GEP (Life structure) Week 3 Flashcards
How do NSAIDS Work
What are COX enzymes and the different types
Selectivity and side effect of NSAIDS
Summary of the mechanism and side effects of NSAIDS
- NSAIDS work by blocking COX enzymes, non selective block COX 1 and 2 (Aspirin, ibuprofen, naproxen - antipyretic, analgesic and anti-inflammatory they are anticoagulants and can also be partially allergic and can induce bronchospasm as some have a role in bronchodilation. Aspirin is unique in that it mostly works to block thromboxane A2 which normally causes platelet aggregation thus aspirin thins the blood. ) or specific which block COX 2 not 1 (COXIBS)
- COX 1 maintains homeostasis particularly in stomach and kidneys and so inhibiting has a bad effect on organs e.g. COX 1 converts arachidonic acid to PGH2 which forms PGE2 and PGI2 which help decrease acid production in the stomach by inhibiting COX 1 you allow more acid to produced in the stomach so side effects, dyspepsia, vomiting nausea and haemorrhage long term high dose consequences.
- In kidney cox 1 converts arachidonic acid into PGH2 which makes E2 and I2 which help maintain renal blood flow therefore NSAIDS can cause nephritis and kidney injury.
- Selective NSAIDS created to reduce side effects of nonselective e.g. paracetamol.
- In kidney cox 1 converts arachidonic acid into PGH2 which makes E2 and I2 which help maintain renal blood flow therefore NSAIDS can cause nephritis and kidney injury.
Revison of NSAIDS from previous modules
Steps of inflammation and healing
Types of Collagen
Type 1: bONE
Type 2: car2lage
Type 3: arte3s
Type 4: basement 4loor
Different types of white blood cells involved in Inflammation
What are the outcomes of Acute inflammation
Brief anatomy of the elbow
The elbow is the joint connecting the upper arm to the forearm. It is classed as a hinge-type synovial joint.
The elbow joint consists of two separate articulations:
-Trochlear notch of the ulna and the trochlea of the humerus
-Head of the radius and the capitulum of the humerus
Note: The proximal radioulnar joint is found within same joint capsule of the elbow, but most resources consider it as a separate articulation.
CRAzy TULips
Capitulum = RAdius (capitulum of the humerus articulates with the head of radius)
Trochlea = ULnar (the trochlea of the humerus articulates with the trochlear notch of the ulna)
The humerus begins proximally as a rounded head and joins the greater and lesser tubercles via the anatomical neck of the humerus. The surgical neck is found just inferior to the tubercles where the shaft begins.
The articulations of the elbow
The elbow is the joint connecting the upper arm to the forearm. It is classed as a hinge-type synovial joint.
The elbow joint consists of two separate articulations:
Trochlear notch of the ulna and the trochlea of the humerus
Head of the radius and the capitulum of the humerus
Ligaments of the elbow
Different types of elbow movements
As the elbow joint is a hinge joint, movement is in only one plane. The movements at the elbow joint involve movement of the forearm at the elbow joint. Flexion of the forearm at the elbow joint involves decreasing the angle between the forearm and the arm at the elbow joint. Extension involves increasing the angle between the arm and forearm. These movements are performed by two groups of muscles in the arm: the anterior compartment and the posterior compartment of the arm.
While flexion and extension are the only movements that can occur at the elbow joint itself, movement is also afforded at the proximal radioulnar joint, which contributes to the elbow joint. Movements at this joint are called pronation and supination. These are rotational movements that occur when the distal end of the radius moves over the distal end of the ulna by rotating the radius in the pivot joint formed by the circular head of the radius, the radial groove of the ulna and the annular ligament.
Pronation and supination of elbow
Pronation and supination are movements that occur at the radioulnar joints. The head of the radius is discoid and fits with the radial neck within the circular annular ligament, that attaches the proximal radius to the ulna. The wheel like rotation of the head of the radius enables supination (palm facing upwards), and pronation (palm facing downwards).
Several tendons connect the muscles and bones of the elbow. The primary tendons are:
biceps tendon, which attaches the biceps on the front of the arm to the radius, enabling you to forcefully bend your bend your elbow
triceps tendon, which attaches the triceps to the ulna, enabling you to forcefully straighten your elbow .
Muscle compartments of the upper arm
Muscle compartments of the upper arm
Anterior Compartment (Flexion) – brachialis, biceps brachii, coracobrachialis
Posterior Compartment (Extension) – triceps brachii and anconeus
Note – pronation and supination do not occur at the elbow – they are produced at the nearby radioulnar joints.
