Region 6 - Forearm and Hand Flashcards
What is the general function of muscles in the anterior compartment of the forearm?
Flexion of wrist and digits
Pronation
What is the common flexor origin?
Medial epicondyle of the humerus
What is the innervation to the anterior compartment of the forearm?
Mostly median nerve
Except ulnar nerve to:
- Flexor carpi ulnaris
- Medial 2 parts of flexor digitorum profundus
What is the origin of palmaris longus?
Medial epicondyle of humerus
What are the insertions of palmaris longus?
Distal half of flexor retinaculum Palmar fascia (aponeurosis)
What are the functions of palmaris longus?
Flexes wrist
Tightens palmar aponeurosis
What is the innervation to palmaris longus?
Median nerve (C7+C8)
What are the origins of pronator teres?
Medial epicondyle of humerus
Coronoid process of ulna
What is the insertion of the pronator teres?
Lateral surface of radius
What are the functions of pronator teres?
Pronation
Assists in elbow flexion
What nerve enters the forearm between the two heads of pronator teres?
Median nerve
What innervates pronator teres?
Median nerve (C6+C7)
What are the origins of flexor carpi ulnaris?
Medial epicondyle of humerus
Olecranon and posterior border ulna
What are the insertions of flexor carpi ulnaris?
Base of pisiform
Hamate (hook)
5th metacarpal
What are the functions of flexor carpi ulnaris?
Flexion of wrist
Adduction of wrist
What is the innervation to flexor carpi ulnaris?
Ulnar nerve (C7+C8)
What is the origin of flexor carpi radialis?
Medial epicondyle of humerus
What is the insertion of flexor carpi radialis?
Base of 2nd metacarpal
What are the functions of flexor carpi radialis?
Flexion of wrist
Abduction of wrist
What is the innervation to flexor carpi radialis?
Median nerve (C6+C7)
What are the origins of flexor digitorum superficialis?
Medial epicondyle of humerus
Coronoid process of ulna
What is the insertion of flexor digitorum superficialis?
Lateral aspect of middle phalanges of digits 2-5
What is the function of flexor digitorum superficialis?
Flexion of MCP and PIP joints
Also assists in wrist flexion
What is the innervation to flexor digitorum superficialis?
Median nerve (C7-T1)
What are the origins of flexor digitorum profundus?
Medial and anterior surfaces of ulna
Interosseous membrane
What are the insertions of flexor digitorum profundus?
Palmar aspect of distal phalanges of digits 2-5
What is the function of flexor digitorum profundus?
Flexion of MCP, PIP and DIP joints
Also assists in wrist flexion
What is the innervation to flexor digitorum profundus?
Ulnar nerve (C8+T1) to medial 2 parts Median nerve (C8+T1 - Anterior interosseous nerve) to lateral 2 parts
What are the origins of flexor pollicis longus?
Anterior surface of radius
Interosseous membrane
What is the insertion of flexor pollicis longus?
Base of distal phalanx of thumb (palmar)
What is the function of flexor pollicis longus?
Flexion of MCP and IP joints in thumb
Also assists in wrist flexion
What is the innervation to flexor pollicis longus?
Median nerve (C8+T1 - Anterior interosseous)
What is the origin of pronator quadratus?
Distal anterior ulna
What is the insertion of pronator quadratus?
Distal anterior radius
What are the functions of pronator quadratus?
Pronation
Stabilise distal radioulnar joint
What is the innervation to pronator quadratus?
Median nerve (C8+T1 - Anterior interosseous)
Where do the ulnar nerve and artery pass in relation to the humerus?
Posterior to medial epicondyle
How does the median nerve enter the hand?
Through the carpal tunnel
How do the ulnar nerve and artery enter the hand?
Above the carpal tunnel
Pass through a groove between pisiform and hook of hamate
What are the branches of the ulnar artery in the hand?
Medial digital arteries
Superficial palmar arch
Why is the capitate bone large?
Axis for movement
What is the purpose of the hook of the hamate bone?
Retinaculum attachment
What type of joint in the wrist?
