Anatomy - AUL Flashcards
Describe the clavicle:
-Slender
-S-shaped bone
-Easily palpable
-Commonly fractured
Where does the clavicle articulate?
-Sternum at its medial end (sternoclavicular joint)
-Acromion of scapula at its lateral end (acromioclavicular joint)
-BOTH SYNOVIAL
-Holds limb away from trunk so it can move freely
Label this diagram:
Describe the scapula:
-Mostly flat
-Some important bony projections
-Some parts can be palpated
What does the posterior surface of the scapula bear and what is its significance?
-Ridge of bone called spine
-Lateral end of spine expands to form acromion
-Articulates with lateral end of clavicle
Label this diagram:
What does the clavicle, scapula and attached muscles form?
Pectoral girdle
What important structure is on the lateral aspect of the scapula?
-Gleniod fossa
-Articulates with proximal humerus to form shoulder (glenohumeral joint)
-Shallow making it a poor fit for humerus
-Increases range of movement but low stability
What is this?
Glenoid fossa
What are superior and inferior to the glenoid fossa?
-Supraglenoid tubercle
-Infraglenoid tubercle
-Important sites for muscle attachment
Label this diagram:
Describe the humerus:
-Long bone in the arm
-Shaft and expanded proximal and distal ends
What part of the humerus is this and what does it articulate with?
-Head
-Articulates with glenoid fossa of scapula
-Bears groove called anatomical neck
Label this diagram:
What does the proximal humerus bear laterally?
-Projection of bone called greater tubercle
-Smaller anterior projection called lesser tubercle
-Important sites for muscle attachment
Label this diagram:
What happens just distal to the tubercles?
-Bone narrows and becomes continuous with shaft
-Region is called surgical neck
-Commonly fractured especially in elderly due to fall
-Axillary nerve runs close to region and can be damaged by fractures of surgical neck or dislocation of humeral head
Label this diagram:
What is this?
-Deltoid tuberosity
-Site for attachment of deltoid muscle
What is this?
-Radial groove
-Marks path of radial nerve over posterior aspect of upper humeral shaft
-Runs very close and can be damaged in mid-shaft humeral fractures
Movement of what bone is vital for normal movement of the shoulder joint?
Scapula
What articulation is there between the scapula and the posterior thoracic wall?
-NONE
-Lies on posterior chest wall
-Surrounded by muscle and so no bony articulation between posterior thoracic wall and scapula
What are the 5 movements of the scapula?
-Protraction - extends upper limb
-Retraction - squaring shoulders
-Elevation - shrugging shoulders
-Depression - lowering shoulders
-Rotation - tilts glenoid fossa cranially to elevate upper limb
Label this diagram:
What movement of the scapula is very important?
-Rotation
-When raising arm above head, for every 2o of abduction of the shoulder, scapula rotates 1o
What is the scapula attached to posteriorly and by what?
-Vertebral column
-By muscles
-Attachment point of muscles and orientation of muscle fibres determine direction scapula moves
What is the key muscle involved in protraction of the scapula?
Serratus anterior
What are the muscles of the anterior pectoral girdle?
-Pectoralis major
-Pectoralis minor
-Serratus anterior
What are the two large superficial muscles of the posterior pectoral girdle?
-Trapezius
-Latissimus dorsi
Label this diagram:
Describe the trapezius and latissimus dorsi:
What is different about the latissimus dorsi?
-Large flat muscles
-Extensive attachments to vertebral column (trapezius to skull)
-Latissimus dorsi attaches to anterior aspect of proximal humerus not scapula
What are the 3 smaller, deeper muscles of the posterior pectoral girdle?
-Levator scapulae
-Rhomboid major
-Rhomboid minor
ATTACH MEDIAL BORDER OF SCAPULA TO VERTEBRAL COLUMN
Label this diagram:
Label this diagram:
Describe how each of these muscles move the scapula:
What is the origin and insertion of Trapezius?
-Origin - Skull, cervical and thoracic vertebrae
-Insertion - Clavicle and scapula (spine and acromnion)
What is the origin and insertion of latissimus dorsi?
-Origin - Lower thoracic vertebrae
-Insertion - Humerus - upper anterior
What is the origin and insertion of levator scapulae?
-Origin - upper cervical vertebrae
-Insertion - scapula - medial border
What is the origin and insertion of rhomboid minor?
-Origin - C7 and T1
-Insertion - Scapula - medial border
What is the origin and insertion of rhomboid major?
-Origin - Thoracic vertebrae
-Insertion - Scapula - medial border
What are most of the muscles of the posterior pectoral region innervated by?
-Branches that arise from brachial plexus
-Complex network of nerves that innervate upper limb
-Does not innervate trapezius
What innervates the trapezius?
-Cranial nerve XI - accessory nerve
What innervates latissimus dorsi?
-Branch of brachial plexus
-Thoracodorsal nerve
What movements are possible at the shoulder joint? (7)
-Flexion
-Extension
-Abduction
-Adduction
-Medial rotation
-Lateral rotation
-Circumduction
Label this diagram:
Act all of these on yourself: Shoulder
-Flexion
-Extension
-Abduction
-Adduction
-Medial rotation
-Lateral rotation
-Circumduction
What is the fit like of the scapula and humerus?
-Poor fit
-Glenoid fossa of scapula and head of humerus
-Extensive mobility of joint
-Most commonly dislocated
What six muscles connect the scapula to the humerus?
-Deltoid
-Supraspinatus
-Infraspinatus
-Subscapularis
-Teres major
-Teres minor
Label this diagram:
What do the six muscles connecting the scapula to the humerus do?
-Move and stabilise shoulder joint
-All except deltoid lie deep to posterior scapula muscles
What is the rotator cuff?
