muscles of forearm Flashcards
The muscles of the snuffbox
Abductor Pollicis Longus
Extensor Pollicis Brevis
Extensor Pollicis Longus
Pronator teres(origin,insertion,action n innervation, blood supply)
Origin: Humeral head: medial epicondyle of humerus
Ulnar head: coronoid process
insertion:Lateral radius (distal to supinator insertion)
innervation: median nerve (C6-7)
Action: Elbow: weak flexor
Forearm: pronation
Flexor carpi radialis(origin,insertion,action n innervation, blood supply)
Origin:Medial epicondyle of humerus
insertion:Base of 2nd metacarpal (variance: base of 3rd metacarpal)
innervation:median nerve (C6-7)
Action:
Wrist: flexion and abduction (radial deviation) of hand
Palmaris longus(origin,insertion,action n innervation, blood supply)
Origin:Medial epicondyle of humerus
insertion:Palmar aponeurosis
innervation:innervation:median nerve (C7-8)
Action:
Elbow: weak flexion
Wrist: flexion tightens palmar aponeurosis
Flexor carpi ulnaris(origin,insertion,action n innervation, blood supply)
Origin: Humeral head: medial epicondyle
Ulnar head: olecranon
insertion:Pisiform; hook of hamate; base of 5th metacarpal
innervation:Ulnar nerve
Action:
Wrist: flexion and adduction (ulnar
deviation) of hand
Flexor digotirium superficialis (origin,insertion,action n innervation, blood supply)
Origin: Humeral head: medial epicondyle of humerus
Ulnar head: coronoid process
Insertion: Sides of middle phalanges of 2nd to 5th digits
innervation: median (C8-T1)
Action: Elbow: weak flexor Wrist, MCP, and PIP joints of 2nd to 5th digits: flexion
Flexor digitorum profundis( (origin,insertion,action n innervation, blood supply))
origin:Ulna (two thirds of flexor surface) and interosseous membrane)
Insertion:Distal phalanges of 2nd to 5th digits (palmar surface)
innervation: anterior interosseus membrane and ulnar nerve
Flexor pollicis longus (origin,insertion,action n innervation, blood supply)
Radius (midanterior surface) and adjacent interosseous membrane
insertion : Distal phalanx of thumb (palmar surface)
innervation: anterior interosseus membrane
Pronator quadratus (origin,insertion,action n innervation, blood supply)
origin:Distal quarter of ulna (anterior surface)
insertion: Distal quarter of radius (anterior surface)
innervation: anterior interosseus membrane
what is a flexor retinaculum and its action
THE FLEXOR TENDONS PASS DEEP or
SUPERFICIAL TO THE FLEXOR
RETINACULUM TO ENTER THE HAND.
The retinaculum prevents bowstringing
when the tendons are flexed at the
wrist. The flexor retinaculum attachment
and concavity of the carpal bones,
convert this area into a carpal tunnel
Definition : Fibrous band
bridging anterior concavity
of carpus & converts it into a
tunnel
FLEXOR RETINACULUM : ATTACHMENTS
medially and laterally
Medially :
(1) pisiform
(2) hook of hamate
Laterally :
(1) tubercle of scaphoid
(2) crest of trapezium
Brachioradialis (origin,insertion,action n innervation, blood supply)
origin:Distal humerus (distal surface), lateral intermuscular septum
insertion:Styloid process of the radius
innervation: radial nerve
actions: Elbow: flexion
Forearm: semipronation
Extensor carpi radialis longus (origin,insertion,action n innervation, blood supply)
origin: Lateral supracondylar ridge of distal humerus, lateral intermuscular septum
insertion: 2nd metacarpal (base)
innervation: radialnerve
Actions: Elbow: weak flexion
Wrist: extension and abduction
Extensor carpi radialis brevis (origin,insertion,action n innervation, blood supply)
Lateral epicondyle of humerus
insertion:3rd metacarpal (base)
innervation: posterior interosseus
actions:
Elbow: weak flexion
Wrist: extension and abduction
Extensor digitorum (origin,insertion,action n innervation, blood supply)
origin: Common head (lateral epicondyle of humerus)
insertion: Dorsal digital expansion of 2nd to 5th digits
innervation:Posterior interosseus nerve
Actions:
Wrist: extension
MCP, PIP, and DIP of 2nd to 5th digits: extension/abduction of fingers
C Extensor digiti minimi (origin,insertion,action n innervation, blood supply)
origin: Common head (lateral epicondyle of humerus)
Ulnar head (dorsal surface)
insertion: Dorsal digital expansion of 5th digit
innervation:Posterior interosseus nerve
actions:Wrist: extension, ulnar abduction of hand MCP, PIP, and DIP of 5th digit: extension and abduction of 5th digit
Extensor carpi ulnaris (origin,insertion,action n innervation, blood supply)
origin:Common head (lateral epicondyle of humerus)
insertion: Base of 5th metacarpal
innervation:Posterior interosseus nerve
actions: Wrist: extension, adduction (ulnar deviation) of hand
Supinator (origin,insertion,action n innervation, blood supply)
origin:Olecranon, lateral epicondyle of humerus, radial collateral ligament, annular ligament of radius
insertion: Radius (between radial tuberosity and insertion of pronator teres)
actions:
Radioulnar joints: supination forearm
Abductor pollicis longus (origin,insertion,action n innervation, blood supply)
origin: Radius and ulna (dorsal surfaces, interosseous membrane)
insertion:Base of 1st metacarpal
actions: Radiocarpal joint: abduction of the hand Carpometacarpal joint of thumb: abduction
Extensor pollicis brevis (origin,insertion,action n innervation, blood supply)
origin: Radius (posterior surface) and interosseous membrane
insertion: Base of proximal phalanx of thumb
Actions :
Radiocarpal joint: abduction (radial deviation) of hand
Carpometacarpal and MCP of thumb: extension
Extensor pollicis longus (origin,insertion,action n innervation, blood supply)
origin: Ulna (posterior surface) and interosseous membrane
insertion:Base of distal phalanx of thumb
actions:
Wrist: extension and abduction (radial deviation) of hand
Carpometacarpal of thumb: adduction
MCP and IP of thumb: extension
R Extensor indicis
origin: Ulna (posterior surface) and interosseous membrane
insertion:Posterior digital extension of 2nd digit Medial side
actions: Wrist: extension
MCP, PIP, and DIP of 2nd digit extension
EXTENSOR RETINACULUM
medially and lateral attachments
Definition : Deep fascia of back of wrist thickened for holding extensor tendons. Prevents bowstringing when the tendons are extended at the wrist
Attachments :
Laterally:
to the lower part of the anterior
border of radius
Medially:
(1) the styloid process of ulna
(2) triquetral
(3) pisiform
weak flexors of the elbow
pronator teres
palmaris longus
flexor digitorium superficialis
extensor carpi radialis longus and brevis
