Anatomy Flashcards
Where are the sensory receptors located to stimulate a cough?
Oropharyngeal mucosa
Laryngopharyngeal mucosa
Laryngeal mucosa
Respiratory tree
What are the nerves involved in sneezing?
CN 5 - Trigeminal
CN 9 - Glosopharyngeal
What are the nerves involved in coughing?
CN 9 - Glosopharyngeal
CN 10 - Vagus
What is the carotid sheath?
A protective tube of cervical deep fascia that attaches superiorly to the bones of the base of the skull. It blends inferiorly with the fascia of the mediastinum
What does the carotid sheath contain?
Vagus nerve
Internal carotid artery
Common carotid artery
Internal jugular vein
How do visceral pleura and respiratory tree visceral afferents connect with the CNS?
The pulmonary visceral afferents travel from the visceral pleura and respiratory tree to to the pulmonary plexus which then follows the vagus nerve to the medulla of the brainstem
How do motor axons connect with the bronchiolar smooth muscle?
They travel from the tracheal bifurication along the branches of the respiratory tree to supply all mucus glands and all bronchiolar smooth muscle
How does the CNS respond rapidly to a stimulation of the sensory receptors?
It coordinates a deep inspiration using the diaphragm (phrenic nerves), intercostal muscles (intercostal nerves) and accessory muscles of inspiration
What is the mechanism of inspiration?
The diaphragm contracts and descends increasing the vertical chest dimension
The intercostal muscles contract elevating the ribs, increasing the anterior-posterior and lateral chest dimensions
The chest walls pull the lungs outwards with them (pleura) allowing air to flow into the lungs via negative pressure. This is due to the parietal pleura being stuck to the chest walls and creating a vacuum that pulls the visceral pleura and therefore the lungs out with them
What nerves supply the diaphragm?
Supplied by the combined anterior rami and cervical spine nerves C3, 4, 5 which are found in the neck on the anterior surface of the scalenus anterior muscle.
What is the route of the phrenic nerves?
They travel from the neck descending over the lateral aspects of the fibrous pericardium anterior to the lung root.
What type of innervation can the phrenic nerves supply?
Somatic sensory and sympathetic axons to the diaphragm and fibrous pericardium and somatic motor axons to the diaphragm.
How do the phrenic nerves influence breathing?
In a deep (forced) inspiration, a greater outflow of action potentials of longer duration via the phrenic nerves occurs causing the diaphragm to flatten then descend maximally
Where does the scalenus anterior muscle run from?
The neck to the first rib
Where is diaphragmatic pain referred to?
The shoulder
What are the muscles of quiet inspiration?
External intercostal muscles
Internal intercostal muscles
Innermost intercostal muscles
What way do the muscle fibres of normal inspiration run?
External intercostal muscles run hands in pocket orientation
Internal intercostal muscles run hands pointing upwards on the chest
Innermost intercostal muscles run hands pointing towards pockets
What happens during a deep inspiration?
The intercostal muscles contract forcefully and raise the ribs maximally
What are the accessory muscles of deep inspiration?
Pectoralis major
Pectoralis minor
Sternocleidomastoid
Where does the pec major attach and what is its function?
Attaches between the sternum/ribs and the humerus
Adducts and medially rotates the humerus and if it is fixed (holding onto the arm of a chair or the thigh) then the muscle can pull the ribs upwards/outwards
What does the pectoralis minor do?
Pulls the ribs 3-5 superiorly towards the coracoid process of the scapula
Where does the sternocleiodomastoid attach?
Between sternum/clavicle and mastoid process of the temporal bone
What is the use of accessory muscles a clinical sign of?
Dyspneoa
What happens to the vocal chords in a cough?
They are adducted to close the rima glottidis (vagus nerve)
What are the intrinsic muscles of the larynx?
All skeletal (voluntary) muscles which attach between the cartilages and move the cartilages resulting in the movement of the vocal chords
What nerve supplies the intrisic muscles of the larynx?
Somatic motor branches of the vagus nerve
What do the instrinsic muscles of the larynx do during the cough reflex?
They adduct the vocal chords
Where does the vagus nerve connect with the CNS?
At the medulla (oblongata) of the brainstem and they travel through the jugular foramen of the base of the skull
Where does the vagus nerve descend through?