-Four muscles work together to provide vital stability to the shoulder joint
-Supraspinatus
-Infraspinatus
-Subscapularis
-Teres minor
Label this diagram:
Where does the deltoid connect?
-Large muscle over lateral shoulder
-Attaches humerus to lateral part of clavicle and spine of scapula
-Gives shoulder its rounded contour
Where does the deltoid insert?
Deltoid tuberosity
What is the action of deltoid muscle?
-Powerful abductor of shoulder
-Cannot initiate abduction - another muscle initiates first 20o before it takes over
-Anterior and posterior deltoid fibres contribute to flexion and extension
What innervates the deltoid muscle?
-Major branch of brachial plexus
-Axillary nerve
-Injury of nerve can cause atrophy and weakness of deltoid
What is the attachment of the teres major?
-Arises from posterior aspect of scapula
-Inserts onto anterior aspect of humerus
What is the action of teres major?
-Medial rotator and adductor of shoulder joint
What is common among the muscles of the rotator cuff?
-All move shoulder joint
-Short muscles which attach the scapula to the tubercles of the humerus
What 3 rotator cuff muscles can be grouped together and why?
-Supraspinatus
-Infraspinatus
-Teres minor
-Originate from posterior scapula surface and insert onto greater tubercle
-Tendons fuse with fibrous capsule that surrounds shoulder joint
What is this?
What is the quadrilateral space?
-Square shaped space bound by:
-Teres minor above
-Teres major below
-Long head of triceps medially
-Surgical neck of humerus laterally
What passes through the quadrilateral space and where does it travel to?
-Axillary nerve
-Enter posterior scapula region and innervate deltoid and teres minor
Label this diagram:
Where does subscapularis originate and insert?
-Originates anterior surface of scapula
-Inserts onto lesser tubercle of the humerus
What is the action, origin and insertion of deltoid?
-Action - Abduction beyond 20 degrees
-Origin - Spine and acromion (plus clavicle)
-Insertion - deltoid tuberosity
What is the action, origin and insertion of teres major?
-Action - Medial rotation, Adduction
-Origin - Posterior surface, inferior part of lateral border
-Insertion - Anterior humerus
What is the action, origin and insertion of supraspinatus?
-Action - First 20 degrees of abduction
-Origin - Supraspinous fossa
-Insertion - Greater tubercle - superior facet
What is the action, origin and insertion of infraspinatus?
-Action - Lateral rotation
-Origin - Infraspinous fossa
-Insertion - Greater tubercle - middle facet
What is the action, origin and insertion of teres minor?
-Action - Lateral rotation
-Origin - Lateral border of scapula
-Insertion - Greater tubercle - inferior facet
What is the action, origin and insertion of subscapularis?
-Action - medial rotation
-Origin - subscapular fossa
-Insertion - Lesser tubercle
what is a painful arc a sign of?
-Tendon of supraspinatus becomes inflamed as it is pinched between acromion and humerus
-Called impingement
As a group, what provides vital stability to the shoulder joint?
-Four rotator cuff muscles
-Contraction holds the head of the humerus in the shallow glenoid
-Rotator cuff tendons fuse with the capsule of the shoulder joint
What three other structures contribute to glenohumeral joint stability?
-Glenoid labrum
-Reinforced by ligaments
-Tendons of biceps brachii
What is the glenoid labrum?
-Rim of fibrocartilage around the margin of the glenoid fossa
-Deepens the shallow glenoid fossa and aids stability
What separates the arm into posterior and anterior components?
-Intermuscular septa
-Extends from deep brachial fascia surrounding arm
What is the single muscle in the posterior compartment of the arm?
Describe it:
-Triceps brachii
-Three muscle bellies
-All converge via a common tendon onto single insertion point - Olecranon of ulna
Label this diagram:
What is the insertion point of the triceps brachii?
What does it do on contraction?
-Olecranon of the ulna
-Crosses posterior elbow joint
-Extends elbow on contraction
Label this diagram:
Where does the long head of triceps brachii originate?
-Infraglenoid tubercle of scapula
-Most medial part of triceps
Where does the lateral head of triceps brachii originate?
-Posterior humerus
-Proximal to radial groove
Where does the medial head of the triceps brachii originate?
-Posterior humerus
-Distal to radial groove
What can the long head of triceps brachii contribute to and why?
-Extension of shoulder joint
-Because of its attachment to scapula
What innervates the three parts of triceps?
-Radial nerve
-Major terminal branch of brachial plexus
What is the path of the radial nerve in the posterior arm?
Winds around posterior aspect of humerus in radial groove between medial and lateral heads of triceps
What does the shaft of the humerus expand to form distally?
-Bony prominences called medial and lateral epicondyles
-Distal humerus bears trochlea and capitellum
Label this diagram:
What do the trochlea and capitellum of the humerus articulate with?
-Trochlear notch of the ulna
-Head of radius
At elbow joint
Describe the axilla:
-Anatomical term for armpit - space between trunk and upper arm
-Pyramid shaped
-Six boundaries
What are the 6 boundaries of the axilla?
- Anterior wall – pectoralis major and minor
- Posterior wall – subscapularis, teres major and latissimus dorsi
- Lateral wall – upper humerus
- Medial wall – serratus anterior and chest wall
- Apex – first rib, clavicle and scapula. It is the passage between the neck and the axilla
- Base – skin and fascia between the chest wall and arm
Label this diagram:
What does it show?
The boundaries and structures that form the axilla
What 5 structures does the axilla contain?
-Fat
-Lymph nodes - upper limb, chest, abdo to umbilicus
-Axillary artery - upper limb
-Axillary vein
-Brachial plexus - upper limb
How many groups of lymph nodes are there in the axilla?
What do they drain?
