Forearm and Hand Flashcards
Why does a “funny bone” happen?
B/c the ulnar nerve passes posterior to the medial epidcondyle of the humerus
What are the muscles of most superficial layer of the anterior forearm?
Pronator teres
Flexor capri radialis
Palmaris longus
Flexor carpi ulnaris
What is the origin of the most superficial layer of the anterior forearm?
Epicondyle of humerus
What is the insertion and action of pronator teres?
I: radius
A: Pronation of the forearm
What is the insertion and action of flexor carpi radialis?
I: anterior side of Base of 2nd metacarpal bone
A: wrist flexion and abduction
What is the insertion and action of palmaris longus?
I: palmar aponeurosis
A: wrist flexion
What is the action and insertion of flexor carpi ulnaris?
I: pisiform, hook of hamate, anterior side of base 5th metacarpal bone
A: wrist flexion and adduction
What is innervated by the median nerve? (anterior forearm first layer)
Pronator teres
Flexor capri radialis
Palmaris longus
What is innervated by the ulnar nerve? (Anterior forearm first layer)
Flexor carpi ulnaris muscle
What are the boundaries of the cubical fossa?
1.Brachioradialis
2. Pronator Teres
3. Line between the epicondyle of the humerus
What is the medial antebrachial cutaneous nerve from?
The medial cord
What is the lateral antebrachial cutaneous nerve from?
Continuation of musculocutaneous nerve
What comprises the second layer of the anterior compartment of the forearm?
flexor digitorum superficilais
What is the origin, insertion, and action of the flexor digitorum superficialis?
O: common flexor tendon
I: middle phalanges of digits 2-5
A: flexes digits 2-5 at proximal interphalangeal joints
What is the nerve supply of the flexor digitorum superficialis?
Median nerve
What comprises the third layer of the anterior compartment of the forearm?
- Flexor pollicis longus
- Flexor digitorum profundus
What is the insertion and action of flexor pollicis longus?
O: Distal phalanx of digit 1
A: Flexes pollen at interphalangeal and metacarpophalangeal
What is the nerve supply of flexor pollicis longus muscle?
Anterior interossesous nerve
What is the the insertion and action of flexor digitorum profundus? (Radial half)
I: Distal phalanges of digits 2 and 3
A: flexes digits 2-3 at distal interphalangeal joints
What is the nerve supply of the flexor digitorum profundus? (Radial half)
Anterior interossesous nerve
What is the insertion and action of the flexor digitorum profundus? (Ulnar half)
I: Distal phalanges of digits 4 and 5
A: flexes digits 4-5 at distal interphalangeal joints
What is the nerve supply of the flexor digitorum profundus? (Digits 4 and 5)
Ulnar nerve
What comprises the fourth layer of the anterior forearm compartment?
Pronator quadratus
What is the origin, insertion, and action of the pronator quadratus?
O: Ulna
I: Radius
A: Pronation of forearm
What is the nerve supply of the pronator quadratus?
Anterior interossesous nerve
What is the hypothenar eminence?
Produced by intrinsic muscles of the little finger
What is the thenar eminence?
Produced by intrinsic muscles of the thumb
What is palmar fibromatosis? (Dupuytren contracture)
Thickening and shortening of longitudinal bands of the palmar aponeurosis
*Persistant contraction of the digits
What is the origin, insertion, and action of the Brachioradialis?
O: humerus
I: proximal to styloid process of the radius
A: flexes forearm
what is the nerve supply of the Brachioradialis muscles?
Radial nerve
What comprises layer 1 of the posterior forearm compartment?
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris
What is the origin of layer 1 of the posterior forearm compartment?
O: Lateral epicondyle of the humerus
Which muscles are innervated by the deep branch of the radial nerve?
Extensor Carpi Ulnaris
Extensor Carpi Radialis brevis
Extensor Digitorum
Extensor Digiti Minimi
What muscle is innervated by the radial nerve?
Extensor carpi radialis longus
What muscles are responsible for wrist extension (layer 1)?
Extensor carpi ulnaris
Extensor carpi radialis longus
Extensor carpi radialis brevis
What muscles are responsible for extension of digits 2-5?
