Clinical Anatomy and Review of the Upper Limb Flashcards
What is the upper limb divided into?
- shoulder = pectoral girdle, between thorax and arm
- arm = between shoulder and elbow
- forearm = between elbow and wrist
- hand = portion distal to wrist
What bones make up the shoulder?
- clavicle
- scapula
- humerus
What joints make up the shoulder?
- sternoclavicular
- acromioclavicular
- glenohumeral
What is the blood supply to the shoulder?
- subclavian
- axillary
- brachial
Where does the subclavian artery become the axillary artery?
- lateral border of 1st rib
Where does the axillary artery become the brachial artery?
- inferior border of teres major
What is the venous drainage of the arm?
- parallel arterial deep veins
- superficial veins
What nerve roots does the brachial plexus consist of?
C5-T1
What are the terminal nerves of the anterior cord?
- musculocutaneous
- median
- ulnar
What are the terminal nerves of the posterior cord?
- axillary
- radial
What is the biggest nerve of the plexus?
Radial
What type of nerves are those in the brachial plexus?
- mixed with both sensory and motor axons
What are the trunks?
superior, middle, inferior
What are the cords?
lateral, posterior, medial
What are the terminal nerves?
Musculocutaneous Axillary Median Radial Ulnar
What causes a clavicular fracture?
- direct or indirect force
- at endpoint of limb
- takes force when falling
- sternoclavicular and acromioclavicular joints are very strong so clavicle will break before dislocation
Who are clavicular fractures more common in and why?
- clavicle stays softer and is weaker
How does a clavicle fracture present?
- drooped shoulder
- in some cases clavicle can be raised if fractured bones override each other = reduction in width
How does shoulder dislocation occur?
- at glenohumeral joint as it is weak because of large range
What does shoulder dislocation affect mainly?
- impacts brachial plexus especially axillary nerve
How does a shoulder dislocation present differently to a clavicular fracture?
- fracture = deltoid profile rounded, normal glenohumeral joint
- dislocation = deltoid more squared off
When may a shoulder dislocation/clavicular fracture be a medical emergency?
- if tingling/reduced peripheral pulses
What can cause deltoid paralysis?
- shoulder fracture/dislocation
How does deltoid paralysis present?
- weakness in abduction of the arm due to axillary nerve damage
- deltoid atrophy = loss of shoulder roundness
- numbness over regimental badge
How is deltoid paralysis treated?
- nerve repair
- muscle transfer from pec major
What are the features of the pectoralis major?
- 2 parts
- clavicular part used to act like a deltoid
- nerve supply is lateral pectoral and not axillary so function regained
To what extent does supraspinatus carry out abduction?
- first 10-15 degrees
- rest by deltoid
How does the shoulder allow movement?
- shoulder and pectoral girdle = hand placed in all directions
- movement of scapula = more range (physiological scapulothoracic joint)
- trapezius and serratus anterior muscles rotate scapula
What is the lymphatic drainage of the shoulder?
5 groups:
- humeral lymph nodes
- central lymph nodes
- subscapular lymph nodes
- apical lymph nodes
- anterior lymph nodes
(mainly nodes in axilla)
Where does the upper limb lymph mainly drain into?
Humeral and central nodes
Where do the lymphatics of the lateral breast drain into?
Axillary nodes
- medial breast drains into parasternal nodes
When may axillary lymph node clearance be carried out?
- metastatic breast cancer surgery
What can axillary lymph node clearance lead to?
- injury to thoracodorsal nerve
- injury to long thoracic nerve = scapular wing as normally kept in place by serratus anterior
What does the thoracodorsal nerve supply?
- latissimus dorsi
What does the long thoracic nerve supply?
Serratus anterior
What causes scapular wing?
- dysfunction of the serratus anterior from long thoracic nerve damage
What are the causes of long thoracic nerve damage?
- axillary lymph node clearance
- stab wound
- thoracic surgery
- chest tube insertion
When may trapezius atrophy occur?
- when damage to spinal accessory nerve
- could be due to tumour around jugular foramen
How does trapezius atrophy present?
- weak shoulder abduction but not as prominent as scapula winging
- shoulder falls
What is the bone of the arm?
humerus
What are the joints of the arm?
- glenohumeral
- elbow
What does the elbow joint consist of?
- humeroulnar
- humeroradial
- proximal radioulnar
What are the arteries and nerves of the arm and where are they?
- Posterior compartment = spiral groove contains radial nerve and deep artery of the arm
- anterior compartment = median and musculocutaneous nerve, and brachial artery
What are the types of humerus fractures? What is the risk of each?
- midshaft = risk of radial nerve injury
- supracondylar = risk of median nerve injury
- medial epicondyle = risk of ulnar nerve injury
Why may a medial epicondyle fracture damage the ulnar nerve?
- ulnar nerve lies just above elbow and goes behind medial epicondyle to then go back into forearm anterior compartment
What type of joint is the elbow?
- hinge and pivot
What are the bones of the forearm?
Radius and ulna
What are the joints of the forearm?
- elbow
- distal radioulnar joint
- radiocarpal joint
What are the nerves of the anterior forearm compartment?
- median nerve
- ulnar nerve
What are the arteries of the anterior forearm compartment?
- radial artery
- ulnar artery
What are the properties of the median nerve?
- innervates majority of forearm flexors
- innervates thenar muscles
- provides sensation to palm of hand and lateral 3.5 digits
- goes through carpal tunnel
- compression = thenar atrophy
What is the nerve of the posterior forearm compartment?
- radial nerve
What is the artery of the posterior forearm compartment?
- posterior interosseous artery
What are the muscles of the posterior forearm compartment?
- extensors
- supinators
What is the main blood supply of the forearm?
- ulnar and radial arteries
- start opposite radius neck in inferior cubital fossa
- ulnar -> superficial palmar arch
- radial -> deep palmar arch
What are the bones of the hand?
- carpals (scaphoid and lunate)
- metacarpals
- phalanges
What are the joints of the hand?
- distal radioulnar
- radiocarpal
- intercarpals
- carpometacarpal
- metacarpophalangeal
- interphalangeal (distal and proximal)
What happens at the wrist?
- ulnar does not articular with carpals
- radius articulates with scaphoid and lunate
What are the muscles of the hand?
- APL
- EPB
- ECR
- EPL
- ED
- EI
- EDM
- ECU
What are the most common wrist injuries?
Fractures of distal radius and ulna
What are the less common wrist injuries?
- carpal injuries
- scaphoid most common to be broken = avascular necrosis
What is Colles fracture?
- presents as dinner fork deformity
- occurs in complete fracture of radius
What does carpal tunnel syndrome result in?
- atrophy of thenar muscles
What are the compartments of the hand and what do they contain?
- superficial = long flexor tendons and their sheaths
- medial and lateral = hypothenar muscles and thenar muscles
- deep = intrinsic muscles of the hand
What 3 nerves terminate in the hand?
- median
- ulnar
- radial
What is the function of the median nerve?
- flexors of the wrist except FDU and medial half of FDP
- sensory to skin on lateral 3.5 digits
What is the function of the radial nerve?
- all muscles of posterior compartment
- sensory to back of arm and forearm and first dorsal web
What is the function of the ulnar nerve?
- intrinsic muscles of hand (FDU and medial half of FDP)
- sensory to skin on medial 1.5 digits