-5 groups
-Drain upper limb, breast, chest wall, scapular region and abdominal region as far as umbilicus
Which axillary lymph nodes receive lymph from all of the others?
-Apical nodes
-Often involved in the spread of cancer (metastasis)
What is the path and branching of the subclavian artery?
-Travels under clavicle and into axilla
-Axillary artery is continuation of subclavian
-Axillary artery continues into arm as brachial artery
Label this diagram:
What branches does the axillary artery give?
-Several branches
-One above pectoralis minor
-Two behind it and three below it
What vein drains the upper limb?
-Axillary vein (large vein)
-Continuous with subclavian vein
-Alongside artery
Label this diagram:
How is the axillary vein formed?
Union of the deep veins of the arm with the basilic vein
What is the brachial plexus?
Network of nerves that provides motor and sensory innervation to the upper limb
What forms the brachial plexus?
-Spinal nerves that leave lower cervical spinal cord segments and first thoracic
-C5-8 and T1
How is the brachial plexus most often described?
-Roots
-Trunks
-Divisions
-Cords
-Branches
Label the sections of the brachial plexus:
Label these nerves of the brachial plexus:
What are the roots of the brachial plexus and where are they found?
-Five spinal nerves (C5-T1)
-Found in neck
What are the trunks of the brachial plexus?
-C5 and C6 combine to form superior trunk
-C7 continues as middle trunk
-C8 and T1 combine to form inferior trunk
What are the divisions of the brachial plexus?
Each trunk divides into an anterior and posterior division under the clavicle
What are the cords of the brachial plexus?
-Named relative to position around second part of axillary artery
-Anterior divisions of superior and middle trunk combine = lateral cord
-Posterior divisions of all trunks = posterior cord
-Anterior division of inferior trunk continues as medial cord
What are the branches of the brachial plexus?
-Axillary - branch of posterior cord
-Radial - continuation of posterior cord
-Musculocutaneous - branch from lateral cord
-Ulnar - branch from medial cord
-Median - branches of lateral and media cords
Other than the 5 main terminal branches, what other nerves arise from the brachial plexus?
-Different segments give rise to other nerves
-Innervate the shoulder and pectoral muscles
What does the axillary nerve innervate?
-Deltoid muscle
-Teres minor
-Small region of skin over upper lateral arm
Describe the axillary nerve path:
-Branch of posterior cord
-Contains fibres from C5 and C6
-Runs down to surgical neck of humerus
What nerve is this?
Axillary nerve
What does the radial nerve innervate?
-Triceps in posterior arm
-All muscles in posterior compartment of forearm - extensors of wrist and digits
-Regions of skin over arm, forearm and hand
Describe the radial nerve path:
-Continuation of posterior cord
-Contains fibres from C5-T1
-Runs along radial groove on posterior surface of humerus
What nerve is this?
Describe the pathway of the musculocutaneous nerve:
-Arises from lateral cord
-Contains fibres from C5-7
-Continues as sensory nerve that innervates skin region over forearm
Describe the pathway of the musculocutaneous nerve:
-Arises from lateral cord
-Contains fibres from C5-7
-Continues as sensory nerve that innervates skin region over forearm
-innervates biceps
What nerve is this and what does it arise from?
What do the median and ulnar nerves innervate in the arm?
-They do not
-They innervate muscles in the anterior forearm and the hand
Describe the median nerve pathway;
-Formed from contributions from both lateral and medial cords
-Contains fibres from C6-T1
-Crosses anterior aspect of elbow in cubital fossa
What nerve is this?
Median nerve
What does the median nerve innervate?
-Most of the muscles of the anterior forearm - flexors of wrist and digits
-Small muscles of thumb
-Skin over lateral aspect of palm of hand and lateral digits
Describe the pathway of the ulnar nerve:
-Formed from continuation of the medial cord after it has given a contribution to median nerve
-Contains fibres from C8-T1
-Lies superficial to medial epicondyle
What does the ulnar nerve innervate?
-Most of small muscles of hand and therefore vital for fine movement of digits
-Skin over medial aspect of hand and medial digits
What is the most catastrophic type of brachial plexus injury?
-All five roots are injured
-Denervates whole of upper limb
-Injuries to different parts results in different clinical presentations
What 3 muscles does the anterior compartment of the arm contain?
-Biceps brachii
-Brachialis
-Coracobrachialis
What are common among the 3 muscles of the anterior arm?
-All act as flexors
-All innervated by musculocutaneous nerve
Label this diagram:
Describe the biceps brachii proximally:
-Lies most superficial in anterior arm
-Two muscle bellies - long and short head
-Both attached to scapula
-Long head - supraglenoid tubercle
-Short head - coracoid process
-Long head tendon pierces shoulder capsule to stabilise joint
Describe the biceps brachii distally:
Two muscle bellies converge via common tendon onto radial tuberosity of radius
What is the action of the biceps brachii on the elbow and shoulder joints?
-Flexor of elbow joint
-Crosses shoulder joint so can contribute to flexion of shoulder joint
What is the action of biceps brachii on the forearm?
-Powerful supinator
-When the elbow is flexed
-Power to turn screwdriver very tightly
What is the attachment of the brachialis?
-Deep to biceps
-Proximally, anterior aspect of lower half of humerus shaft
-Crosses elbow joint to insert distally upon ulnar tuberosity
What is the action of brachialis?
-Powerful flexor of elbow joint
-Does not cross shoulder so doesn’t act on it
What is the attachment of the coracobrachialis?
-Smaller muscle
-Attaches proximally to coracoid process of scapula
-Distally to medial aspect of middle humerus
What is the action of coracobrachialis?
-Crosses shoulder
-Weak flexor
What is the cubital fossa?
