Upper limb 3+4 anatomy Flashcards
In the anterior forearm, what are the actions of the 4 superficial muscles?
- Flexors of wrist
- Pronators of forearm
What are the 4 superficial muscles of anterior forearm, going from lateral to medial?
- Pronator teres
- Flexor carpi radialis
- Palmaris longus
- Flexor carpi ulnaris
Where does the common flexor tendon of the 4 superficial muscles of anterior forearm attach to?
Medial epicondyle of humerus
What is the action of pronator teres?
Pronates forearm and flexes wrist
What nerves innervate the 4 superficial nerves of forearm?
Median nerve innervates
- Pronator teres
- Flexor carpi radialis
- Palmaris longus
Ulnar nerve innervates
-Flexor carpi ulnaris
What superficial muscle is responsible for adduction as well as flexion of wrist?
Flexor carpi ulnaris
What superficial muscle is responsible for abduction as well as flexion of wrist?
Flexor carpi radialis
What is the main action of brachioradialis?
Flexion of elbow joint
What nerve innervates brachioradialis?
Radial nerve
Why is it unusual for radial nerve to innervate brachioradialis?
General rule is that radial nerve supplies only extensor muscles (brachioradialis is flexor muscle) and that all flexors lie in anterior compartment
What muscle makes up the intermediate group of muscles of the anterior forearm?
Flexor digitorum superficialis (FDS)
The FDS has 4 tendons. What is the distal attachment of these 4 tendons?
Middle phalanges of medial 4 digits
What nerve innervates FDS?
Median nerve
What are the 3 deep muscles of the anterior forearm?
- Flexor digitorum profundus (FDP)
- Flexor pollicis longus
- Pronator quadratus
What bone of the forearm is the flexor digitorum profundus related to?
Ulna
What bone of the forearm is the flexor pollicis longus related to?
Radius
What part of the forearm is the pronator quadratus related to?
Distal radioulnar joint
Does the FDP act on all the fingers?
Not first digit (thumb)
What is the distal attachment of the FDP?
Distal phalanges of 2-5 digits
What is the main action of FDP on wrist and interphalangeal joints of digits 2-5?
Flexion
The FDP has a dual nerve supply. What part is innervated by
- Ulnar nerve
- Median nerve?
- Ulnar nerve: medial part (digits 4 and 5)
- Median nerve: lateral part (digits 2 and 3)
What is the action of flexor pollicis longus?
Flexion of thumb
What is the innervation of flexor pollicis longus?
Median nerve
What is the action and innervation of pronator quadratus?
Pronation of forearm, median nerve
The median nerve is the main nerve in the anterior compartment of the forearm. In the cubital fossa, where can you find the median nerve in relation to the brachial artery?
Medial to brachial artery
What muscles does the median nerve NOT supply in the forearm? What nerve supplies these?
- Flexor carpi ulnaris: Ulnar nerve
- Medial half of flexor digitorum profundus running to digits 4+5: Ulnar nerve
The flexor retinaculum is a fibrous band on the palmar side of the hand. Does the median nerve enter the hand above or below this?
Below
Describe the path of the ulnar nerve through the forearm?
Passes posterior to medial epicondyle –> Enters forearm by passing between heads of flexor carpi ulnaris muscle–> descends close to ulnar artery
Where is the ulnar nerve in the forearm in relation to the ulnar artery?
Medial
What are the two terminal branches of brachial artery?
Radial and ulnar artery
Closely related to what part of the radius bone does the brachial artery divide?
Neck of radius
What are the bones making up the medial and lateral boundaries of the carpal tunnel?
Lateral: Trapezium and scaphoid
Medial: Hamate and pisiform
What are the contents of the carpal tunnel that pass through to the hand?
- Median nerve
- 4 tendons of flexor digitorum superficialis
- 4 tendons of flexor digitorum profundus
- Tendon of flexor pollicis longus
What joint of the finger does flexor digitorum superficialis flex?
Proximal interphalangeal joint of medial 4 digits
What joint of the finger does flexor digitorum profundus flex?
Distal interphalangeal joint of medial 4 digits
What nerve is affected in carpal tunnel syndrome?
Median nerve
What muscle of the forearm is continuous with the palmar aponeurosis in the palm?
Palmaris longus
What are the 5 compartments where the intrinsic muscles of the hand lie?
- Thenar compartment
- Hypothenar compartment
- Adductor compartment
- Lumbricals and long flexor tendons - central compartment
- Interosseous compartment
Where are the thenar muscles of the hand located?
Lateral part of palm, responsible for mainly the apposition of thumb
What are the three thenar muscles of hand?
- Abductor pollicis brevis
- Flexor pollicis brevis
- Opponens pollicis (located deep to other two muscles)
What nerve innervates the thenar muscles?
Median nerve
The median nerve carries what root values to the thenar muscles?
C8, T1
Where are the hypothenar muscles in the hand?
Medial side of the palm, move pinky finger
What are the three hypothenar muscles of the hand?
- Abductor digiti minimi
- Flexor digiti minimi
- Opponens digiti minimi
What nerve innervates the hypothenar muscles? what root values does it carry?
Ulnar nerve, C8-T1
What are the two heads of the adductor pollicis muscles?
Transverse and oblique heads. Transverse can be found more distally
What nerve innervates adductor pollicis?
Ulnar nerve (C8, T1)
What is the action of adductor pollicis?
Adducts thumb towards palm
From which long flexor tendon does the lumbricals originate?
Flexor digitorum profundus
What is the action of the lumbricals?
Flex fingers at MCP joint and simultaneously extend the interphalangeal joint of digits 2-5
What is the innervation of the lumbricals?
