Random anatomy Flashcards
Features of an epidural haematoma
First
- Backpain - initial 75% of cases
- If haematoma infected, fever 66%
- Lower limb weakness developing after stopping an epidural infusion or weakness of the lower limbs which fails to resolve within four hours of cessation of infusion of epidural local anaesthetic
- Delayed presentation after weeks or months following discharge from hospital
- Only 13% of patients with epidural abscess present with the classical triad of fever, back pain and neurological change
- Meningism.
Diaphragm
develops from what
where does it receive nerve supply
Where does this nerve pass
Openings
aorta
oesop
vc
The diaphragm is a domed fibromuscular sheet separating the thorax from the abdomen.
It develops mainly from septum transversum (central tendon) and cervical myotomes (muscular component).
The mesothelial linings are derived from the pleuro-peritoneal membranes (failure of its development leads to Bochdalek’s foramen and hernia).
Oesophageal mesentery also contributes to the formation of the diaphragm.
Morgagni’s foramen is a congenital defect arising at the junction of the costal and xiphoid origins.
Because of its cervical myotomal origin, it receives nerve supply from cervical roots - phrenic nerves. The left phrenic nerve pierces the muscular portion of the diaphragm approximately 1 cm to the left of the pericardium and 3 cm anterior to the central tendon The right phrenic nerve however pierces the central tendon accompanied by the inferior vena cava.
The lower intercostal nerves give only proprioceptive supply to the periphery of the diaphragm.
The openings in diaphragm are
Aortic opening - T12
Oesophageal opening - T10
Vena caval opening - T8.
what % of pop have a cervical rib
where does it oringate from
do they cause sy often?
what sy cause
0.58-6.2% of individuals )depending upon the population studied) the costal elements of the seventh cervical vertebra form projections called cervical ribs.
Commonly they have a head, neck, and tubercle, with varying amounts of body. They extend into the posterior triangle of the neck where they may be free anteriorly, or be attached to the first rib and/or sternum.
Usually these ribs cause no symptoms, and are diagnosed after incidental finding on CXR.
In some cases, the subclavian artery and the lower trunk of the brachial plexus are kinked where they pass over the cervical rib.
Compression of these structures between this extra rib and the anterior scalene muscle may produce symptoms of nerve and arterial compression, producing the “neurovascular compression syndrome”, however in 90% of patients, they are asymptomatic.
Often the tingling, numbness, and impaired circulation to the upper limb do not appear until the age of puberty when the neck elongates and the shoulders tend to droop slightly.
First rib
Describe antom
what runs in its groove
What attaches to it
Relationships Superior inferior posterio anterior
The first rib is short and thick and it has a single facet which articulates at the costovertebral joint. It has a head, neck and shaft but lacks a discrete angle. Laterally the shaft is indented with a groove for the subclavian artery, this also contains the lower brachial plexus trunk an the subclavian artery. Anterior to the scalene tubercle is an indentation for the subclavian vein.
The first rib has the scalenus anterior muscle attached to the scalene tubercle, separating the subclavian vein (anteriorly) from the suclavian artery (posteriorly).
This anatomical relationship is of major importance with regard to subclavian vein cannulation.
The 1st rib has the following relationships:
superior: lower trunk of the brachial plexus; subclavian vessels; clavicle
inferior: intercostal vessels and nerves;
posterior and inferior: pleura
anterior: sympathetic trunk (over neck); superior intercostal artery; ventral T1 nerve root
Muscle of respiration
The internal intercostals are muscles of expiration.
Latissimus dorsi has a role in forced expiration.
The rectus abdominus aids expiration by pushing the relaxing diaphragm upwards and pulling the ribs down and in.
In deep forced inspiration, every muscle that can raise the ribs is brought into action, including the scalenus anterior and medius and the sternocleidomastoid muscle.
PTCA
Benefit?
Percutaneous translumimal coronary angioplasty (PTCA) produces endothelial disruption in the treated vessel. It is mainly for symptom relief rather than for its prognostic benefits since coronary artery bypass grafting (CABG) is the treatment of choice for left main stem stenosis (not PTCA).
It is not contraindicated in unstable angina.
The procedure is almost always done under local anaesthesia rather than under general anaesthesia.
Stellate ganglion formed from what
how many patient
whats the landmark for the block
what lies in front of it
is it useful for surgery on the arm
The stellate ganglion is formed by the fusion of the inferior cervical ganglion and the first thoracic ganglion. It occurs in 80% of subjects.
Chassaignac’s tubercle is the transverse process of the sixth cervical vertebra at the level of the cricoid cartilage, and is the bony landmark used when performing a stellate ganglion block. The vertebral artery lies in front of the ganglion.
A stellate ganglion block is not used for surgical anaesthesia but may be performed for painful arm conditions which are sympathetically mediated (for example, complex regional pain syndrome type 1, herpes zoster and phantom limb pain) and to improve circulation (for example, in Raynaud’s syndrome).
What lies anterior to firs part of ax nerve
The axillary nerve lies at first behind the axillary artery, and in front of the subscapularis, and passes downward to the lower border of that muscle.
It then winds backward, in company with the posterior humeral circumflex artery and vein, through a quadrilateral space bounded above by the subscapularis (anterior) and teres minor (posterior), below by the teres major, medially by the long head of the triceps brachii, and laterally by the surgical neck of the humerus.
It then divides into an anterior (supplying the deltoid), and a posterior (supplying teres minor, posterior part of deltoid and upper lateral cutaneous nerve of the arm).
Path of CSF
Lateral ventricles, interventricular foramina, third ventricle, aqueduct, fourth ventricle and subarachnoid space
Cerebrospinal fluid (CSF) is formed in the choroid plexus (approximately 80%) and parenchyma (20%) of the lateral ventricles. It is an ultrafiltrate of plasma that is produced at a rate of about 20 mL/hour.
