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Musculoskeletal Block > Anatomy of Upper Limb > Flashcards

Anatomy of Upper Limb Flashcards

1
Q

Upper Limb Movements

A

Shoulder movements: above 90 degrees abduction requires abduction of the scapula (glenohumeral joint can only go 90 degrees)
Can also circumduct glenohumeral joint
Achieve long axis rotation of humerus and easily seen when arm bent
At elbow: two joints ulnarhumeral joint that allows flexion and extension only, and then the radiohumeral joint allows for long axis rotation and flexion and extension
Radius rotates around the ulna

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2
Q

Hand/Wrist Movements

A

Wrist – F and E, adduction and abduction (think anatomical position in relation to these)
Circumduction at the wrist because can do all four movements

Hand: adduction and abduction is relative to the middle finger (2nd digit in foot)
Abduction powered by dorsal interossei (no palmar attached because only in adduction)
Thumb is rotated 90 degrees when hands are relaxed and can pivot it around at carpal and metacarpal joint
Orient yourself to the thumbnail to tell which direction; move thumb in relation to its nail
Can also long axis rotation = opposition via opponens pollicis

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3
Q

Intrinsic Muscles and Extensor Hood of Phalanges

A

Flexor digitorum profundus tendon inserts on the middle phalanx, but the flexor digitorum superficialis tendon goes between the FDP tendon and inserts on the distal phalanx

Extensor hood is a CT covering that binds the tendons to the skeleton as well as serves as an insertion point for interosseous and lumbricle muscles

Actions: Interossei and lumbricals help flex the MCP joint and extend the IP joints

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4
Q

Precision Grip

A

Contraction of FDP alone flexes digits so that tips digit into palm

Precision grip requires:
partial flexion of IP joints
lower levels of FDP contraction
passive tension in lumbricals (ulnar and median nn.)
or active force by interossei (ulnar n.)

Contraction of digitorum profundus = arched view (OK sign) and without the influence of the interossei muscle you can bend all 3 joints at the same time; anytime trying to bring tips of finger it is hard without lumbricles and interossei

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5
Q

Types of Nerve Injuries

A

Avulsion = pull root out of spinal cord
Rupture: father out from CNS
Neuroma: spinal nerve torn and partially healed
Neuropraxia: nerve damaged by stretching; usually traction injuries and can recover well

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6
Q

Testing Myotomes

A 
C5: abduction of arm
C5/6: flexion of elbow
C7: elbow extension
C8: flexion of digits (gripping)
T1: adduction or abduction of fingers (hold piece of paper between fingers)
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7
Q

Bicipital Reflex

A

Bicipital reflex = tests C6 spinal nerve and musculocutanous nerve
Patient can be unconscious

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8
Q

Triceps Reflex

A

Triceps reflex: test above olecranon and arm should jerk in response
Patient must be conscious
Tests radial nerve and C7 spinal nerve

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9
Q

Dermatomes of Overlap

A 
C4 – Acromioclavicular joint 
C5 – Upper lateral arm
C6 – Pad of thumb (I)
C7 – Pad of middle finger (III)
C8 – Pad of little finger (V)
T1 – Medial elbow
T2 – Axilla
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10
Q

Cutaneous Nerves: Shoulder

A

Supraclavicular nn - cervical plexus

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11
Q

Cutaneous Nerves: Arm

A
  • Intercostobrachial n. is extension of 2nd intercostal n.
  • Medial cutaneous n. of the arm - medial cord of brachial plexus
  • Posterior cutaneous n of the arm - radial n.
  • Superior lateral cutaneous n. of arm - axillary n.
  • Inferior lateral cutaneous n. of arm - radial n.
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12
Q

Cutaneous Nerves: Forearm

A
  • Posterior cutaneous n. of the forearm - radial n.
  • Lateral cutaneous n. of the forearm - musculocutaneous n.
    Medial cutaneous n. of the forearm - medial cord of brachial plexus
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13
Q

Cutaneous Nerves: Hand

A

Superficial branch of radial n.
Ulnar n.
Median n.