Extensor digitorum (2-5)
Extensor digiti minimi (5)
What is the insertion of the extensor digitorum / digit minimi
I: extensor expansions of digits 2-5 (EDM)
I: extensor expansions of digit 5 (EDMM)
How does a mallet finger happen?
Avulsion of extensor tendon from distal phalanx
What comprises layer 2 of the posterior compartment of the forearm?
Supinator muscle
Extensor pollicis longus
Extensor indicis
Abductor pollicis longus
Extensor pollicis brevis
What is the origin, insertion, and action of the supinator muscle?
O: lateral epicondyle
I: radius
A: supination of the forearm
What is the nerve supply of the supinator?
Deep branch of the radial nerve
What is the origin of layer 2 except the supinator muscle?
O: Posterior forearm
What is the insertion of the extensor pollicis longus?
Posterior side of Distal phalanx of digit 1
What is the insertion of the abductor pollicis longus?
Lateral aspect of base of the 1st metacarpal
What is the insertion of the extensor indicis?
Extensor expansion of digit 2
What is the insertion of the extensor pollicis brevis?
Posterior side of proximal phalanx of digit 1
When does the deep branch of the radial nerve change its name?
After passing the supinator muscle
*Changes to posterior interossesous nerve
What does the posterior interossesous nerve innervate?
Extensor pollicis longus
Extensor indicis
Abductor pollicis longus
Extensor pollicis brevis
Where is the anatomical snuff box?
Between extensor pollicis brevis and extensor pollicis longus tendons
What is found in the snuff box?
The radial artery
What is De Quervain Tensosynovitis?
Repetitive use injury resulting in inflammation of Abductor Pollicis Longus Tendon and Extensor Pollicis Brevis tendon
What is the origin and insertion of the lumbrical muscles?
O: Flexor digitorum profundus tendons
I: Extensor Expansions
What is the nerve supply of Lumbricals (1 & 2)
Median nerve
What is the nerve supply of lumbricals (3 & 4)
Deep branch of ulnar nerve
What is the nerve supply of the radial half of the flexor digitorum profundus muscle?
Anterior interossesous nerve
What is the nerve supply of the ulnar half of the flexor digitorum profundus muscle?
Ulnar nerve
What are the actions of the lumbrical muscles?
- Flex digits 2-5 at metacarpophalangeal joints
- Extend digits 2-5 at the proximal and distal interphalangeal joints
What muscles abducts digits 2 and 4?
Dorsal interosseous muscle
What muscles adducts digits 2,4,5?
Palmar interosseous muscle
What is the nerve supply of the palmar and dorsal interosseous muscle?
Deep branch of the ulnar nerve
What are the thenar compartment muscles?
Abductor pollicis brevis
flexor pollicis brevis
Opponens pollicis
What is the origin of the thenar compartments muscles?
Tuberclesof the scaphoid and trapeizum bones
What is the insertion of the abductor pollicis brevis and flexor pollicis brevis muscles?
I: Lateral side of proximal phalanx of the thumb
What is the insertion of the opponens pollicis muscle?
I: Lateral side of 1st metacarpal
Wha is the actions of the muscles of the thenar compartment?
Abductor pollicis brevis: Thumb abduction
Flexor pollicis brevis: Thumb flexion
Opponens pollicis: Medial rotation of 1st metacarpal
What is the nerve supply of the thenar compartment?
Recurrent branch of the median nerve
where is the recurrent branch of the median nerve located?
Directly deep to the thenar skin
*A laceration will result in weakness or paralysis
What is the origin, insertion, and action of the adductor pollicis muscle?
O: 2nd and 3rd metacarpals, capitate bone
I: medial side of proximal phalanx of thumb
A: thumb adduction
What is the nerve supply of the adductor pollicis?
Deep branch of the ulnar nerve
What are the muscles of the Hypothenar compartment?
Abductor digiti minimi
Flexor digiti minimi brevis
Opponens digiti minimi
What is the nerve supply of the hypothenar compartment?
Deep branch of the ulnar nerve
What is the insertion of the hypothenar muscles
Medial side of proximal phalanx of digit 5
What is the origin of the abductor digiti minimi muscle?
