ANATOMY-3-Axilla-and-Arm-Forearm-and-Hand.pdf

Anatomy of Axilla and Arm, Forearm and Hand

Resources from Snell's Clinical Anatomy by Region 11th Edition

1. DON QUIXOTE
AXILLA AND ARM

Apex - the cervical axillary canal,
- passageway between
Anterior axillary fold - border of pectoralis major
Inferior axillary gold

POSTERIOR WALL - formed by scapula and subscapularis

MEDIAL WALL - formed by thoracic wall ribs 1-4, intercostal
muscles and intercostal anterior
LATERAL WALL - intertubercular nerve of

BRACHIAL PLEXUSES
Axillary artery - begins at the lateral border of the 1st rib
Passes posteriorly to the
Axillary artery is a branch of subclavian artery - divided by
pectoralis minor

1
ST
PART - between lateral border of first rib and medial
border of pectoralis minor
Branch - STA superior thoracic artery
2
ND
PART - has 2 parts: lateral thoracic artery and
thoracoacromial artery
3
RD
PART - lateral border of pectoralis minor and anterior of
teres minor
- has 3 branches: anterior and posterior circumflex
artery and subscapular artery

AXILLLARY VEIN – formed by union of brachial vein and
basilic vein
Has 3 parts: corresponding to the parts of axillary artery

LYMPH VESSELS
- arranged in 5 parts
- related to triangular place
1) Pectoral nodes/ anterior nodes - receive vessels from
lateral quadrants of the breast
2) Subscapular nodes/posterior group - lies in front of
subscapularis muscle
3) Humeral group/ humeral lymph node - medial aspect of
axillary vein, receives most of upper lymph
4) Central nodes - lies in center of axilla between the
axillary fat, receives the from the three which is pectoral,
5) Apical nodes - lies in apex of axilla, receive from other
axillary nodes; don’t belong to the group
6) Infraclavicular node/deltopectoral node - located
outside the axilla, not really part of axillary node, lie in the
groove between the deltoid, receive vessels


BRACHIAL PLEXUS
- major nerve network beginning from the neck, to the axilla
and upper lymph
- formed by the union rami of the 5th, 6th, 7th, 8th cervical
spinal nerve and 1 thoracic spinal nerve
- passes between the anterior scalene and the middle
scalene together with subclavian artery

Naay relation sa second aprt sa axillarya rtery

TEerminal branches
Below the clavicle - infraclavicular branches

SUPRASCAPULAR NERVES
1) Dorsal scapular nerve - innervates rhomboids
2) Long thoracic nerve - innervates the serratus anterior,
acronmy SA(serratus anterior) .LT (long thoracic)
3) Suprascapular nerve - courses laterally, superior to the
brachial plexus, innervates the supraspinatus and
infraspinatus
4) Subclavian nerve - superior trunk receiving fibers from c5
to C6, posterior to the clavicle, innervates the subclavius



INFRACLAVICULAR BRANCHES
1) Lateral pectoral nerve - innervates the pectoralis major,
some of it passes the pectoralis minor
2) Upper and lower subscapular nerves - fibers from C7,
passes posteriorly and innervates subscapular nerve
Lower subscapular nerve innervates inferior portion of
subscapularis and tere
3) Medial pectoral nerve - receiving from C8 to T1,
innervates pectoralis minor mainly, some
4) Medial cutaneous nerve of arm - smallest nerve of
brachial plexus, innervating the skin of the medial side of the
arm, from the medial epicondyle to the olecranon,
5) Medial cutaneous nerve of the forearm
6) Thoracodorsal nerve - innervates the latissimus dorsi
7) Musculocutaneous nerve - receive fibers from C5-C7,
innervates anterior compartment and lateral compartment of
arm

Axillary nerve - innervates glenohumeral joint, deltoid
muscles, teres minor
Radial nerve - largest terminal branch of the posterior cord
receiving fibers from C5 to T1, posterior compartment of both
arm and forearm, dorsum of the hand
Median nerve - Branch of lateral and medial cord, from C5
to T1, innervates the anterior forearm compartment except
for FCU and ulnar half of flexor digitorum profundus (FDP)
Ulnar nerve - receiving fibers from medial cord from the C1
and T1, innervates flexor carpi ulnaris and ulnar half of
FDP

