Upper Limb Flashcards
What is the biggest organ in the body?
How much body weight does it take up?
Skin
16% of body weight
What is the upper limb designed for
Prehension (gripping)
How is the upper limb connected to the axial skeleton
The pectoral girdle
What are the 3 anatomical spaces in the upper limb through which important structures pass
Axilla
Cubital fossa
Carpal tunnel
What are the 9 joints in the upper limb
1) Sternoclavicular and acromioclavicular
2) glenohumeral (shoulder)
3) elbow
4) radioulnar (proximal, middle and distal)
5) radiocarpal (wrist)
6) intercarpal
7) carpometacarpal
8) metacarpophalangeal
9) interphalangeal
Where does the clavicle articulate
With the scapula at the acromioclavicular joint and with the sternum at the sternoclavicular joint
What kind of joint is the glenohumeral joint
Synovial ball and socket
What kind of joint is the elbow joint
How does its stability compare to that of the shoulder joint
Synovial Hinge
Elbow is more stable
What kind of joint is the wrist
What bones are involved
A synovial ellipsoid
A joint between the distal radius and the scaphoid and lunate
Which joint allows the thumb to be fully opposable
An independent saddle shaped joint between the trapezium and the base of the 1st metacarpal
Which muscles attach the pectoral girdle to the axial skeleton (7)
Pectoralis major and minor Trapezius Rhomboid major and minor Latissimus Dorsi Serratus anterior
Which muscles connect the upper limb to the pectoral girdle
Deltoid
Rotator cuff muscles
Biceps
Long head of triceps
What divides the compartments of the arm
Medical and lateral intermuscular septa
Which nerve supplies the anterior compartment of the arm
What about the posterior?
Musculocutaneous
Radial nerve
Which 2 nerves supply the anterior compartment of the forearm
What about the posterior
Median and ulnar
Radial
Which compartment of the arm is bulkier and why
Flexor (anterior)
for the necessary power of gripping
What forms the brachial plexus
The anterior primary rami of C5 to C8 and T1
Which arty supplies the upper limb
The subclavian which becomes the axillary artery at the outer border of the first rib and eventually is continuous with the brachial artery
What are the 2 main superficial veins of the upper limb
Where do they arise from
Where do they connect
Cephalic (on the radial side) and basilic (on the ulnar side)
They arise from the dorsal venous arch of the Hand
The medial cubital vein
What does the lymphatic drainage of the arm follow
Follows the arteries for deep structures and veins for superficial structures
Describe the course of the cephalic and basilic veins
Cephalic: from the dorsal venous arch of the hand it runs along the radial side towards the shoulder where is lies in the deltopectoral groove
It then pierces the clavipectoral fascia you join the axillary vein
Basilic: from dorsal venous arch it runs on ulnar side. It pierced the deep fascia in the mid-arm and joins the venae comitantes og the brachial artery for form the axillary vein
What is the epidermis
A physical and chemical barrier between the body and the exterior
What are the 4 layers of the epidermis from deep to superficial
Stratum basale (basal) Stratum spinosum (spinous ) Stratum granulosum (granular cell layer) Stratum Corneum (horny layer)
Tell me about the stratum basale
A single layer of cells which continually divide, forming new cells and replacing those that are shed from the skin surface.
Melanocytes, which produce melanin, are located in this layer
Describe the stratum spinosum
The thickest layer with prickle cells which are linked by numerous processes
Describe Stratum granulosum
The granular cell layer
Cells here accumulate keratohyalin granules which eventually overfill the cells, destroying nuclei and organelles
Describe the stratum corneum
The horny layer of epidermis
thickest in the palms and soles Contains dead keratinocytes or squames which are continually shed from the surface
What is the extra layer of the epidermis that is present in the hands and feet
Where does it appear
What do its cells contain
Stratum lucidum
Deep to the stratum corneum
Tonofibrils
What are tonofibrils
Densely packed keratin filaments found in the stratum Lucidum
How does the epidermis adhere to the dermis
What is this called
By the interlocking of its downward projections (the epidermal pegs/ ridges) with upward projections of the dermis (dermal papillae)
This is referred to as the dermoepidermal junction
What does the dermoepidermal junction allow
Allows skin to withstand abrasive forces
Without this the layers would move apart, forming a blister
Describe the dermis’ function (3)
Supports epidermis structurally and nutritionally
Its collagen and elastic fibres provide strength to the skin
It is vital for the survival of the epidermis
Where is the dermis thin?
Where is it thin?
What happens with age?