Pisiform bone
What is the origin of the flexor digiti minimi brevis muscle?
Hook of hamate bone
What is the origin of the opponens digiti minimi muscle?
Hook of hamate bone
What creates the superficial palmar arch?
Ulnar artery and radial artery
What digits are supplied by the C8 dermatome?
4 and 5
What digits are supplied by the C7 dermatome?
2 and 3
What digits are supplied by the C6 dermatome
1
What causes Distal median neuropathies?
Suicide attempts
Carpal tunnel syndrome
Laceration of thenar eminence
What nerve is spared during carpal tunnel syndrome?
palmar branch of the median nerve
What nerve is affected during carpal tunnel syndrome?
Digital nerves
*Medial side of digit 1
Digits 2 and 3
Lateral side of digit 4
What dermatomes are affected during carpal tunnel syndrome?
C6 and C7
What can ulnar canal syndrome present with?
The “claw”
*on attempted extension, there is weakness of the lumbrical muscles
*MCP hyper extension
*PIP and DIP hyperflexion
What is a positive Froment sign?
Patient will use their flexor pollicis longus and brevis muscles while pulling (thumb is flexed)
What does long-term ulnar nerve present with?
Wasting of the first dorsal interossesous and adductor pollicis muscles
How does cubital tunnel syndrome happen?
Compression of the ulnar nerve as it passes within a tunnel formed by the ulnar collateral ligament of the elbow and the flexor carpi ulnaris muscles
How does cubital tunnel syndrome present?
Paralysis of
1. Flexor Carpi Ulnaris
2. Ulnar half of Flexor Digitorum Profundus muscle
*Weakness of flexion of digits 4 and 5
*radial deviation
Where do proximal median nerve injuries happen?
Injury to the median nerve as it passes deep to the pronator teres and flexor digitorum superficialis muscles
How does proximal median nerve injury present?
Paralysis of
1. Flexor carpi radialis muscle
2. Flexor digitorum superficialis muscle (2-3)
3. Radial half of flexor digitorum profundus muscles (2-3)
With a proximal median nerve injury how will the patients hand present when trying to make a fist?
Hand of benediction
*Flexion deficit in digits 2 and 3
Does ulnar or radial deviation happen from proximal median nerve injury?
Ulnar
**due to reduced opposition to flexor carpi ulnaris muscle
How does a radial nerve lesion present?
Wrist-drop sign
*Weakness of forearm flexion
What is damaged during Erb’s palsy? (high brachial plexopathy)
Injury to C5 and C6 roots of the brachial plexus
*affects proximal muscles
How does a high brachial plexopathy happen?
Excessive angulation between the shoulder and neck
*Lesion to the superior trunk
What is affected during a high brachial plexopathy?
- Arm flexors
- Initiation of Arm abduction
- Lateral rotators
What is spared during a high brachial plexopathy?
- Arm extensors
- Arm adductors
- Medial rotators
What is the presentation of high brachial plexopathy?
Waiter’s tip deformity
*Arm is extended, adducted, and medially rotated
What is damaged during low brachial plexopathy? (Klumpke’s palsy)
Injury to C8 and T1 roots of the brachial plexus
*Affects distal muscles
How does a low brachial plexopathy occur?
Excessive angulation between the upper limb and trunk
*Lesion to the inferior trunk
What is the presentation of a low brachial plexopathy?
Clawing of digits 2-5
What is a Colles Fracture
Distal radius fracture
-from falling on a outstretched hand
What vein is common used for vein puncture?
Median cubital vein
Where can the brachial artery pulse be palpated?
Medial to the biceps brachii tendon
What does the superficial branch of the radial nerve supply?
Dorsum of the hand
What does the deep branch of the radial nerve supply?
Motor to muscles in the posterior compartment of the forearm
What are the outcropping muscles?
Abductor pollicis longus
Extensor pollicis brevis
What hooks around listers tubercle?
Extensor pollicis longus
What does and doesn’t pass deep to the out cropping muscles?
Out cropping muscles: Abductor pollicis longus, extensor pollicis brevis
Does: Extensor carpi radialis longus/brevis
Doesnt: Brachioradialis tendon