Anterior Forearm and Palmer Hand Flashcards
Which group of muscles crosses the elbow?
superficial group, deep group does NOT
What is the innervation rule for the anterior forearm?
“mostly median” C6-T1
exception: 1.5 muscles are innervated by ulnar nerve (flexor carpi ulnaris and ulnar half of flexor digitorum profundus)
What are the actions of the anterior compartment of the forearm?
Flex wrist joint
Flex fingers
Pronation
Abduction/Adduction of wrist joint
Where do the SF muscles of the anterior forearm originate?
Medial epicondyle of the humerus
What is medial epicondylitis?
AKA “golfer’s elbow”
inflammation of the common flexor origin and periosteum of the medial epicondyle
What muscles make up the SF group of the anterior compartment of the forearm?
pronator teres
flexor carpi radialis
flexor carpi ulnaris
palmaris longus
flexor digitorum superficialis
Insertion of pronator teres?
lateral radius
Action of pronator teres?
protonate forearm
Insertion of flexor carpi radialis?
radial side of hand
Action of flexor carpi radialis?
flex wrist joint, abduct wrist joint
Insertion of flexor carpi ulnaris?
ulnar side of hand
Action of flexor carpi ulnaris?
flex wrist joint, adduct wrist
What innervates flexor carpi ulnaris?
ulnar nerve
exception to innervation rule
Which muscle of the anterior forearm is missing in 15% of ppl? Where does this muscle insert?
palmaris longus
palmar aponeurosis
Action of palmaris longus?
flex wrist joint
Insertion of flexor digitorium superficialis?
middle phalanges of digits 2-5
Actions of flexor digitorum superficialis?
flex digits 2-5 at MCP & PIP joints
flex wrist joint
What are the origins of the deep group of the anterior compartment of the forearm?
ulna, radius, interosseous membrane
do not cross elbow
What are the muscles of the deep group of the anterior forearm?
flexor digitorum profundus
flexor pollicis longus
pronator quadratus
Insertion of flexor digitorum profundus?
distal phalanges of digits 2-5
Actions of flexor digitorum profundus
flex digits 2-5 at MCP, PIP & DIP joints
flex wrist joint
How can you test flexor digitorum profundus (FDP)?
have pt flex DIP joint
digits 2&3: median nerve, digits 4&5 ulnar nerve
How can you test flexor digitorum superficialis (FDS)?
have pt flex PIP joint
What innervates flexor digitorum profundus?
radial 1/2 (digits 2 &3): median nerve
ulna 1/2 (digits 4&5): ulnar nerve
Action of flexor pollicis longus?
Flex pollex, flex wrist joint
Insertion of pronator quadratus?
distal radius
Action of pronator quadratus?
pronate forearm
What is the flexor retinaculum?
band of deep fascia holding long flexor tendons in place as they cross the wrist joint
tendons are surrounded by synovial sheaths to permit movement
What forms the roof of the carpal tunnel?
flexor retinaculum
What are the contents of the carpal tunnel?
9 tendons & median nerve:
tendons of FDSF (4)
tendons of FDP (4)
tendon of flexor pollicis longus (1)
What are the compartments of the palm?
thenar compartment
adductor compartment
hypothenar compartment
central compartment
interosseous compartments
Central compartment of palm
deep to palmar aponeurosis
contains long flexor tendons (FDSF, FDP) and lumbricals
Where can infections of the central compartment of the hand spread to? how?
infections can travel deep to flexor retinaculum through carpal tunnel and into the anterior forearm
Interosseous compartments of palm
between metacarpals, contain interossei
Thenar compartment of palm
contains 3 thenar muscles, act on thumb
Adductor compartment of palm
contains adductor pollicis muscle
hypothenar compartment of palm
contains 3 hypothenar muscles, acting on digit 5
What innervates the intrinsic muscles of the hand?
most are innervated by ulnar nerve (C8-T1) but some are innervated by the median nerve (C8-T1)
What are the thenar muscles>
Abductor pollicis brevis
Flexor pollicis brevis
opponens pollicis
What innervates the thenar muscles?
recurrent branch of the median nerve
What movements can occur at the CMC joint of the pollex?
Flexion/Extension
Abduction/Adduction
Opposition/Reposition
Actions of abductor pollicis brevis?
abduct thumb at CMC joint
Action of flexor pollicis brevis?
flex thumb at CMC and MCP joints
Action of opponens pollicis?
opposition of thumb (CMC joint)
What makes up the adductor compartment of the palm?