CLINICAL CORRELATIONS

Upper brachial plexus injuries
- excessive angle of neck and
shoulder apart
- Due to motor cycle injury and
handling during birth

2. DON QUIXOTE
ERB DUCHENNE PALSY - waiter tip
deformity, policeman tip, porter's tip
→ Arm: Adducted, medially rotated
→ Elbow: exended
→ Forearm: pronated
→ Wrist: flexed

BACKPACKER'S PALSY
- chronic microtrauma to superior trunk of the brachial plexus
- musculocutaneous nerve, radial nerve

Lower brachial plexus injuries
- Upper limb is pulled superiorly, baby is pulled during
delivery

KLUMPKE'S PALSY
- finger does not adduct or abduct, claw hand
- Elbow: Extended
- Forearm: Supinated
- Wrist: Extended
- Fingers - Flexed

ARM
Biceps brachii
O: Short Head: Tip of coracoid process of scapula
Long Head: Supraglenoid tubercle of Scapula
I: Radial tuberosity
N: musculocutaneous nerve
A: supinates and flexes forearm

Coracobrachialis
O: Tip of coracoid process of scapula
I: Middle third of medial surface of humerus
N: musculocutaneous nerve
A: helps in adduction resist dislocation

Brachialis
O: distal half of anterior surface of the humerus
I: Coronoid process and tuberosity of ulna
N: musculocutaneous nerve
A: flexes forearm in all positions

Triceps Brachii - known as chief extensor of the forearm
O: Long head : infraglenoid tubercle of scapula
Medial and Lateral head: Posterior surface of humerus
I: olecranon process of ulna
N: radial nerve
A:


Anconeus
O: lateral epicondyle of humerus
I: olecranon and posterior surface of ulna
N: Radial nerve
A- Assist the triceps

BRACHIAL ARTERY
- begins in inferior border of teres major and ends with
cubital fossa on the opposite of the neck of the radius
- starts at teres major and goes down to cubital fodssa

Different branches of brachial artery
- Nutrient artery
- Profunda artery
- Superior ulnar collateral artery
- Inferior ulnar collateral artery
Anastamosis - around the elbow joint


VEINS OF UPPER LIMB
NERVES OF UPPER LIMB
Musculocutaneous nerve - anterior part of the arm,
supplies the lateral aspect of the forearm
Median nerve - thenar hand muscles and nail beds, skin of
the lateral side of the palm, first three and half of index
Ulnar nerve - known as the funny bone,
Radial nerve - innervats the skin of radial side of the hand,
and the two digits of proximal phalanx

CARPAL TUNNEL SYNDROME
– median nerve is compressed and squeezed at the wrist
area
HAND OF BENEDICTION
– unable to make a fist, radial nerve damage, preachers
hand
WRIST DROP
- decreased in grip strength, murag R so radial nerve
CLAW HAND - injured the ulnar nerve, permanent flexion
ILL - FITTING AXILLARY CRUTCHES
- radial nerve palsy

CUBITAL FOSSA - triangular depression in the arm and
helps identify the brachial artery
Medial: Pronator Teres
Lateral: Brachiodradialis
Contents: Median nerve, Brachial artery, Tendon of biceps
brachii, radial nerve

SATURDAY NIGHT PALSY - injured radial nerve, prolonged
and direct pressure, deep sleep in the arm after axillary
decompression
HONEYMOON PALSY - injured radial nerve compression
overnight sleeping of lying on the arm of the patient

3. DON QUIXOTE
FOREARM AND HAND

FOREARM
- Distal unit of the articulated strut of the upper limb
- Extends from the elbow to the wrist
- 2 Bones: Radius and Ulna joined by an interosseus
membrane
RADIUS
- Lateral and shorter of the 2 forearm bones
- Proximal end includes a short head, neck and medially
directed tuberosity
ULNA
- longer bone than the radius
- stabilizing bone of the forearm,
- medial and longer of the two forearm bones
- more massive proximal end is specialized for articulation
with the humerus proximally & head of the radius laterally
- does not participate in wrist (radiocarpal) joint

FOREARM MUSCLES
Anterior Compartment
Muscles: Flexors and Pronators
Attachment: Medial epicondyle and Supra-epicondylar ridge
Innervation: Median Nerve (one and a half exceptions –
Ulnar Nerve)

