Upper Limb Flashcards
State the muscles and bones that make up the four borders of the axilla.
Anterior - pectoralis major/minor, subclavius
Medial - ribcage, intercostal muscles, serratus anterior
Posterior - latissimus dorsi, subscapularis, teres major, costal surface
Lateral - intertubecular groove of humerus
What forms the axillary sheath and what does it contain?
Fascia.
Contains major vessels and nerves
What are the two veins in the arm, and describe the changes as they pass through the axilla and over the first rib.
Cephic vein (follows deltoid, more lateral) and basilic vein (follows triceps, more medial). Merge to the axillary vein, then becomes the subclavian vein after passing over the first rib.
Describe the passage of the subclavian artery to the forearm.
Becomes the axillary artery in the anterior wall, passing the lateral border of the first rib.
Passes the inferior border of the teres major to become the brachial artery.
Then becomes the radial and ulnar arteries.
What are the nerve roots of the brachial plexus?
C5-8, T1
What muscle overlays the nerve roots of the brachial plexus?
Sternocleidomastoid
Where can the axillary nerve be found?
Deep behind the humerus, passes to the deltoid
Where can the radial nerve be found?
Passes down the radial groove
Where can the musculocutaneous nerve be found?
Passes between the biceps
Where can the ulnar nerve be found?
Posterior to the medial epicondyl of the humerus.
Where can the medial nerve be found?
Passes through the fossa.
What vein connects the basilic and cephalic veins in the cubital fossa?
Median cubital vein
Innervation of deltoid
Axillary nerve
Function of the deltoid
Abduction of the arm from 50 to 130 degrees
Function of the biceps brachii
Mainly for supination of the forearm, also for flexion.
Innervation of the biceps brachii
Musculocutaneous nerve
Attachments of the biceps brachii
Long head - tendon passes up intertubecular groove to attach to the supraglenoid tubercle
Short head - coracoid process
Fans to the bicipital aponeurosis and radial tuberosity.
Function of the brachialis
Flexion of the arm
Innervation of the brachialis
Musculocutaneous nerve
Function of the coracobrachialis
Flexion and adduction of the arm, stabilisation of the glenohumeral joint
Innervation of the coracobrachialis
Musculocutaneous nerve
What deep, posterior artery follows the course of the radial nerve?
Profunda brachii
What arteries wrap around the humeral head?
Posterior and anterior humeral circumflex artery
Function of the triceps brachii
Long - Aids in extention and adduction of the arm. Helps to stabalise the adducted glenohumeral joint.
Lateral - strongest. Primary muscle against resistance.
Medial - forearm extension, always active.
From lateral to medial, name the innervation and vasculature in the antecubital fossa.
Biceps tendon
Brachial artery
Medial nerve
Function of pronator teres
Pronation of the forearm
Innervation of the brachioradalis
Radial nerve
Give the muscle and innervation involved in extension at the elbow
Triceps
Radial nerve
Give the two joints that the shoulder articulates at.
Glenohumeral joint
Scapulothoracic joint
What is the glenoid labrum and what is it’s function?
A fibrocartilage rim around the glenoid cavity which increases the surface for articulation, providing more stability.
Why is the glenohumeral joint inherently unstable?
Shallow
Disproportion of articular surfaces
Multiplanar movements
Lax capsule
What muscles are the most important in improving stability of the glenohumeral joint?
Rotator cuff muscles
Attachments of the glenohumeral capsule
Glenoid labrum Glenoid cavity Anatomical neck of the humerus Bridges down intertubecular groove Dips medially to the surgical neck
What is the function of the small anterior opening in the synovial membrane of the glenohumeral capsule?
So the joint can communicate with the subscapular bursa
Describe the synovial membrane of the glenohumeral joint
Lines the capsule and bone up to the edge of the articular surface. Secretes synovial fluid
Describe the three glenohumeral ligaments.
Superior, middle and inferior.
Extend between the glenoid labrum and humerus.
Part of the fibrous capsule and reinforces the capsule anteriorly.
Can only be seen from inside the capsule.
Describe the extracapsular ligaments.
Coracromial ligament - most important. Between the acromion and coracoid process. Supports and stabilises the shoulder joint.
Coracohumeral ligament - from the base of the coracoid process to the anterior part of the greater tubercle. Strengthens the upper part of the capsule of the shoulder joint.
Transverse humeral ligament - holds the tendon of the long head of the biceps in place during shoulder movement. Inserts into the intertubecular groove.
All together forms the coracoacromial arch, a strong osseoligamentous structure which overlies the humeral head. This prevents the upper displacement of the humerus.
State the four muscles which make up the rotator cuff.
