MSK1 - Upper Limb Flashcards
What forms the walls of the axilla?
Anterior: pec major and minor
Posterior: subscapularis
Medial: thoracic wall and serratus anterior
Lateral: intertubercular sulcus of humerus
Inferior: teres major and latissimus dorsi
The axillary artery is a continuation of which vessel? Which vessel does it become? And what are the anatomical borders for these?
Continuation of subclavian from lateral border of first rib
Becomes brachial at inferior border of teres major
What forms the brachial plexus? Which roots form each trunk?
Ventral rami of C5-T1
Upper/superior trunk: C5-6
Middle trunk: C7
Lower/inferior trunk: C8-T1
Damaging one of the trunks would result in what palsies? How do they appear on examination?
Upper: Erb’s palsy - medially rotated arm with flexed wrist
Lower: Klumpke’s palsy - claw hand
What are common reasons for damage to each trunk?
Upper: Hyperextension of head from shoulder e.g. fall, birth injury
Lower: undue abduction of the arm
Which nerves come from each CORD of the brachial plexus?
Lateral: lateral pectoral, lateral root of median, musculocutaneous
Posterior: thoracodorsal, axillary, radial, upper and lower subscapular nerve
Medial: medial pectoral, medial root of median, ulnar, medial cutaneous nerve of arm, and medial cutaneous of forearm
Describe the venous drainage of the upper limb?
Dorsal venous network in hand goes into cephalic (lateral) and basilic (medial) veins.
These veins communicate (cephalic to basilic) via the median cubital vein.
Describe the dermatome distribution of the upper limb
C6: thumb and lateral border of arm
C7: lateral palm and 2nd/3rd fingers
C8: 4th/5th fingers, medial palm and medial border of arm
C5/T1 down centre of anterior arm
Describe the lymphatic drainage of the upper limb
Axillary nodes
- anterior/pectoral group
- posterior/subscapular group
- apical group
- central group
- lateral group
Label the scapula
Acromion
Coracoid Process
Glenoid cavity
Spine
Supraspinous and infraspinous fossa
Subscapular fossa
Medial and lateral border
Inferior and superior angle
Supra and infraglenoid tubercles
What type of joints are the AC and SC joints?
AC: plane synovial
SC: saddle synovial
What is the scapulo-humeral rhythm?
Beyond the first 30 degrees of arm abduction, every further 3 degrees of movement is from 2 at the glenohumeral and 1 at the scapulo-thoracic
What muscles are responsible for each movement of the scapula?
Elevation: upper trapezius, rhomboids, levator scapulae
Depression: lower trapezius, pec minor, lower serratus anterior
Protraction: serratus anterior
Retraction: middle trapezius and rhomboids
Lateral rotation (elevates glenoid cavity): upper trapezius Medial rotation (depresses glenoid): gravity, levator scapulae, rhomboids and pec minor
What name is given to the cartilage surrounding the glenoid cavity and what purpose does it serve?
Glenoid labrum - deepens the socket for stability
Which ligaments surround the glenohumeral joint?
Coracohumeral
Coracoacromial
Glenohumeral ligaments
Which part of the shoulder joint is weakest and why?
Inferior - no muscle or ligaments
What are the two important bursae around the glenohumeral joint? Which communicates with the joint cavit?
The subacromial and subscapular bursae
- subscapular communicates
What are the muscles of the rotator cuff?
Subscapularis
Supraspinatus
Infraspinatus
Teres minor
What is the most important function of the rotator cuff?
Stability of the joint
What is the nerve supply to the deltoids? What injury may damage it?
Axillary nerve
- surgical neck of humerus fracture can damage
Where would you test for loss of sensation to see if axillary nerve injury had occurred?
Lateral shoulder
What is the action of the pec major?
Adducts and medially rotates humerus
Which vein is located in the deltopectoral triangle, and what is its clinical significance?
Subclavian vein
- used for central lines
What is the nerve supply of the serratus anterior? What clinical sign is seen when it is injured?
Long thoracic - C5-7
- winged scapula if damaged
What procedure commonly causes damage to the long thoracic nerve?
Mastectomy
Which nerve innervates the trapezius?
Accessory (CNXI)
What are the actions of teres major?
Adducts and medially rotates the arm
What are the actions of latissimus dorsi?
Extends, adducts, and medially rotates
Which shoulder muscles are responsible for each shoulder movement?
- flexion/extension
- adduction/abduction
- medial/lateral rotation?
Flex: Pec Major, Anterior Deltoid, Coracobrachialis
Extend: Posterior Deltoid, Latissimus Dorsi, Teres Major
Adduct: Pec Major, Latissimus Dorsi, Teres Major
Abduct: Middle Deltoid, Supraspinatus
Medial rotation: Subscapularis, Latissimus Dorsi, Pec Major, Teres Major
Lateral rotation: Teres Minor, Infraspinatus
Label the humerus
Head
Greater Tubercle
Lesser Tubercle
Intertubercular Sulcus
Body
Deltoid Tuberosity
Lateral and Medial Epicondyles
Radial Fossa
Coronoid Fossa
Capitulum
Trochlea
What are the origins and insertions of the muscles of the anterior arm?