The carotid sheath in the neck and then for a cough reflex supplies sensory nerves to the mucosa lining the pharynx and motor nerves to the intrinsic muscles of the larynx
Descends through the posterior aspect of the lung root to supply a parasympathetic axon to the chest organs (including lungs via pulmonary plexus)
Passes through the diaphragm on the oesophagus and onto the surface of the stomach where it divides into parasypathetic branches for the foregut and midgut organs
Why do the anterolateral abdominal wall muscles contract in a cough reflex?
To build up intra-abdominal pressure which pushes the diaphragm superiorly and builds up pressure in the chest/respiraotry tree inferior to the adducted vocal chords
What is the mechanism of expiration?
The diaphragm relaxes and rises back up, the intercostal muscles relax and so the ribs lower, all of this decreases the chest dimensions, the lungs are made of elastic tissue and so elastic recoil takes place, pushing air out of the lungs.
What are the accessory muscles of deep expiration?
The diaphragm relaxes and the right and left anterolateral abdominal wall muscles contract forcefully increasing the intra-abdominal pressure. The diaphragm is forced superiorly by the compressed abdominal contents and the intra-thoracic pressure increases, increasing the pressure within the respiraotry tree inferior to the vocal chords
What are the anterolateral abdominal wall muscles?
Right and left rectus abdominis
Right and left external oblique
Right and left interal oblique
Right and left transversus abdominus
What is the linea alba?
Where the aponeurosis of the right external oblique blends with the aponeurosis of the left external oblique at the midline
Where do the external obliques attach?
Superiorly to the superficial aspects of the lower ribs and inferiorly to the anterior part of the iliac crest and pubic tubercle
Where do the internal obliques attach?
Superiorly at the inferior border of the lower ribs and inferiorly at the iliac crest and the thoracolumbar fascia of the lower back
Where do the transversus abdominus attach?
They are deep to the internal oblique
Attach superiorly at the deep aspects of the lower ribs
Attach inferiorly to the iliac crest and the thoracolumbar fascia of the lower back
What do the rectus abdominis form?
The tendinous intersections divide each of the 2 long flat muscles into 3 or 4 smaller quadtrate muslces - “6-pack”
What path do the thoracoabdominal nerves run in?
The 7th to the 11th intercostal nerves travel anteriorly then their terminal branches leave the intercostal spaces in the plane between the internal oblique and the transverse abdominus as the thoracoabdominal nerves
What level does the subcostal nerve come from?
T12 anterior rami
What level does the iliohypogastric nerve come from?
Half of L1 anterior ramus
Where does the iliolingual nerve come from?
Other half of L1 anterior ramus
Why does the soft palate tense?
To elevate it to close off the entrance into the nasopharynx and direct the stream of air through the oral cavity as a cough rather than through the nasal cavity as a sneeze
What can dynamic airway compression in asthma cause?
Difficult expiration that leads to a build up of air trapped in the alveoli which can lead to the rupture of the lung and visceral pleura
What is a small pneumothorax?
When a small amount of air enters the pleural cavity via a penetrating injury to the parietal pleura or by the rupture of the visceral pleural the vacuum is lost and the elastic tissue recoils towards the lung root and a small pneumothorax is formed
What is the difference between a small and large pneumothorax?
A small pneumothorax has less than a 2cm gap between the lung and the parietal pleura and a large pneumothorax has more than 2cm between the lung and parietal pleura
How is a pneumothorax diagnosed?
History
Examination: reduced ipsilateral chest expansion, reduced ipsilateral breath sounds, hyper-resonance on percussion
Investigation: Absent lung marking peripherally
Lung edge visible
What is a tension pneumothorax?
The torn pleura can create a one-way valve that permits air to enter the pleural cavity on each inspiration but prevents lung escaping again on expiration and therefore on each inspiration more air enters the pleural cavity and the pneumothorax expands and the lung collapses towards its root
Why can the mediastinal structures shift?
The build up of air in the pleural cavity applies tension (pressure) to the mediastinal structures
What are the 4 areas of the mediastinum?
Superior and middle mediastinum, posterior and anterior mediastinum
What does the sternal angle separate?
