Applied anatomy of the upper limb

1. Injuries of the nerves of
the upper limb
Dr. Mohammed Mahmoud Mosaed

2. Functions of the nerves in the upper
limb
• The nerves entering the upper limb provide the
following important functions:
• 1. Sensory innervation to the skin and deep
structures, such as the joints;
• 2. Motor innervation to the muscles;
• 3. Influence over the diameters of the blood
vessels by the sympathetic vasomotor nerves;
• 4. Sympathetic secretomotor supply to the
sweat glands

3. Formation of the brachial plexus
• The roots of the brachial plexus is formed by the union
of the anterior rami of the 5th , 6th , 7th , and 8th cervical
and the 1st thoracic spinal nerves,
• The roots of C5 and 6 unite to form the upper trunk.
• The root of C7 continues as the middle trunk.
• The roots of C8 and T1 unite to form the lower trunk.
• Each trunk then divides into anterior and posterior
divisions.
• The anterior divisions of the upper and middle trunks
unite to form the lateral cord. The anterior division of
the lower trunk continues as the medial cord. The
posterior divisions of all three trunks join to form the
posterior cord

5. • The plexus can be divided into roots,
trunks, divisions and cords.

6. Branches of the brachial plexus
• Roots
• Dorsal scapular nerve (C5)
• Long thoracic nerve (C5, 6, and 7)
• Upper trunk
• Nerve to subclavius (C5 and 6)
• Suprascapular nerve (supplies the
supraspinatus and infraspinatus
muscles)

7. Branches of the cords
• From the lateral cord
• Musculocutaneous nerve (C5,6).
• Lateral pectoral nerve (C5,6).
• Lateral root of median nerve (C5,6,7).
• From the medial cord
• Medial pectoral nerve (C8 ,T1)
• Medial cutaneous nerves of arm (C8 ,T1).
• Medial cutaneous nerves of forearm(C8 ,T1).
• Ulnar nerve(C7, 8 ,T1)
• Medial root of median nerve (C8 ,T1).
• From the posterior cord
• Upper subscapular nerves (C5,6).
• lower subscapular nerves (C5,6).
• Nerve to latissimus dorsi (thoracodorsal nerve) (C 6, 7,8).
• Axillary nerve(C5,6).
• Radial nerve (C5,6,7,8,T1).

8. BRACHIAL PLEXUS INJURIES
• 1. INJURIES OF THE TRUNKS:
• Upper trunk lesion of brachial plexus
• Lower trunk lesions of brachial plexus
• 2. INJURIES OF INDIVIDUAL NERVES
• Long thoracic nerve
• Axillary nerve
• Radial nerve
• Median nerve
• Ulnar nerve

9. Upper trunk lesion of brachial plexus
• Traction or even tearing of C5 and C6 root
• Cause:
• Excessive displacement of head to opposite side
and depression of shoulder on same side
• In infants during a difficult delivery
• In adults following a fall on or a blow to the
shoulder
• Nerves involved:
• Suprascapular nerve, Nerve to Subclavius
Musculocutaneous nerve and Axillary nerve

10. Causes of upper trunk lesion

11. MUSCLES AND FUNCTIONS LOST
• Loss of lateral rotation of arm:
• Due to paralysis of teres minor and Infraspinatus
• Loss of abduction of shoulder
• Due to paralysis of supraspinatus and
deltoid
• Weakness of flexion of shoulder:
• due to paralysis of corobrachialis and
biceps brachii
• Loss of flexion of elbow:
• Due to paralysis of brachialis and
biceps brachii
• Weakness of supination of forearm
• Due to paralysis of Biceps brachii

12. Manifestations of upper trunk injury
(Erb’s Palsy)
• Loss of muscle function
innervated by C5 and C6 known as
Erb’s Palsy or waiter’s tip
Manifestations
• Arm medially rotated, adducted,
hangs by side
• Forearm extended and pronated

13. Lower trunk lesions of brachial plexus
• Fibers of C8 and mostly T1 root
are torn
Causes:
• Excessive abduction of arm as in:
• 1. Birth injury
• 2. Person falling from a height
holding an object to save himself
• Compression of lower trunk as in
case of:
• 1. Cervical rib
• 2. Malignant lower deep cervical
lymph nodes
Nerves involved
• Ulnar and median nerves

14. Lower trunk lesions of brachial
plexus (klumpke’s palsy)
• Muscles involved
• All small muscles of the hand (interossei
and lumbricals)
• Note: The lumbricals are intrinsic muscles of the
hand that flex the metacarpophalangeal joints
and extend the interphalangeal joints

