatomical features and surface landmarks of the thoracic vertebrae, ribs and sternum. Describe the anatomy of the joints between the ribs, vertebrae, costal cartilages and sternum. Explain their contribution to the movements of ventilation Intercostal muscles: describe the anatomy of the intercostal muscles. Describe a neurovascular bundle in a typical intercostal space and outline the structures its components supply Breast: describe the anatomy of t
How many pairs of ribs are there?
12.
What are the three types of ribs?
True (1-7 reach the sternum). False (8-10) reach the costal cartilage above, the costal cartilages of ribs 3-7 indirectly join these ribs to the sternum. Floating (11 and 12) lack anterior attachment. All emerge from the thoracic curvature.
What is an alternative name for joints?
Articulations.
Describe the anatomy of the articulations between the vertebral column and rib.
Joined via the head and tubercle of the ribs. Tubercles articulated to the transverse facets of the transverse process of each thoracic vertebra (costotransverse joint). Articular facets of the head of the ribs articulate to superior and inferior costal (demi)facets, found on the pedicles of each thoracic vertebra (costovertebral joint).
What is the costal margin?
Lies on the inferior surface of the 10th rib. Marking the end of the thoracic cavity and where the diaphragm is attached.
What is the anatomy of the sternum?
Manubrium, body of the sternum, xiphoid process. Jugular notch (or suprasternal). Xiphisternal joint. Clavicular notch – articulation between the clavicle and manubrium. Sternal angle – manubriosternal joint.
Where do the costal cartilages articulate with the sternum? How?
1st CCs – manubrium. 2nd CCs – to the manubriosternal joint. 3rd-7th CCs – to sternum (7th joins at the area between the body and xiphoid). 8th-10th CCs – to the costal cartilages above. 11th and 12th – floating. Articulation: Articular facets on the sternum join with the costal cartilage of the ribs.
How can the breathing movement of the ribs be described?
Bucket handle movement. When breathing in, ribs move superiorly and anteriorly in a handle-like movement – swinging out anteriorly THEN superiorly.
How many pairs of intercostal muscles are there?
11.
What are the three intercostal muscle layers?
External intercostals – angled inferio-medially from lower border of rib above (just in front of the costal groove), to rib below of you look at the anterior. Replaced by anterior intercostal membrane at COSTOCHONDRAL JUNCTION (rib cartilage joins with the ribs). MOVE RIBS SUPERIORLY DURING INSPIRATION.
Internal intercostals – angled 90 degrees from the external intercostals i.e. superiomedially. Attached from the most inferior edge of the costal groove of the above rib, to the superior border of the below rib. MOVE RIBS INFERIORLY DURING EXPIRATION.
Innermost intercostals – also run superiomedially (same orientation as the internal intercostals). Attached to the medial edge of the costal groove of the above rib, and internal aspect of the superior margin of the lower rib. Important for stiffening of chest to improve the efficiency of breathing.
How are the intercostal spaces named relative to the ribs?
Correspond to the above rib. E.g. the 1st intercostal space is below the first rib.
What is the gross anatomy of the intercostal nerves in the thorax?
11 pairs T1-T11, plus 1 subcostal nerve T12. Mixed – contain motor and sensory. Supply the intercostal spaces. Nerves come from spinal cord and run along intercostal spaces. There are lateral (found laterally i.e. side of rib) and anterior (found anteriorly i.e. next to sternum) cutaneous branches which allow for sensation in the skin. Motor neurones innervate the muscle. The lateral cutaneous branch branches off to innervate skin posteriorly and anteriorly. Meanwhile, the anterior cutaneous branches off to innervate skin laterally and medially.
How are the intercostal nerves arranged inside the intercostal spaces?
Neurovascular bundle found between internal and innermost intercostals. Found below and above each rib. Inferior to the rib, the neurovascular bundle is arranged with the intercostal vein superiorly, followed by intercostal artery and then intercostal nerve. The costal groove protects the vasculature but leaves nerve vulnerable. The small collateral (meaning side-branch or accessory part) branch of the neurovascular bundle are present superior to each rib. They are arranged such that the intercostal vein is again, most superior.
What is associated superficially and deeply in the intercostal muscles?
Deeper = endothoracic fascia which contains fat. Superficially (working outwards) = deep fascia, superficial fascia, skin. Muscle also found in back.
What area is considered safe for insertion of a chest drain?
The safe triangle. Posterior: Anterior border of the latissimus dorsi. Posterior-axillary line. Anteriorly: the lateral border of the pectoralis major muscle. Anterior-axillary line. Inferiorly: a line superior to the horizontal level of the nipple. 5th intercostal space at mid-axillary line. Superiorly: an apex below the axilla. Insertion of needle in the 2nd-5th intercostal spaces.
Why is the safe triangle ‘safe’?
Safe because it is the area where the apex of the lung arches medially, so there is pleural space that’s thicker and running more medially also.
Where do the intercostal arteries originate?
Each intercostal artery has major artery at the end of the intercostal space – to the AORTA posteriorly and the INTERNAL THORACIC ARTERY anteriorly. (The internal thoracic artery bifurcates to form the musculophrenic and superior epigastric arteries just superior to the diaphragm.) Each anteriorly-originating and posteriorly-originating intercostal artery joins – forming anastomoses in the middle of the intercostal spaces. The intercostal spaces 1 and 2 are not supplied by the descending aorta, because the aorta doesn’t go this high. Instead, the POSTERIOR (remember, the aorta supplies the posterior) intercostal spaces 1 and 2 are supplied by the left and right subclavian arteries, which branch into the supreme intercostal artery on each side.