CSF moves by bulk flow from the lateral ventricles to the interventricular foramina, third ventricle, aqueduct, fourth ventricle and then the subarachnoid space. Here the CSF is absorbed by the arachnoid villi into the major dural sinuses by unidirectional flow, once a critical pressure is reached. Other routes of absorption include the mucosa of the paranasal sinuses, nasal mucosa, cranial nerve root sheaths and cervical lymph nodes.
Diaphragm openings
Lung sym fibre from where
Paraysymp form where
Then run where
Lower margin pleura what level where
Is there 2 oblique and 2 TV fissures
Trachea extends where to where
The diaphragm has three foramina through which structures pass from the thorax to the abdomen:
At the level of T8 (inferior vena cava)
T10 (oesophagus, oesophageal vessels and vagi) and
T12 (aorta, thoracic duct and azygous vein).
Sympathetic fibres from T2 - T4 and parasympathetic fibres from the vagus, form a posterior pulmonary plexus at the root of the lung.
Fibres then pass around the root of the lung to form the anterior pulmonary nerve plexus. Fibres then accompany the blood vessels and bronchi into the lungs.
The lower margin of the pleura is at the level of:
The eighth rib in the midclavicular line
The tenth rib in the midaxillary line (lowest level)
The twelfth thoracic vertebra at its termination.
Each lung has an oblique fissure but only the right lung has a transverse fissure.
The trachea extends from the lower margin of the cricoid cartilage, at the level of the sixth cervical vertebra, to the carina.
Cervical disc herniations
commenst where
if there is a c5-c6 herniaton - what nerve root is compressed
Where does the vertebrl artery pass thru
Do all thoracic vertebrae posses costal facets
Do all lumbar vertebra have faces
vertebral discs thruut column?
Cervical disc herniations are less common and the discs most affected are those between the fifth and sixth or sixth and seventh vertebrae. Each spinal root emerges above the corresponding vertebrae; thus, the C5-C6 disc protrusion compresses the C6 nerve root.
Each transverse process of the cervical vertebrae possesses foramen transversarium but the vertebral artery passes only through the foramen transversarium of C1-C6.
Costal facets are present on the sides of the bodies of all the thoracic vertebrae and transverse processes of only the first ten thoracic vertebrae.
The lumbar vertebrae have no facets for articulation with the ribs and no foramina in the transverse processes. The intervertebral discs contribute to one quarter of the length of the vertebral column. They are thickest in the cervical and lumbar region.
No discs are found between the first two cervical vertebrae or in the sacrum or coccyx.
What structures pass thru the foramen magnum
What passes thru jugular foramen
Structures passing through the foramen magnum include:
The spinal roots, passing through the foramen magnum, join with the cranial roots to form the accessory nerve. Meningeal lymphatics Spinal cord Spinal meninges Sympathetic plexus of vertebral ateries Vertebral arteries Vertebral artery spinal branches
The jugular foramen, which contains the inferior petrosal sinus (anterior compartment) and termination of the sigmoid sinus (posterior compartment), also contains the vagus nerve, the accessory nerve and glossopharanygeal nerve.
The vertebral veins do not pass into the skull.
Inguinal canal - is what
What legnth
Anterior wall
lat assis wat
Floor
Roof
Post wall
The inguinal canal is an oblique intermuscular passage through the anterior abdominal wall.
It extends from the deep inguinal ring, an invagination of the transversalis fascia just above the midpoint of the inguinal ligament, to the superficial ring, a deficiency in the external oblique aponeurosis, lying just above the pubic tubercle.
The canal is approximately 4 cm long.
Its anterior wall is formed by the external oblique aponeurosis, assisted laterally by a portion of the internal oblique muscle.
Its floor is the inrolled lower edge of the inguinal ligament, reinforced medially by the lacunar ligament.
Its roof is formed by the lower edges of the internal oblique and transversus muscles.
The posterior wall is formed by the conjoint tendon (combined tendons of internal oblique and transversus muscle which insert into the pubic crest and pectineal line of the pubic bone) and the weak transversalis fascia laterally.
Oesophagus - muscle
Upper
Lower
middle
Epithelium is what
How is lower end anchored
max pressure - normal pressure in oes
Oes - brainstem death
The oesophagus is composed of striated muscle (upper) and smooth muscle (lower) with a mixture of the two in the middle.
Thus striated muscle does end at the junction of the middle and lower third.
Except for a short segment of columnar epithelium in the distal esophagus at the gastroesophageal junction, the normal esophageal epithelium is a tough, nonkeratinizing, stratified, squamous epithelium.
The lower end of the oesophagus is anchored by the phreno-oesophageal ligament.
Manometric measurements can show pressures as high as 500 mmHg within the oesophagus, but are more commonly approximately 100 mmHg.
The disappearance of spontaneous contractions and low amplitude provoked contractions have been used to indicate brainstem death. This is not used in the United Kingdom criteria. Although EEG, cerebral angiography and oesophageal contractility testing are carried out in some centres they are not required by law in the UK to make a diagnosis of brainstem
Jugular foramen allows what
Where vertebral artery enter
Where middle menigneal artery pass
where does carotid artery pass
Where does hypolglossal enter
The jugular foramen allows the following to exit the skull:
Internal jugular vein Vagus nerve Glossopharyngeal nerve, and Accessory nerve. The vertebral arteries enter the skull vault through the foramen magnum.
The middle meningeal artery is transmitted through the foramen spinosum.
The carotid canal transmits the carotid artery and sympathetic fibres.
The hypoglossal nerve travels through the hypoglossal canal.