Supraspinatus, infraspinatus, teres minor and subscapular
Function of the supraspinatus
Initiation and first 15 degrees of abduction of the arm
Innervation of the supraspinatus
Suprascapular nerve (C5/6)
Function of the infraspinatus
Lateral rotation of the arm
Innervation of the infraspinatus
Suprascapular nerve (C5/6)
Function of the teres minor
Lateral rotation
Weak adductor
Innervation of the teres minor
Axillary nerve
Function of the subscapular muscle
Medial rotation of the arm
Innervation of the subscapular muscle
Upper and lower subscapular nerve
Describe the tendinous cuff of the glenohumeral joint
Tendons blend together to form a cuff.
Fuses with the capsule and strengthens it.
Tone in the muscles holds the head close to the glenoid cavity.
What separates the supraspinatous tendon from the arch?
Subacromial bursa
What movement of the arm risks impingement of soft tissue?
Abduction
Describe the function of the subscapular bursa
Facilitates movement of the tendon of subscapularis muscle over the scapula and communicates with the joint cavity.
Describe the function of the subacromial bursa.
Facilitates movement of the supraspinatus tendon under the coracoacromial arch and deltoid muscle over the capsule and greater tubercle of the humerus.
What is the function of the suprascapular artery?
Supplies the skin over the acromion and upper part of the chest.
Has a small role in supplying the sternocleidomastoid and subscapularis.
What is the origin of the suprascapular nerve?
Upper trunk of the brachial plexus
What is the function of the suprascapular nerve?
Innervates the supraspinatus and infraspinatous muscle.
Sensory for the acromioclavicular and glenohumeral joints
What is the origin of the axillary nerve?
Posterior cord of the brachial plexus
What is the function of the axillary nerve?
Innervates the deltoid, teres minor and long head of the triceps brachii.
Sensory from the shoulder joint and regimental badge area.
Where does the lateral pectoral nerve penetrate?
Deep surface of the pectoralis major
What are the axillary nerve and posterior circumflex artery vulnerable to at the front of the humerus?
Intramuscular injection of the deltoid muscle
What are the axillary nerve and posterior circumflex artery vulnerable to at the back of the humerus?
Injury during shoulder joint dislocation and surgical neck fractures
Function of the aconeus
Abduction of the ulna, accessory extensor at the elbow.
Innervation of extensor carpi radialis longus
Radial nerve
Function of extensor carpi radialis longus
Extension and abduction of the wrist
Innervation of the extensor carpi radialis brevis
Deep branch of radial nerve
Function of extensor carpi radialis brevis
Extension and abduction of the wrist
Innervation of the supinator
Posterior interosseus nerve
Function of the supinator
Supination
Innervation of abductor pollicus longus
Posterior interosseus nerve
Function of abductor pollicus longus.
Accessory extensor of the thumb
Innervation of extensor pollicus brevis
Posterior interosseus nerve
Function of the extensor pollicus brevis
Extends metacarpophalangeal and carpometacarpal joint.
Innervation of extensor indices
Posterior interosseus nerve
Function of extensor indicies
Extends the index finger
Innervation of extensor pollicus longus
Posterior interosseus nerve
Innervation of extensor carpi ulnaris
Posterior interosseus nerve
Function of extensor carpi ulnaris
Extends and adducts the wrist
Innervation of extensor digiti minimi
Posterior interosseus nerve
Function of extensor digiti minimi
Extends the little finger
Innervation of extensor digitorum
Posterior interosseus nerve
Function of extensor digitorum
Extends the four fingers and wrist
Innervation of the aconeus
Radial nerve
Function of extensor pollicus longus
Extends all joints of the thumb
What muscles produce the hinge movement in the forearm?
Biceps brachii
Triceps brachii
Brachioradialis
What part of the humerus articulates with the ulna?
Trochlea
What part of the humerus articulates with the radius?
Capitulum
What type of joint is the elbow?
Synovial hinge joint
What is the maximum extension with the ulna at the elbow?
170 degrees
What ligaments strengthen the elbow laterally and medially?
Laterally - Radial collateral ligament
Medially - Ulnar collateral ligament
What joint shares a capsule with the elbow?
Proximal radioulnar joint
Describe the ulnar collateral ligament
3 bands
Anterior - large, stiff and rigid. Attaches the distal humerus to the coronoid process
Posterior - fan like. Attaches the humerus to the ulna.
Oblique - deeper socket for the trochlea of the humerus in the trochlear notch
Describe the radial collateral ligament
Fan-like band passing from the humerus to radius. Blends with the annular ligament.
What two bursae are important in the elbow and where are they found?
Subcutaneous olecranon bursa - superficial, over the olecranon process. Posterior.
Subtendinous olecranon bursa - beneath the triceps tendon over the olecranon process.
Describe the inbuilt redundancy of vasculature in the elbow.
Recurrent branches of the radial and ulnar arteries pass around the elbow and anastamose with others.