Plane synovial joint
What forms the roof of the carpal tunnel?
Flexor retinaculum
What are the medial attachments of the flexor retinaculum?
Pisiform
Hook of hamate
What are the lateral attachments of the flexor retinaculum?
Tubercle of scaphoid
Ridge on trapezium
A septum from what carpal bone joins the tendon of flexor carpi radialis?
Trapezium
What muscle groups attach to the flexor retinaculum?
Thenor
Hypothenar
What forms the floor of the carpal tunnel?
Wrist bones
What are the contents of the carpal tunnel?
Four tendons of flexor digitorum profundus
Four tendons of flexor digitorum superficialis
Flexor pollicis longus tendon
Median nerve
What structures run superficial to the carpal tunnel?
Ulnar artery
Ulnar nerve
What is the origin of anconeus?
Lateral epicondyle of humerus
What is the insertion of anconeus?
Olecranon of ulna
What is the function of anconeus?
Extension of elbow
What is the innervation to anconeus?
Radial nerve (C7+C8 [T1])
What is the origin of brachioradialis?
Supra-epicondylar ridge of the distal humerus
What is the insertion of brachioradialis?
Radius proximal to styloid process
What is the function of brachioradialis?
Flexion of forearm (especially when semi-prone)
What is the innervation to brachioradialis?
Radial nerve (C5-C7 - Before division into superficial and deep)
What is the common extensor origin?
Lateral epicondyle of humerus
What are the general functions of the posterior compartment of the forearm?
Extensors of digits and wrist
Abduction of thumb
Supination
What is the innervation to the posterior forearm compartment?
Radial nerve
What is the origin of extensor carpi radialis longus?
Lateral supra-epicondylar ridge of distal humerus
What is the insertion of extensor carpi radialis longus?
Base of 2nd metacarpal
What are the functions of extensor carpi radialis longus?
Extension of wrist
Abduction of wrist
What is the innervation to extensor carpi radialis longus?
Radial nerve (C6+C7 - Pre-division)
What is the origin of extensor carpi radialis brevis?
Lateral epicondyle of humerus
What is the insertion of extensor carpi radialis brevis?
(Dorsal aspect) of base of 3rd metacarpal
What are the functions of extensor carpi radialis brevis?
Extension of wrist
Abduction of wrist
What is the innervation to extensor carpi radialis brevis?
Radial nerve (C7+C8 - Posterior interosseous nerve)
What is the posterior interosseous nerve?
The continuation of the deep (muscular) branch of the radial nerve
What are the origins of extensor carpi ulnaris?
Lateral epicondyle of humerus
Posterior ulna
What is the insertion of extensor carpi ulnaris?
Base of 5th metacarpal
What are the functions of extensor carpi ulnaris?
Extension of wrist
Adduction of wrist
What is the innervation to extensor carpi ulnaris?
Radial nerve (C7+C8 - Posterior interosseous nerve)
What is the origin of extensor digitorum?
Lateral epicondyle of humerus
What is the insertion of extensor digitorum?
Dorsal expansion of digits 2-5
What are the functions of extensor digitorum?
Extension of MCP (mainly), PIP and DIP joints of digits 2-5
What is the innervation to extensor digitorum?
Radial nerve (C7+C8 - Posterior interosseous nerve)
What are the origins of extensor indices?
Posterior surface (of distal 1/3) of ulna Interosseous membrane
What is the insertion of extensor indices?
Dorsal expansion of 2nd digit (index finger)
What are the functions of extensor indices?
Extension of MCP, PIP and DIP joints in index finger
Extension of wrist
What is the innervation to extensor indices?
Radial nerve (C7+C8 - Posterior interosseous nerve)
What are the origins of extensor pollicis longus?
Posterior surface (of middle 1/3) of ulna Interosseous membrane
What is the insertion of extensor pollicis longus?
Base of distal phalanx of thumb
What are the functions of extensor pollicis longus?
Extension of CMC, MCP and IP joints in thumb
Extension of wrist
What is the innervation to extensor pollicis longus?