-Region anterior to elbow joint
-Clinically - antecubital fossa ACF
Describe the borders of the cubital fossa:
-Lateral border - brachioradialis
-Medial border - pronator teres
-Superior border - Line drawn between medial and lateral epicondyles of the humerus
Label the borders of the cubital fossa:
What can be traced into the cubital fossa as it travels to its insertion point?
-Tendon of biceps brachii
-Travels to insertion point on radial tuberosity
-Easily palpated when flexed elbow
What extension of the biceps tendon exists in the cubital fossa and what is its significance?
-Bicipital aponeurosis
-Fascial extension of biceps tendon
-Separates superficial veins from deeper structures in fossa - brachial artery and median nerve
What is the pathway of the brachial artery into the cubital fossa?
-Lies medial to biceps tendon
-Bifurcates into its terminal branches in the cubital fossa - radial and ulnar arteries
Label this diagram:
What is the pathway of the median nerve in the arm and what does it innervate here?
-Medial to brachial artery
-Does not innervate any muscles in the arm
-Travels through anterior component and cubital fossa to anterior forearm and hand
What is the pathway of the radial nerve in the arm?
-Passes through lateral aspect of cubital fossa
-Deep to brachioradialis
What is the clinical significance of the superficial veins of the cubital fossa and where are they?
-Subcutaneous tissue over cubital fossa
-Venepuncture
-Intravenous access
-Must not mistake median nerve or brachial artery
What are the two bones of the forearm and what are they connected by?
-Radius and ulna
-Connected by interosseous membrane
What is the articulation of the humerus with the two bones of the forearm?
-Ulna + radius articulate at proximal ends with humerus
-Trochlea notch of ulna + trochlea of humerus
-Radial head + capitellum
What can the radius and ulnar do with each other and how?
-Ariculat with each other
-Proximal and distal radioulnar joints
-Allow pronation and supination of the forearm and hand
-Radius pivots around ulna
-Anterior compartment of the forearm contains two muscles that act as pronators
What is the articulation of the distal radius?
-Articulates with two of the small bones of the wrist (carpus)
-Forms radiocarpal joint (wrist joint)
What movements are allowed at the radiocarpal joint?
How are they achieved?
-Flexion
-Extension
-Abduction
-Adduction
Muscles in the anterior and posterior forearm
What are all of these?
Movements of the wrist joint
What is the carpus comprised of and how is it roughly arranged?
-8 small bones that articulate with each other at small joints
-Roughly arranged into two rows of four bones - one proximal and one distal
What bones does the distal radius articulate with?
-Scaphoid and lunate
-Forms the radiocarpal joint
What are the bones in the proximal row of carpal bones?
What is different about one of them?
Lateral to medial:
-Scaphoid
-Lunate
-Triquetral
-Pisiform
Pisiform is not a true carpal bone, small bone that develops in the tendon of flexor carpi ulnas
What are the bones in the distal row of carpal bones?
Lateral to medial:
-Trapezium (base of thumb)
-Trapezoid
-Capitate (central and largest)
-Hamate
What does P show?
Hook of the hamate
What is the most commonly fractured carpal bone?
-Scaphoid
-Usually by fall onto an outstretched hand
What is the hand composed of on a very basic level?
Many bones and joints
What bones lie distal to the carpus?
Metacarpals
What are the bones of the digits and how many are in each?
-Phalanges
-Three in each finger and two in the thumb
What do several muscles of the forearm do?
Travel into the hand and move the fingers and thumb
What 4 important structures are found in the cubital fossa?
-Biceps tendon
-Median nerve
-Brachial artery - bifurcated into radial and ulnar arteries
-Superficial veins - subcutaneous tissue over the cubital fossa
What are these and their significance?
All pass through the cubital fossa
How many muscles are there in the anterior compartment of the forearm?
How are they arranged and what do they have in common?
-8 muscles
-Three layers: Superficial, middle, deep
-Most are flexors of wrist, fingers or thumb
-Most innervated by median nerve
What are the muscles of the superficial layer of the anterior forearm?
-4 muscles:
-Pronator teres
-Flexor carpi radialis
-Palmaris longus
-Flexor carpi ulnaris
Label these:
What are they?
Four muscles of the superficial layer of the anterior forearm
What are the 4 superficial anterior forearm muscles connected to proximally?
-Medial epicondyle of the humerus
-This region of the humerus is also commonly referred to as the ‘common flexor origin’
What does this show?
Medial epicondyle is the ‘common flexor origin’
Name it and its action:
Pronator of the proximal radioulnar joint
NOT a flexor
Name it and its action:
-Flexes and abducts wrist
-Inserts onto the radial ‘side’ of the wrist hence its name
Name it and its action:
Describe its structure:
-Small muscle belly but a long, thin easily recognisable tendon when present (15% don’t have one)
-Inserts into the fascia of the palm of the hand
Name it and its action
-Flexes and adducts the wrist
-Inserts onto the ‘ulnar’ side of the wrist hence its name
-EXCEPTION TO GENERAL RULE - innervated by the ulnar nerve not the median
-Ulnar nerve and artery lie at the lateral side of its tendon at the wrist
What does this show?
Ulnar nerve and artery running in close proximity to the tendon of the flexor carpi ulnaris muscle
What are the muscles of the middle layer of muscles of the anterior forearm?
-One muscle
-Flexor digitorum superficialis (FDS)
Name and describe its action:
What is it innervated by?
-Gives rise to four tendons
-Flexor of the digits
-Tendons must travel beyond the wrist into the hand and to the fingers (digits 2-5)
-Median nerve which travels between flexor digitorum superficialis and one of deep muscles (Digitorum profundus)
What does the median nerve move inbetween in the anterior forearm?
