3-4 Forearm and Hand. Muscles of the Forearm Anterior Compartment – Superficial layer –...
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Transcript of 3-4 Forearm and Hand. Muscles of the Forearm Anterior Compartment – Superficial layer –...
Muscles of the Forearm
• Anterior Compartment– Superficial layer– Intermediate layer– Deep layer
• Posterior Compartment– Superficial Layer– Deep Layer
Flexor Carpi Ulnaris•Origin•Humeral head—medial epicondyle; •ulnar head—olecranon and posterior border of ulna•Insertion•Pisiform bone (via pisohamate and pisometacarpal ligaments into the hamate and base of metacarpal V)•Innervation•Ulna nerve (C7, C8, T1)•Function•Flexes and adducts the wrist joint
Palmaris Longus•Origin•Medial epicondyle of humerus•Insertion•Palmar aponeurosis of hand•Innervation•Median Nerve (C7, C8)•Function•Flexes wrist joint;• because the palmar aponeurosis anchors the skin of the hand, contraction of the muscle resists shearing forces when gripping
Flexor Capri Radialis•Origin•Medial epicondyle of humerus•Insertion•Base of metacarpals II and III•Innervation•Median Nerve (C6, C7)•Function•Flexes and abducts the wrist
Pronator teres•Origin:•Humeral head—medial epicondyle and adjacent supraepicondylar ridge• ulna head—medial side of coronoid process•Insertion•Roughening on lateral surface, midshaft, of radius•Innervation•Median Nerve (C6-C7)•Function•Pronation
Flexor Digitorum Superficialis•Origin•Humero-ulnar head—medial epicondyle of the humerus and adjacent margin of coronoid process •radial head—oblique line of the radius•Insertion•4 Tendons, which attach to the palmar surfaces of the middle phalanges (index, middle, ring, and little fingers)•Innervation •Median nerve (C8, T1)•Function•Flexes proximal interphalangeal joints of the fingers; also flexes metacarpophalangeal joints
Flexor Digitorum Profundus•Origin:•Anterior and medial surfaces of the ulna and anterior medial half of interosseous membrane•Insertion•Four tendons, which attach to the palmar surfaces of the distal phalanges of the index, middle, ring and little finger•Innervation•Lateral half by median nerve (ant. Interosseous nerve); medial half by ulna nerve (C8, T1)•Function•Flexes distal interphalangeal joints of the fingers; can also flex metacarpophalangeal joints of same fingers and wrist joint
Flexor pollicis longus•Origin•Anterior surface of the radius and radial half of interosseous membrane•Insertion•Palmar surface of the base of distal phalanx of thumb•Innervation•Median Nerve (anterior interosseous n.) (C7, C8)•Function•Flexes interphalangeal joint of the thumb; can also flex metacarpophalangeal joint of the Thumb
Pronator quadratus•Origin•Linear ridge on distal anterior surface of ulna•Insertion•Distal anterior surface of radius•Innervation•Median Nerve (anterior interosseous nerve) (C7, C8)•Function•Pronation
Brachioradialis•Origin•Proximal part of lateral supraepicondylar ridge of humerus and adjacent intermuscular septum•Insertion•Lateral surface of distal end of radius•Innervation•Radial nerve (C5, C6) before division into superficial and deep branches•Function•Accessory flexor of elbow joint when forearm is midpronated
Extensor Carpi Radialis Longus•Origin•Distal part of lateral supraepicondylar ridge of humerus and adjacent intermuscular septum•Insertion•Dorsal Surface of base of metacarpal II•Innervation•Radial Nerve (C6, C7) before division into superficial and deep branches•Function•Extends and abducts the wrist
Extensor Carpi Radialis Brevis•Origin•Lateral epicondule of humerus and adjacent intermuscular septum•Insertion•Dorsal surface of base of metacarpals II and III•Innervation•Deep branch of radial nerve (C7, C8) before penetrating supinator muscle•Function•Extends and abducts the wrist
Extensor Digitorum•Origin•Lateral epicondyle of humerus and adjacent intermuscular septum and deep fascia•Insertion•4 tendons, insert via extensor hoods into the dorsal aspects of the bases of the middle and distal phalanges•Innervation•Posterior interosseous nerve (C7, C8)•Function•Extends the fingers; also can extend wrist
Extensor digiti minimi•Origin•Lateral epicondyle of humerus and adjacent intermuscular septum together with extensor digitorum•Insertion•Extensor hood of the little finger•Innervation•Posterior interosseous nerve (C7, C8)•Function•Extends the little finger•“Tea muscle”