Radial nerve (C7+C8 - Posterior interosseous nerve)
What are the origins of extensor pollicis brevis?
Posterior surface (of distal 1/3) of radius Interosseous membrane
What is the insertion of extensor pollicis brevis?
Base of proximal phalanx of thumb
What are the functions of extensor pollicis brevis?
Extension of CMC and MCP joints in thumb
Extension of wrist
What is the innervation to extensor pollicis brevis?
Radial nerve (C7+C8 - Posterior interosseous nerve)
What are the origins of abductor pollicis longus?
Posterior surface (of proximal halves) of radius and ulna Interosseous membrane
What is the insertion of abductor pollicis longus?
Base of 1st metacarpal
What are the functions of abductor pollicis longus?
Abduction of thumb
Extension of thumb at CMC joint
Extension of wrist
What is the innervation to abductor pollicis longus?
Radial nerve (C7+C8 - Posterior interosseous nerve)
What are the origins of supinator?
Crest of ulna
Lateral epicondyle of humerus
Radial collateral and annular ligaments
What is the insertion of supinator?
Proximal 1/3 of lateral radius
What is the function of supinator?
Supination (rotates radius)
What is the innervation to supinator?
Radial nerve (C7+C8 - Deep branch/Posterior interosseous nerve)
What muscles in the anterior forearm does the radial nerve continue inferiorly between after piercing the lateral intermuscular septum?
Brachialis
Brachioradialis
Where does the radial nerve divide?
Anterior to the lateral epicondyle
How does the deep branch of the radial nerve reach the posterior forearm?
Passes through supinator laminae
What is the function of the superficial branch of the radial nerve?
Sensory cutaneous to dorsum of hand and fingers
Where does the radial artery run in the forearm?
Along a line joining the:
- Midpoint of cubital fossa AND
- Just medial to radial styloid
How does the radial artery enter the hand?
Winds around lateral aspect of wrist and crosses the anatomical snuffbox
What forms the anterior boundary of the anatomical snuffbox?
Tendons of:
- Abductor pollicis longus
- Extensor pollicis brevis
What forms the posterior boundary of the anatomical snuffbox?
Tendon of extensor pollicis longus
What forms the proximal boundary of the anatomical snuffbox?
Styloid process of radius
What forms the floor of the anatomical snuffbox?
Scaphoid (and trapezium)
What vein originates in the anatomical snuffbox?
Cephalic vein
What is the function of the dorsal expansion?
Allows long flexors and short hand muscles to act on all 3 finger joints (MCP, PIP and DIP)
What are the contents of the extensor retinaculum from lateral to medial?
- Abductor pollicis longus and extensor pollicis brevis
- Extensor carpi radialis longus and brevis
- Extensor pollicis longus
- Extensor indicis and extensor digitorum
- Extensor digiti minimi
- Extensor carpi ulnaris
What type of joints are the interphalangeal joints?
Synovial hunge
What type of joints are the MCP joints?
Synovial condyloid
What type of joint is the CMC joint in the thumb?
Synovial saddle
What type of joint is the CMC joint in the digits?
Synovial plane
What type of joints are the intercarpal joints?
Synovial plane
What are the origins of palmaris brevis?
Palmar aponeurosis
Flexor retinaculum
What is the insertion of palmaris brevis?
Dermis
What is the function of palmaris brevis?
Aid with palmar grip
What is the innervation to palmaris brevis?
Ulnar nerve (C8+T1 - Superficial branch)
What are the thenar muscles?
Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis
Adductor pollicis
What are the origins of abductor pollicis brevis?
Scaphoid
Trapezium
What is the insertion of abductor pollicis brevis?
Base of proximal phalanx of thumb
What is the function of abductor pollicis brevis?
CMC joint abduction in thumb
What is the innervation to abductor pollicis brevis?
Median nerve (C8+T1 - Recurrent branch)
What are the origins of flexor pollicis brevis?
Flexor retinaculum
Capitate
Trapezium
What is the insertion of flexor pollicis brevis?
Base of proximal phalanx of thumb
What is the function of flexor pollicis brevis?