Anterior compartment of the arm
There are 3 muscles located in the anterior compartment of the upper arm:
Biceps Brachii
Coracobrachialis
Brachialis
They are innervated by the musculocutaneous nerve.
A memory aid for this is BBC - Biceps, brachialis and coracobrachialis.
Arterial Supply to the anterior compartment of the upper arm is via muscular branches of the brachial artery.
Muscles that act on the elbow to move forearm
Main artery supply to the upper limb
The main artery supplying blood to the upper limb is the subclavian artery. The trunk of the subclavian artery is continuous throughout the entire upper limb.
During its pathway, the artery changes its name based on the region it supplies. Thus the major named arteries of the upper limb are: the subclavian artery, the axillary artery, the brachial artery, and the ulnar and radial arteries.
What is the cubital fossa
The cubital fossa is triangular in shape and consists of three borders, a roof, and a floor:
Lateral border – medial border of the brachioradialis muscle.
Medial border – lateral border of the pronator teres muscle.
Superior border – horizontal line drawn between the epicondyles of the humerus.
Roof – bicipital aponeurosis, fascia, subcutaneous fat and skin.
Floor – brachialis (proximally) and supinator (distally).
Mnemonic for contents of the cubital fossa – Really Need (radial nerve) Beer To (biceps tendon) Be At (brachial artery) My Nicest (median nerve).
Anatomy of the shoulder
The sternal end is a large facet that articulates with the manubrium to form the sternoclavicular joint (Saddle-shaped synovial joint)
The shaft of the clavicle has attachment sites for the deltoid, trapezius, subclavius, pectoralis major, sternocleidomastoid and sternohyoid.
The acromial end attaches to the scapula via the acromioclavicular joint (Plane type synovial joint)
The scapula connects to 17 different muscles!
The costal surface is on the side of the ribs and from the subscapular fossa originates the subscapularis muscle from the coracoid process (The big hooky bit) Originates the pectoralis minor, coracobrachialis and the short head of the biceps brachii (Brachii = 2). The posterior surface is the site of origin for the majority of the rotator cuff muscles (SITS muscles = Supraspinatus, Infraspinatus, Teres minor and Subscapularis)
The humerus has a greater and lesser tuberosity. The greater tuberosity provides an attachment site for three of the rotator cuff muscles (SIT - Supraspinatus, infraspinatus, and teres minor)
The lesser tuberosity is an attachment site for the last rotator muscle - The subscapularis
Important injury site = Surgical neck fracture -> risk of damage to axillary nerve and posterior circumflex artery
Important fact!! Surgical neck fracture damaging the axillary nerve lead to difficulty abducting the affected limb (Paralysed deltoid and teres minor) and numbness over the regimental badge area
Muslces involved in the movement of the shoulder
What is an Articular Capsule
The envelope surrounding a joint it is continuous with the periosteum of the two articulating bones.
Made of 2 parts:
The outer fibrous layer = Ligament
The inner synovial layer = highly vascularised serous connective tissue that absorbs and secretes synovial fluid.
Synovial fluid has 3 functions: Lubrications, nutrient distribution and shock absorption.
If an articular capsule is ineffective or damaged this can result in physical findings such as crepitus, swelling, redness and reduced movement of the joint due to pain.
A side note to the ligaments, these are made up of collagen and there are many conditions that affect the formation of collagen such as marfan’s syndrome, and ehlers danlos. This is why people with these conditions are more likely to get dislocations. 90% of collagen in the body is made up of type 1 collagen. But in conditions like Marfan’s and Ehlers Danlos there is a problem with collagen IV naturally this doesn’t suggest it should cause any problems with ligaments, however in actual fact collagen IV regulates the formation of collagen 1 which leads to the characteristic dislocations that occur in these conditions. So if you get a patient that is very tall with very slim long fingers and a high arched palate that it might be suggesting the patient is getting dislocations due to having Marfan’s syndrome.
The other big condition that affects joints is the good old arthritis. The joint capsule ends up thickening due to wear and tear which decreases all the space needed for the synovial fluid, less synovial fluid = more rubbing and more pain!
What are the major bursae of the shoulder
The subacromial bursa acts as a cushion between the area of the rotator cuff tendons and the acromion preventing friction on arm movement. This is why bursitis of this bursa leads to anterior or lateral shoulder pain with difficulty lifting or reaching for things.
