ANAT Upper Limb

ANAT1451- Upper limb

LO1 To identify anatomical features of the bones of the pectoral girdle and arm

Pectoral Girdle:

Clavicle (collarbone)
Scapular
Connected to acromioclavicular joint (acromial end of scapula/clavicle – back end)
Girdle connected to axial skeleton (midline – skull, vertebral column) at sternoclavicular joint
Girdle connected to the rest of the upper limb (arm) at glenohumeral joint (humerus and scapular articulate – shoulder joint)

Articulate – 2 bones at a joint

Clavicle:

S shape
Convex anterior
Concave posterior
Shaft/body is main part of bone between the ends
Superior surface is smooth
Inferior surface has lumps/bumps, rough patches (tubercle) at lateral end – posterior – attachment of conoid
Impression for costoclavicular ligament – (costo – rib, costal cartilage, join to sternum). 1^st costal cartilage
Subclavian groove – beneath the clavicle – subclavius muscle present
Trapezoid line – lateral – attachment of trapezoid

Tubercle – bump/lump

Ligament – connect 2 bones together, restrict too much movement

Scapula:

Posterior – spine (lump)
Anterior – nil
Lateral – shoulder joint
Angles (pointy) – superior, inferior and lateral
Borders – superior, medial and lateral – Inferior – lateral – lateral – superior – superior – medial (between angles)
Processes (stick out bit) – acromion, coracoid (deep, below clavicle), spine (back point – turns into acromion towards shoulder)
Fossae (bone spaces) – supraspinous (above spine of scapular, infraspinous (below scapular spine) , subscapular (deep below scapular spine), glenoid (cavity for humerus)
Tubercle – supraglenoid (above glenoid cavity), infraglenoid (below glenoid cavity)
Movement: Elevation/depression, retraction/protraction (add/abd), lateral(up/ant)/medial (down/pos) rotation

Humerus:

Proximal attaches to glenohumeral joint (shoulder)
Neck – anatomical (line along head of bone – head used to be separate bone when growing – growth plate – fuses to shaft of bone), surgical (around bone – narrowest/weakest part of bone – most susceptible fracture – below anatomical neck line)
Tubercle – greater (next to head, superior), lesser (bilateral posterior of head). Intertubercular sulcus (gap between – turns to lips)
Lip – medial (closer to midline), lateral (outer)
Facet (flattened section – muscle attachment) – superior, middle, inferior – visible on posterior

Lo2 To identify key features of the shoulder, pectoral region and the arm on a living person (surface anatomy)

Items you can palpate on the body

LO3 To understand the structure of the acromioclavicular, sternoclavicular and glenohumeral (shoulder) joints

3 mutually dependent joints – movement together

Sternoclavicular:

Articulating Surfaces: Clavicle (sternal end), manubrium (clavicular notch)
Disc between aids fit of surfaces – help clavicle articulate better with manubrium
Synovial saddle joint (modified - rotation)
Movement: Elevation/depression, protraction/retraction, axial rotation
Supporting ligaments: anterior and posterior sternoclavicular (between sternum and clavicle), interclavicular (between – runs along top of joint), costoclavicular (between clavicle and first costal cartilage)
Elevation limited by costoclavicular ligament (stretched when arm lifted) and subclavius (muscle in groove on clavicle)
Depression limited by interclavicular ligament and disc

Acromioclavicular:

Articulating Surfaces: clavicle (acromial end) and acromion
Disc is wedged – doesn’t aid congruency as much
Synovial plane (gliding) joint (modified - rotation)
Movement: elevation/depression, protraction/retraction, axial rotation
Supporting ligaments: superior and inferior acromioclavicular
Coracoclavicular ligament (2 parts) – conoid ligament (posterior attachment - limit protraction - forward) and trapezoid ligament (anterior attachment – limit retraction - back)

Scapulothoracic ‘Joint’:

Not a true anatomical joint – not articulation with cartilage between
Important for positioning of shoulder joint
Scapula glides against chest wall
The subscapular/anterior surface of scapula and superolateral surface of the thoracic wall
Separated by the subscapularis muscle and serratus anterior muscles (and space between)
Stabilised by muscles
Movement: elevation/depression, protraction/retraction, medial/lateral rotation

Glenohumeral:

Articulating surfaces: head of humerus (large and spherical), glenoid fossa (cavity - shallow, small, pear-shaped, 1/3 size of humerus)
Incongruent joint – unstable, big range of motion
Synovial ball and socket
Movement: flexion/extension, abduction/adduction, medial/lateral rotation, circumduction
Ligaments: superior, middle and inferior (stronger – longer and thicker – if weak, increase dislocation) glenohumeral (located internally on anteroinferior joint capsule, limit excessive lateral rotation, middle and inferior limit excessive abduction), transverse humeral (capsular lig – between greater/lesser tubercle – holds down tendons on long headed bicep along intertubercular groove), coracohumeral (capsular lig – blends with supraspinatus tendon – between coracoid process to humerus), coracoacromial (accessory lig – helps prevent superior shoulder dislocation – coracoid process and acromion)
Stabilising Structures: Glenoid labrum (outside of fossa – deepens socket, fibrocartilage rim, triangular in cross section, tendon of long head of bicep brachii blends with labrum), Coracoacromial arch (fibro-osseous – ligament and 2 bones), formed by coracoid process, acromion, and coraco-acromial ligament, strong to prevent superior dislocation
Joint capsule – thick but loose (range of motion) around whole bones, attaches beyond labrum anteriorly and inferiorly, to labrum posteriorly and superiorly, to the anatomical neck of humerus, internal surface lined with synovial membrane, filled with synovial fluid, tendon of long head biceps (to supraglenoid tubercle) within joint capsule
Rotator Cuff Muscles – MOST IMPORTANT STABILISERS – tendon blend with joint capsule, dynamic ligaments, from scapular to humerus, close packed of GH joint when in abduction and external rotation (most congruent – tight)
4 muscles – Supraspinatus, Infraspinatus, Teres Minor, Subscapularis (TISS – back to front) – strengthen rotator cuff for increase shoulder stability
Bursae – fluid filled sacs, lined with synovial membrane, and filled with synovial fluid (designed to reduce friction)
Subdeltoid – deep between joint capsule and deltoid
Subacromial – deep between coracoacromial arch and acromion
Subscapular – deep between joint capsule and subscapularis
Communication/connection between subdeltoid and subacromial, and subscapular and joint cavity – if one affected, both affected
Bursitis – infection or swelling (overuse)

Capsular ligament – thickening of fibrous joint capsule

Accessory ligament – sit around joins

Lo4 To correlate the structure of the shoulder joint to its functional movements and stability

Rotator Cuff Muscles - Posterior:

Supraspinatus

Attached to supraspinous fossa and superior facet of greater tubercle
Action: Initiate and assist deltoid with abduction and stabilise GH joint
Nerve Supply: Suprascapular nerve
In use majority of time

Infraspinatus

Attached to infraspinous fossa and middle facet of greater tubercle
Action: Laterally rotate humerus and stabilise GH joint
Nerve Supply: Suprascapular Nerve

Teres Minor

Attached to lateral border of scapula and inferior facet of greater tubercle
Action: Laterally rotate humerus and stabilise GH joint
Nerve Supply: Axillary nerve (wraps around surgical neck of humerus)

Rotator Cuff Muscles – Inferior:

Subscapularis

Attached to subscapular fossa and lesser tubercle
Action: Medically rotate humerus (strongest rotator), stabilise GH joint, assist with adduction
Nerve Supply: Upper and Lower subscapular nerves

Upper Limb to Vertebral Column (Superficial)

Trapezius:

Attachments:
Skull (superior nuchal line and external occipital protuberance) and nuchal ligament
Vertebral column (Spinous processes C7-T12)
Clavicle (lateral 1/3)
Scapula (acromion and spine)
Actions (unilateral):
Superior/lateral rotates glenoid fossa (abduction)
Retracts scapula
Elevate scapula (upper part)
Depress scapula (lower part)
Laterally flex neck
Actions (bilateral):
Extend neck
Nerve Supply:
Spinal accessory nerve (motor)
C3-C4 (pain and proprioception)

Latissimus Dorsi:

Attachments:
Vertebral Column (spinous processes of T6-T12, thoracolumbar fascia, iliac crests)
Humerus (floor of intertubercular groove)
Actions:
Adducts arm
Medially rotates arm
Extends a flexed arm
Raises body towards arm
If humerus is fixed, can pull trunk forward and ‘hitch’ hips
Nerve Supply:
Thoracodorsal nerve

Upper Limb to Vertebral Column (Deep)

Levator scapulae:

Attachments:
Vertebral Column (transverse processes C1-C4)
Scapula (medial border, superior to root of spine)
Actions:
Elevate scapula
Medially rotate scapula
Nerve Supply:
Dorsal scapular nerve
Anterior rami C3-C4

Rhomboid Major:

Attachments:
Vertebral Column (nuchal ligament and spinous processes C7-T1)
Scapula (medial border adjacent to root of spine)
Actions:
Elevates scapula
Retracts scapula
Medially rotates glenoid fossa
Nerve Supply:
Dorsal scapular

Rhomboid Minor:

Attachments:
Vertebral Column (spinous processes T2-T5)
Scapula (medial border inferior to root of spine)
Actions:
Elevates scapula
Retracts scapula
Medially rotates glenoid fossa
Nerve Supply:
Dorsal scapular

Upper Limb to Scapula

Teres Major:

Attachments:
Scapula (lower 1/3 lateral border)
Humerus (medial lip of intertubercular groove)
Actions:
Adducts arm
Medially rotate arm
Nerve Supply:
Inferior subscapular nerve

Deltoid:

Attachments:
Clavicle (lateral 1/3)
Scapula (acromion and spine)
Humerus (deltoid tuberosity)
Actions:
Flexes and medially rotates arm (anterior fibres)
Abducts arm (middle fibres)
Extends and laterally rotates arm (posterior fibres)
Nerve Supply:
Axillary Nerve

Upper Limb to Scapula (Anterior)

Biceps Brachii:

Attachments:
Scapula – long head: supraglenoid tubercle and labrum
Short head – coracoid process
Radius (radial tuberosity and deep forearm fascia)
Actions:
Weak flexor of shoulder
Short head resists shoulder dislocation
Supinates forearm
Flexes forearm
Nerve Supply:
Musculocutaneous nerve

Coracobrachialis:

Attachments:
Scapula (coracoid process)
Humerus (middle 1/3 of shaft medially)
Actions:
Assists in flexion of shoulder
Assist in adduction of shoulder
Nerve Supply:
Musculocutaneous nerve

Upper Limb to Scapula (Posterior)

Triceps Brachii:

Attachments:
Scapula – long head: infraglenoid tubercle
Humerus (posterior): lateral head – superior to radial groove, medial head – inferior to radial groove
Ulna – proximal end of olecranon (elbow lump – blend together) and deep fasica
Actions:
Extends shoulder (weakly as it crosses the shoulder joint)
Extends forearm
Nerve Supply:
Radial nerve

Upper Limb to Thoracic wall

Serratus Anterior:

Attachments:
Ribs (lateral aspects of ribs 1-8)
Scapula (anterior surface of medial border) SCAPULOTHORACIC ‘JOINT’
Actions:
Protract scapula
Superior/lateral rotation of scapula
Nerve Supply:
Long thoracic nerve

Pectoralis Major:

Attachments:
Clavicle (medial ½ anterior surface)
Sternum (anterior manubrium and body)
Costal cartilages 1-6
Humerus (lateral lip of intertubercular groove)
Actions:
Adducts arm
Medially rotates arm
Clavicular head flexes arm
Sternocostal head extends arm (when flexed)
Assists latissimus dorsi to raise trunk towards arms
Nerve Supply:
Medial and lateral pectoral nerves

Pectoralis Minor (deep to Major):

Attachments:
Ribs 3-5
Scapula (coracoid process)
Actions:
Stabilises scapula (holds against thorax)
Nerve Supply:
Medial pectoral nerve

Accessory Muscle

Subclavius:

Attachments:
Junction of rib 1 and its costal cartilage
Clavicle (subclavian groove)
Actions:
Depress clavicle
Nerve Supply:
Nerve to subclavius

Clavicle:

ROM – permitted by movements at the sternoclavicular joint
Synovial Saddle joint (modified)
Circumduction requires coordinated movements at pectoral girdle and glenohumeral joint

Abduction Cycle (arm from side to up next to ear):

Stage 1 –

Glenohumeral movement alone 1^st 30 deg, inferior angle of scapula should not move
Max 3mm upward displacement of humeral head
Lateral rotation of the humerus occurs by stage 1

Stage 2 –

Scapular elevation and upward rotation points glenoid fossa superiorly
Humeral head glides inferiorly by 90 deg revealing a sulcus

Stage 3 –

Scapula glides around rib cage (scapulothoracic)
Inferior angle of scapula should not protrude further than 1cm from chest wall

Shoulder Joint:

Flexion/extension
Abduction/adduction
Medial/lateral rotations
Circumduction (combination of all)

Scapulohumeral Rhythm (2°:1°):

Abduction of shoulder joint
Total range is ~180 deg
120 performed by movement at GH
60 performed by lateral rotation of scapula
For every 3 of abduction, 2 at shoulder, 1 at scapulothoracic joint (2:1)

Scapular Rotation:

Lateral:

Serratus anterior
Trapezius (upper and lower fibres)

Medial:

Levator scapulae
Rhomboids
Pectoralis minor

LO5 To understand how stability and function of the shoulder joint can be altered as a result of dislocation, fractures and muscular injuries

LO6 To identify normal anatomical features and injuries on radiographs of the shoulder and pectoral girdle

On X-ray: Bones – white, Soft tissue – grey, Air – black

Clavicle Fracture:

Caused by direct force to shoulder or indirect force transmitted from an outstretched hand
Weakest part of clavicle is the junction of its middle and lateral thirds
Sternal end pulled up (sternocleidomastoid muscle)
Gravity, pectoralis major pulls medial-lateral end down
Minor fractures (clean break) – sling only, pull clavicle back up to align

Dislocation of AC Joint:

Caused by direct force to shoulder or indirect force transmitted from an outstretched hand
Can be accompanied by rupture of coracoclavicular ligament (serious fracture)
Will be able to palpate - Acromial end will be pulled upwards (higher = more damage)

Dislocation of GH Joint:

Can be caused by direct or indirect trauma
Can involve nerve damage (typically axillary or radial)
Overarm throw – abduction, lateral rotation – shoulder joint stable and tight – very susceptible to knocks and dislocation
Head of humerus moves downwards due to gap in rotator cuff (blocked on all other sides by structures)
Called anterior dislocation due to final muscle pull (end location)
Once dislocated, joint capsule is weakened and more susceptible to further dislocations

Rotator Cuff Tendinopathy or Tear:

Caused by repetitive use
Cuff is impinged on coracoacromial arch
Results in degenerative tendinosis of rotator cuff
Most commonly in supraspinatus (muscle built up, increase in size – reduced gap, tight fit, bursae swell)
May be caused due to sudden strain of muscles
TEST: slowly lower arm from ear to side. May be sudden drop close to 15° from side. Also, resistance test (abduction vs push down)

LO7 To know the muscles that attach to the scapula and humerus (attachments, nerve supply & functions)

Nerves – supply body structures with electrical impulse to muscle fibres to shorten and contract – hence movement
Veins – thin walled, deoxygenated blood back to heart
Arteries – thick walled, oxygenated blood to limbs

LO8 To know the blood vessels of the scapular and pectoral regions and understand lymphatic drainage of the upper limb

Subclavian artery supplies upper limbs

Left:

Left subclavian and left carotid artery directly off aorta

Right:

Brachiocephalic trunk branches into right subclavian and carotid
Becomes axillary artery at lateral border of first rib
Continues underneath (pec Major) arm until inferior border of teres major becomes Brachial artery
Branches to subscapular artery
Branches to 2
Circumflex scapula – posterior – anastomose with dorsal scapular
Thoracodorsal – posterior to Lat Dorsi – join to dorsal scapular
Follows til elbow and splits into
Radial artery on lateral side
Ulnar artery on medial
Hand supplied by both radial and ulnar arteries

Subclavian Artery:

Branches into thyrocervical trunk, then suprascapular and transverse cervical (travel towards scapular)

Suprascapular:

Travels posterior
Gives off small branches to supraspinous and infraspinous fossa

Transverse cervical:

Branches into 2
Only interested in dorsal scapular artery
Comes down medial border – anastomose with suprascapular and subscapular (from axillary)

Major joints have anastomoses: Connection between 2 arteries

Offers blood an alternative route to a destination (if a path is blocked)
Ligature – blocking, blood clot – tightening of blood vessel

Venous Draining

Superficial – visible underneath skin

Superficial venous palmar arch drains to
Basilic (medial) drains to Axillary
Cephalic (lateral) – between deltoid and pectoralis – deltopectoral groove – drains to
Axillary

Deep – same name as arteries

Deep venous palmar arch
Ulnar
Radial
Brachial join to form Axillary
Axillary*
Subclavian*
Brachiocephalic

*Only 1 artery and vein

Lymphatic Drainage of Upper Limb (not tested)

Many lymph nodes in axillary area and drain up towards subclavian area
Drain into right or left Venus angle (subclavian meets internal jugular vein)

BRACHIAL PLEXUS and ARM

LO1 To identify anatomical features of the humerus

LO2 To identify key features of the arm and elbow region on a living individual (surface anatomy)

Deltoid tuberosity on mid latera shaft
Posterior surface – radial groove. Radial nerve travels through

Distal End:

1 Condyle
Capitulum: rounded ball (little head) – lateral. Articulate with radius
Trochlea: pulley. Articulate with ulnar – medial
2 Epicondyles
Medial
Lateral
3 Fossae
Radial: (anterior) little pit for radius to sit in (during elbow flexion)
Coronoid: (anterior) Ulnar has coronoid process sits here (during elbow flexion)
Olecranon: (Posterior) pointy bit of elbow is olecranon (during extension of elbow)

Medial supracondylar ridge: Medial edge of bone. Muscles attach

Lateral supracondylar ridge: Lateral edge of bone. Muscles attach

LO3 To know the muscles of the arm (attachment, nerve supply and actions)

Arranged into 2 compartments: Anterior and Posterior
Separated by intermuscular septum (wall between 2 groups of muscle)
Anterior: Supplied by musculocutaneous nerve
Posterior: Supplied by radial nerve

Anterior Group:

Coracobrachialis:

Attachments:
Scapula (coracoid process)
Humerus (middle 1/3 of shaft medially)
Actions:
Assists in shoulder flexion
Assists in shoulder adduction
Nerve Supply:
Musculocutaneous Nerve

Biceps Brachii:

Attachments:
Scapula:
Long Head: supraglenoid tubercle and labrum
Short Head: coracoid process
Radius (radial tuberosity and deep forearm fascia)
Actions:
Weak flexor of shoulder
Short head resists shoulder dislocation
Supinates forearm
Flexes forearm
Nerve Supply:
Musculocutaneous Nerve

Brachialis:

Attachments:
Humerus (anterior distal ½)
Ulna (coronoid process and ulnar tuberosity)
Actions:
Prime flexor of elbow joint
Nerve Supply:
Musculocutaneous Nerve

Posterior Group:

Triceps Brachii:

Attachments:
Scapula: Long head – infraglenoid tubercle
Humerus (posterior):
Lateral head: superior to radial groove
Medial head: inferior to radial groove
Ulna: (lateral and medial heads blend) proximal end of olecranon and deep fascia
Actions:
Extend shoulder (weak)
Extend forearm
Nerve Supply:
Radial Nerve

Anconeus:

Attachments:
Humerus (lateral epicondyle)
Actions:
Extend forearm
Nerve Supply:
Radial Nerve

Trauma and Pathology:

Fracture of surgical neck: Commonly result of fall on outstretched hand (anterior and posterior circumflex artery, axillary nerve)
Fracture of shaft: Result from direct blow or torsion. Produce various types of fractures (Profunda brachii, radial nerve)
Avulsion fracture of greater tubercle: Bone section torn off/pulled away. Common in middle-aged and elderly.
Rupture of Tendon of Biceps Brachii:
Usually result of ‘wear and tear’
Tendon is weakened by friction as it passes through the intertubercular groove
Rupture results from repetitive overhead motions (eg. Baseball, cricket, swimming)
Occurs in individuals >35 years old
Tendon is torn from its superior attachment to the scapula (coracoid process and supraglenoid tubercle)
Associated with popeye deformity (head of muscle has slipped down towards elbow)

LO4 To describe the boundaries, contents and clinical relevance of the cubital fossa

Located on anterior aspect of elbow region
Triangular in shape
Boundaries:
Superior: Imaginary line between epicondyles
Medial: lateral border of pronator teres
Lateral: medial border of brachioradialis
Roof: deep fascia and bicipital aponeurosis
Floor: brachialis, supinator and elbow joint
Contents:
Medial to Lateral - Median nerve, Brachial artery, Tendon of biceps brachii
Close relationship to fossa (not within) – ulnar nerve, redial nerve

Clinical Relevance:

Veins and arteries are subcutaneous
Cephalic and basilic vein meet at make median cubital vein
Median Cubital vein: prominent, used for drawing blood, injections
Not everyone has one. Natural variation in superficial vein pattern
Brachial Artery: Used to take blood pressure

LO5 To know the blood vessels of the arm and forearm

Axillary Artery:

2 major branches: anterior and posterior circumflex humeral

Brachial Artery:

Origin: Axillary artery
Begins at inferior border of teres major
Course:
Travels medial with median nerve
Passes anterior to trochlea of the humerus to enter lateral side the cubital fossa
Terminates by branching into radial and ulnar artery
Major Branches:
Profunda brachii
Ulnar collateral branches

Radial Artery:

Origin: Branches from brachial artery
Course:
Travels deep to brachioradialis with superficial branch of the radial nerve and veins
Sits between the tendons of the brachioradialis and flexor carpi radialis in the wrist

Ulnar Artery:

Origin: Branches from Brachial Artery
Course:
Passes between flexor digitorum superficialis and flexor carpi ulnaris
Travels with the ulnar nerve and ulnar veins

Deep Veins of the Arm and Forearm

Paired Veins:

Each artery is usually accompanied by smaller paired veins called ‘venae comitantes’
They have the same names as the arteries (eg. Brachial, radial, ulnar)

Unpaired Veins:

Subclavian and axillary veins do not have associated venae comitantes and have a single vein associated with them
Together with the jugular veins the, subclavian veins form the right and left brachiocephalic veins that drain into the superior vena cava

Superficial Veins of the Arm and Forearm

Superficial Veins:

Located in subcutaneous layer
Highly variable
Drian into axillary vein (can be variable)
Cephalic (located in anterior antebrachium, travels in deltopectoral groove)
Basilic (located at the medial border of biceps)
Median Cubital

Venous Drainage:

Superficial Veins (subcutaneous)
Perforating Veins (subcutaneous to deep)
Deep Veins (usually paired and have same name as arteries)

LO6 To describe the structure of the brachial plexus

Spinal cord runs between each vertebra and down to lumbar region
Spinal nerves come off spinal cord and become peripheral nerves. Go off to supply muscles, joints, limbs
Cervical (C1-C8), thoracic (T1-T12), lumbar, sacral, coccygeal
C5, C6, C7, C8, T1 make up brachial plexus
Brachial plexus pass under clavicle
Plexus: coming together and share nerve fibres
REMEMBER TO DRINK COLD BEER (RTDCB)
Roots: Anterior rami of vertebral levels C5-T1 make up brachial plexus
Trunks: Located between anterior and middle scalene muscles (in neck)
Division: Every trunk has Anterior and Posterior.
All posterior divisions join together
Upper/Middle anterior join. Lower does not move
Cords: Named according to their position around axillary artery
Posterior branches travel behind
Ulnar is medial on arm, hence, medial cord
Branches: Supply skin and muscles of the arm, forearm and hand

LO7 To describe the formation, course and distribution (structures supplied) by the branches of the brachial plexus

LO8 To correlate lesions of the branches of the brachial plexus to functional and sensory deficits

Nerves supply all muscles and skin of the upper limb

Roots:

Long Thoracic (C5, C6, C7): Serratus anterior
Dorsal Scapula (C5): Rhomboid major, rhomboid minor, Levator scapulae

Trunks:

Upper:
Suprascapular (C5, C6): Supraspinatus, Infraspinatus
Subclavius (C5, C6): Subclavius

Divisions:

Cords:

Lateral:
Lateral pectoral (C5, C6, C7): Pectoralis Major, Pectoralis Minor
Posterior:
Thoracodorsal (C5, C6, C7): Latissimus Dorsi
Upper Subscapular (C5, C6, C7): Subscapularis
Lower Subscapular (C5, C6, C7): Subscapularis
Medial:
Medial cutaneous nerve of arm: Skin
Medial cutaneous nerve of forearm: Skin
Medial pectoral (C5, C6, C7): Pectoralis Major

Branches from the Posterior Cord:

Axillary (C5-C6):

Supplies:
Deltoid
Teres Minor
Skin covering the lateral upper arm
Course:
Passes through quadrangular space
Winds around the surgical neck of the humerus with posterior circumflex humeral artery
At risk with a fracture of the surgical neck of the humerus
Also at risk with dislocation of the glenohumeral joint
Lesions of the Axillary Nerve affect:
Flexion beyond first 15°
Sensation over the lateral upper arm

Radial (C5-T1):

Supplies:
Extension of arm and forearm
Skin over the extensors and dorsum of the hand
Course in the shoulder and arm:
Passes through the triangular interval with the profunda brachii artery
Sits between medial and lateral heads of triceps
Travels in the intertubercular groove towards the cubital fossa
Course in cubital fossa:
Sits between brachialis and brachioradialis
In front of the lateral epicondyle it divides into superficial and deep branches
**NOTE: Triceps innervation occurs high in the arm
Course in forearm and wrist:
Superficial Branch:
Sensory
Travels on anterolateral forearm
Travels deep to the brachioradialis muscle with the radial artery and veins
Sits in anatomical snuffbox (located on dorsal surface of the hand)
Deep Branch:
Muscular and articular
Pierces the supinator muscle
Changes name to posterior interosseous nerve
Travels along the posterior surface of the interosseous membrane (between radius and ulnar)
Radial Nerve at risk of:
Mid-shaft humeral fracture
Supracondylar fracture
Penetrating wound to the posterior forearm
Lesions of the Radial Nerve affect:
Function of the extension of the arm and forearm
Sensation over the dorsal surface of the hand, particularly in the area known as the anatomical snuffbox (radial fossa)

Branches from the Lateral Cord:

Musculocutaneous (C5, C6, C7):

Supplies:
Muscles of the anterior compartment of the arm
Skin over the lateral aspect of the anterior forearm
Course in shoulder and arm:
Passes through the coracobrachialis muscle
Travels inferiorly between brachialis and biceps brachii muscles
Emerges lateral to these muscles and changes its name to the lateral cutaneous nerve of the anterior forearm
Lesions of the Musculocutaneous Nerve affect:
Weakened elbow flexion
Sensory loss in lateral half of anterior forearm
Reduced biceps reflex

Branches from the Medial Cord:

Ulnar (C8-T1):

Supplies:
The flexor carpi ulnaris and the medial ½ of flexor digitorum profundus in the forearm
The intrinsic muscles of the hand except for the thenar group of muscles and the lateral 2 lumbricals
Skin over the medial 1½ digits (palmar and dorsal surface)
Course in arm:
Passes medial to the brachial artery
Travels posterior to the medial epicondyle
Course in forearm and wrist:
Travels on the medial side of forearm deep to the flexor carpi ulnaris muscle
Travels with the ulnar artery and veins
DOES NOT pass through carpal tunnel
Enters palm on medial side
Lesions of the Ulnar Nerve affect:
ELBOW: the flexor carpi ulnaris and the flexor digitorum profundus muscles of the forearm
The intrinsic group of muscles and medial 2-digit muscles in hand
WRIST: Sensation over the lateral 1 ½ digits (palmar and dorsal surfaces)
A person’s ability to form a fist or grip an item
At risk with medial epicondylar fractures, compression in wrist
Can cause: Claw Hand

Branch from Lateral and Medial Cords:

Median (C5-T1):

Supplies:
The anterior muscles of the forearm except flexor carpi ulnaris and flexor digitorum profundus
The intrinsic group of muscles in the hand expect for the medial 2 muscles, (supplied by ulnar)
Skin over palmar the surface of the lateral 3 ½ digits, including finger tips
Course:
Travels anteriorly in the arm
Travels with the brachial artery, beginning lateral to it and then crossing to its medial side
In cubital fossa: lies between the biceps brachii muscle and the brachial artery
In forearm: passes between heads of pronator teres
Travels between the flexor digitorum profundus and flexor digitorum superficialis
In wrist and hand: passes through carpal tunnel
Gives off palmar cutaneous branches to the intrinsic group of muscles and the lateral 2 thenar muscles
Lesions of the Median Nerve affect:
A person’s ability to form a fist or grip an item
Hand of Benediction
Pronator syndrome
Carpal tunnel syndrome
At risk with:
Supracondylar fracture or deep penetrating wound to forearm
Compression at elbow or wrist

LO9 To describe the difference between dermatomes and myotomes

LO10 To know the myotome, dermatome and peripheral nerve distribution of the upper limb

Dermatome:

Area of skin supplied by a single spinal nerve
Severing a spinal nerve will cause loss of sensation over a particular area of skin
Lots of overlaps of dermatomes in trunk but more defined nerve supply in limbs
Number and Letter – eg C5

Peripheral Nerve:

Named nerve eg. Radial nerve
Input from multiple spinal nerves
When a spinal nerve enters plexus, their fibres are exchanged and redistributed
Although some spinal nerves enter plexuses, others do not and the dermatomal pattern remains

Myotome:

Mass of muscle supplied by a single spinal nerve
Motor fibres travel in the same peripheral nerves as sensory fibres
Therefore, upper limb muscles receive motor fibres form several spinal cord levels (or myotomes)

Elbow and Forearm

Lo1 To identify anatomical features of the bones of the forearm

Ulna:

Medial in forearm
Large proximal, small distal end
Olecranon: pointy bit of elbow
Trochlear notch: articulate with trochlear of humerus
Coronoid process: stick out ridge on anterior
Radial notch: head of radius sits there (lateral side)
Supinator crest and fossa: associated with supinator muscle (lateral side)
Tuberosity of ulna: on anterior, brachialis attaches here
Roughening for Anconeus: lateral side for Anconeus muscle
Interosseous border: (lateral) border between ulna and radius – pointed/sharp
Head (distal)h: rounded lump
Styloid process: top of head

Radius:

Small proximal, large distal end
Head (proximal)
Fovea: pit on head, articulate with capitulum of humerus
Radial tuberosity: biceps brachii attaches here
Interosseous border: medial and sharpest border – border between radius and ulna
Ulnar notch: ulna sits there
Styloid process: lump of bone on lateral side
Dorsal tubercle: (posterior) can palpate
Articulates with scaphoid and lunate bone

Lo2 To identify key features of elbow region and forearm on a living person (surface anatomy)

Medial and lateral epicondyle of humerus
Olecranon
Posterior border of ulna
Styloid process of ulna
Dorsal tubercle of radius
Styloid process of radius
First layer of forearm muscles (digits 2-4 on supinated forearm)
Palmaris longus
Flexor carpi radialis
Flexor carpi ulnaris
MAYBE: ulnar nerve and artery
Extensor digitorum tendon on dorsal surface of hand
Anatomical snuffbox (medial wrist)

Lo3 To understand the structure and function of the elbow and radioulnar joints

Elbow Joint:

During flexion, coronoid process in coronoid fossa
During extension, radius in radial fossa
Articular surfaces:
Trochlea of humerus with trochlear notch of ulna
Capitulum of humerus with fovea of radius
Type:
Synovial hinge
Capitulum/fovea is similar to ‘ball and socket’
Movements:
Flexion and extension

Elbow Joint Space:

Communicates with proximal radioulnar joint
Cushioned with fat pads (protect bone-bone connection during flexion)
Lined with synovial membrane (continuous with synovial membrane of the proximal radioulnar joint)
Sacciform recess (filled with synovial fluid, prevents friction between bone and ligament) extends deep to the annular ligament
Joint capsule is reinforced medially and laterally
Radius is free from capsular attachment

Elbow Ligaments:

Lateral (radial) collateral:
Y-shaped
From the lateral epicondyle to the annular ligament
Medial (ulna) collateral:
Triangular
3 bands: anterior, posterior and oblique
From the medial epicondyle to the coronoid process and olecranon

Bursae:

Many around the elbow
Intratendinous olecranon bursa
Subtendinous olecranon bursa
Subcutaneous olecranon bursa – deep to skin, elbows rested on hard surface, most clinically relevant

Carrying Angle:

Ulna axis deviates laterally from that of the humerus in full extension
Angle keeps arm out from side
Makes the forearm diverge laterally forming the carrying angle
Approximately: 10-15° in males, 10-25° in females

Radioulnar Joints:

Between radius and ulna
3 joints
Bones orientate differently depending on whether arm is in pronation or supination
Elbow joint capsule does not attach to radius (radius would not be able to move)

Proximal:

Articular surfaces:
Head of radius and radial notch of the ulna
Ligaments:
Annular:
Ring-shaped
Attached to anterior and posterior margins of radial notch
Holds head of radius against ulna
Quadrate:
Attached to lower border or radial notch and medial surface of neck of radius
Other features:
Sacciform recess: Prevents friction between radius and annular ligament
Joint Type:
Synovial pivot
Movement:
Rotation of radius
Referred to as supination and pronation of the forearm
Head of radius rotates in the ‘socket’ formed by the annular ligament and the radial notch of the ulna
Both movements require rotation of the radius around its longitudinal axis
Pronation = palm of hand faces posteriorly, and dorsum faces anteriorly
Supination = palm of hand faces anteriorly and dorsum faces posteriorly

Middle:

Articular surfaces:
Interosseous borders of the radius and ulna
Function:
Holds radius and ulna together during pronation and supination
Force transfer
Muscle attachment
Joint Type:
Fibrous - syndesmosis
Movement:
Most fibrous joints are immovable
However, a small amount of movement occurs

Distal:

Articular surfaces:
Head of ulna and ulna notch of radius
Function:
Holds radius and ulna together during pronation and supination
Force transfer
Muscle attachment
Joint Type:
Synovial pivot
Movement:
Articular disc (TFCC – triangular fibrocartilage complex)
Palmar and dorsal capsular ligaments
Sacciform recess

Lo4 To correlate the structure of the elbow and radioulnar joints to their functional movements and stability

Interosseus Membrane (between radius and ulna):

Compression Force:
Force transmitted through wrist, mainly via radius (larger at wrist)
Force tightens (central band)
Force transferred to ulna (as now larger head)
Force transferred to humerus
Distraction Force:
Force loosens the central band of the interosseous membrane
Oblique cord (proximal – run from radius to ulna), annular ligament and brachioradialis tighten to support the load

Lo5 To understand how stability and function of the elbow and radioulnar joints can be altered as a result of dislocation, fractures and muscular injuries

Dislocation of proximal radioulnar joint:

Common in young children
Caused by distraction forces applied to forearm and hand
Head of radius displaced anteriorly
Head may be palpated in cubital fossa
Can cause tearing of annular ligament
Treatment consist of supination of forearm while elbow is flexed

Dislocation of Elbow Joint:

Posterior dislocation is most common (easy to push ulna backwards)
Caused by hyperextension of blow that pushes ulna posteriorly
Often associated with a fracture of the coronoid process
Can also have an associated fracture of the radial head or olecranon

Bursitis:

Can be injured during falls on elbows, exposed to infection from abrasions of skin covering olecranon, inflamed by excessive pressure and friction
Subtendinous olecranon bursa can also be inflamed by repeated flexion-extension of the forearm

Colles Fracture:

Extra-articular fracture of the distal radius
Referred to as ‘broken wrist’ (not actually wrist)
Caused by falling on an outstretched wrist (pronation, extension of wrist and forearm)
Particularly common in elderly females (osteoporosis)
Often results in ‘dinner fork’ deformity

Tennis Elbow:

Lateral epicondylitis
Repetitive use of extensor muscles, particularly ECRB
ECRB stabilises wrist when elbow is extended, and hand is pronated (eg. During backhand in tennis)
Overuse causes micro-tears in ECRB where it attaches to the lateral epicondyle
Pain felt over the lateral epicondyle on wrist extension
Pain when gripping and reduced grip strength
Also common in labourers that use heavy tools, workers that grip or lift repetitively, painters

Golfers Elbow:

Medial epicondylitis
Cause by repetitive use of flexor and pronator muscles
Causes micro-tears in the common flexor tendon
Pain felt over the medial epicondyle on the wrist flexion (eg gold swing)
Pain when gripping and reduced grip strength
Also common in, tennis players with powerful forehand with lots of topspin,
Athletes with poor throwing, weightlifting or stroke techniques in racquet sport,
Admin staff with a lot of typing,
Occupations with forceful gripping actions, heaving lifting, or constant exposure to vibrations at the elbow

Pronator Syndrome:

Entrapment of median nerve
Compression of nerve between heads of pronator teres
Trauma or muscle hypertrophy
Pain in proximal anterior forearm
Hypesthesia of the palmar aspects of the lateral 3 ½ digits and adjacent palm (or pins and needles)
Often occurs during activities with repeated pronation
Weakness in deeper muscles – FPL, FDP, PQ (and deep hand muscles supplied by median nerve)

Lo6 To identify normal anatomical features and injuries on radiographs of the elbow and radioulnar joints

Elbow ROM:

Activities of daily living (ADL)
Need ~30-130° of flexion
0° in extension

Wrist ROM:

Between 50° of pronation and 50° of supination
Mostly in pronation throughout daily living

Normal elbow:

Extension: tip of olecranon and epicondyles in a straight line
Flexion: epicondyles form the base of a triangle, olecranon forms the apex
Important for diagnosing dislocation

Lo7 To know the muscles of the elbow region and forearm (attachments, nerve supply & functions)

Muscles of Elbow Joint:

Arranged into 2 compartments: anterior and posterior

Anterior:

Shoulder flexors
Elbow flexors
Biceps brachii, coracobrachialis and brachialis
Supplied by musculocutaneous

Biceps Brachii:

Attachments:
Scapula:
Long Head: supraglenoid tubercle and labrum
Short Head: coracoid process
Radius (radial tuberosity and deep forearm fascia)
Actions:
Weak flexor of shoulder
Short head resists shoulder dislocation
Supinates forearm
Flexes forearm
Nerve Supply:
Musculocutaneous Nerve

Brachialis:

Attachments:
Humerus (anterior distal ½)
Ulna (coronoid process and ulnar tuberosity)
Actions:
Prime flexor of elbow joint
Nerve Supply:
Musculocutaneous Nerve

Brachioradialis (forearm):

Attachments:
Humerus (proximal 2/3 of supracondylar ridge)
Radius (distal, lateral to styloid process)
Actions:
Flexes forearm (especially in mid-pronation)
Pronation (return to mid-pronation)
Supination (return to mid-pronation)
Nerve Supply:
Radial Nerve

Flexion:

Brachialis: recruited first
Biceps Brachii: stronger when flexed and supinates simultaneously (used when resistance applied)
Brachioradialis (forearm): assists with flexion, places hand into mid-pronation

Posterior:

Shoulder extensors
Elbow extensors
Triceps brachii and anconeus
Supplied by radial

Triceps Brachii:

Attachments:
Scapula: Long head – infraglenoid tubercle
Humerus (posterior):
Lateral head: superior to radial groove
Medial head: inferior to radial groove
Ulna: (lateral and medial heads blend) proximal end of olecranon and deep fascia
Actions:
Extend shoulder (weak)
Extend forearm
Nerve Supply:
Radial Nerve

Anconeus:

Attachments:
Humerus (lateral epicondyle)
Actions:
Extend forearm
Nerve Supply:
Radial Nerve

Extension:

Anconeus: recruited first
Triceps Brachii (main extensor): medial head = workhorse, lateral head = recruited next, long head = recruited last (back-up)

Muscles of Radioulnar Joints:

Supination

Supinator – recruited first
Biceps brachii – when supinating against resistance
Brachioradialis – when in pronated position

Supinator:

Attachments:
Humerus (lateral epicondyle)
Ulna (supinator crest and supinator fossa)
Radius (proximal 1/3 of anterior, lateral and posterior surface)
Actions:
Supinate forearm
Nerve Supply:
Radial nerve (deep branch)

Biceps Brachii:

Attachments:
Scapula:
Long Head: supraglenoid tubercle and labrum
Short Head: coracoid process
Radius (radial tuberosity and deep forearm fascia)
Actions:
Weak flexor of shoulder
Short head resists shoulder dislocation
Supinates forearm
Flexes forearm
Nerve Supply:
Musculocutaneous Nerve

Brachioradialis:

Attachments:
Humerus (proximal 2/3 of supracondylar ridge)
Radius (distal, lateral to styloid process)
Actions:
Flexes forearm (especially in mid-pronation)
Pronation (return to mid-pronation)
Supination (return to mid-pronation)
Nerve Supply:
Radial Nerve
Pronation

Pronator quadratus – (smaller) recruited first
Pronator teres - when pronating against resistance
Brachioradialis – when in supinated position

Pronator Quadratus:

Attachments:
Ulna (distal ¼ of anterior surface)
Radius (distal ¼ of anterior surface)
Actions:
Pronate forearm
Nerve Supply:
Median Nerve

Pronator Teres:

Attachments:
Ulna (coronoid process)
Humerus (medial epicondyle)
Radius (lateral surface of radial shaft)
Actions:
Pronate forearm
Flexes forearm (weakly)
Nerve Supply:
Median Nerve

Muscles of the Forearm:

Arranged into 2 compartments – anterior and posterior
Anterior: wrist flexors, forearm pronators, pronantor teres, FCR, palmaris longus, FCU, FDS, FDP, FPL, pronator quadratus
Supplied by median or ulnar nerve
Posterior: wrist extensors, forearm supinators, brachioradialis, ECRL, ECRB, ED, EDM, ECU, supinator, APL, EPB, EPL, EI
Supplied by radial nerve (deep branches)

Anterior Compartment:

4 layers
Superficial to deep, 4:1:2:1 muscle arrangement
1^st and 2^nd layer muscles have attachment to medial epicondyle (common flexor origin)
ALL supplied by MEDIAN NERVE
EXCEPT flexor carpi ulnaris and medial ½ of flexor digitorum profundus (ulnar)

Anterior Layer 1:

Pronator Teres:

Attachments:
Ulna (coronoid process)
Humerus (medial epicondyle)
Radius (lateral surface of radial shaft)
Actions:
Pronate forearm
Flexes forearm (weakly)
Nerve Supply:
Median Nerve

Palmaris longus (NOT ALWAYS PRESENT):

Attachments:
Humerus (medial epicondyle)
Flexor retinaculum (distal ½)
Palmar aponeurosis (apex)
Actions:
Flex wrist
Tenses palmar aponeurosis
Nerve Supply:
Median Nerve

Flexor Carpi Radialis (FCR):

Attachments:
Humerus (medial epicondyle)
Metacarpals (base of 2^nd)
Actions:
Flexes wrist
Abducts hand
Nerve Supply:
Median Nerve

Flexor Carpi Ulnaris (FCU):

Attachments:
Humerus (medial epicondyle)
Ulnar (olecranon and posterior border of ulna)
Pisiform
Hook of hamate
5^th metacarpal
Actions:
Flexes wrist
Adducts hand
Nerve Supply:
ULNAR Nerve

Anterior Layer 2:

Flexor Digitorum Superficialis (FDS):

Attachments:
Radius (superior ½ of anterior border)
Humerus (medial epicondyle)
Ulna (coronoid process)
Hand (shaft of middle phalanx of digits 2-5)
Actions:
Flexes PIP joints of digits 2-5
Nerve Supply:
Median Nerve

Anterior Layer 3:

Flexor Digitorum Profundus (FDP):

Attachments:
Ulna (proximal ¾ of medial and anterior surfaces)
Interosseous membrane
Base of distal phalanges digits 2-5
Actions:
Flexes DIP joints of digits 2-5
Nerve Supply:
Medial ½ = ULNAR nerve
Lateral ½ = median nerve

Flexor Pollicis Longus (FPL):

Attachments:
Radius (anterior surface)
Interosseous membrane
Base of distal phalanx of 1^st digit (thumb)
Actions:
Flexes PIP and DIP joint of 1^st digit
Nerve Supply:
Median Nerve (anterior interosseous nerve)

Anterior Layer 4:

Pronator Quadratus:

Attachments:
Ulna (distal ¼ of anterior surface)
Radius (distal ¼ of anterior surface)
Actions:
Pronate forearm
Nerve Supply:
Median Nerve

Posterior Compartment:

Superficial (6 muscles) and deep (5 muscles)
ECRB, ED, EDM, ECU and supinator: attach to lateral epicondyle (common extensor origin)
ALL muscles supplied by radial nerve (deep branches)

Posterior Superficial:

Brachioradialis:

Attachments:
Humerus (proximal 2/3 of supracondylar ridge)
Radius (lateral surface of distal end, proximal to styloid process)
Actions:
Weak flexion of forearm (especially in mid-pronation)
DOES NOT CROSS WRIST JOINT
Nerve Supply:
Radial Nerve

Extensor Carpi Radialis Longus:

Attachments:
Humerus (lateral supracondylar ridge
2^nd metacarpal (base of dorsal aspect)
Radius (lateral surface of radial shaft)
Actions:
Extend wrist
Abduct wrist
Nerve Supply:
Radial Nerve

Extensor Carpi Radialis Brevis:

Attachments:
Humerus (lateral epicondyle)
3rd metacarpal (base of dorsal aspect)
Actions:
Extend wrist
Abduct wrist
Nerve Supply:
Radial Nerve

Extensor Digitorum:

Attachments:
Humerus (lateral epicondyle)
Extensor expansion (of digits 2-5)
Actions:
Extend digits 2-5 at MCP and IP joints
Nerve Supply:
Radial Nerve

Extensor Digiti Minimi:

Attachments:
Humerus (lateral epicondyle)
Extensor expansion of digit 5 (pinky)
Actions:
Extend digit 5 at MCP and IP joints
Nerve Supply:
Radial Nerve

Extensor Carpi Ulnaris:

Attachments:
Humerus (lateral epicondyle)
Ulna (posterior border)
5^th metacarpal (base of dorsal aspect)
Actions:
Extend wrist
Abduct wrist
Nerve Supply:
Radial Nerve

Posterior Deep:

Supinator:

Attachments:
Humerus (lateral epicondyle)
Ulna (supinator crest and supinator fossa)
Radius (proximal 1/3 of anterior, lateral and posterior surface)
Actions:
Supinate forearm
Nerve Supply:
Radial nerve (deep branch)

Abductor Pollicis Longus:

Attachments:
Ulna (posterior surface, proximal ½)
Radius (posterior surface, proximal ½)
Interosseous membrane
1^st metacarpal (base of dorsal aspect)
Actions:
Abducts 1^st digit
Extends CMC joint of 1^st digit
Nerve Supply:
Radial nerve (posterior interosseous branch)

Extensor Pollicis Brevis:

Attachments:
Radius (posterior surface of distal 1/3)
Interosseous membrane
Proximal phalanx of 1^st digit (base of dorsal aspect)
Actions:
Extends CMC and MCP joints of 1^st digit
Nerve Supply:
Radial nerve (posterior interosseous branch)

Extensor Pollicis Longus:

Attachments:
Ulna (posterior surface of middle 1/3)
Interosseous membrane
Proximal phalanx of 1^st digit (base of dorsal aspect)
Actions:
Extends 1^st digit at MCP and IP joints
Nerve Supply:
Radial nerve (posterior interosseous branch)

Extensor Indicis:

Attachments:
Ulna (posterior surface of distal 1/3)
Interosseous membrane
Extensor expansion (of digit 2)
Actions:
Extends digit 2
Nerve Supply:
Radial nerve (posterior interosseous branch)

Lo8 To know the blood vessels and nerves of the forearm

Median nerve travels between anterior layers 3 and 4

Ulnar artery:

Origin:
Branches from the brachial artery
Course:
Passes between the flexor digitorum superficialis and flexor carpi ulnaris
Travels with the ulnar nerve and veins

Ulnar Nerve:

Origin:
Medial cord of the brachial plexus
Course:
Travels posterior to the medial epicondyle
Travels on the medial side of the forearm deep to the flexor carpi ulnaris
Travels with ulnar artery and veins
Supplies:
Flexor carpi ulnaris and the medial ½ of the flexor digitorum profundus

Radial Artery:

Origin:
Branches from the brachial artery
Course:
Travels deep to brachioradialis with the superficial branch of the radial nerve and radial veins
Sits between the tendons of brachioradialis and flexor carpi radialis in wrist

Radial Nerve:

Origin:
Posterior cord of the brachial plexus
Course:
Sits between brachialis and brachioradialis
In front of the lateral epicondyle it divides into superficial and deep branches
Superficial:
Travels on anterolateral forearm
Travels deep to the brachioradialis with radial artery and veins
Deep:
Pierces supinator
Changes name to posterior interosseous nerve
Travels along posterior surface of interosseous membrane
Supplies:
Superficial: skin over the anterior of the arm and forearm and dorsum of hand
Deep: extension of the wrist and fingers

Median Nerve:

Origin:
Medial and lateral cord of the brachial plexus
Course:
Lies between biceps brachii the and the brachial artery
Passes between heads of pronator teres
Travels between flexor digitorum profundus and flexor digitorum superficialis
Supplies:
The anterior and intrinsic muscles of forearm EXCEPT flexor carpi ulnaris and medial ½ of flexor digitorum profundus
Skin over palmar surface of lateral 3 ½ digits, including fingertips

Wrist and Hand

Lo1 To identify anatomical features of the bones of the wrist and hand

Distal Radius:

Dorsal tubercle on posterior. Extensor pollicis longus tendon runs around
Ulnar notch
Styloid process on lateral side
Distal view has facet for scaphoid and lunate bone (Lateral to medial)
Interosseous border = sharp
Posterior border = pointed
Anterior border= smooth/round

Distal Ulna:

Head
Styloid process (attachment of articular disc)
Posterior border = sharp (follow olecranon down)

Carpal Bones:

8 bones – 4 in distal row, 4 in proximal row
Proximal – (L to M) Lunate and Scaphoid (articulate with radius), triquetrum and pisiform
Distal – (L to M) Trapezium (thumb), trapezoid, capitate, hook of hamate

Skeleton of Hand:

8 carpal bones in wrist
5 metacarpals
5 proximal phalanges
4 middle phalanges
5 distal phalanges
All have base, body, head (proximal to distal)

Lo2 To identify key features of the wrist and hand on a living person (surface anatomy)

Dorsal tubercle
Styloid process (radius and ulna)
Pisiform
Hook of hamate
Palmaris longus
Flexor carpi ulnaris
Flexor carpi radialis
Radial artery
Thenar eminence
Hypothenar eminence
Anatomical snuffbox
Cephalic vein (lateral side)
Dorsal venous network (wrist posterior)
Extensor digitorum tendons

Lo3 To understand the structure and function of the radiocarpal joint and the joints of the hand

Wrist Joint (Radiocarpal Joint):

Articular surfaces
Distal radius and the lunate and scaphoid
Articular disc and the radius and ulna
Ulna is NOT part of joint
Type
Synovial Condyloid
Movements
Flexion/Extension
Abduction/Adduction
**Circumduction

Ligaments:

Ulnar collateral carpal ligament: Stabilise ulna side of joint
Radial collateral carpal ligament: Stabilise radial side of joint
Dorsal radiocarpal ligament
Palmar radiocarpal ligament
Palmar ulnocarpal ligament
Intercarpal ligaments

Midcarpal and Intercarpal Joints:

Synovial plane
Stabilised by intercarpal ligaments
Supplement movement at the wrist joint and increase overall ROM
Intercarpal: between each carpal bone
Midcarpal: between the proximal and distal row of carpal bones

Interphalangeal Joints (PIP and DIP):

Synovial hinge
Flexion/extension

Metacarpophalangeal Joint (MCP):

Synovial Condyloid
Flexion/extension
Adduction/abduction

Carpometacarpal Joints (CMC):

Synovial plane
EXCEPT 1^st CMC is saddle synovial
Flexion/extension
Adduction/abduction
Axial rotation (Opposition)

Intermetacarpal Joints:

Synovial Plane

Ligaments:

Collateral Ligaments:
On sides of metacarpophalangeal and interphalangeal joints
Stabilise side of joints
Palmar Ligaments/Plates:
Fibrocartilage plate
Firmly attached to proximal phalanx
Loosely attached to metacarpal
Protect joint surfaces
Help prevent the tendons in the forearm flexors getting impinged in the joint (during flexion)
Deep Transverse Metacarpal Ligaments:
Bind the heads of metacarpals 2-5
Attach to palmar plates
Limit abduction of digits 2-5

Lo4 To correlate the structure of the radiocarpal joint and the joints of the hand to their functional movements and stability

Medial:
Flexor carpi ulnaris
Extensor carpi ulnaris
**Adduct wrist
Lateral:
Flexor carpi radialis
Extensor carpi radialis longus
Extensor carpi radialis brevis
**Abduct wrist

Movement Axis:

Midline through capitate, lunate and radius
Slightly more flexion than extension (small difference)
7° abduction vs 30° adduction – styloid process of radius inhibits abduction, more proximal and smaller styloid process at ulna

Lo5 To describe the attachment points of the long flexor and extensor tendons in the hand

Synovial Sheaths:

Wrap around tendons to stop friction

Extensor Retinaculum:

Band of fibrous tissue
Holds tendons against bone
~1 per extensor tendon

Flexor Retinaculum:

Forms roof of carpal tunnel
1 synovial sheath for all flexor tendons
1 separate sheath for flexor pollicis longus
Attach to hook of hamate, pisiform, scaphoid tubercle, trapezium tubercle

Flexor Sheath (Fibrous Digital Sheath):

Form tunnel for long flexor tendons to pass through
Hold tendons close to phalanges to prevent ‘bowstrings’
A synovial sheath encloses the tendons to prevent friction
Sheaths have 2 fibre patterns; transverse (straight across), cruciate (cross)

Extensor Tendons:

Surrounded by synovial sheaths
Pass deep to extensor retinaculum
Can attach to:
Carpals
Metacarpals
Proximal phalanges
Distal phalanges
Extensor expansion

Extensor Expansion (Dorsal Digital Hood):

Flattened triangular expansion of extensor digitorum tendons
Passes around the sides of the MCP joint and assists in stabilising the joints
Important attachment point for some intrinsic muscles of hand:
Lumbricals
Interossei

Lo6 To describe the anatomical snuffbox and carpal tunnel including structure, contents and clinical relevance

Carpal Tunnel:

Pass deep to flexor retinaculum
Except palmaris longus (attaches to retinaculum and palmar aponeurosis) or flexor carpi ulnaris, flexor carpi radialis
Most pass-through carpal tunnel:
4 tendons of flexor digitorum superficialis
4 tendons of flexor digitorum profundus
Tendon of flexor pollicis longus
Median nerve
Formed by: distal row of carpal bones, flexor retinaculum

Anatomical Snuffbox:

Triangular depression on the posterolateral wrist formed by the extensor tendons passing into the thumb
*Identifiable when thumb in hitch-hiking position
Borders:
Lateral: Extensor pollicis brevis and abductor pollicis longus
Medial: Extensor pollicis longus
Floor: Scaphoid and Trapezium
Contents: Radial artery (pulse can be felt)
Passing subcutaneously:
Superficial branch of radial nerve
Origin of cephalic vein

Lo7 To describe the fascia of the hand and associated pathologies

Palmar Aponeurosis (Fascia):

Triangular shape
Apex located proximally
Base located distally
Fibres run in two directions; longitudinal (follow finger) and transverse (between longitudinal)
Connected to skin
Blends with digital sheaths of the flexor tendons
Palmaris longus attaches

Dupuytren’s Contracture:

Often bilateral
Tends to occur in men >50 years
Usually affects 4^th and 5^th digits
Progressive changes in palmar aponeurosis:
Shortening (pull digits toward palm)
Thickening
Fibrosis
Treatment involves surgical excision of all fibrotic parts of the palmar aponeurosis

Lo8 To describe traumas and pathologies associated with the wrist and hand

L11 To identify normal anatomical features and injuries on radiographs of the wrist and hand