CMC joint flexion in thumb
What is the innervation to flexor pollicis brevis?
Median nerve (C8+T1 - Recurrent) (+/- Ulnar nerve)
What is the origin of opponens pollicis?
Trapezium
What is the insertion of opponens pollicis?
1st metacarpal
What is the function of opponens pollicis?
CMC joint opposition of thumb
What is the innervation to opponens pollicis?
Median nerve (C8+T1 - Recurrent branch)
What are the origins of adductor pollicis?
Transverse head from 3rd metacarpal
Oblique head from capitate and 2nd/3rd metacarpals
What is the insertion of adductor pollicis?
Base of proximal phalanx of thumb
What are the functions of adductor pollicis?
Thumb CMC adduction
Thumb MCP joint flexion
What is the innervation to adductor pollicis?
Ulnar nerve (C8+T1 - Deep branch)
What is the origin of abductor digiti minimi?
Pisiform
What are the insertions of abductor digiti minimi?
Base of 5th proximal phalanx
Dorsal digital expansion
What are the functions of abductor digiti minimi?
Abduction and flexion of MCP joint of the little finger
What are the origins of flexor digiti minimi?
Hamate
Flexor retinaculum
What is the insertion of flexor digiti minimi?
Base of 5th proximal metacarpal
What is the function of flexor digiti minimi?
Flexion of MCP joint of little finger
What are the origins of opponens digiti minimi?
Hamate
Flexor retinaculum
What is the insertion of opponens digiti minimi?
5th metacarpal
What is the function of opponens digiti minimi?
Weak opposition of little finger
What are the hypothenar muscles?
Abductor digiti minimi
Flexor digiti minimi
Opponens digiti minimi
What is the innervation to the hypothenar muscles?
Deep branch of the ulnar nerve (C8+T1)
What is the common origin of the lumbrical muscles?
Tendons of flexor digitorum profundus
Which lumbrical muscles are unipennate?
1st (index)
2nd (middle)
Which lumbrical muscles are bipennate?
3rd (ring)
4th (little)
Which lumbrical muscles are supplied by the digital branch of the median nerve (C8+T1)?
1st and 2nd
Which lumbrical muscles are supplies by the deep branch of the ulnar nerve (C8+T1)?
3rd and 4th
Where do the lumbrical muscles insert?
Dorsal digital expansion
What are the functions of the lumbrical muscles?
MCP joint flexion of digits 2-4
ICP joint extension of digits 2-4
Where is the 1st palmar interossei?
From 2nd metacarpal to base of 2nd proximal phalanx and dorsal expansion
Where is the 2nd palmar interossei?
From 4th metacarpal to base of 4th proximal phalanx and dorsal expansion
Where is the 3rd palmar interossei?
From 5th metacarpal to base of 5th proximal phalanx and dorsal expansion
What are the functions of the palmar interossei?
Adduction (towards middle finger)
(Flex MCP joints)
(Extend IP joints)
What is the innervation to the palmar interossei?
Deep branch of the ulnar nerve (C8+T1)
What are the origins of the dorsal interossei?
From the sides of the 2 adjacent metacarpals (eg, 4th is from 4th and 5th etc)
What are the insertions of the 1st dorsal interossei?
2nd proximal phalanx
Digital dorsal expansion
What are the insertions of the 2nd and 3rd dorsal interossei?
3rd proximal phalanx
Digital dorsal expansion
What are the insertions of the 4th dorsal interossei?
4th proximal phalanx
Dorsal digital expansion
What are the functions of the dorsal interossei?
Abduction
(MCP flexion)
(IP extension)
What is the innervation to the dorsal interossei?
Deep branch of the ulnar nerve (C8+T1)
What artery contributes mostly to the superficial palmar arch?
Ulnar
What artery contributes mostly to the deep palmar arch?
Radial
What muscle does the radial artery run between the heads of to anastomose with the ulnar artery?
Adductor pollicis
What is the principal artery of the thumb and where does it run?
Princeps pollicis
Along medial aspect of 1st metacarpal