Biceps brachii - Long head from supraglenoid tubercle, short head from coracoid process.
- Both insert into the radial tuberosity and the fascia of the forearm via the bicipital aponeurosis.
Coracobrachialis - Originates from coracoid, passes through the axilla and attaches to medial humerus shaft, at the level of the deltoid tubercle
Brachialis- Originates from medial and lateral surfaces of humeral shaft and inserts into ulna tuberosity, just distal to the elbow joint
Which biceps head runs in the bicipital groove?
Long head
What are the actions of the biceps? What nerve supplies it (and segmental fibres)?
Elbow flexion
Shoulder flexion
Supinator (radio-ulnar joint)
Musculocutaneous nerve supply (C6) (+5 and 7?)
What is the action of the coracobrachialis? Which nerve supplies?
Shoulder flexion and (weak) adduction
Musculocutaneous supply
What is the action of brachialis? Which nerve supplies?
Elbow flexion
Musculocutaneous supply
What is the continuation of the musculocutaneous nerve?
Lateral cutaneous nerve
Where does the brachial artery begin and end? What are the branches given off by it?
Begins at lower border of teres major (from axillary)
Ends in cubital fossa close to neck of radius
- divides into radial and ulnar
- gives off profunda brachii/deep artery of the arm
Describe the path of the median nerve
What muscles does it supply?
What areas does it carry sensory information for?
Arises in axilla from medial and lateral cords
Descends along lateral side of axillary artery and upper part of brachial artery
In middle arm the nerve crosses to th emedial side of brachial artery and enters the cubital fossa
It gives no branches in either the exilla or upper arm
Supplies anterior forearm except FCU and part of FDP
- also supplies thenar muscles and lateral two lumbricals
Sensory for lateral aspect of the palm, and lateral three and a half fingers on the anterior (palmar) surface of the hand.
Describe the path of the ulnar nerve?
What muscles does it supply and where does it carry sensory fibres from?
Arises from medial cord
Descends along medial side of brachial artery then enters the posterior compartment through the medial intermuscular septum
Runs along medial head of triceps and to the back of the medial epicondyle
Motor for Flexor Carpi Ulnaris and ulnar half of FDP
Also motor for majority of hand muscles (deep branch)
- hypothenar muscles, medial two lumbricals, adductor pollicis, palmar and dorsal interossei, palmaris brevis
Sensory for medial half of the palm/dorsum and the associated one and a half fingers
What are the three common sites of the humerus where nerves may be damaged due to fracture?
Radial nerve from radial groove
Ulnar nerve from medial epicondyle
Axillary nerve from surgical neck
What are the borders of the cubital fossa?
What are the contents?
Base - between the two epicondyles
Medial border - pronator teres
Lateral border - brachioradialis
Contents:
- radial nerve
- biceps tendon
- brachial artery
- median nerve
What are the origins and insertion of the triceps?
Long head originates from the infraglenoid tubercle.
Lateral originates from the humerus, superior to the radial groove.
Medial head originates from the humerus, inferior to the radial groove.
The heads converge and insert into the olecranon of the ulna.
What is the action of the anconeus? What is the nerve supply?
Situated in the extensor compartment of the forearm. It is blended with the fibres of the triceps brachii, and the two muscles can be indistinguishable.
Extends and stablises the elbow joint. Abducts the ulna during pronation of the forearm.
Radial nerve
What are the segmental values for the radial nerve? Which vessel accompanies it in the radial groove?
C5-T1
Next to profunda brachii artery
What is the characteristic clinical sign of radial nerve injury?
Wrist drop
Which ligament holds the head of the radius?
Annular ligament
What are the flexors and extensors of the elbow joint?
Flexors: biceps, brachialis, bracioradialis, pronator teres assists
Extensors: triceps, anconeus
What type of joint are the proximal and distal radio-ulnar joints?
Synovial Pivot joints
Which muscles are mainly responsible for supination and pronation? Which is most powerful for each?
Supination: Supinator and Biceps (stronger)
Pronation: Pronator teres (stronger) and Pronator Quadratus
Which muscles are in the anterior forearm?
Superficial: pronator teres, FCR, palmaris longus, FCU
Intermediate: Flexor Digitorum Superficialis
Deep: FDP, FPL, Pronator Quadratus
What is the common flexor origin of the superficial muscles of the anterior forearm?
Attached by common flexor tendon to the medial epicondyle
What is the innervation of the superficial anterior forearm?
Median nerve except FCU and medial of FDP (ulnar)
Why is brachioradialis strange?
It is a posterior muscle but flexes the elbow
- supplied by radial nerve
Where does Flexor Digitorum Superficialis originate and insert? What is its innervation?
Origin medial epicondyle of the humerus, and radius
Inserts on middle phalanx of 4 fingers (no thumb) via carpal tunnel
Median nerve innervates
Where does FDP originate and insert? How is it unique? What is its innervation?