Thin on eyelids
Thick on back
Thins and loses its elasticity with age
Describe the structure of the layers of the dermis
Composed of 2 layers: a thin papillary layer and a thicker reticular layer
What do nails do
Why is most of the nail bed pink?
Provide a firm base for the pulp of the digit
Due to underlying capillaries supplying the dermis
Discuss the different types of sweat glands
Eccrine: control body temperature and are controlled by sympathetic nerves
Apocrine: only present in axilla, mammoth areola and anogenital regions
Sebaceous: present throughout the skin, except palms and soles. These produce sebum which provides a protective covering for the skin
What mediates thermoregulatory blood supply to the skin
Arteriovenous anastomoses
What is responsible for light touch reception
Where are concentrated?
Meissner’s corpuscles
In sensitive areas eg fingers and lips
What are Pacinian corpuscles
Sensitive to vibration and pressure
Which sex has thicker superficial fascia
What is superficial Fascia
Women
Loose connective tissue and subcutaneous fat
Where is fat absent from the superficial fascia
Eyelids
Scrotum
Penis
What is deep fascia composed of
Collagen fibres arranged to respond to lines of stress
Name 1 benefit of fascial compartments
Limiting spread of infection
Describe a first degree burn
A superficial burn where the epidermis is damaged but intact
Describe a second degree burn
Also called a partial thickness burn
It extends through to the dermis
Blisters are the first sign of a second degree burn
As the epidermis cannot perform its function, victims may lose heat, fluid and the ability to combat infections
What is a 3rd degree burn
A full thickness burn
Involves the destruction of both epidermis and dermis
How is surface area calculated
Using the rule of nines
Body = 11 sections
Each section is covered by 9% of total area of skin with genitals as the remaining 1%
What are the 11 sections of the body for the rule of 9
What is the remainder
1. Head 2 and 3. Upper right and left limbs 4. Chest 5. Abdomen 6. Upper back 7. Lower back 8 and 9. Right and left thighs 10 and 11. Right and left legs
Genitals account for remainder of skin
How do blisters occur
Separation of dermis and epidermis, typically due to prolonged friction, leads to fluid moving between the layers
What are Langer’s lines
Who are they particularly important for
Tension/ cleavage lines
Follow orientation of collagen fibres
Surgeons: incisions are made parallel to these lines heal faster and leave neater scars
What in the skin accounts for some of the visual signs of aging
The flattening of the dermoepidermal junction
Loss of elastin causes skin to become loose and lined
What is the best vein in the arm for cannulation
What about for venipuncture
Cephalic - it is large and has a constant position
Median cubital vein
How is the arm divided into compartments
By medial and literal intramuscular septa from the deep fascia that merge with the periosteum of the humerus
What are the 3 muscles of the anterior compartment of the arm
Biceps
Brachialis
Coracobrachialis
What runs in the spiral groove of the humerus
Radial nerve
Profunda brachii artery
What forms the base of the triangle of the medial cubital fossa
What forms its sides
What is the roof and floor
A line joining the humeral epicondyles
Pronator teres and brachioradialis
Roof: deep fascia of forearm
Floor: brachialis and supinator
The long head of biceps originates from the supraglenoid tubercle, how does it then emerge
In a sleeve of synovial tissue in the bicipital groove
Does the musculocutaneous nerve pass superficial to biceps?
Musculocutaneous passes deep to biceps and superficial to brachialis
Does biceps affect the shoulder?
Yes it stabilises the humeral head at the shoulder joint
Name a vein and a nerve that pass superficial to the bicipital aponeurosis and an artery and nerve that lie deep to it
Superficial: basilic vein and medial cutaneous nerve of the forearm
Deep: brachial artery and median nerve
What is the main flexor of the elbow?
Where does it insert?
Brachialis
Coronoid process
From Which cord does the musculocutaneous nerve arise
Which muscle does it perforate
How does it then proceed
Lateral cord
Coracobrachialis
It runs down the lateral side between biceps and brachialis. Just above the elbow it becomes cutaneous as the lateral cutaneous nerve of the forearm
How is the median nerve formed
Which artery does it run with? Until when?