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14
Q

Erb-Duchenne Palsy

A

damage to root of C5 and C6
from traumatic lateral neck bending
during childbirth
from fall on shoulder

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15
Q

Erb-Duchenne Palsy: Nerves and Muscles Affected

A

Nerves downstream:

  • Suprascapular n,
  • Axillary n.
  • Musculocutaneous n.
  • Radial n. (partial)

Paralysis or weakness:
Deltoid and supraspinatus: arm adducted, cannot abduct
Infraspinatus: arm medially rotated by pec. major and latissimus dorsi, cannot laterally rotate
Biceps, brachialis: elbow extended, cannot flex, forearm pronate ad fingers extended, waiter’s tip” position (medial rotation)

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16
Q

Klumpke’s Palsy

A

Damage to roots of C8 and T1

From traumatic hyperabduction of arm during childbirth or grabbing object in fall
Paralysis or weakness of short muscles of hand
“Claw hand” and wasting

Also can be from thoracic outlet syndrome, when it will be accompanied by poor circulation in arm due to compression of the subclavian artery as well as nerve roots

17
Q

Klumpke’s Palsy: Nerves and Muscles Affected

A

T1 controls most intrinsic hand muscles (via ulnar n.); unopposed flexors (profundus) and extensors leads to hyper extended MP joints and flexed IP joints (claw hand); also wasting of the hand muscles

Wasting of non-thenar intrinsic hand muscles

Horner’s syndrome: distinguishes between proximal ulnar nerve lesion and inferior brachial plexus lesion
Interrupted sympathetic innervation of head because T1-L2 and unopposed constriction of pupil

18
Q

Axillary Nerve Damage

A

Common Causes

  • Fracture of surgical neck of humerus
  • Dislocation of glenohumeral joint
  • Improper use of crutches

Axillary nerve runs under head of humerus and then out the quadrangular space through the deltoid
If you dislocated head of humerus and will slide posteriorly and inferiorly and this movement will stretch the axillary nerve and impinge it
Proximal humerus fractures from improper use of crutches

Sensory: loss of sensation on “regimental badge”, (superior lateral cutaneous nerve)
Motor: weakness/paralysis of deltoid with possibly atrophy

19
Q

Median Nerve Muscles

A 
1/2 LOAF
L- lumbricles 2/4
O- opponens pollicis
A – abductor pollicis brevis
F- flexor pollicis brevis

All flexors in the forearm except flexor carpi ulnaris and medial ½ of digitorum profundus (ulnar nerve)

*Ulnar nerve innervates the two muscles named above + adductor pollicis (transverse and oblique), opponens digit minimi, flexor digit minimi, and abductor digit minimi

20
Q

Musculocutaneous Nerve

A

Motor: biceps, coracobrachialis and brachialis
Symptoms: weak elbow flexion and forearm supination

Sensory: lateral cutaneous n. of forearm
Symptoms: loss of sensation on lateral radial aspect of forearm

21
Q

Ligament of Struthers Syndrome

A

Weakness of all median n. muscles, including pronator teres, 1/2 LOAF, all forearm muscles except flexor carpi ulnaris and 1/2 of digitorum profundus (ulnar head portion)
Thenar eminence wasting, “ape hand”
Benediction Hand, sensory loss over thenar eminence

22
Q

Pronator Teres Syndrome

A

Compression due to pronator teres on the median nerve, but spares pronator teres and affects downstream mm., especially thenar mm., Benediction hand
Pain on pronation, sensory loss over thenar eminence, Thenar eminence wasting, “ape hand”
Benediction Hand, sensory loss over thenar eminence

23
Q

Anterior Interosseous Nerve and Carpal Tunnel Syndrome

A

Median Nerve Neuropathies

Anterior interosseous nerve
Weak flexion of 1st IP joint (cannot make OK sign with thumb and index)

Carpal tunnel syndrome
Thenar eminence wasting, “ape hand”
Spares sensory to thenar eminence, palmar branch arise in forearm and median cutaneous branch doesn’t go through the tunnel
Ulnar nerve is spared because goes through Guyon’s tunnel

24
Q

Proximal Median Nerve Injury

A

Highest injuries (above elbow) results in loss of pronation and medial deviation during wrist flexion

25
Q

Flexor Pollicis Longus

A

FPL only flexor of thumb IP joint

Innervated by anterior interosseous n., branch of median n., in forearm.