15. Manifestations of klumpke’s palsy
• Hyperextension of
metacarpophalangeal joint----- by
unopposed extensor digitorum
• Flexion at interphalangeal joint by
unopposed flexor digitorum
superficialis and profundus
• This deformity known as clawed
hand
• Sensory loss: along the medial side
of forearm

16. LONG THORACIC NERVE
• Arise from roots C5 , C6 and C7
• Causes:
• Blows or pressure in posterior
triangle of neck
• In radical mastectomy
• Muscles involved: Serratus
anterior
• Functions lost: Abduction
above 90 degrees
• Protraction
• Deformity
• Winging of scapula: medial
border and inferior angle of
scapula prominent

17. Axillary nerve
• Origin: Root value; (C 5 & 6).
• Posterior cord of brachial plexus.
• Course:
• It passes downward and laterally
along the posterior wall of the
axilla, then it exit the axilla and
it passes posteriorly around the
surgical neck of the humerus.
• It is accompanied by the
posterior circumflex humeral
vessels.
• Branches:
• Motor to the deltoid and teres
minor muscles.
• Sensory:
• Upper lateral cutaneous nerve
of arm that loops around the
posterior margin of the deltoid
muscle to innervate the skin
over that region.

18. Axillary nerve lesion
• Causes
a. Fracture of surgical neck of humerus
b. Inferior dislocation of shoulder joint
c. Misplaced injection into deltoid
• Muscles involved : Deltoid and Teres minor
 Manifestations
 Loss of abduction from 18° to 90°
• Shoulder weakness
• As the deltoid atrophies, the rounded
contour of the shoulder is lost and becomes
flattened compared to the uninjured side.
• Sensory loss
 Injury of the upper lateral cutaneous nerve of
arm leads to loss of skin sensation over the
lower half of deltoid muscle

19. Radial nerve (C5 – T1)
• Origin: from the posterior cord of the brachial plexus
Course:
• Posterior wall of the axilla: courses on the posterior wall of
the axilla (on subscapularis, latissimus dorsi, teres major)
• Triangular interval: it then runs through the triangular
interval with profunda brachii artery in posterior
compartment between long head of triceps and humerus
• Spiral groove: next it courses through the spiral groove
between lateral and medial heads of triceps
• next it passes through the lateral intermuscular septa
runs between brachialis and brachioradialis (anterior to
lateral epicondyle)
• At the level of radiohumeral joint line it divides into 2
terminal branches: superficial sensory branch and deep
branch (posterior interosseous nerve)

20. Branches of the radial nerve
• Branches in axilla
• Posterior cutaneous nerve of arm
• Nerve to long head of triceps
• Nerve to medial head of triceps
• Branches in spiral groove
• Lower lateral cutaneous nerve of arm
• Posterior cutaneous nerve of forearm
• Nerve to lateral head of triceps
• Nerve to medial head of triceps
• Branches in anterior compartment of arm:
• Nerve to small lateral part of brachialis
• Nerve to brachioradialis
• Nerve to extensor carpi radialis longus
• Branches in cubital fossa:
• Deep branch (posterior interosseous nerve) to all muscles in posterior
compartment of forearm
• Superficial branch provides sensation to dorsum of hand and dorsum of
the fingers

22. Radial nerve injury in axilla
• Causes
• Pressure of badly fitted crutch into armpit
• Falling a sleep with arm over the back of chair (Saturday
night palsy)
• Motor loss:
• loss of extension of elbow due to paralysis of triceps and
anconeus
• Loss of extension of wrist and fingers due to paralysis of
extensors of wrist and all muscles of posterior compartment
• Supination can still be performed by biceps muscle
• Deformity known as WRIST DROP: flexion of wrist as a result
of action of unopposed flexors of wrist and fingers
• Sensory loss
• posterior surface of arm and forearm
• Dorsum of hand and dorsal surface of lateral 3 ½ fingers

23. Radial nerve injury in spiral groove
• Most commonly in distal part of groove beyond
the origin of nerves to triceps and anconeus and
cutaneous nerves
• Causes:
• Fracture of shaft of humerus
• Prolonged pressure on the back of arm as in
unconscious patient by edge of operating table
• Prolonged application of tourniquet in thin lean
person
• Motor loss: loss of extension of wrist, fingers and
thumb (wrist drop)
• Sensory loss: Dorsum of hand and dorsum of
lateral 3 ½ fingers