From two heads from the medial and lateral cords of the brachial plexus
Brachial artery until midway along the arm where it crosses anterior to the brachial artery to lie medial to it
What branches does the median nerve give in the arm
None
Name the 3 nerves that arise from the medial cord of the brachial plexus
Ulnar
Medial cutaneous nerve of arm and of forearm
Describe the course of the medial cutaneous nerve of the arm
Arises from the medial cord
Pierces the deep fascia in the superior arm to supply medial and anterior aspects of skin
Describe the course of the ulnar nerve in the arm
Arises from medial cord
Passes down medial side of the axillary and brachial arteries to the mid-arm, then inclines posteriorly to pierce the medial inter muscular septum and passes down to the groove between the olecranon and medial epicondyle
How many branches does the ulnar nerve give in the arm
None
Where does the brachial artery extend from
Lower border of teres major to just distal of the elbow
What is the course of the brachial artery
Proximally runs next to ulnar nerve , on the medial border of coracobrachialis and biceps
As it reaches the elbow, it runs deep to the bicipital aponeurosis, with the medial nerve lying medially
It ends by dividing into the radial and ulnar arteries
What are the branches of the brachial artery in the arm
Profunda brachii
Nutrient branches to humerus
Superior and inferior ulnar collateral branch
Branches to anterior compartment muscles
What are the deep veins of the arm
Venae comitantes
Paired veins that accompany main arteries
What forms the brachial vein
The radial and ulnar veins
When does the axillary vein form
At the lower border of teres major
Which head of triceps is deepest
Medial
How do the nerves and arteries run in relation to the heads of triceps
Radial nerve and profunda brachii run between medial and lateral heads
How many branches are given off from the radial nerve?
3 muscular and 3 cutaneous
They are characteristically given off very proximally to the innervated part
What are the cutaneous branches of the radial nerve
Posterior cutaneous and lower lateral cutaneous of arm
Posterior cutaneous nerve of forearm
What is the most common biceps rupture
What is a key sign of this injury
How is function affected
Rupture if the proximal biceps tendon accounts for >90%
Almost exclusively involves the long head
Popeye muscle: the retracted muscle bunches up leading to a bulge
Minimal functional loss is minimal as the short head is intact
When is biceps tendon rupture most commonly seen
In 40-60 year olds with a history of shoulder problems, secondary to wear and tear of the shoulder
Can be seen in younger individuals during heavy weightlifting or in a fall/ sports accident etc
What can a humeral shaft fracture lead to
What sign can be seen
How do most people recover
radial nerve injury
Wrist drop (extensors not innervated)
Spontaneously
When are supracondylar fractures of the humerus most common
What complications are associated
When would this be a surgical emergency
Childhood (caused by a fall with outstretched hands)
Damage to brachial artery and medial nerve (these structures lie anteriorly)
A pulse less hand resulting from artery compression
What is the most common dislocation in childhood
What is the most common form of dislocation
Elbow (shoulder is most common in adults)
Posterior dislocation of elbow
Which arteries form the superficial and Deep palmar arches
Radial forms deep
Ulnar superficial
Which muscle does the ulnar nerve run through
What does it divide into
Between the 2 heads of flexor carpi ulnaris
The superficial and deep palmar branches in the hand
Which muscle has a function that doesn’t fit with the rest of the posterior compartment
Brachioradialis - it is not a wrist extensor or supinator but instead flexes the elbow with the forearm in a mid prone position
Which superficial wrist extensor muscles don’t extend from the common extensor origin
Brachioradialis
Extensor carpi radialis longus
Where is the common extensor origin
Lateral epicondyle
Where does the extensor retinaculum extend from
Therefore?
The distal radius to the pisiform and triquetral
It is unaffected by pronation and supination
Which wrist flexors arise from the common flexor origin
Superficial layer muscles
Which muscle’s 2 heads does the median nerve pass between
Pronator teres
Where does flexor carpi radialis insert
What is unusual about this
Which muscles does it work with the to abduct the wrist
2nd and 3rd metacarpals
Its tendon does not run in the carpal tunnel - it is in a separate compartment, lying in the groove of the trapezium
Radial extensors
Where does palmaris longus insert?
How does this match its function?