Posterior Compartment
Muscles: Extensors and Supinators
Attachment: Lateral epicondyle
Innervation: Radial Nerve (directly or by its deep branch)

Flexor- Pronator Muscles
Superficial
- Pronator teres
- Flexor carpi radialis
- Palmaris longus
- Flexor carpi ulnaris
Intermediate
- Flexor digitorum superficialis
Deep
- Flexor digitorum pfundus
- Flexor pollicis longus
- Pronator quadratus

PRONATOR TERES
- Most lateral of the superficial forearm flexors
O: Ulnar head-coronoid process of humeral head
I: Lateral surface of radius
N: Median nerve
A: Pronates & flexes forearm at elbow

FLEXOR CARPI RADIALIS
- long fusiform muscle located medial to the pronator teres
- Acts with flexor carpi ulnaris → Flexion
- Acts with extensor carpi radialis longus and brevis →
Abduction of the wrist
- Acts alone → moves hand anterolaterally
- Radial artery lies just lateral to it
O: Medial epicondyle of humerus
I: Base of 2
nd
metacarpal
N: Median nerve
A: Flexes & abducts hand at wrist


PALMARIS LONGUS
- Absent on one or both sides (usually left) in approx. 14% of
people
- Short belly and long cord-like tendon that passes superficial
to the flexor retinaculum and attaches to the apex of the
palmar aponeurosis
O:
I:
N:
A:

FLEXOR CARPI ULNARIS
- Most medial of the superficial flexor muscles
- Exception among muscles of the anterior compartment,
being fully innervated by the ulnar nerve
- Ulnar nerve and artery → lateral side of the FCU tendon
O: Humeral head: Medial epicondyle of humerus
Ulnar head: Olecranon & posterior border of ulna
I: Pisiform, hook of hamate, 5
th
metacarpal
N: Ulnar nerve
A: Flexes & adducts hand at work

FLEXOR DIGITORUM SUPERFICIALIS
- Forms an intermediate layer between the superficial and
the deep group of forearm muscles
- The median nerve and the ulnar artery enter the forearm
by passing between its humero-ulnar and radial heads
- Gives rise to 4 tendons which pass deep to the flexor
retinaculum through the carpal tunnel to the fingers
- Flexes the middle phalanges of the medial 4 fingers at the
proximal interphalangeal joints
O: Humero-ulnar head: Medial epicondyle
Radial head: Superior half of the anterior border
I: Shafts of middle phalanges of medial 4 digits
N: Median nerve
A: Flexes middle phalanges at PIP of middle 4 digits; Flexes
proximal phalanges of metacarpophalangeal joints

FLEXOR DIGITORUM PROFUNDUS
- The only muscle that can flex the distal interphalangeal
joints (DIP) of the medial 4 digits
- Thick muscle that covers the anterior aspect of the ulna
O: Proximal three quarters of medial & anterior surfaces of
ulna & interosseus membrane
I: Medial: Bases of distal phalanges of 4
th
& 5
th
digits
Lateral: Bases of distal phalanges of 2
nd
& 3
rd
digits
N: Ulnar nerve
A: Flexes DIP of middle 4 digits

4. DON QUIXOTE
FLEXOR POLLICIS LONGUS
- long flexor of the thumb
- lies lateral to the FDP, where it covers the anterior aspect of
the radius
- The flat FPL tendon passes deep to the flexor retinaculum,
enveloped in its own synovial tendinous sheath
O: Anterior surface of the radius & adjacent interosseus
membrane
I: Base of distal phalanx of thumb
N: Anterior interosseus nerve from median nerve
A: Flexes phalanges of 1
st
digit

PRONATOR QUADRATUS
- Quadrangular muscle
- Deepest muscle in tha tnerior aspect of the forearm
- the only muscle that attaches to the ulna at one end and
only to the radius at the other end
- PRIME MOVER FOR PRONATION
O: Distal quarter of anterior surface of ulna
I: Distal quarter of anterior surface of radius
N: Anterior interosseus nerve from median nerve
A: Pronates forearm