24. Median nerve
• Origin: Formed in axilla by lateral and medial
roots from lateral and medial cords respectively.
• Course: In the anterior compartment of arm
crosses brachial artery from lateral to medial .
• At elbow crossed by bicipital aponeurosis.
Passes between 2 heads of pronator teres to
enter forearm.
• At wrist lies at lateral border of flexor digitorum
profundus. It enter palm beneath flexor
retinaculum
• Branches in axilla and arm no branches
• Branches in proximal forearm
• To all anterior compartment muscles except
flexor carpi ulnaris and medial half of flexor
digitorum profundus
• Branches in distal forearm Palmar cutaneous
branch
• Branches in palm to:
• Muscle of thenar eminence
• First 2 lumbricals
• Skin of palmar surface of lateral 3 ½ fingers

25. Injury of median nerve at elbow
• Cause: Supracondylar fracture of humerus
• Motor loss
• Paralysis of pronators of forearm
• Paralysis of long flexors of wrist and fingers except
medial half of flexor digitorum profundus and flexor
carpi ulnaris
• paralysis of the flexor pollicis longus
• Paralysis of thenar muscles (wasted)
• Deformity:
• Forearm: loss of pronation (supinated)
• Wrist: flexion is weak accompanied by adduction
• Fingers: no flexion of interphalangeal joint of index
and middle fingers
• Thumb: loss of flexion, abduction and opposition
• APE’S HAND: thumb laterally rotated, adducted and
thenar eminence flattened
• Sensory loss Lateral side of palm, Palmar surface of
lateral 3 ½ fingers and distal part of dorsal surface of
lateral 3 ½ fingers

26. Injury to median nerve at wrist
• Most common injury of median
nerve
• Causes
• Due to penetrating injuries or
stab wound at the wrist
• Motor loss
• Muscle of thenar eminence
• First two lumbricals
• Deformity APE’S HAND
• Sensory loss
• Same as in elbow lesion

27. Injury to median nerve in carpal tunnel
• Carpal tunnel---Osseo fibrous space formed by anterior
concave surface of carpus and flexor retinaculum. It is a
Passage of long flexor tendon and median nerve
• Causes: Inflammation of retinaculum- Arthritis of carpal
bones
• Inflammation of synovial sheaths of flexor tendons
• Clinically, the syndrome consists of a burning pain along
the distribution of the median nerve to the lateral three
and a half fingers and weakness of the thenar muscles.
• No paresthesia occurs over the thenar eminence because
this area of skin is supplied by the palmar cutaneous
branch of the median nerve, which passes superficially to
the flexor retinaculum.

29. ULNAR NERVE
• Arise from medial cord in axilla
• Descends in anterior compartment of arm on medial side of brachial artery
• Pierces medial intermuscular septum to enter in posterior compartment. At elbow
lies behind medial epicondyle. Enter forearm between 2 heads of flexor carpi ulnaris.
At wrist lies between tendons of flexor carpi ulnaris and digitorum profundus. Enter
palm superficial to flexor retinaculum
• Branches in axilla or arm No branches
• Branches in proximal forearm: branches to flexor carpii ulnaris and Medial half of
flexor digitorum profundus
• Branches in distal forearm
• Palmar cutaneous branch -----skin of hypothenar eminence
• Posterior cutaneous branch----skin of medial third of dorsum of hand and dorsal side
of medial one and half finger
• Branches in palm
• Superficial branch ---- skin of palmar surface of medial one and half finger
• Deep branch -- -- All small muscles of hand except of thenar muscles and first 2
lumbricals

31. ULNAR NERVE INJURY AT THE ELBOW
• Most commonly injured at this site
• Cause: Fracture of medial epicondyle
• Motor loss
• Flexor carpi ulnaris and medial half of flexor digitorum profundus
• Small muscle of hand are paralyzed except thenar muscles and first 2 lumbricals
• Deformity
• Wasting of ulnar border of forearm
• Loss of flexion of terminal phalanges of little and ring finger
• Inability to abduct and adduct fingers
• Loss of adduction of thumb
• CLAW HAND: Metacarpophalangeal joints of fourth and fifth finger are hyper
extended and the interphlangeal joint s are flexed
• Flattening of hypothenar eminence
• Hollowing between metacarpals on dorsum of hand due to paralysis of dorsal
interossei
• Sensory loss
• Anterior and posterior surfaces of medial half of hand and medial one and half
fingers

32. ULNAR NERVE INJURY AT WRIST
• Due to superficial position
• Causes
• Penetrating wounds
• Motor loss
• Small muscles of hand except those of thenar eminence and
first 2 lumbricals
• Deformity
• Claw hand more prominent
• Sensory loss
• On the medial side of palm and palmar and dorsal surface of
1 ½ fingers
• Sensation on posterior medial surface of hand is intact