Between flexor digitorum superficialis and one of deep muscles - flexor digitorum profundus
What are the three muscles in the deep layer of the anterior forearm?
-Flexor digitorum profundus
-Flexor pollicis longus
-Pronator quadratus
What is this?
Flexor digitorum superficialis
Only middle muscle of anterior forearm
What are these?
Deep muscles of the anterior forearm
Name and describe:
What is its innervation?
-Flexor of the digits and is deep to flexor digitorum superficialis
-Gives rise to 4 tendons with travel into the hands to digits (2-5) - closely related to tendons of superficialis
-Dual innervation by median and ulnar
Describe the innervation of flexor digitorum profundus (FDP):
-Lateral half - tendons to index + middle fingers - median nerve
-Medial half - tendons to ring + little finger - ulnar
nerve
Injuries to either of the nerves only affects one half of the muscle
Name and describe the action:
-Flexes the thumb (pollex = thumb)
-‘Longus’ distinguishes it from another muscle (flexor pollicus breves) which is much smaller and lies within the hand
Name and describe the action
-Deepest forearm muscle (considered 4th layer by some)
-Square-shaped and lies over the distal ends of the radius and ulnar
-Pronated the distal radioulnar joint
What is this?
Pronator quadratus
Summarise the anterior forearm muscles:
(Action + innervation)
-Flexors except from pronator teres and pronator quadratus
-Innervated by the median nerve, except FCU and medial half of FDP
What is this and what are its dimensions formed by?
-Carpal tunnel -> narrow passageway at the wrist
-Floor and sides = carpal bones
-Roof = fibrous band called flexor retinaculum
What are the attachments for the flexor retinaculum?
Laterally = scaphoid + trapezium
Medially = hook of hamate + pisiform
What passes through the carpal tunnel?
-Tendons of the anterior forearm muscles that insert into the digits:
-Flexor digitorum superficialis (digits 2-5)
-Flexor digitorum profundus (digits 2-5)
-Flexor pollicis longus (digit 1)
-Median nerve
What is this?
Flexor pollicis longus
What feature about the carpal tunnel has clinical significance?
-Very narrow so tendons and median nerve are tightly packed into it
-Any condition further reducing this space (swelling of tendons or arthritis) increases pressure
-Can compress median nerve and cause carpal tunnel syndrome
What does the brachial artery do in the cubital fossa?
Bifurcates into two terminal branches:
-Radial artery
-Ulnar artery
What are the pathways of the radial and ulnar arteries?
-Radial artery travels along lateral aspect of forearm and usually easily palpated in wrist
-Ulnar artery travels along medial aspect of forearm
What do the radial and ulnar arteries do in the hand?
-Anastamose in the palm of the hand to form palmar arteries
-These anastomoses ensure that the hand remains adequately perfused in the event either artery becomes occluded or injured
What does this show?
Anastamoses (palmar arteries) of the radial and ulnar arteries
What is the general venous drainage of the upper limb?
-Both superficial and deep veins in the upper limb
-Communicate with each other
-Ultimately all venous blood drains to the axillary vein
What are the two most important superficial veins of the upper limb?
-Cephalic vein
-Basilic vein
-Cephalic courses laterally in the forearm and the basilic courses medially
-Typically connected to each otherin the region of the cubital fossa by the median cubital vein
What are these?
Two most important superficial veins of the forearm
What is this and its significance?
Median cubital vein connects the basilic and cephalic vein
What happens to the superficial veins of the forearm proximally?
-Basilic vein courses proximally into the arm and receives the deep veins of the arm to form the axillary vein
-Cephalic vein courses proximally in the lateral arm to frain into the axillary vein
What does this show?
-Basilic vein continues to form axillary vein
-Cephalic vein joins axillary vein more proximally
Describe the deep veins of the forearm:
-Accompany arteries and often paired
-Two brachial veins accompany brachial artery
-Deep veins of the upper limb ultimately drain into the axillary vein
What is the carpus composed of?
-8 small bones that articulate with each other at small joints
-Roughly arranged into two rows of four bones (proximal and distal)
What lie distal to the carpals?
-Metacarpals
-Numbered 1-5 from lateral (thumb) to medial (little finger)
What are the bones of the digits?
-Phalanges (phalanx)
-3 in each finger (digits 2-5) and 2 in thumb (digit 1)
How are the phalanges named?
-Proximal
-Middle
-Distal
PHALANX
Label and describe:
-Lie between distal row of carpal bones and proximal parts of metacarpals (bases)
Label and describe:
-Metacarpophalangeal joints
-Between distal part of metacarpals (heads) and proximal phalanges
Label and describe:
-Between phalanges
-Thumb only has two phalanges so just one interphalangeal joint
-Fingers have PIP joint and DIP joint
What do movements of the hand and digits usually involve?
The actions of lots of muscles working together
What action of the hand allow us to manipulate objects in a myriad of ways?
-The hand and digits can perform a wide range of grips
Describe 3 grip movements:
Power grip - hold or squeeze objects tightly
Hook grip - carrying objects with handles such as bags
Precision grip - hold objects between the pads of our thumb and index finger such as pen or needle (with or without power)
What are the 4 movements of the fingers?
Flexion
Extension
Abduction (fingers apart)
Adduction (fingers together)
What are the 5 movements of the thumb?
Flexion
Extension
Abduction
Adduction
Opposition
What types of muscles control the movements of the fingers and hands?
Extrinsic and intrinsic
What are the intrinsic and extrinsic muscles of the hand?
-Extrinsic = lie in anterior and posterior forearm and their tendons travel into the hand
-Intrinsic = lie within the hand
What muscles of the anterior forearm are the prime flexors of the wrist and where do they insert?