EXTENSOR MUSCLES
BRACHIORADIALIS
- Fusiform muscle that lies superficially on the anterolateral
surface of the forearm
- Forms the lateral border of the cubital fossa
- Weak flexion of forearm
O: Proximal 2/3 of supra-epicondylar ridge of humerus
I: Lateral surface of distal end of radius proximal to styloid
process
N: Radial nerve
A: Weak flexion of forearm

EXTENSOR CARPI RADIALIS LONGUS
- partly overlapped by the brachioradialis with which it often
blends
- Indispensible when clenching the fist
O: Lateral supra-epicondylar ridge of humerus
I: Dorsal aspect of base of 2
nd
metacarpal
N: Radial nerve
A: Extend & abduct hand at the wrist joint

EXTENSOR CARPI RADIALIS BREVIS
- ECRB is a shorter muscle than ECRL
- ECRB and ECRL pass under the extensor retinaculum
together within the tendinous sheath of the ECR
O: Lateral epicondyle of humerus
I: Dorsal aspect of base of 3
rd
metacarpal
N: Deep branch of radial nerve
A: Extend and abduct hand at the wrist joint

EXTENSOR DIGITORUM
- Principal extensor of the medial 4 digits
- Occupies much of the posterior surface of the forearm
- Proximally, its 4 tendons join the tendon of the extensor
indicis to pass deep to the extensor retinaculum through the
tendinous sheath of the ED an EI (common extensor
synovial sheath)
O: Lateral epicondyle of humerus
I: Extensor expansions of medial 4 digits
N: Deep branch of radial nerve
A: Extends medial 4 digits primarily at metacarpophalangeal
joints, secondarily at interphalangeal joints

EXTENSOR DIGITI MINIMI
- Partially detached part of the extensor digitorum
- The tendon of this extensor of the little finger runs through
a separate compartment of the extensor retinaculum,
posterior to the distal radio-ulnar joint within the tendinous
sheath of the EDM
O: Lateral epicondyle of humerus
I: Extensor expansion of 5
th
digit
N: Deep branch of radial nerve
A: Extends 5
th
digit

EXTENSOR CARPI ULNARIS
- Long fusiform muscle located on the medial border of the
forearm
- Distally, its tendon runs in a groove between the ulnar head
and its styloid process, through a separate compartment of
the extensor retinaculum within the tendinous sheath of the
ECU
O: Lateral epicondyle of humerus; Posterior border of ulna
via a shared aponeurosis
I: Dorsal aspect of base of 5
th
metacarpal
N: Deep branch of radial nerve
A: Extends & adducts hand at wrist joint

SUPINATOR
- Lies deep in the cubital fossa and form its floor (with
brachialis)
- envelops the neck and proximal aprts of the shaft of the
radius
- Prime mover for slow, unopposed supination, esp. When
the forearm is extended
O: Lateral epicondyle of humerus; radial collateral & anular
ligaments; supinator fossa; crest of ulna
I: Lateral, posterior & anterior surfaces of proximal 3
rd
of
radius
N: Deep branch of radial nerve
A: Supinates forearm

ABDUCTOR POLLICIS LONGUS
- The APL has a long, fusiform belly that lies just distal to the
supinator and is closely related to the extensor pollicis brevis
- Its tendon passes deep to the extensor retinaculum within
the tendon of the extensor pollicis brevis in the common
synovial tendinous sheath of the abductor pollicis longus and
extensor pollicis brevis
O: Posterior surface of proximal halves of ulna, radius &
interosseous membrane
I: Base of 1
st
metacarpal
N: Posterior interosseous nerve, continuation of deep branch
of radial nerve
A: Abducts thumb & extends it at carpometacarpal joint

EXTENSOR POLLICIS BREVIS
- Fusiform short extensor of the thumb
- The belly of EPB lies distal to the APL and is partly covered
by it
- Its tendon lies parallel and immediately medial to that of the
APL but extends farther, reaching the base of the proximal
phalanx
O: Posterior surface of distal 3
rd
of radius and interosseous
membrane
I: Dorsal aspect of base of proximal phalanx of thumb
N: Posterior interosseous nerve, continuation of deep branch
of radial nerve
A: Extends proximal phalanx of thumb at
metacarpophalangeal joint, extends carpometacarpal joint