Denervated by ant. inteross. n. palsy (compression, cutting) or median n. in cubital fossa or above

Lesion: unable to make the OK sign; Interphalangeal joint of thumb not able to bend because flexor pollicis longus can only do that

26
Q

Testing Flexor Digitorum Profundus and Superficialis

A

FDS supplied in cubital fossa by median nerve
Test by holding all other fingers down except middle finger and have patient flex

FDP supplied by anterior interosseous nerve
Test by holding down the middle finger up to the PIP joint, and have patient flex the PIP joint of the middle finger

27
Q

Ulnar Nerve Neuropathies

A 
Elbow 
Loss of dexterity, decreased grip and pinch strength
Weakness in adduction at wrist
Ulnar claw hand, Froment sign
Digit IV-V numbness

Forearm
Loss of dexterity, decreased grip and pinch strength
Ulnar claw hand, Froment sign
Digit IV-V numbness

Wrist
Mannerfelt’s and Froment’s signs
Weakness in finger abduction

28
Q

Mannerfelt’s Sign

A

Testing ulnar nerve function using the pinch testMannerfelt’s sign reflects dorsal interosseous weakness

Mannerfelt’s sign - Patient employing forceful precision grip between tips of index finger and thumb displays hyperflexion of index finger PIP joint because flexors of PIP joint are weakly opposed; dorsal interosseous weakness
Ulnar nerve affected

29
Q

Froment’s Sign

A

Testing nerve function using the pinch testFroment’s sign reveals adductor pollicis m. weakness

Froment’s sign - Patient employing forceful “precision grip” between tips of index finger and thumb displays flexion of thumb IP joint because adductor pollicis is compromised but FPL is still functioning
ulnar nerve affected

30
Q

Test for Deep Branch of Ulnar Nerve

A 
Ulnar nerve (deep branch) – knocks out interosseous muscles (which flex MP joints), and 2/4 lumbricles 
Only way to flex the fingers is to recruit the digitorum profundus and superficialis when interosseous muscles aren’t working
Flexion with fingers straight can only be achieved with interossei
Hold object between straight fingers and can see how much resistance they can generate
31
Q

Ulnar vs. Median Nerve Tests

A

To test ulnar nerve:
Can you pinch grip with forefinger and thumb without flexing your thumb IP joint?
Froment’s (flexed IP joint) finds median’s (FPL) fine, ulnar nerve is not

To test median nerve:
Can you flex your thumb IP joint? = Can you make a round OK sign?
Flat thumb shows ulnar nerve is fine, median nerve is not

32
Q

Ulnar Nerve Palsy

A

loss of ulnar nerve function
loss of most of the intrinsic muscles of the hand
long term - claw hand = intrinsic minus hand due to
hyperextension of MCP joints
flexion of IP joints
lack of interossei & lumbricals
NB also atrophy of 1st dorsal interosseous

33
Q

Radial Nerve Neuropathies: Upper and Lower Humerus

A 
Upper humerus (Crutch & Sat. night palsy)
Weakness in all elbow and wrist extensors, weak wrist abduction and extension
Numbness on dorsum of hand radial side

Lower humerus
Triceps spared (elbow extension retained)
Lose brachioradialis (negligible effect on elbow flexion)
Lose ECRL&B (weak wrist abduction)
Lose wrist extensors (wrist drop)
Numbness on dorsum of hand radial side

34
Q

Radial Nerve Neuropathies: Posterior Interosseous and Superficial Radial

A

Posterior interosseous:
Brachioradialis and triceps functioning, but wrist drop
Sensation normal on hand radial side dorsum

Superficial radial n.:
No motor symptoms
Numbness hand radial side dorsum

35
Q

Radial Nerve Injury

A

Common Causes

  • Fracture of humerus
  • Improper use of crutches
  • “Saturday night” palsy

Sensory
- loss of sensation on lateral elbow,
posterior forearm and dorsum of
hand

Motor
Triceps, brachioradialis, supinator
and extensors of wrist and fingers
- If lesion beyond humerus, triceps not effected
“Wrist drop” - patient unable to extend wrist

36
Q

Long Thoracic Nerve

A

Innervates serratus anterior (C5-7)

Lesion: winged scapula

37
Q

Accessory Nerve (CN XI)

A

Provided motor innervation to trapezius m.

Common causes of injury:
Surgery in posterior triangle of neck
Penetrating wound in neck
Blunt trauma to neck

Profound weakness in shrugging/lifting shoulders

Musculoskeletal Block (29 decks)

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