-Flexor carpi radialis - 2nd metacarpal
-Flexor carpi ulnaris - 5th metacarpal
-Palmaris longus - palmar fascia
What anterior component muscles flex the digits?
-Travel through carpal tunnel and into hand
-Flexor digitorum superficialis
-Flexor digitorum profundus
-Flexor pollicus longus
What can flexors of the digits also contribute to?
Wrist flexion
Label:
Label:
Describe the tendon of flexor digitorum superficialis and its action:
-Splits into 2 slips
-Insert on either side of the middle phalanx of digits 2-5
-Flexes the MCP and PIP joints of digits 2-5
Describe the tendon of flexor digitorum profundus and its action:
-Passes through slit in FDS tendon to insert onto palmar aspect of distal phalanx of digits 2-5
-Only muscle capable of flexing DIP joint
-Also flexes PIP joint and MCP joints of digits 2-5
Describe the tendon of flexor pollicis longus and its action:
-Inserts distal phalanx of the thumb
-Flexes IP joint of thumb
-Only muscle that can do so
What encloses the long flexor tendons?
-Fibrous sheaths
-Maintain position of tendons in midline of each finger
-Within these, tendons enclosed by synovial sheath which reduces friction and allows tendons to slide freely within fibrous sheath during flexion and extension
What is this and what does it do?
Protects the long flexor tendons, tendon sheaths and vessels in the central palm
What are the groups of intrinsic muscles of the hand?
-4 groups and one single muscle that doesnt fit into other groups
-Thenar eminence - 3 muscles
-Hypothenar eminence - 3 muscles
-Lumbricals - 4
-Interossei - 7
Remaining muscle is muscle of thumb called adductor pollicis
What are the intrinsic muscles of the hand innervated by?
Median and ulnar nerves
Describe the Thenar eminence generally:
Fleshy mass on the palm of the hand at the base of the thumb
What muscles make up the Thenar eminence and their actions?
-Flexor pollicis brevis (FPB - flexes thumb
-Abductor pollicus brevis (APB) - abducts thumb
-Opponens pollicis - opposes thumb - DEEP TO OTHER 2
ALL attach to carpal bones proximally
Label, what do they make up?
Thenar eminence
Label, what do they make up?
What are the movements and insertions of the Thenar muscles?
What is the nerve innervation to the Thenar muscles?
Recurrent branch of median nerve
Where does the recurrent branch of the median nerve leave and whats its significance?
After it has passed through carpal tunnel so thenar eminence muscles are affected by carpal tunnel syndrome
Why is the adductor pollicis different to the thenar eminence?
-Lies deep in the palm, not in thenar eminence
-innervated by the ulnar nerve
What are the actions and attachments of the adductor pollicis?
-Attached to 3rd metacarpal and to proximal phalanx of the thumb
-Contraction pulls thumb towards the palm - adduction
What are the thenar muscles important for?
-Precision grip
-The thumb is abducted, flexed and medially rotated at CMC joint so it can oppose with one of the fingers
-Can be performed with or without power
Describe the hypothenar eminence generally:
-Fleshy mass on the medial side of the palm of the hand, proximal to little finger
-3 small muscles that act upon little finger
what are the muscles of the hypothenar eminence and their actions?
-Flexor digiti minimi (FDM) - flexes little finger
-Abductor digiti minimi (ADM) - abducts little finger
-Opponens digiti minimi (ODM) - opposes little finger
What do the hypothenar muscles attach to proximally?
Carpal bones
What are the movements and insertions of the hypothenar muscles?
What innervates the hypothenar muscles?
Deep branch of the ulnar nerve
What are the lumbrical muscles?
Describe their pathways:
-Four, one for each finger
-Arise from tendons of flexor digitorum profundus
-Travel along lateral aspects of digits 2-5
-Insert onto dorsal aspect of digits 2-5
What do the lumbricals do?
Flex the MCP joints and simultaneously extend the IP joints
What is the innervation to the lumbrical muscles?
Follows that of the FDP tendons from which they arise
-Lateral two (2-3) median nerve
-Medial two (4-5) ulnar nerve
Describe the interossei muscles generally:
-Attached to and lie between the metacarpals and insert onto the dorsal aspects of digits 2-5
-Two groups - palmar (1-3) and dorsal groups (1-4)
What do the arrangements of the palmar and dorsal interossei muscles allow them to do?
-Palmar - Adduct the fingers when they contract (towards from middle finger)
-Dorsal - abduct the fingers when they contract (away from middle finger)
-Also contribute to extension of finger joints at IP joints
How can you remember the actions of the palmar and dorsal interossei muscles?
PAD DAB
Palmar ADDuct
Dorsal ABducts
What are the origins and insertions of the 3 palmar interossei muscles?
First - arises medial side of 2nd metacarpal and inserts medial aspect of 2nd proximal phalanx
Second - arises lateral side of 4th metacarpal and insertss onto lateral aspect of 4th proximal phalanx
Third - arises lateral side of 5th metacarpal and inserts onto lateral aspect of 5th proximal phalanx
Describe the origin and insertion of the first and second dorsal interosseous muscles:
First - arises medial side of 1st metacarpal and lateral side of 2nd metacarpal, inerts onto lateral side of 2nd proximal phalanx
MOVES INDEX NOT THUMB
Second - arised medial side of 2nd metacarpal and lateral side of 3rd metacarpal, inserts lateral aspect of 3rd proximal phalanx
Describe the origin and insertion of the third and fourth interosseous muscles?
Third - arises from medial 3rd metacarpal and lateral 4th metacarpal, inserts lateral 3rd proximal phalanx
Fourth - arises from medial 4th metacarpal and lateral 5th metacarpal, inserts onto medial aspect of 4th proximal phalanx
What muscles in the hand does the radial nerve supply?