Inserts onto palmar aponeurosis
As well as flexing the wrist, it also tenses the palmar fascia
Which ligaments is the flexor carpi ulnaris associated with
The pisohamate and pisometacarpal ligaments
What is decussation
Which muscle is associated with it in the forearm
What does it allow
Tendons divide into 2 slips which then insert into radial and ulnar aspects of the base of the middle phalanx
Flexor digitorum superficialis
Allows the tendon of flexor digitorum profundus to pass through
Does the FDS flex the elbow
Yes weakly
What is the primary and secondary actions of the flexor digitorum profundus
Primary: flexion of distal interphalangeal joints
Secondary: flexion of proximal interphalangeal, metacarpophalangeal, and wrist joints
Does flexor pollicis longus pass through the carpal tunnel
Yes
How do the fibres of pronator quadratus run
From medial to lateral
What does anconeus do
Extends elbow and pulls ulna posterolaterally
Does the extensor digitorum communis only extend finger joints
No it also contributes to wrist extension as it crosses the wrist
What happens to the tendons of extensor digitorum communis along the fingers
As it crosses the metacarpophalangeal joint it forms an expansion which covers the dorsal side of the proximal phalanx
Over the proximal interphalangeal joint the tendon divides into 3 slips
The middle slip attaches to the middle phalange while the outer 2 extend to the distal phalanx
When is supinator the prime mover for supination
When is supinator weakest
In a fully extended elbow
In a fully flexed elbow
What is the extensor property of the extensor pollicis brevis
Extends thumb at both metacarpophalangeal and carpometacarpal joints
IT DOES NOT EXTEND INTERPHALANGEAL JOINT OF THUMB
Which tendon winds around Lister’s tubercle (dorsal tubercle)
Extensor pollicis longus
What causes carpal tunnel syndrome
What do patients present with
How is it treated
Nerve entrapment caused by compressed median nerve within carpal tunnel
Pain/ paraesthesia in distribution of median nerve and a weakened thenar eminence
Splints to prevent wrist flexion, steroid injections and ultimately surgery to divide flexor retinaculum
What muscle can fractures of distal radius affect
What is sign
Can rupture tendon of extensor pollicis longus due to association with dorsal tubercle
Unable to extend the interphalangeal joint of thumb
What is De Quervain’s disease
What do they present with
How can it be treated
What is another name
Thickening of synovial tendon sheaths of 2 tendons to the thumb (abductor pollicis longus and extensor pollicis brevis)
Pain, tenderness and swelling as well as a difficultly gripping
May be an overuse injury
Surgery can provide relief but there is a risk of injury to sensory branches of radial nerve
De Quervain’s tenosynovitis
What is mallet finger
What is it indicative of
An inablikith to extend the distal interphalangeal joint
An injury to the insertion of the extensor digitorum communis tendon at the base of the distal phalanx
When is mallet finger common
How is it treated
Common sports injury, sustained when there is forced hyperflexion of the distal interphalangeal joint
Splinting DIP joint in slight hypertension
How are patients in A and E with snuffbox tenderness treated
Treated as a scaphoid fracture
By applying plaster cast and X Raying after 4 weeks
What is tennis elbow
Presentation and cause
Treatment
Lateral epicondylitis
Presents with pain over common extensor origin
Resisted wrist extension aggravates pain
Caused by overuse leading to degenerative tear
Rest and steroid injections
What is golfer’s elbow
Presentation and cause
Treatment
Medial epicondylitis
Inflammation of common flexor origin
Presents with Pain over this region
Caused by overuse leading to degenerative tear
Rest and steroid injections
True or false
Breast lymphatic drainage is to the axilla only
False there are also internal thoracic channels
The brachial plexus supplies the whole upper limb. What are the 2 expectations?
Trapezius is supplied by the spinal accessory nerve
Skin on the medial arm is supplied by the intercostobrachial nerve from T2
What is the breast divided into
Lobules
What is the axilla bound by
What does it communicate with superiorly
The anterior and posterior axillary folds
The posterior triangle of the neck
What forms the floor of the axilla
Deep fascia, subcutaneous tissue and skim
What forms the walls of the axilla
Anterior: pec major and minor, subclavius and clavipectoral fascia
Posterior: subscapularis, teres major, and the tendon of latissimus dorsi
Medial: serratus anterior
Lateral: bicipital groove of humerus
What does the axillary artery branch into in the axilla
Subscapular
Anterior and posterior circumflex humeral arteries (these anastomose around the surgical neck of humerus)
How does the axillary vein receive the cephalic vein
As the cephalic pierces the clavipectoral fascia
Where are the trunks of the brachial plexus
Where are the divisions
Posterior triangle of neck
Apex of axilla
What does the axillary nerve supply
Teres minor and deltoid
Where does the palmar cutaneous branch of the ulnar nerve arise
Mid forearm
What does the superficial terminal branch of the ulnar supply
What about the deep terminal branch
Palmaris brevis and the skin of the ulnar fingers
Supplies muscles of hypothenar eminence, all interossei and 2 ulnar lumbricals. It also supplies adductor pollicis
What are the muscles of the hypothenar eminence
Flexor digiti minimi
Abductor digiti minimi
Opponens digiti minimi