ANATOMICAL SNUFFBOX
Borders:
Medial: Extensor pollicis longus
(EPL) Tendon
Lateral: Extensor pollicis brevis
(EPB) & Abductor pollicis longus
(APL) tendon
Proximal: Styloid process of radius
Floor: Carpal bones; Scaphoid &
Trapezium
CONTENTS:
- Radial Artery
- Superficial Branch of
Radial Nerve
- Cephalic vein

5. DON QUIXOTE
EXTENSOR POLLICIS LONGUS
- Its tendon passes under the extensor retinaculum in its own
tunnel, within the tendinous sheath of the EPL, medial to the
dorsal tubercle of the radius
- Uses the tubercle as trochlea (pulley) to change its line of
pull it proceeds to the base of the distal phalanx of the thumb
O: Posterior surface of middle 3
rd
of ulna & interosseous
membrane
I: Dorsal aspect of base of distal phalanx of thumb
N: Posterior interosseus nerve, continuation of deep branch
of radial nerve
A: Extends distal phalanx of thumb at interphalangeal joint,
extends metacarpophalangeal & carpometacarpal joints

EXTENSOR INDICIS (EI)
- Has narrow, elongated belly that lies medial to and
alongside that of the EPL
- Extend the index finger at the PIP joint as in pointing
- Also helps extend the hand
O: Posterior surface of distal 3
rd
of ulna & interosseus
membrane
I: Extensor expansion of 2
nd
digit
N: Posterior interosseous nerve, continuation of deep branch
of radial nerve
A: Extends 2
nd
digit; helps extend hand at wrist

CUBITAL FOSSA
Laterally: Brachioradialis
Medially: Pronator teres
Base: Imaginary drawn line between the 2 epicondyles of
the humerus
Floor: Supinator muscle, Brachialis
Roof: Skin & Fascia, bicipital aponeurosis
Contents: Median nerve, Bifurcation of the bracial artery
into the ulnar & radial arteries, Biceps tendon, Radial nerve
& its deep branch

ARTERIES OF THE FOREARM
ULNAR ARTERY
- Pulsations of the ulnar artery can be palpated on the lateral
side of the FCU tendon, where it lies anterior to the ulnar
head
- Supply the muscles of the medial and central forearm, the
common flexor sheath & the ulnar & median nerves

Branches of the Ulnar Artery
- Anterior and Posterior Ulnar Recurrent Arteries
- Common Interosseus Artery
- Anterior & Posterior Interosseous Artery
- Muscular branches
→ Supply muscles on the medial side of the forearm
(flexor-pronator group)

RADIAL ARTERY
- The pulsations of the radial artery can be felt throughout
the forearm
- Distally, it lies on the anterior surface of the radius and is
covered by only skin and fascia, making this an ideal location
for checking the radial pulse
- Leaves the forearm by winding around the lateral aspect of
the wrist and crosses the floor of the anatomical snuffbox
- Radial Recurrent Artery → anastamose with the Radial
Collateral Artery (branch of Profunda Brachii Artery)
- Palmar and Dorsal Carpal Branches
- Muscular Branches
→ Supply the anterolateral aspects of both the flexor and
the extensor compartments

SUPERFICIAL VEINS
- Cephalic vein
- Basilic vein
- Median cubital vein
- Median antebrachial vein

DEEP VEINS
- Accompanying veins (venae comitantes) arise from the
anastomosing deep venous palmar arch in the hand
- Lateral side - paired radial veins arise and accompany the
radial artery
- Medial side – paired ulnar veins arise and accompany the
ulnar artery
MEDIAN NERVE
- Principal nerve of the anterior compartment of the
forearm
- Supplies muscular branches to the superficial and
intermediate layers of forearm flexors (except FCU) and
deep muscles (except for the medial ulnar half of the FDP)
- Branches of the median nerve:
→ Articular branches – Elbow Joint
→ Muscular branches – Nerve to pronator teres: FCR,
palmaris longus and FDS
→ Anterior interosseus nerve – Deep forearm flexors
(except FDP); Pronator quadratus
→ Palmar cutaneous branch – Skin of the central part of
the palm