NONE OF THEM!
All small muscles in the hand are innervated by ulnar and medial nerves
What is this and its primary function?
-Flexor retinaculum
-Prevents the flexor tendons from bowing when the wrist is flexed
What important structures pass through the carpal tunnel?
-Long flexor tendons (FDS,FDP,FPL)
-Median nerve
What structures cross the wrist but travel superficial to the flexor retinaculum?
-Tendons of FCR, FCU and PL
-Radial artery - lateral aspect of wrist
-Ulnar artery and ulnar nerve - medial aspect of wrist close to FCU tendon
How can sensation in the hand be assessed?
By examining:
-Territories of the peripheral nerves
-Dermatomes
What is the territory of the median nerve in the hand?
-Palmar surface of the lateral side of the hand
-Palmar surface of the lateral 3 1/2 digits
-Skin over the dorsum of the distal phalanges of the lateral 3 1/2 digits
What is the territory of the ulnar nerve in the hand?
Palmar and dorsal surfaces of the medial side of the hand and the medial 1 1/2 digits
What is the territory of the radial nerve in the hand?
-Dorsal surface of the lateral hand
-Skin over the dorsum of the lateral 3 1/2 digits as far as the DIP joint
What nerve territory does this show?
Median
What nerve territory does this show?
Ulnar
What nerve territory does this show?
Radial
What are the certain areas you can test for each of the peripheral nerves of the hand?
Median: Palmar surface of middle finger
Ulnar: Medial border of the hand
Radial: Dorsum of the hand, lateral aspect
Why does injury to median or ulnar nerves as wrist not impair sensation over the palm of hand?
-Cutaneous branches of median and ulnar nerves that supply palm of hand arise in forearm
-Injury at wrist does result in sensory impairment over the palmar aspect of the corresponsing fingers as cutaneous branches to the fingers arise from the nerves distal to the wrist
What is a dermatome?
Region of skin innervated by a single spinal nerve
What are dermatomes of the upper limb innervated by?
Brachial plexus and spinal nerves C5-T1
What dermatomes do spinal segments C4-6 innervate?
C4: Upper shoulder
C5: Lateral side of the anterior and posterior aspect of arm
C6: Lateral side of anterior and posterior surfaces of forearm, lateral sides of anterior and posterior surfaces of palm, anterior and posterior surfaces of thumb and index finger
What dermatomes do spinal cord segments C7-T1 innervate?
C7: Anterior and posterior surfaces of the middle finger and middle of the palm (over 3rd metacarpal)
C8: Medial side of anterior and posterior surfaces of the forearm, medial side of anterior and posterior surfaces of palm and the anterior and posterior surfaces of the 4th and 5th fingers
T1: Medial side of the anterior and posterior surface of the arm
What does testing sensation on dermatomes C5-T1 give you information about?
The spinal nerves and their corresponding spinal cord segments
How are areas of skin innervated by the spinal nerves (dermatomes) different to the areas supplied by peripheral nerves?
Spinal nerve fibres are ‘shuffled’ in the brachial plexus and distributed within the peripheral nerves
What areas do you test sensation in to test the dermatomes of the upper limb?
C5: upper lateral arm
C6: Thumb
C7: Middle finger
C8: Medial border of hand
T1: Medial border of the arm
What is the main arterial supply of the hand and where does it arise?
-Radial and ulnar arteries
-Terminal branches of the brachial artery
What is the pathway of the radial artery?
Courses down the lateral aspect of the forearm, radial pulse can be palpated over the lateral aspect of the wrist.
What is the pathway of the ulnar artery in the forearm. and hand?
-Coursed medial aspect of the forearm
-Ulnar pulse can be palpated over medial aspect of the wrist but may be partially covered by the tendon of the flexor carpi ulnaris
-Travels alongside the ulnar nerve
What do the radial and ulnar arteries do deep in the palm of the hand?
Anastamose to form the two palmar arches
What forms the deep and superficial palmar arches?
Superficial - Largely by ulnar artery with smaller contribution from radial artery
Deep - Largely by radial artery with a smaller contribution from the ulnar artery
What do. thepalmar arches give rise to?
-Metacarpal and digital arteries that supply the palm of the hand and digits
-Accompanied by digital nerves
What is the function of the anastomoses of the radial and ulnar arteries?
Ensures perfusion of the hand is maintained in the event that one of the vessels is occluded or injured
What are 3 general statements about the posterior forearm muscles?
-Arranged in two layers: superficial and deep
-Most are extensors of the wrist, digits or thumb
-All innervated by the radial nerve
What are the 6 superifical muscles of the posterior forearm?
Lateral to medial:
-Brachioradialis
-Extensor carpi radialis longus
-Extensor carpi radialis brevis
-Extensor digitorum
-Extensor digiti minimi
-Extensor carpi ulnaris
What are the superfiical muscles of the posterior forearm connected to proximally?
Lateral epicondyle of the humerus - known as the ‘common extensor origin’
Describe brachioradialis:
-Exception to some of the rules
-Lies on boundary between posterior and anterior components
-Originates from humerus, proximal to lateral epicondyle
-Inserts on distal radius
-Weak flexor of elbow joint
-Innervated by radial nerve
Describe Extensor carpi radialis longus and brevis:
-Lie on radial side of posterior component
-ECRl inserts onto 2nd metacarpal and ECRB inserts onto 3rd metacarpal
-Extend and abduct the wrist
Describe extensor digitorum:
-Extends digits via four long tendons that insert onto dorsal aspect of the fingers (digits 2-5)
-Tendons are connected by fibrous bands which makes it difficult to fully extend middle or ring fingers independantly
Describe extensor digiti minimi:
Extends little finger via its insertion onto the dorsum of the little finger
Describe extensor carpi ulnaris:
-Most medial of the superficial muscles
-Extends and adducts the wrist via its insertion onto the 5th metacarpal
Brachioradialis
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris
What do the tendons of the superficial muscles of the posterior forearm pass?