The manubrium to the sternal body and also the superior mediastinum to the other 3 quadrants
How is the sternal angle palpated?
Palpate the 2nd rib and then move medially - this is the sternal angle at T4. The arch of the aorta starts here and the bifurcation of the trachea is here
What is in the posterior mediastinum?
Nerves and vessels
What are the consequences of the mediastinal shift?
Tracheal deviation away from the side of a unilateral tension pneumothorax is palpabale in the jugular notch
SVC compression reduces venous return to the heart leading to hypotension
How is large pneumothorax managed?
Needle aspiration (thoracentesis) Siting of a chest drain Both the procedures are performed via the 4th or 5th intercostal space in the midaxillary line
What is the safe triangle?
Anterior border of latissimus dorsi
Posterior border of pectorallis major
Axial line superior to the nipple
What is the purpose of the triangle of saftey?
Won’t pierce the diaphragm
The intercotal bundles run just under the ribs in the intercostal groove
You should aim for the middle of the intercostal space, never just under or just over the rib
What layers does the needle aspiration pierce through?
Skin
Superficial/deep fascia
3 layers of intercostal muscles
Parietal pleura
What is the emergency management of a tension pneumothorax?
Insertion of a large gauge cannula into the pleural cavity via the 2nd or 3rd intercostal space in the midclavicular line on the side of the tension pneumothorax
The sternal angle is the level of rib 2
What is a consequence of a chornic cough?
Herniae
What two factors are usually required for the development of a hernia?
Weakness of one structure: commonly part of the body wall
Increased pressure on one side of that part of the wall
Where do diaphragmatic herniae develop?
The normal anatomical weakness is at the attachement to the xiphoid
I ate 10 eggs at 12
IVC T8, oesophagus T10, aorta T12
This is called a hiatus herniae
What is a paraoesophageal hiatus hernia?
The herniated part of the stomach that passes through the oesophageal hiatus to become parallel to the oesophagus and in the chest
What is a sliding hiatus hernia?
The herniated part of the stomach slides through the oesophageal hiatus into the chest with the gastro-oesophageal junction
What is an inguinal hernia
Between the anterior superior iliac spine and the public tubercle. The boundary is between the trunk and lower limb and the abdomen and genitalia
Where are the inguinal ligaments?
They attach between the anterior superior iliac spine and the pubic tubercle. Their medial halves form the floors of the inguinal canals
The inguinal ligaments are the inferior borders of the external oblique aponeuroses
Where does the inguinal canal pass through?
A 4cm long passageway through the anterior abdominal wall in the inguinal region. Each canal floor is the medial half of the inguinal ligament. Each canal runs between a deep ring (entrance to canal) and a superficial ring (exit from canal)
What does the deep ring communicate with?
The abdomen
What does the superficial ring communicate with?
The genitalia
Where will an inguinal herniae form
In the medial half of the inguinal region, it may be unilateral or bilateral
The weakness in the inguinal herniae is the presence of the inguinal canal in the inguinal part of the anterolateral abdominal wall
When is the inguinal canal formed?
Embryologically during the passage of the testes or the round ligament of the uterus into the perineum. In the adul the canal contains the spermatic cord or the round ligament of the uterus
What can cause an increased pressure in the intra-abdominal region?
Chronic cough
Chronic constipation
Occupational lifting of heavy weights
Athletic effort
Where are the vas deferens attached?
Inferiorly in the pelvis in the region of the developing prostate gland
What layers of muscle do the testes run through to descend into the sccrotum?
Parietal peritoneum Testicular artery Testicular vein Trasversalis fascia Transversus abdomins Internal oblique External oblique aponeurosis Deep fascia Superficial fascia Tunica vaginalis Scrotal skin
What does skeletal muscle in the internal oblique allow the testes to do?
Move and contract
What occurs in the transversalis fascia?
Fluid is produced to allow the testes to descend without causing friction or damaging any organs
What is the spermatic cord?
The 3 layers of coverings gained as the testis pass through the inguinal canal and the structures contained within
What does the spermatic cord contain?
Vas deferens, testicular artery and pampiniform plexus
The vas deferns transports sperm
Testicular artery supplies oxygenated blood to the testis
Pampiniform venous plexus drains deoxygenated blood from the testis
