C&M Upper limb- movement Flashcards
Origin, insertion and function of superior fibres of trapezius
Origin: external occipital protuberance, superior nuchal line, ligamentum nuchae & spinous process of C7
Insertion: lateral 1/3 of clavicle and acromion process
Function: Elevate scapula
Origin, insertion and function of middle fibres of trapezius
Origin: T1-T5 spinous processes
Insertion: superior border of spine of scapula (lateral 2/3)
Function: Retract scapula
Origin, insertion and function of inferior fibres of trapezius
Origin: T6-T12 spinous processes
Insertion: medial 1/3 of spine of the scapula
Function: Depress scapula
Innervation of trapezius
Accessory cranial nerve 11
Origin, insertion and function of levator scapulae
Origin: Transverse processes C1-C4
Insertion: medial border of scapula superior to root of spine
Function: elevate scapula and rotates scapula medially (downwards).
Origin, insertion and function of rhomboid major
Origin: spinous processes T2-T5
Insertion: medial border of scapula inferior to level of spine
Function: retract the scapula medially and superiorly. Used in squaring the shoulders
Origin, insertion and function of rhomboid minor
Origin: spinous processes of C7-T1
Insertion: medial border of scapula at the level of the spine
Function: retract the scapula medially and superiorly. Used in squaring the shoulders
Innervation of deep dorsal muscles (LS, RMa, Rmi)
Dorsal scapular nerve (C5)
Origin, insertion, function and innervation of serratus anterior
Origin: Ribs 1-9
Insertion: Medial border of scapula
Function: Protract scapula, rotate scapula laterally
Innervation: Long thoracic nerve (C5-C7)
Causes of winged scapula (medial border and inferior angle of scapula pull away from posterior thoracic wall)
Long thoracic nerve damage (superficial)
Penetrating injuries when arm abducted e.g. knife wound
Accidentally e.g. insertion of chest drain, during breast surgery (iatrogenic)
Neuritis (inflammation of the nerve)
How is the stability of the glenohumeral joint improved
Glenoid labrum- ring of cartilage
Ligaments
Biceps tendon
Rotator cuff muscles
Where is the glenohumeral joint weakest (therefore more likely to dislocate in this direction)
inferiorly
95% of shoulder (glenohumeral joint) dislocations occur in an anteroinferior direction
What structures prevent superior displacement of the humerus in the glenohumeral joint
Coracoacromial arch: Made up of the acromion, coracoid process + coracoacromial ligament
What is painful arc syndrome
Calcific Bursitis
Caused by inflammation e.g. after excessive use of glenohumeral joint
Pain during 50-130 degrees of shoulder abduction
Rotator cuff muscles
Supraspinatus
Infraspinatus
Teres Minor
Subscapularis
What is the only muscle that can initiate arm abduction
Supraspinatus
Abducts from 0-15 degrees then deltoid takes over
Origin, insertion, function and innervation of supraspinatus
Origin: Supraspinous fossa
Insertion: Greater tubercle
Function: Initiates abduction of arm (first 15°) and Stabilises glenohumeral joint
Innervation: Suprascapular nerve
Origin, insertion, function and innervation of infraspinatus
Origin: Infraspinous fossa
Insertion: Greater tubercle
Function: Lateral rotator of humerus and stabilises glenohumeral joint
Innervation: Suprascapular nerve
Origin, insertion, function and innervation of teres minor
Origin: Middle part of lateral border of scapula
Insertion: Greater tubercle
Function: Laterally rotates and adducts humerus (with infraspinatus) and Stabilises glenohumeral joint
Innervation: Axillary nerve
Origin, insertion, function and innervation of subscapularis
Origin: subscapular fossa
Insertion: Lesser tubercle
Function: Medial rotator and adductor of humerus and stabilises glenohumeral joint
Innervation: Upper and Lower sub scapular nerves (C5-C6)
Origin, insertion, function and innervation of teres major
Origin: inferior angle of scapula
Insertion: Medial lip of intertubercular of humerus
Function: Adducts and medially rotates humerus
Innervation: Lower subscapular nerve (C5 – C6)
Which muscle is most likely to be torn in a rotator cuff injury
Supraspinatus
Symptoms- pain when arm is overhead and weakness
Test - abduct arm fully, lower arm slowly with control. At about 90°, arm will fall suddenly to side.
What is the most common cause of glenohumeral dislocation
excessive extension and lateral rotation of humerus
usually in young adults
Which nerve can be damage in shoulder dislocation
Axillary nerve - passes inferior to the humeral head and winds round the surgical neck of the humerus.