Originates from ulna and associated interosseous membrane. Splits into four tendons that pass through the carpal tunnel and attaches to distal phalanges of the four fingers
- only muscle that can flex the distal IPJ
Medial FDP ulnar innervated (4th and 5th fingers)
Lateral FDP median innervated (2nd and 3rd fingers)
What is the relationship of brachial artery to the median nerve in the cubital fossa?
The neve is medial to the artery
What is the median nerve’s relationship to the flexor retinaculum
Median nerve passes deep to flexor retinaculum
What is the ulnar nerve’s relationship to the ulnar artery?
Ulnar nerve is medial to the artery
What are the contents of the carpal tunnel?
Median nerve
4 tendons of FDS
4 tendons of FDP
1 tendon of FPL
What forms the walls of the carpal tunnel?
Flexor retinaculum is roof
Carpal bones form floor/sides
Between scaphoid/trapezium on lateral side and hamate/pisiform on medial
What are the five compartments of the intrinsic hand muscles?
Thenar compartment
Hypothenar compartment
Adductor compartment
Lumbricals and long flexor tendons - central compartment
Interosseus compartment
What are the thenar muscles and what is their function?
What is their innervation?
Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis
Responsible mainly for apposition/fine thumb movements
Median nerve innervates
What are the hypothenar muscles? What are their functions? What innervates (including segmental values)?
Abductor Digiti Minimi
Flexor Digiti Minimi
Opponens Digiti Minimi
Ulnar nerve innervates (deep branch) - C8,T1
What innervates adductor pollicis? What are the two heads?
Ulnar (deep branch)
Transverse and oblique head
From which long flexor tendons do the lumbricals originate? What are their actions and innervation?
Tendon of FDP
Flex MCP Joint
Extend at IP Joints
Medial two innervated by ulnar
Lateral two by median
How many interossei are there and what are their actions? How are they innervated (including segmental values)
4 dorsal and 3 palmar
Dorsal Abduct
Palmar Adduct
Ulnar (deep branch) - C8,T1
Describe the anatomy of the superficial and deep palmar arches
Both formed by combination of radial and ulnar arteries
Superficial is primarily ulnar
Deep is primarily radial
What areas of the hand does the radial nerve supply?
No muscles, but sensory for dorsal aspect
Which nerve supplies the hand muscles, with what exceptions?
Ulnar
- except thenar muscles (median)
- except first and second lumbricals (median)
What is the dermatomal distribution of each nerve in the hand?
Palmar
- median: thumb, two fingers, lateral aspect of 4th finger, thenar area
- ulnar: medial aspect of 4th finger, 5th finger, hypothenar area
Dorsal
- median: thumb, next two finger from PIPJ, half of 4th finger from PIPJ
- ulnar: dorsum of above
- radial: rest of dorsum of hand
Name the carpal bones?
Proximal lateral to medial:
- scaphoid
- lunate
- triquetrum
- pisiform
Distal lateral to medial
- trapezium
- trapezoid
- capitate
- hamate
What type of joint is the wrist joint?
What bones form it?
Synovial condyloid/ellipsoid
Radius proximally
Scaphoid, Lunate, Triqeutrum distally
Which muscles are responsible for what movements at the wrist?
Flexion: anterior forearm (FCU, FCR, FDS assists)
Extension: posterior forearm (ECR (L+b), ECU, Extensor Digitorum assists)
Adduction: ECU and FCU
Abduction: ECR (L+b), FCR, Abductor Pollicis
What muscles are involved in clenching of the fist?
ECR and ECU with FCR
Where does extensor digitorum arise and insert?
Arises from common extensor origin from lateral epicondyle
Ends in a tendon which passes under extensor retinaculum and divides into four tendons for the fingers (extensor hood)
Which muscles extend or abduct the thumb?
Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus
Just to be sure, name all the muscles in the posterior forearm
Superficial:
- brachioradialis
- ECR (L+b)
- Extensor Digitorum
- Extensor Digiti Minimi
- ECU
- Anconeus
Deep:
- Supinator
- Abductor Pollicis Longus
- Extensor Pollicis Longus and Brevis
- Extensor Indicis Proprius
What are the divisions of the radial nerve? What do they innervate?
Divides into superficial and deep branches in the cubital fossa
- deep also called Posterior Interosseus - everything except ECR Longus and Brachioradialis (Radial nerve itself)
- superficial is sensory: dorsum of hand
What term is given for a common fracture of the distal radius?
Colles fracture - ‘dinner fork deformity’
What forms the anatomical snuffbox?
Tendon of APL and EPB laterally
Tendon of EPL medially
Scaphoid and Trapezium
How do the functions of EPL and EPB differ? Where do they arise and attach?
EPL from posterior surface of the ulna/interosseous membrane. Attaches and extends distal phalanx
EPB from posterior surface of the radius/interosseous membrane. Attaches and extends from proximal phalanx base
Where does Abductor Pollicis Longus arise/attach?
Originates from interosseous membrane and adjacent posterior surfaces of radius/ulna
Attaches to the lateral side of the base of metacarpal I
Name the tendons/muscles attaching to the extensor hood
Extensor digitorum
Lumbricals
Interossei
[Extensor digiti minimi/extensor indicis]