Medial 2 lumbricals - deep branch of Ulnar nerve
Lateral 2 lumbricals - median nerve
There are 4 dorsal and 3 palmar interossei. What is the useful mnemonic to remember the action of each of these
DAB - Dorsal interossei ABduct fingers
PAD - Palmar interossei ADuct fingers
What nerve innervates dorsal and palmar interossei?
Deep branch of Ulnar nerve
What spinal segmental levels provide nerve fibres to the nerve innervating interossei?
C8, T1
Lesion of which trunk affects the short muscles of hand?
Lower trunk (C8, T1) - called Klumpke’s paralysis
What artery is the main contributor for the superficial and deep palmar arches of the hand?
Superficial - ulnar artery
Deep - radial artery
Where are the arterial and venous arches found on the hand
Arterial - palmar
Venous - dorsal
What do the median/ulnar/radial nerves supply in the hand (generally)?
Median and ulnar supply the muscles
Radial supplies skin on dorsal aspect of hand
Where does the median nerve enter the hand?
Carpal tunnel
The ulnar nerves innervates most of the intrinsic hand muscles except from what?
Thenar and 1st/2nd lumbricals (median nerve)
The ulnar nerve is a branch of which brachial plexus cord?
Medial cord
Median and ulnar nerves carry what segmental fibres to the intrinsic hand muscles?
C8 and T1
What is the mnemonic for remembering the bones of hand?
Some (Scaphoid) Lovers (Lunate) Try (Triquetrium) Positions (Pisiform) That (Trapezium) They (Trapezoid) Can't (Capitate) Handle (Hamate)
What type of joint is the wrist?
Synovial condyloid joint
What structures form the proximal part of the wrist joint?
Articular disc/radius
What structures (bones) form the distal part of the wrist joint?
Scaphoid, lunate, triquetrium
What movements can occur at the wrist joint?
Flexion, extension, circumduction, adduction, abduction
What is the action of most of the anterior compartment muscles of forearm on the wrist?
Flexion
What is the combined action of extensor/flexor carpi ulnaris on wrist joint?
Adductors, ulnar deviation
What muscles abduct wrist?
- Flexor carpi radialis
- Extensor carpi radialis longus/brevis
- Abductor pollicis longus
What do most of the posterior compartment muscles of forearm do to the wrist?
Extension
What 3 groups are muscles of the posterior forearm organised into?
- Muscles extending/abducting/adducting hand at wrist joint
- Muscles extending medial 4 digits
- Muscles that extend or abduct the thumb
What muscles extend/adduct/abduct hand at wrist joint?
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
- Extensor carpi ulnaris
What does extensor carpi radialis longus/brevis do at wrist?
Extension and abduction (abduction assisted by flexor carpi radialis
What muscles help extend the medial 4 digits?
- Extensor digitorum
- Extensor indicis
- Extensor digiti minimi
Where do the extensor muscles of the forearm originate?
Lateral epicondyle
When abducting your fingers what tendons can you see on the dorsum of your hand?
Extensor digitorum
What muscles extend/abduct the thumb?
- Abductor pollicis longus
- Extensor pollicis brevis
- Extensor pollicis longus
What nerve innervates ALL the posterior compartment muscles of forearm?
Radial nerve
Action of extensor digitorum?
Extend medial 4 digits at MCP joints
Action of Extensor carpi radialis longus/brevis?
Extend/abduct wrist
Action of brachioradialis?
Flexes elbow joint
Action of extensor carpi ulnaris?
Extends and adducts wrist
Action of supinator?
Supinates forearm
Action of extensor digiti minimi?
Extends 5th finger at MCP joint
The supinator envelops the neck of radius. What is its action and innervation?
Supinate forearm, deep branch of radial nerve (exits from supinator muscle)
Where is the superficial branch distributed?
Dorsum of hand, sensory
What muscle tendons bound the anatomical snuff box medially and laterally?
Abductor pollicis longus and extensor pollicis brevis laterally, extensor pollicis longus medially
What is the anatomical snuff box?
Shallow depression on lateral aspect of wrist when thumb is fully extended
What bones make up the floor of the anatomical snuff box?
Scaphoid, trapezium
What arterial pulse can you feel in the anatomical snuff box?
Radial artery
What nerve innervates abductor pollicis longus, extensor pollicis brevis and extensor pollicis longus?
Radial nerve
Action of extensor pollicis longus?
Extension of wrist and thumb
Action of extensor pollicis brevis?
Extension of wrist and thumb
Action of abductor pollicis longus?
Extension of wrist, extension and abduction of thumb (at carpometacarpal joint)
What do the 4 extensor digitorum tendons flatten to form?
Extensor expansion (triangular tendinous aponeurosis wrapping around dorsum and sides of head of metacarpal and base of proximal phalanx)
What muscles attach to extensor expansion?
Lumbricals, dorsal/palmar interossei, extensor digitorum
Action of pronator teres on ELBOW joint?
Flexion
Nerver innervating brachioradialis?
Radial nerve
Combined action of flexor carpi ulnaris and extensor carpi ulnaris on wrise?
Adduction
Nerve innervating flexor carpi ulnaris?
Ulnar nerve
Action of lumbricals?
Flex MCP joint, extend interphalangeal joints
Action of adductor pollicis?
Adduct thumb
What type of joint is interphalangeal joint?
Synovial hinge
Action of dorsal interossei of fingers?
Abduction of fingers
Innervation of dorsal interossei?
Ulnar nerve
Action of abductor pollicis longus on wrist?
Extension
Action of abductor pollicis longus on thumb?
Abduction and extension at carpometacarpal joint
Type of joint between radius and ulnar bone?
Synovial pivot
Two muscles supinating forearm?
Supinator, biceps brachii