-Travel under a band of tissue called the extensor retinaculum
-Prevents the tendons from bowing when the wrist is extended
What are the deep muscles of the posterior forearm?
Lateral to medial:
-Supinator
-Abductor pollicis longus
-Extensor pollicis brevis
-Extensor pollicis longus
-Extensor indicis
Where do the deep posterior forearm muscles attach proximally?
-Attach proximally to forearm bones and the interosseous membrane
-Except supinator
What two deep muscles of the posterior forearm are exceptions to the rules?
-Not extensors
-Supinator - supinates forearm and hand and is attached proximally to the humerus. Wraps around upper radius
-Abductor pollicis longus - absucts the thumb and inserts onto 1st metacarpal
Describe extensor pollicis brevis and extensor pollicis longus:
-Both extend thumb
-EPB inserts on proximal phalanx and extends MCP joint
-EPL inserts on distal phalanx and is only muscle capable of extending IPJ of thumb
-Proximal muscle attachments are deep in forearm, tendons lie superficially at wrist as they wrap around distal radius
Describe extensor indicis:
Inserts on dorsum of index finger, allowing independant extension of the digit
Supinator
Abductor pollicis longus
Extensor pollicis longus
Extensor pollicis brevis
What are 2 features of all posterior forearm muscles?
-All extensors except for: brachioradialis, supinator, abductor pollicis longus
-All innervated by radial nerve
MUSCLES THAT CROSS THE WRIST ALSO CONTRIBUTE TO WRIST EXTENSION
What are the muscles, bones and tendons of the dorsum of the hand?
-Only four dorsal interossei muscles seen
-Metacarpal bones are palpable
-Extensor tendons often visible under skin
What is the venous drainage of the dorsum of the hand?
-Superficial veins often visible
-Comprise the dorsal venous network but pattern is variable
-Dorsal venous network drains into the cephalic vein laterally and basilic vein medially
Label and describe:
-Also called extensor expansion
-Fibrous structure overlies dorsal aspect of digits
-Attached to base of proximal phalanx and gives rise to central slip and two marginal slips
-Central slip inserts on middle phalanx and marginal slips converge on distal phalanx
What inserts onto the extensor expansion and where?
-Tendons of ED, EI and EDM insert onto dorsal aspect of extensor expansion which helps keep tendons fixed on midline of the digits
-Lumbricals and interossei insert into the sides of the proximal parts of the extensor expansion and contribute to extension of the interphalangeal joints via this attachment
What is the anatomical snuffbox (ASB)?
-Triangular-shaped depression on the lateral aspect of the wrist
-At the base of the thumb, seen when thumb is extended
What are the boundaries of the ASB?
-Tendon of EPL medially
-Tendons of EPB and APL laterally
What are 3 clinically important details about the ASB?
-Scaphoid lies in floor of ASB so tenderness here may indicate fracture
-Radial artery travels through it
-Cephalic vein arises in ASB can be cannulated here if nevessary
Label:
What does it show?
Anatomical snuffbox
What passes over the anatomical snuffbox?
Superficial branch of the radial nerve runs over the anatomical snuffbox to supply the skin over the latral aspect of the dorsum of the hand
What is the blood supply to and from the posterior compartment of the forearm?
-Branch of the ulnar artery accompanied by deep veins
-Major superficial veins of the forearm - cephalic and basilic
-Blood from dorsal venous network on the dorsum of the hand drains towards both cephalic and basilic veins
What innervates the muscles of the posterior forearm?
-Radial nerve innervates all muscles of posterior forearm
-Proximal radial nerve injuries result in inability to extend wrist and fingers
What does the posterior branch of the radial nerve innervate?
-Skin over the lateral aspect of the dorsum of the hand
-Including skin over the anatomical snuffbox and the skin over the dorsum of the lateral 3 1/2 digits as far as the DIP joint
Describe the shoulder joint:
-Synovial ball and socket joint
-Formed by articulation between the glenoid fossa of the scapula and the head of the humerus
Describe the fit of the shoulder joint:
-Articular surfaces are poor fit which compromises stability but increases range of movement
-Joint capsule is lax, allowing mobility
What increases stability of the shoulder joint?
-Reinforced by ligaments
-Glenoid deepened by rim of fibrocartialge called glenoid labrum
-Rotator cuff is vital for stability
-Tendon of long head of biceps brachii constributes stability to joint
Describe the elbow joint:
-Synovial hinge joint formed by articulations between the trochlea of humerus and trochlear notch of ulna, and capitellum of humerus and radial head
What reinforces the joint capsule of the elbow joint?
Medial (ulnar) and lateral (radial) collateral ligaments
Describe the proximal and distal radioulnar joints:
-Synovial, pivot-type joints between the radius and ulna
-Radius rotates around the ulna when the forearm is pronated and supinated
What holds the radial head in place?
-Annular ligament
-Attached to the ulna
-Radial head rotates within it to produce pronation and supination
Describe the wrist joint and carpus:
-Condyloid synovial joint formed by the articulation of the distal radius with scaphoid and lunate
-Surrounded by a joint capsule which is reinforced by ligaments
-Intercarpal joints between carpal bones are synovial joints which are also reinforced by ligaments
What types of joints are the different joints of the hands?
-Synovial
-First CMC lies between trapezium and 1st metacarpal and is a saddle joint (key to range of movement
-MCP joints are condyloid
-Interphalangeal are hinge joints
-CMC.MCP and IP joints are all reinforced by ligaments