ULNAR NERVE
- Supplies flexor carpi ulnaris (FCU) & ulnar part of the
flexor digitorum profundus (FDP)
- The ulnar nerve & artery emerge from beneath the FCU
tendon & become superficial just proximal to the wrist
- They pass superficial to the flexor retinaculum & enter the
hand by passing through a groove between the pisiform and
the hook of the hamate.
- A band of fibrous tissue from the flexor retinaculum bridges
the groove to form the small ulnar canal (Guyon canal)
- Branches of the Ulnar Nerve:
→ Articular branches: Elbow joint; between the olecranon
& Medial epiconle
→ Muscular branches: FCU and medial half of FDP
→ Palmar and Dorsal Cutaneous Branches: Skin of the
hand

Ulnar nerve - guyon canal
Median nerve - carpal tunnel

RADIAL NERVE
- The radial nerve serves motor & sensory functions in both
arm & the forearm but only sensory functions in the hand.
- Distributed in the forearm by 2 branches: Superficial
(sensory or cutaneous) & Deep Radial/Posterior
Interosseous Nerve

BONES OF THE HAND
CARPAL BONES
SCAPHOID – Boat-shaped bone
- articulates with the radius proximally
- Largest bone in the proximal row of carpals
LUNATE – Moon-shaped bone
- articulates proximally with the radius and is broader
anteriorly than posteriorly

6. DON QUIXOTE
TRIQUETRUM – Pyramidal bone on the medial side
- articulates proximally with the articular disc of the distal
radio-ulnar joit
PSIFORM – small, pea-shaped bone
- lies in the palmar surface of the triquetrum
- smallest and a sesamoid bone
TRAPEZIUM – Four-sided bone on the lateral side
- articulates with the 1
st
and 2
nd
metacarpals, scaphoid, &
trapezoid bones
TRAPEZOID – wedge-shaped bone
- articulates with the 2
nd
metacarpal, trapezium, capitate &
scaphoid bones
CAPITATE – head-shaped bone with a rounded extremity
- largest bone in the carpus
- Articulates primarily with the 3
rd
metacarpal distally and with
the trapezoid, scaphoid, lunate & hamate
HAMATE – wedge-shaped bone on the medial side of the
hand
- articulates with the 4
th
and 5
th
metacarpal, capitate &
triquetral bones

COMPARTMENTS OF THE HAND
- Hypothenar
- Thenar
- Central
- Adductor
- Interosseous

MUSCLES OF THE HAND

Thenar Muscles
- Abductor Pollicis brevis
- Flexor Pollicis brevis
- Opponens pollicis

ABDUCTOR POLLICIS BREVIS
- The short abductor of the thumb
- Forms the anterolateral part of the thenar eminence
- Also assist the opponens pollicis during the early stages of
opposition by rotating its proximal phalanx slightly medially


FLEXOR POLLICIS BREVIS
- Short flexor of the thumb located medial to the
- Flexes the thumb at the carpometacarpal &
metacarpophalangeal joints & aids in opposite thumb
-Has 2 bellies that differ in their innervation:
→ Larger superficial head of the FPB → Recur branch of
the median nerve
→ Smaller deep head → Deep palmar branches ulnar
nerve

Opponens pollicis
- Quadrangular muscle that lies deep to the APB and lateral
to the FPB
- Opposes the thumb, flexes and rotates the 1
st
metacarpal
medially at the carpometacarpal joint during opposition

Thenar muscles
- Abductor pollicis brevis
- Flexor pollicis brevis
- Opponens pollicis

ADDUCTOR POLLICIS
- Adductor compartment
- Fan-shaped muscle that has 2 heads of origin separated by
the radial artery as it enters the palm to form the deep
palmar arch
- Adducts the thumb

HYPOTHENAR MUSCLES
- Abductor digiti minimi
- Flexor digiti minimi brevis
- Opponens digiti minimi

OPPONENS DIGITI MINIMI
- Quadrangular muscle that lies deep to the abductor and
flexor muscles of the 5
th
finger
- Draws the 5
th
metacarpal anteriorly & rotates it laterally
- Acts exclusively at the carpometacarpal joint

PALMARIS BREVIS
- Small, thin muscle in the subcutaneous tissue of the
hypothenar muscle
- Wrinkles the skin of the hypothenar eminence & deepend
the hollow of the palm, aiding in palmar grip
- Covers & protects the ulnar nerve & artery

SHORT MUSCLES OF HAND
→ Lumbricals (1-4)
→ Dorsal interossei (1-4)
→ Palmar interossei (1-3)
LUMBRICALS
- Four slender muscles with worm-like form
- Flex the fingers at the metacarpophalangeal joints and
extend the interphalangeal joints