The shoulder has five main bursae:
Subacromial-subdeltoid bursa
Subscapular recess
Subcoracoid bursa
Coracoclavicular
Supra-acromial
Medial extension of supra-acromial (Only some texts mention this)
The good news is, even though there are 5 or in some books 6 of these the big bad problematic one is the subacromial bursa. As shown on the diagram. Luckily bursae aren’t too hard to understand they are a nice little pocket of softness to protect where bone meets bone and are held together by tendons. The main condition that comes up is simply bursitis. Which as always with world etymology itis = inflammation. An inflamed bursae becomes swollen due to injury or infection. If a bursae swells it puts pressure on all the nerves around it causing pain alongside the pain caused by the inflammation too. As this subacromial bursae is a cushion for the rotator cuff tendons when it becomes swollen then the rotator cuff muscles cannot lift the arm due to impingement and pain.
What is the brachial plexus and its many divisions
This is the bit I honestly struggled with the most. It looks horrific and unless you can think in 3D space which I admit I can’t it is tricky to visualise it especially when they don’t give you images! But we’ll break it down step by step the brachial plexus is a complex set of nerves located around the shoulder joint it consists of nerves originating from the spinal roots C5, C6, C7, C8 and T1. This image on the left is a great way to visualise it when you think of doing sensory testing for your OSCE’s but I find the right image to make more sense to me.
What is the Pneumonic way of remembering Brachial plexus
3 Musketeers
Assassinated (Finger gun)
5 Mice
5 Rats
and 2 Unicorns
This is a great diagram and a life saver for all those brachial plexus questions on what nerve has been pinched! 3 Musketeers assassinated 5 Mice, 5 Rats and 2 Unicorns. It is also a great way of remembering the terminal branches in order as you can see we go Musculocutaneous, Axillary, Median, Radial and finally Ulnar nerve
Another memory hack for remembering Brachial plexus
Remember To Drink Cold Beer
Two Peaks and Three horizontal lines
Divisions
In the Dark Dingy bowling alley we want strikes over spares
Cords
Lateral cord = 1 (Lateral pectoral)
Posterior cord = 2 lines (Upper subscapular, Lower subscapular, Thoracodorsal
Medial cord = 3 Medial pectoral, medial brachial cutaneous, medial antebrachial cutaneous
Branches
When we are at the beach we want two small waves and a big one
MARMU Musketeers, Assassinated, Rats, Mice and Unicorns
C5
Five branches = Lateral pectoral, dorsal scapular, Suprascapular, Subclavius and Long thoracic
Complications of shoulder dislocation- Muslce
Some dislocations of the shoulder can cause the humerus to snap separating the greater and lesser tuberosity.
Why is this important? Remember in the earlier slides where I discussed the attachment sites of the muscles of the rotator cuff? This is when it is important to know this. These fractures result in an inability to do a lot of the arm movements as three out of four of the rotator cuff muscles are now unable to put the force on the humerus as this is now loose. Don’t worry too much about fractures though, this is just a nice sideline to remember why dislocations can damage or tear these muscles.
If you get a strange question about a shoulder dislocation and it is discussing peripheral pulses disappearing an important thing to know is that within the shoulder joint the axillary artery is just superior to the axillary nerve which means it can be torn open during a dislocation. This means no peripheral pulses and possibly a big expanding haematoma.
The most important thing to remember about the shoulder capsule is the positioning of the tendons of the rotator cuff. The subscapularis is anterior to the capsule the supraspinatus is superior to the capsule and the infraspinatus muscle is posterior to the capsule. It’s a good one to remember because dislocations of the shoulder are usually anterior so the subscapularis is the most commonly affected muscle
Complications of muslce dislocation- Nerve
Due to the pathway of the axillary nerve it is easily injured in dislocations. This X-ray shows a very clear dislocation and the yellow line shows the axillary nerve which is being pulled away from its natural position.
The other side of the coin is the risk of nerve damage. The axillary nerve originates from the posterior cord of the brachial plexus (C5 and C6 roots) its path then leaves the axilla and travels medially to the surgical neck of the humerus it then divides into three terminal branches
The anterior branch.
The posterior branch.
The articular branch.
The anterior branch winds around the surgical neck of the humerus, posteriorly, with the posterior circumflex humeral vessels and supplies the anterior aspect of the deltoid muscle.
The posterior branch supplies the posterior aspect of the deltoid muscle as well as the teres minor. Following this, it passes around the lower border of the deltoid and is then referred to as the superior/upper lateral cutaneous nerve of the arm. This nerve supplies the skin over the lower part of the deltoid and over the upper part of the long head of triceps both anteriorly and posteriorly.
The articular branch supplies the glenohumeral joint.