Describe the anatomy of the vertebral column.
Cervical: 7 vertebrae, C1-7 spinal nerves above; C8 spinal nerve below – anteriorly convex. Thoracic: 12 vertebrae, spinal nerves emerge below each rib – anteriorly concave. Lumbar: 5 vertebrae, spinal nerves emerge below each rib – anteriorly convex. Sacral: 5 fused vertebrae, spinal nerves emerge below each vertebra– anteriorly concave. Coccygeal: 2-4 fused vertebrae to produce one bone with coccygeal nerve – anteriorly concave.
What is the upper limb girdle?
Comprises clavicles and scapulae – attach upper limbs to axial skeleton. Glenoid cavity – shallow articular surface that articulates with head of humerus. Acromion process – bony process of the scapula. Posterior. Coracoid process – small hook-like structure on lateral, anterior edge of scapula. Supra and infra spinous fossae. Subscapular fossa. Spine of the scapula – prominent posterior plate of scapula. Acromioclavicular joint – joint between scapula and clavicle believe it or not. Superior and inferior angle.
What is the structure of vertebrae?
Divided into vertebral body (anterior) and vertebral arch (posterior). Vertebral body: weight-baring and linked to the superior/inferior vertebra by inter-vertebral discs and ligaments which increase in size inferiorly as they must bear more weight. Vertebral arch: forms the lateral and posterior region, with the vertebral foramen in the centre. Vertebral foramen: all the foramina combined form the vertebral canal to contain and protect the spinal cord. Pedicles: bony pillars that attach vertebral arch to vertebral body. Laminae: flat sheets extending medially from the pedicles to meet in the midline to enclose the vertebral arch. Spinous process: projects posteriorly and inferiorly from the junction of the laminae to allow for the attachment of muscles and ligaments – palpable from CVII to TIV. Transverse process: extends posteolaterally from the pedicle-lamina junctions on each side to allow articulation with the ribs. Superior/inferior processes: interact using facets with the inferior/superior processes of the adjacent vertebrae respectively. Superior/inferior vertebral notches: superior/inferior aspects of pedicles, forming the intervertebral foramina where the mixed spinal nerves may emerge.
Superior costal (demi)facet – found on the superior margin of the body – pedicle. Inferior costal (demi)facet – found on the inferior margin of the body – pedicle. Articulate with Superior articular facet – associated with superior process. Articulate with inferior facet of inferior process in adjacent vertebrate. Inferior articular facet – associated with inferior process. Articulate with superior facet of superior process in adjacent vertebrate. Transverse costal facets – articulate with the tubercles of the rib. Found on the transverse process.
Name the vertical lines of the thorax surface.
Mid-clavicular line – from the mid-point of the clavicle and down. In males, the nipple lies just lateral of this line. Anterior axillary line. Midaxillary line. Posterior axillary line. Scapula line – medial border of the scapula on the back.
What is the embryology of the breast?
Derived from precursor ectoderm cells and form a mammary bud at the fourth intercostal space. Secondary buds form and continue to lengthen and branch, forming a complex network of radially arranged breast ducts that connect the developing nipple with the growing mammary lobules.
What is the anatomical structure of the breast?
Gland is comprised of 15-20 lactiferous ductal-lobular units, each draining into a main duct. Fat lies interspersed between the ductal lobular units. Fibrous septae extend from the skin to the pectoral fascia – divide breast into lobes and lobules. Cooper’s ligaments are connective tissue that connects the anterior and posterior fascial planes – supporting structure. Suspensory ligaments. Behind the nipple, there are 4-18 milk ducts (mammary glands) open on the summit of the nipple or on the areola.
How is blood drained from the breast? Clinical significance of one route?
Three routes: 1. From the medial region of the breast, parasternally into the internal mammary vein (another name for internal thoracic vein). 2. From lateral and superior part of the breast to the axilla via tributaries of the axillary vein. 3. Perforating branches of the posterior intercostal veins. These lie in continuity with the vertebral plexus of veins (the interconnection between the anterior intercostal neurovascular bundle and posterior intercostal neurovascular bundle) – so it is an important area for the spread of breast cancer in the blood into the spine and other regions of the body.
How is the breast innervated?
Mainly the anterolateral and anteromedial branches of thoracic intercostal nerves – T3-T6. There is also innervation from the supraclavicular nerves to the upper and lateral parts of the breast. The nipple is supplied from the lateral cutaneous branch of T4.
What is the lymphatic drainage of the breast? (x2 types – and all the sub-categories).
There are three routes of drainage: 1. MOST: passes from lateral and superior part of the breast to the axilla into axillary nodes: split into five groups – humeral (lateral), subscapular (posterior), pectoral (anterior), central and apical. This axillary area is called the pyramidal space and drains into the subclavian trunks. 2. Some drains from the medial region of the breast, parasternally into the internal mammary nodes (also called parasternal nodes). Drains into the bronchomediastinal trunks. 3. Small amounts of drainage from the inferior part of the breast into the inferior phrenic (abdominal) node, or lymphatic vessels that follow the lateral branches of the posterior intercostal arteries that connect with the intercostal nodes situated near the heads of ribs.