INTEROSSEI
- Four dorsal interosseous muscle (dorsal interossei) are
located between the metacarpals
- Three palmar interosseous muscles (palmar interossei) are
on the palmar surface of the metacarpals in the interosseous
compartment of the hand
- The 4 dorsal interossei abduct the fingers
- The 3 palmar interossei adduct them
- Mnemonic: DAB PAD

ARTERIES OF THE HAND
ULNAR ARTERY
- Enters the hand anterior to the flexor retinaculum between
the pisiform and the hook of hamate via the ulnar canal
(Guyon canal)
- Ulnar artery lies lateral to the ulnar nerve

RADIAL ARTERY
- Curves dorsally around the scaphoid and trapezium and
crosses the floor of the anatomical snuffbox
- Enters the palm by passing between the heads of the 1
st

dorsal interosseous muscle & dorsal interosseous muscle &
then turns medially, passing between the heads of the
adductor pollicis
- Ends by anastomosing with the deep branch of the ulnar
artery to form the deep palmar arch

Veins of the Hand
- Superficial and deep venous palmar arches → Deep veins
of the forearm
- Dorsal digital vein → Dorsal metacarpal veins → Dorsal
venous network → Cephalic (lateral)/ Basilic (medial

Nerves of the Hand
(TABLE)

MEDIAN NERVE
- Enters the hand through the carpal tunnel deep to the
flexor retinaculum, along with the nine tendons of the FDS,
FDP, and FPL
- Supplies two and a half thenar muscles and the 1
st
and 2
nd

lumbricals
- Sensory fibers to the skin on the eniter palmar surface, the
sides of the first 3 digits, the lateral half of the 4
th
digit & the
dorsum of the distal halves of these digits.

7. DON QUIXOTE
ULNAR NERVE
- Nerve of fine movements
- Leaves the forearm by emerging from deep to the tendon of
the FCU
- Continues distally to the wrist via the Ulnar (Guyon) canal)
- Passes between the pisiform medially and the ulnar artery
laterally
- Palmar cutaneous branch – supplies the skin on the
medial side of the palm
- Dorsal cutaneous branch – supplies the medial half of the
dosum of the hand, the 5
th
finger & the medial half of the 4
th

finger
- Ulnar nerve extends at the distal border of the flexor
retinaculum by dividing into superficial and deep branches

RADIAL NERVE
- The radial nerve supplies no hand muscles
- Superficial branch → Entirely sensory
- Supplies the skin and fascia over the lateral 2/3 of the
dorsum of the hand, dorsum of the thumb and proximal parts
of the lateral one and a half digits

JOINTS OF THE FOREARM AND HAND

ELBOW JOINT

8. DON QUIXOTE
CLINICAL CORRELATIONS
Fractures of the Humerus
- most common location → Surgical neck
- Common in elderly people with osteoporosis
- Parts of the humerus in direct contact with the indicated
nerves
- Surgical neck: Axillary nerve
- Radial groove: Radial nerve
- Distal end of humerus: Median nerve
- Medial epicondyle: Ulnar nerve

Subluxation and dislocation of radial head
- nursemaid's elbow or pulled elbow

Monteggia vs. Galleazzi fracture
Monteggia - ulna fracture with dislocation of the radial head
- A is proximal, bones affected proximally
Galeazzi - radius fracture with dislocation distal radioulnar
joint
- “Z” is distal, bones affected distally

COLLES FRACTURE
- complete transverse fracture of the distal 2cm of the
radius
- most common fracture of the forearm
- distal fragment is displaced dorsally and is often
comminuted
- "dinner fork" deformity
- results from forced extension of the hand, as a result
- fracture of the distal end of the radius resulting from a fall
on the outstreched hand

Smith Fracture/ Reverse Colles
- fracture of the distal end of the radius and occurs from a fall
on the back of the hand

Fracture of Scaphoid
- most frequently fractured carpal bone
- Often results from a fall on the palm when the hand is
abducted
- Pain occurs primarily on the lateral side of the wrist, esp.
during dorsiflexion and abduction of hand