Scaphoid Fracture:

Most frequently fractured carpal bone
Caused by fall on outstretched hand
Most common fracture site is ‘waist’ (narrowest)
Pain and tenderness located:
Anatomical snuffbox
Palpating floor of snuffbox will cause pain
Initial X-ray may not reveal fracture.
Cut off blood supply to proximal end, leading to necrosis and bone shrinkage

Lo9 To know the muscles of the hand (nerve supply and functions)

Perform intricate and precise movements of the hand
Arranged into 5 compartments
Thenar: Move 1^st digit, Median nerve
Central: Move 2-5^th digits. Median or Ulnar nerve
Hypothenar: Move 5^th digit. Ulnar nerve
Adductor: Move 1^st digit, Ulnar nerve
Interosseous: Move 1-5^th digits, Ulnar nerve

**Don’t need to know attachments

Thenar Muscles:

Abductor Pollicis Brevis:

Attachments:
Flexor retinaculum
Scaphoid
Trapezium
Base of proximal phalanx of thumb (lateral side)
Action:
Abduct thumb
Assists with opposition
Nerve Supply:
Median Nerve

Flexor Pollicis Brevis:

Attachments:
Flexor retinaculum
Scaphoid
Trapezium
Base of proximal phalanx of thumb (lateral side)
Action:
Flexes thumb
Nerve Supply:
Median Nerve

Opponens Pollicis (deep):

Attachments:
Flexor retinaculum
Scaphoid
Trapezium
1^st metacarpal (lateral side)
Action:
Opposes thumb (medially rotate and draws 1^st metacarpal to centre of palm)
Nerve Supply:
Median Nerve

Central Muscles:

Lumbricals 1 and 2:

Attachments:
Lateral 2 tendons of FDP (unipennate)
Extensor expansion of digits 2-5 (lateral side)
Action:
Flexes MCP joints digits 2-5
Extend IP joints digits 2-5
Nerve Supply:
Median Nerve

Lumbricals 3 and 4:

Attachments:
Medial 3 tendons of FDP (bipennate)
Extensor expansion of digits 2-5 (lateral side)
Action:
Flexes MCP joints digits 2-5
Extends IP joints of digits 2-5
Nerve Supply:
Ulnar Nerve

Hypothenar Muscles:

*may see palmaris brevis covering hypothenar muscles (supplied by Ulnar)

Abductor Digiti Minimi:

Attachments:
Pisiform
Base of proximal phalanx of digit 5 (medial side)
Action:
Abduct digit 5
Assists with flexion
Nerve Supply:
Ulnar Nerve

Flexor Digit Minimi Brevis:

Attachments:
Flexor retinaculum
Hook of hamate
Base of proximal phalanx of digit 5 (medial side)
Action:
Flexes proximal phalanx of digit 5 (medial side)
Nerve Supply:
Ulnar Nerve

Opponens Digiti Minimi (Deep):

Attachments:
Flexor retinaculum
Hook of hamate
5^th metacarpal (medial side)
Action:
Draw 5^th metacarpal anteriorly and rotate towards centre of palm
Nerve Supply:
Ulnar Nerve

Adductor Pollicis:

Attachments:
Transverse head: shaft of 3^rd metacarpal (anteriorly)
Oblique head: base of 2^nd and 3^rd metacarpals, capitate and adjacent carpals
Base of proximal phalanx of thumb (medial side)
Action:
Adduct thumb
Nerve Supply:
Ulnar Nerve

Interossei Muscles (deep and between bones):

Dorsal Interossei (4):

Attachments:
Adjacent sides of 2 metacarpals (bipennate)
Bases of proximal phalanges
Extensor expansion of digits 2-4
Action:
Abduct digits 2-4
Assist with flexion of MCP joints
Assist with extension of IP joints
Nerve Supply:
Ulnar Nerve

**DAB – Dorsal abduct

Palmar Interossei (3):

Attachments:
Palmar surface of 2^nd, 4^th and 5^th metacarpals (unipennate)
Bases of proximal phalanges
Extensor expansion of digits 2, 4, 5
Action:
Adduct digits 2, 4, 5
Assist with flexion of MCP joints
Assist with extension of IP joints
Nerve Supply:
Ulnar Nerve

**PAD – Palmar adduct

L10 To describe the purpose of different hand grips including types of power and precision grips

Prehension (Grip):

The way in which hand grips an object depends on shape, size, weight and use
Generally, 2 types:
Power:
Thumb, finger and palm involved
Used when considerable force required
Precision:
Thumb and fingers involved
Object usually small and fragile

Power Grip:

Long flexors and extensors fix the position of wrist
Long finger flexors and intrinsic muscles grip the object
Oblique Palmar: most powerful, hand and fingers wrap around object whose long axis lies across palm
Ball: ball shaped and enclosed by palm
Span: palm may not make contact increasing power needed in fingers and thumb
Cylinder: object held transversely across palm, digits and thumb
Hook: secure but only 1 direction, thumb not involved in true hook

Precision Grip:

Object held between pads of digits
Action involves rotation at CMC and MCP joint of thumb
Also involve rotation at MCP joints of digits
Pincer: tips of pads or nails used, finest and most precise
Tripod: palmar surface of thumb, digit 2 and possible other digits (hold pen)
Pinch: pads of thumb and digit 2 oppose, tested by pulling sheet of paper out of grip
Key: pad of thumb presses against side of digit 2, less fine but strong

L12 To know the blood vessels and nerves of the wrist and hand, and understand the effects of nerve lesions on the function of the wrist and hand

Superficial and Deep Palmar Arches:

Formed by anastomosis of the radial and ulnar arteries
Superficial is easy to view, lies mid-palm and more distal
Deep is close to bone

Median Nerve:

Course:
Passes through carpal tunnel
Gives off branches to the thenar group of muscles and the lateral 2 lumbricals
Lesion Affects:
Sensation over dorsal surface of the lateral 3 ½ digits and tips of fingers
Ability to form a fist or grip an object

Carpal Tunnel Syndrome:

Causes increase in the size of the structures passing through tunnel.
Including fluid retention, infection, swelling of tendons or synovial sheaths
Compress the median nerve
May result in
Paraesthesia
Hypoesthesia
Anaesthesia
Progressive loss of coordination and strength of thumb
Atrophy of thenar eminence

Hand of Benediction:

Caused by lesion of median nerve
Symptoms:
When the person tries to form a fist, the ‘hand of benediction’ is formed instead
Flexion of the PIPs of digits 1-3 is lost and weakened in digits 4-5
Flexion of the DIPs of 2-3 is also lost
Thenar muscle function is also lost
Sensation over the lateral palm and palmar surface and finger tips of the lateral 3 ½ digits is also affected

Ulnar Nerve:

Course:
Travels with ulnar artery and veins
DOES NOT go through carpal tunnel
Enters palm on medial side
Gives off branches to the hypothenar group of muscles and the medial 2 lumbricals (3 and 4)
Also supplies palmar and dorsal interossei
Lesion Affects:
Sensation over medial 1 ½ digits
Ability to form a fist or grip an item
Ability to flex and extend digits

Claw Hand:

Caused by lesion of ulnar nerve
Symptoms:
At elbow:
Wrist adduction impaired
Flexion at wrist causes hand to move laterally
At wrist:
When person attempts to form fist, ‘claw’ hand is formed
Hyperextended 4^th and 5^th MCP joints
Unable to flex the DIP of the 4^th and 5^th digits
Ability to form fist or grip an item
Loss of sensation over medial 1 ½ digits
**Also adductor pollicis

Radial Nerve:

Course:
Superficial:
Sensory
Travels deep to the brachioradialis muscle with radial artery and veins
Sits in region known as anatomical snuffbox on dorsum of hand
Deep:
Muscular and articular
Ends at wrist after supplying all extensor muscles of forearm
Lesion Affects:
Sensation over the lateral side of dorsum aspect of hand
Sensation over the anatomical snuffbox

Wrist Drop:

Caused by mid-shaft humeral fracture, supracondylar fracture, penetrating wound to posterior forearm
Symptoms:
Unable to extend wrist
Unable to extend 1^st digit and MCP joints of digits 2-5
**AT wrist, only superficial branch impacted. ONLY sensation lost