Describe the proximal radioulnar joint
Pivot joint.
The head of the radius is sat in the radial notch. Annular ligament wraps around the radial head, forming a ligamentous collar which prevents subluxation of the radius.
Describe a pulled elbow.
Common in children.
Caused by traction in the forearm which causes subluxation of the radius which can lead to dislocation.
Most common in children because the annular ligament isn’t fully descended and the ligaments aren’t as strong. The radial head is also not fully developed.
Describe the difference between subluxation and dislocation
Subluxation is partial dislocation, so the bone may be misaligned but is still in contact.
In dislocation there is complete loss of contact of the joint surfaces.
Describe the muscles that allow pronation of the forearm.
Pronator quadratus - deep and distal
Pronator teres - superficial and proximal
What muscles are involved in supination of the forearm?
Supinator - proximal
Biceps brachii
Describe articulation of the radius with the humerus on supination.
Head of the radius rotates at the capitulum of the humerus - mini ball and socket joint.
Describe the interosseus membrane
Fibrous joint which runs inferomedially. Allows distribution of force from the radius to the ulna.
Describe the distal radioulnar joint.
The distal head of the ulna articulates with the ulnar notch of the radius.
Has the articular disc which is a specialisation of ligaments.
Clear separation between the distal joint and wrist.
No true pivoting, but the articular disc allows stretching.
Has the sacciform recess - specialisation of the synovial membrane which allows twisting of the capsule.
What bones articulate at the wrist joint?
Scaphoid
Lunate
Triquetrium
Radius
Function of opponens pollicis
Opposes the thumb by medially rotating and flexing the metacarpophalangeal
Innervation of opponens pollicis
Median nerve
Function of abductor pollicis brevis
Abducts the thumb
Innervation abductor pollicis brevis
Median nerve
Function of flexor pollicis brevis
Flexes the metacarpophalangeal joint of the thumb
Innervation of flexor pollicis brevis
Median nerve
Function of abductor digiti minimi
Abducts the little finger
Innervation of abductor digiti minimi
Ulnar nerve
Function of opponens digiti minimi
Rotates the metacarpal of the little finger towards the palm, producing opposition
Innervation of opponens digiti minimi
Ulnar nerve
Function of flexor digiti minimi brevis
Flexes the metacarpophalangeal joint of the little finger
Innervation of flexor digiti minimi brevis
Ulnar nerve
Function of the lumbricles of the hand
Link extensor tendons to flexor tendons
Flexion of the metacarpophalangeal joint of the four fingers
Extension of the interphalangeal joints of the four fingers
Innervation of the lumbricles of the hand
I and II - median nerve
III and IV - ulnar nerve
How many interossei are there on the dorsal and palmar surfaces?
Dorsal - 4
Palmar -
Innervation of the interossei of the hand
Ulnar nerve
Innervation of adductor pollicis
Ulnar nerve
Innervation of palmaris brevis
Ulnar nerve
Function of the dorsal interossei
Abducts in index, middle and ring fingers and assists in flexion of the metacarpophalangeal joints and extension at the interphalangeal joints.
Function of the palmar interossei
Adduct the fingers
Assists in flexion of the metacarpophalangeal joints and extension at the interphalangeal joints.
Function of adductor pollicis
Adducts the thumb
Function of palmaris brevis
Tenses the skin of the palm on the ulnar side during gripping.
Function of flexor carpi ulnaris
Flexion and adduction at the wrist.
Innervation of flexor carpi ulnaris
Ulnar nerve
Function of palmaris longus
Causes flexion at the wrist
Innervation of palmaris longus
Median nerve
Function of flexor carpi radialis
Flexion and abduction at the wrist
Innervation of flexor carpi radialis
Median nerve
Function of pronator teres
Forms the medial border of the cubital fossa
Pronation of the forearm
Innervation of pronator teres
Median nerve
Function of flexor digitorum superficialis
Flexes the metacarpophalangeal joints and proximal interphalangeal joints of the four fingers.
Flexes at the wrist.
Innervation of flexor digitorum superficialis
Median nerve
Function of flexor digitalis profundus
Flexes distal interphalangeal joints and the wrist
Innervation of flexor digitalis profundus
Median nerve and ulnar nerve
Function of flexor pollicis longus
Flexor of the phalanges of the thumb and assists in flexing the wrist when the thumb is fixed
Innervation of flexor pollicis longus
Median nerve
Function of pronator quadratus
Pronates the forearm
Innervation of pronator quadratus
Median nerve
Where does the common extensor tendon of the forearm attach?
Lateral epicondyle
Where does the common flexor tendon of the forearm attach?
Medial epicondyle
Describe the pathology of lateral epicondylitis (tennis elbow)
Inflammation of the periosteum of the lateral epicondyle.