1 muscle: adductor pollicis (oblique and transverse heads)
What innervates adductor pollicis?
ulnar nerve
Action of adductor pollicis?
Adduct thumb
What makes up the hypothenar compartment of the palm?
3 “digiti minimi” muscles:
- Abductor digiti minimi
- Flexor digiti minimi brevis
- Opponens digiti minimi
What innervates the hypothenar muscles?
the ulnar nerve
Action of abductor digiti minimi?
abduct digit 5 at MCP joint
Action of flexor digiti minimi brevis?
flex digit 5 at CMC and MCP joints
Action of opponens digit minimi?
opposition of digit 5 (CMC) joint
What are the muscles of the central compartment of the palm?
lumbricals (n=4) originate on the tendons of FDP and insert on the extensor expansions of digits 2-5
Action of lumbricals?
Flex MCP joint and extend PIP &DIP joints of digits 2-5
What innervates the lumbricals?
medial nerve (radial 1/2)
ulnar nerve (ulnar 1/2)
What innervates the interossei?
ulnar nerve
Action of interossei?
PAD: palmar interossei (3) adduct digits 2, 4 and 5
DAB: dorsal interossei (4) abduct digits 2-4
What does the median nerve innervate?
courses through cubital fossa and innervates most of the muscles of the anterior forearm
recurrent branch-thenar muscles
common and proper digital nerves- motor to lumbricals to digits 2&3, sensory to skin on lateral palm and lateral 3.5 digits
Does NOT innervate structures in the arm
Compression of what nerve leads to carpal tunnel syndrome?
median nerve
What will occur if there is a proximal lesion of the median nerve?
pronation lost
flexion and abduction of wrist dramatically weakened
flexion of MCPs, PIPs and DIPs of digits 2-3 lost, flexion of MCPs and PIPs
flexion and opposition of thumb lost
abduction of thumb weakened
lumbricals of digits 2 & 3 paralyzed
skin on lateral palm and lateral 3.5 digits anesthetized
What causes carpal tunnel syndrome?
any significant reduction in the size of the carpal tunnel, such as inflammation of the synovial sheaths of the flexor tendons
clinical presentation of carpal tunnel syndrome
progressive weakening of thenar muscles which weaken grip
loss of sensation on lateral 3.5 digits also affects grip
treatment of carpal tunnel syndrome
usually conservative treatment but can require surgery-partial to full opening of the flexor retinaculum
What does the ulnar nerve innervate
Flexor carpi ulnaris and ulnar .5 of FDP (digits 4&5)
does not innervate structures in the arm
Where does the ulnar nerve travel?
posterior to the medial epicondyle in the cubital tunnel (can be compressed here-cubital tunnel syndrome)
travels superficial to the flexor retinaculum with the ulnar artery
What do the branches of the ulnar nerve innervate?
deep branch: motor to hypothenar muscles, all interossei, lumbricals to digits 4&5 and adductor pollicis
common and proper digits nn: sensory to skin on ulnar palm, and ulnar 1.5 digits and ulnar aspect of dorsal hand
What will a proximal lesion of the ulnar nerve result in?
flexion &adduction of wrist weakened
flexion of DIPs of digits 4-5 lost
flexion of MCP & PIPs of digits 4-5 weakened
affects grip (hypothenar/adductor pollicis)
interossei paralyzed- no abduction/adduction
lumbricals to digits 4&5
skin of medial pal and 1.5 digits
How can you test for a proximal lesion of the ulnar nerve?
abduct/adduct digits 2-5, cutaneous sensation of tip of digit 5
How can you test for a proximal lesion of the median nerve?
pad-pad opposition of thumb, cutaneous sensation tip of digit 2
What does the brachial artery give rise to in the cubital fossa?
ulnar and radial arteries
What are the main branches off the ulnar artery?
ulnar recurrent aa.
common interosseous a.
superficial palmer arch
What does the SF palmar arch give off?
common and proper digits aa. which anastomose with the deep palmer arch from the radial a.
What does the common interosseous artery give off?
the anterior and posterior interosseous artery
What are the branches off the radial artery?
radial recurrent a
deep palmer arch- anastomoses with SF palmer arch
Where can you palpate the radial pulse?
lateral to the tendon of flexor carpi radialis