Fracture of Metacarpals
- Boxer’s fracture → Fracture of the 5
th
metacarpal; occurs
when an unskilled person punches someone with a closed
and abducted fist
- The head of the bone rotates over the distal end of the
shaft, producing a flexion deformity

INJURY TO RADIAL NERVE IN ARM
- Injury to the radial nerve superior to the origin of its
branches to the triceps brachii results in paralysis of the
triceps, brachioradialis, supinator & extensor muscles of the
wrist and fingers and loss of sensation in areas of the skin
supplied by this nerve
- Nerve is injured in the radial groove → triceps only
weakened; muscles in the posterior compartment of the
forearm are paralyzed
- Characteristic clinical sign: wrist-drop
- Inability to extend the wrist & the fingers at the
metacarpophalangeal joints
- Flexed position owing to the unopposed tonus flexor
muscles & gravity

ELBOW TENDINITIS OR LATERAL EPICONDYLITIS
- painful musculoskeletal condition that results from repetitive
use of the superficial extensor muscles of the forearm
- repeated forceful flexion & extension of the wrist strain the
attachment of the common extensor tendon, producing
inflammation of the periosteum of the lateral epicondyle
- pain over the lateral epicondyle & radiates down the
posterior surface of the forearm

FRACTURE OF OLECRANON
- “Fractured elbow”
- Typical mechanism of injury is a fall on the elbow combined
with sudden powerful contraction of the triceps brachii

DISLOCATION OF ELBOW JOINT
- Most common direction of dislocation → Posterior
dislocation
- Ulnar collateral ligament is often torn
- Injury to the ulnar nerve – Numbness of the little finger &
weakness of flexion & adduction of the wrist

Measuring Pulse Rate
- Where the radial artery lies on the anterior surface of the
distal end of the radius, lateral to the tendon of the FCR
- When measuring the PR, the pulp of the thumb should not
be used because it has its own pulse, which could obscure
the patient’s pulse
- A radial pulse may also be felt by pressing lightly in the
anatomical snuff box

CARPAL TUNNEL
- Carpal tunnel → passageway for the 9 tendons and their
investing synovial sheaths of the flexor muscles of the
thumbs and fingers
- Boundaries:
→ Posterior: Concave surfaces of the carpal bones
→ Anterior: Flexor retinaculum or transverse carpal
ligament
- Contents:
* 4 tendons each of the FDS
* 4 tendons each of the FDP
* Tendon of the FPL
* Median nerve – lies between the tendons of the FDS
(medial) & FCR (lateral)

CARPAL TUNNEL SYNDROME
- more common in women
- results from the entrapment of the median nerve within the
carpal tunnel resulting in pain, sensory paresthesia & muscle
weakness
- Manifestations:
→ Burning pain or “pins” & “needles” along the
distribution of the median nerve to the lateral three and a half
fingers and weakness of the thenar muscles
→ NO PARESTHESIA OVER THE THENAR EMINENCE
(supplied by palmar cutaneous branch of the median nerve
which passes superficially to the flexor retinaculum)
- Tx: Surgery

MEDIAN NERVE INJURY
- aka “Hand of Benediction” or Bishop’s Hand
- nerve severed in the elbow region:
→ Flexion of the proximal interphalangeal joints of the 1
st
-
3
rd
is lost

9. DON QUIXOTE
➔ Flexion of the 4
th
& 5
th
digits is weakend
➔ Flexion of the distal interphalangeal joints of the 2
nd
&
3
rd
digits is lost
➔ Thenar muscle function is lost

INJURY TO THE ULNAR NERVE
- Ulnar nerve injury locations:
→ Posterior to the medial epicondyle of the humerus –
most common
→ Cubital tunnel
→ At the wrist
→ In the hand
- paresthesia of the median part of the dorsum of the hand
- Numbness & tingling (paresthesia) of the medial part of the
palm & the medial one and a half fingers
- Severe: elbow pain that radiates
- aka CLAW HAND

Radial Nerve Injury
- produce serious hand disability
- Inability to extend the wrist resulting from paralysis of
extensor muscles of the forearm, all of which are innervated
by the radial nerve
- Wrist-drop → hand is flexed at the wrist and lies flaccid

Dermatoglyphics
- science of studying ridge patterns of the palm
- Trisomy 21 (Down syndrome) -> Simian Crease