Caused by repeated use of the superficial extensor muscles which strains their common tendinous attachment to the lateral epicondyle.
Describe the potential causes of wrist drop and explain the pathology behind it.
Axilla - humeral dislocation or fracture of the proximal humerus
Radial groove - mid-shaft fracture of the humerus.
It’s a sign of radial nerve injury proximal to the elbow.
All extensor muscles are paralysed so the tone of flexor muscles causes unopposed flexion.
Give all the superior muscles in the anterior compartment of the forearm from lateral to medial
Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor carpi ulnaris
Give the intermediate muscle of the anterior compartment of the forearm
Flexor digitorum superficialis.
Give the deep muscles of the anterior compartment of the forearm.
Flexor digitalis profundus
Flexor pollicis longus
Pronator quadratus
The majority of muscles in the anterior compartment of the forearm have the same innervation.
What nerve is this, and state the exceptions.
Median nerve.
Exceptions are flexor carpi ulnaris (ulnar nerve) and flexor digitalis profundus (medial - ulnar nerve, lateral - median nerve)
Give the superficial muscles of the posterior compartment of the forearm from lateral to medial.
Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris Aconeus
Give the deep muscles of the posterior compartment of the forearm from lateral to medial.
Supinator Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indices
Give the function of the trapezius
Upper - elevates and rotates the scapula during abduction of the arm
Middle - retracts the scapula
Lower - pulls the scapula inferiorly
Innervation of the trapezius
Accessory nerve
How would you check for damage of the accessory nerve?
Shrug the shoulders against resistance
Function of levator scapulae
Elevates the scapula
Innervation of levator scapulae
Dorsal scapular nerve
Function of rhomboid major and minor
Retracts and rotates the scapula
Innervation of rhomboid major and minor
Dorsal scapular nerve
Nerves originating from the lateral cord of the brachial plexus
Musculocutaneous
Median (part)
Nerves originating from the posterior cord of the brachial plexus
Radial nerve
Axillary nerve
Nerves originating from the medial cord of the brachial plexus
Ulnar nerve Median nerve (part)
Root origin of the musculocutaneous nerve
C5
C6
Root origin of the median nerve
C5
C6
C8
T1
Root origin of the radial nerve
C7
Roor origin of the ulnar nerve
C8
T1
Describe the cause and symptoms of Erb’s palsy
Upper brachial plexus injury generally caused during delivery of the neonate
Nerves with C5/C6 nerve roots damaged - Musculocutaneous, median, nerve to subclavius and suprascapular
Loss of shoulder abduction, lateral rotation, supination and flexion.
Causes ‘waiter’s tip’
Describe the cause and symptoms of Klumpke palsy
Upper brachial plexus injury caused by excessive abduction of the arm.
Damages T1 so the ulnar and median nerves are affected.
All the small muscles of the hand are affected and there is loss of sensation along the medial arm
No flexor muscles are affected as they are innervated by a different nerve root.
Give the three bursa that can be found around the shoulder joint.
Subcoracoid bursa
Subscapular bursa
Subacromial bursa
Describe the glenohumeral ligament and give its function
Stabilises the anterior aspect of the joint.
Three bands run with the joint capsule from the glenoid fossa to the anatomical neck of the humerus.
Describe the coracohumeral ligament and give its function
Supports the superior part of the joint capsule
Base of the coracoid process to the greater tubercle of the humerus
Describe the transverse humeral ligament and give its function
Holds the tendon of the long head of the biceps in the intertubecular groove
Spans the distance between the two tubercles of the humerus
Describe the coracoacromial ligament and it’s function
Overlies the shoulder joint, preventing superior displacement of the humeral head
Runs between the acromion and coracoid process to form the coraco-acromial arch
What arteries supply the glenohumeral joint?
Posterior circumflex humeral artery
Suprascapular artery
Branches of these then anastamose around the joint.
What nerves supply the shoulder joint?
Axillary
Suprascapular
Lateral pectoral
(all from roots C5/C6)
What type of joint is the shoulder?
Ball and socket synovial joint
What muscles allow extension at the shoulder?
Posterior deltoid
Latissimus dorsi
Teres major
What muscles allow flexion at the shoulder?
Biceps brachii (both heads)
Pectoralis major
Anterior deltoid
Coracobrachialis
What muscles allow medial rotation at the shoulder?
Subscapularis Pectoralis major Latissimus dorsi Teres major Anterior deltoid
What muscles allow lateral rotation at the shoulder?
Infraspinatus
Teres minor
Describe painful arc in the shoulder
Pain in the middle of abduction caused by rotator cuff tendonitis.
Inflammation of the muscle tendons, usually caused by overuse.
Causes degenerative changes in the subacromial bursa, and the supraspinatous tendon, which increases friction between the structures of the joint.