Leads to deltoid atrophy + regimental badge anaesthesia
Nerve roots of Musculocutaneous nerve
C5-C7
Nerve roots of Median nerve
C6-T1
Nerve roots of ulnar nerve
C7-T1
Nerve roots of axillary nerve
C5-C6
Nerve roots of radial nerve
C5-T1
Boundaries of the quadrangular space
Superior: Teres minor
Inferior: Teres major
Medial: Long head of triceps brachii
Lateral: Surgical neck of the humerus
Contents of the quadrangular space
Axillary nerve
Posterior circumflex humeral artery and vein
Quandrangular space syndrome- Transient blockage of the posterior humeral circumflex artery and axillary nerve
Typically occurs when the arm lies in a position of abduction, extension, and external rotation
Patients note shoulder pain and paraesthesia down the arm
Often associated with fibrotic bands in quadrangular space
Uncommon condition that mostly affects athletes who perform overhead movements e.g. tennis
When does limb development occur
Mid to late embryonic phase: 4 to 8 weeks
Origin of limb buds
Buds consist of a core of tissue = lateral plate mesoderm
Mesoderm core differentiates into mesenchyme = bones and connective tissue of the limbs
Skeletal muscle of the limbs = paraxial mesoderm/somites
Somite Differentiation
Ventral part= sclerotome = vertebral column
Dorsolateral part = dermamyotome = dermis + skeletal muscles
Myotome differentiation
Dorsal epimere = back muscles which are innervated by the dorsal rami of spinal nerves
Ventral hypomere = muscles of thoracic and abdominal walls and muscles of limbs which are innervated by the ventral rami of spinal nerves
What does the posterior condensation of the hypomere become
Extensors and supinators of the upper limbs
Extensors and abductors of lower limb
What does the anterior condensation of the hypomere become
Flexors and pronators of the upper limbs
Flexors and adductors of the lower limb
When does limb rotation occur
6-8 weeks
What direction do upper limbs rotate
90° laterally so flexors lie anteriorly
What direction do lower limbs rotate
90° medially so flexors lie posteriorly
What are the 3 axes that limb development occurs along
- Craniocaudal- the thumb is most cranial digit and the little finger is most caudal
- Proximodistal- from the shoulder/hip to the hand/foot
- Dorsoventral-
How is proximodistal growth controlled
By growth factors secreted by the Apical ectodermal ridge (AER)
How is the AER formed
The lateral plate mesoderm forming the mesenchymal core of the limb bud secretes a fibroblast growth factor Fgf 10
This induces thickening of the overlying ectoderm along the tip of the limb bud - the AER
What FGFs does the AER express
Fgf 4 and 8
Causes rapid proliferation of mesenchymal cells underlying the AER – the progress zone (this maintains proximodistal growth).
What does inserting FGF soaked beads into embryos cause
Supernumerary limb growth
How is dorsoventral growth controlled
Dorsal ectoderm express Wnt7
Ventral ectoderm expresses Engrailed-1
Engrailed 1 inhibits Wnt7
How is craniocaudal growth controlled
Zone of Polarising Activity (ZPA) - small region of mesenchyme in the caudal part of the limb bud
Where sonic hedgehog (Shh) gene is expressed
Which direction does Shh diffuse to
from ZPA in a cranial direction
What does Shh do
High concentration of Shh induces formation of caudal structures e.g. little finger
Low concentration induces formation of cranial structures e.g. thumb.
What happens when you transplant the ZPA so that there are 2 on a limb
Mirror image polydactyly of the limb
What is amelia
Complete absence of a Limb
e.g. early loss of Fgf signalling
What is phocomelia
Digits develop prematurely.
Proximal elements of limb absent aka flipper limb.
Can be due to genetic factors or teratogen e.g. Thalidomide inhibits Fgf 10 and 8 expression
What is meromelia
Partial absence of a Limb
e.g. later or partial loss of Fgf signalling
What direction do most dislocations of the elbow occur in
Posterior dislocation- The distal end of humerus is driven through the weak anterior part of the joint capsule
What nerve can be affected in elbow dislocations and what are the symptoms
Ulnar nerve injury
Numbness of medial part of palm and medial 1.5 fingers and weakness of flexion and adduction of the wrist
What are the 3 flexors of the elbow joint
Brachialis- main flexor
Biceps Brachii
Brachioradialis- accessory flexor of elbow joint when forearm is mid-pronated
The origins of triceps brachii
Long head - Infraglenoid tubercle (scapula)
Lateral head - Posterolateral humerus above spiral groove
Medial head - Posteromedial humerus below spiral groove
Insertion of triceps brachii
Olecranon process
Innervation of triceps brachii
Radial nerve (C5-T1)
What is the function of the annular ligament of the radius
Maintains stability of radius
Allows rotation of the radius during pronation and supination of the forearm.
Why is the radius more prone to subluxation/dislocation in childhood
Annular ligament relatively weak
What nerve controls pronation
Median nerve
Pronator teres and pronator quadratus contract
What nerves control supination
Radial and musculocutaneous nerves
Supinator and biceps brachii contract
What is Golfers elbow
Inflammation at insertion of wrist flexor tendons into the medial epicondyle
What is Tennis elbow
Inflammation at insertion of the wrist extensor tendons into the lateral epicondyle
What nerve can be damaged when the medial epicondyle is avulsed
Ulnar nerve
What nerve can be damaged when the surgical neck of the humerus is fractured
Axillary nerve
What nerve can be damaged when the shaft of the humerus is fractured
Radial nerve in the radial groove
What structures can be damaged when the supracondylar humerus is fractured
Median nerve- supplies flexors of the forearm
Brachial artery - stopping all blood flow past elbow, can lead to necrosis of forearm and possibly amputation
Which tendon does not pass through the carpal tunnel and goes straight to the flexor retinaculum
Flexor Carpi Radialis
Which structures lie above the flexor retinaculum
Ulnar nerve + Ulnar artery (in Guyons canal)
Palmaris Longus tendon
Which nerve supplies most of the intrinsic hand muscles
Ulnar nerve
EXCEPT thenar muscles and 1st and 2nd lumbricals – median nerve
Which branch of the median nerve supplies the thenar muscles
Recurrent branch
Which branch of the median nerve is given off before it enters the carpal tunnel
Palmar cutaneous branch- supplies lateral side of palmar skin
What do the digital branches of the median nerve supply
1st and 2nd lumbricals
Palmer - lateral 3 ½ digits
Dorsal - distal half of lateral 3 ½ digits
What is the action of the lumbricals
Flexion at metacarpophalangeal joint and extension at interphalangeal joint
“bye-bye” muscles
Symptoms of carpal tunnel syndrome
Wasting of thenar eminence because recurrent branch of median nerve is affected
Pins and needles in the cutaneous distribution of digital branches of median nerve e.g. tip of fingers etc
What nerve can be damaged in lunate dislocation
Median nerve
(FOOSH) Lunate displaced anteriorly
Similar symptoms to carpal tunnel syndrome
What does the palmar branch of the ulnar nerve supply
Medial palmar skin
What does the dorsal branch of the ulnar nerve supply
Lateral side of dorsum and lateral 1 ½ digits
What does the superficial branch of the ulnar nerve supply
Palmer surface of lateral 1 ½ digits
Palmaris brevis
What does the deep branch of the ulnar nerve supply
Hypothenar muscles, adductor pollicis, palmar and dorsal interossei and 4th + 5th lumbricals.
What symptoms does ulnar nerve compression/handlebar neuropathy cause
Sensory loss palmer surface of lateral 1 ½ digits
Motor weakness in the intrinsic muscle of the hand (except thenar eminence and lateral 2 lumbricals)
Hyperextension of metacarpophalangeal joints of digits 4 and 5 (extension is unopposed due to paralysis of lumbricals) = clawhand
What is the most common bone fractured in the wrist
Scaphoid
Causes tenderness in the anatomical snuffbox
Why can avascular necrosis occur after a scaphoid fracture
Blood enters the scaphoid distally, therefore, in the event of a fracture, blood supply to the proximal part may be disrupted
What is Colles fracture
Fracture of the distal end of the radius
Most common in old people/ women due to osteoporosis
Usually the result of FOOSH
Often the ulnar styloid process is avulsed
Dinnerfork deformity
How do the vertebral arteries become to basilar artery
Vertebral artery branches of subclavian artery
Travel upwards through transverse foramina C6-C1
Passes through foramen magnum
Unite to form basilar artery
What is subclavian steal syndrome
Occlusion of the subclavian artery proximal to the vertebral artery origin (atherosclerosis) causing reversed flow in the ipsilateral vertebral artery
Blood is ‘stolen’ from the circular vertebrobasilar system to supply the distal territory of the occluded or stenosed artery
What arteries given off by the axillary artery are at risk of rupture when the surgical neck of the humerus is fracture
Anterior and posterior circumflex humeral arteries
Where does the axillary artery become the brachial artery
Inferior border of teres major
What are the 3 main branches given off the brachial artery
Profunda brachii artery
Superior ulnar collateral artery
Inferior ulnar collateral artery
Where does the brachial artery divide into the radial and ulnar arteries
Cubital fossa
What does the profunda brachii artery supply and where does it run
Posterior muscle compartment of the arm- triceps
Radial groove alongside the radial nerve- can be damaged in fracture of shaft of humerus
What are peri-articular anastamoses
Network of anastomoses of brachial and profunda brachii arteries in the arm with radial and ulnar arteries in the forearm.
Ensures blood flow to the forearm even if elbow is fully flexed.
What are the arteries involved in the peri-articular anastamoses
Profunda brachii gives off radial collateral artery which anastamoses with radial recurrent artery
Superior and inferior Ulnar collateral arteries anastamose with Anterior and posterior ulnar recurrent arteries
What does the radial artery supply
Supplies the anterolateral aspect of the forearm including flexors and extensors
What does the ulnar artery supply
Supplies the medial side of forearm – mainly flexors and pronators
Gives off common interosseous artery which gives off anterior and posterior interosseous arteries which supply the middle of the flexor and extensor compartments respectively.
What does the cephalic vein drain and where does it run
Drains lateral side of dorsal venous arch
Runs lateral side of arm into deltopectoral triangle and pierces clavipectoral fascia
Drains into axillary artery
What does the basilic vein drain and where does it run
Drains medial side of dorsal arch and median cubital vein
Runs medial side of arm
Joins with deep arm veins/venae comitantes to form axillary vein