Extensor Carpi Ulnaris•Origin•Lateral epicondyle of humerus and posterior border of ulna•Insertion•Tubercle on the base of the medial side of metacarpal V•Innervation•Posterior interosseous nerve (C7, C8)•Function•Extends and adducts the wrist
Anconeus•Origin•Lateral epicondyle of humerus•Insertion•Olecranon and proximal posterior surface of ulna•Innervation•Radial Nerve (C6, C7, C8)…via branch to medial head of triceps brachii)•Function•Abduction of the ulna in pronation; accessory extensor of the elbow joint
Supinator•Origin•Superficial part—lateral epicondule of humerus, radial collateral and unular ligaments•Deep part—supinator crest of the ulna•Insertion•Lateral surface of radius superior to the anterior oblique line•Innervation•Posterior interosseous nerve (C6, C8)•Function•Supination
Abductor pollicis longus•Origin•Posterior surfaces of ulna and radius (distal to the attachments of supinator and anconeus), and intervening interosseous membrane•Insertion•Lateral side of base of metacarpal I•Innervation•Posterior interosseous nerve (C7, C8)•Function•Abducts carpometacarpal joint of thumb; accessory extensor of the thumb
Extensor pollics brevis•Origin•Posterior surface of radius (distal to abductor pollicis longus) and the adjacent interosseous membrane•Insertion•Dorsal surface of base of proximal phalanx of the thumb•Innervation•Posterior interosseous nerve (C7, C8)•Function•Extends metacarpophalangeal joint of the thumb; can also extend the carpometacarpal joint of the thumb
Extensor pollicus longus•Origin•Posterior surface of ulna (distal to the abductor pollicis longus) and the adjacent interosseous membrane•Insertion•Dorsal Surface of base of distal phalanx or thumb•Innervation•Posterior interosseous nerve (C7, C8)•Function•Extends interphalangeal joint of the thumb; can also extend carpometacarpal and metacarpophalangeal joints of the thumb
Extensor indicis•Origin•Posterior surface of ulna (distal to extensor pollicis longus) and adjacent interosseous membrane•Insertion•Extensor hood of index finger•Innervation•Posterior interosseous nerve (C7, C8)•Funtion•Extends index finger
Intrinsic Muscles of the Hand
• Thenar Muscles – 3 muscles associated with the thumb– Thenar Eminence = the prominent swelling on the
lateral side of the palm at the base of the thumb• Hypothenar Muscles — 3 muscles associated
with the little finger – Hypothenar Eminence = The swelling on medial
side of the palm at the base of the little finger
Opponens pollicis•Origin•Tubercle of trapezium and flexor retinaculum •Insertion•Lateral margin and adjacent palmar surface of metacarpal I•Innervation•Recurrent branch of median nerve (C8, T1)•Function•Medially rotates thumb
Abductor pollicis brevis•Origin•Tubercles of scaphoid and trapezium and adjacent flexor retinaculum•Insertion•Proximal phalanx and extensor hood of thumb•Innervation •Recurrent branch of median nerve (C8, T1)•Function•Flexes thumb at metacarpophalangeal joint
Flexor Pollicis Brevis•Origin•Tubercle of the trapezium and flexor retinaculum•Insertion•Proximal Phalanx of the thumb•Innervation•Recurrent branch of median nerve (C8, T1)•Function•Flexes thumb at metacarpophalangeal joint
Opponens digiti minimi•Origin•Hook of hamate and flexor retinaculum•Insertion•Medial aspect of metacarpal V•Innervation•Deep branch of ulna nerve (C8, T1)•Function•Laterally rotates metacarpal V
Abductor Digiti Minimi•Origin•Pisiform, the pisohamate ligament, and tendon of flexor carpi ulnaris•Insertion•Proximal phalanx of little finger•Innervation•Deep Branch of ulna nerve (C8, T1)•Function•Abducts little finger at metacarpophalangeal joint
Flexor digiti minimi brevis•Origin•Hook of the hamate and flexor retinaculum•Insertion•Proximal phalanx of little finger•Innervation•Deep branch of ulna nerve (C8, T1)•Function•Flexes little finger at metacarpophalangeal joint
Adductor Pollicis•Origin•Transverse head—metacarpal III; Oblique head—capitate and bases of metacarpals II and III•Insertion•Base of proximal phalanx and extensor hood of thumb•Innervation•Deep branch of ulna nerve•Function•Adducts Thumb
Palmar (Unipennate) Interosseous (4 muscles)•Origin•Sides of metacarpals•Insertion•Extensor hoods of the thumb, index, ring and little fingers and the proximal phalanx of the thumb•Innervation•Deep Branch of ulna nerve (C8, T1)•Function•Adduction of the thumb, index, ring, and little fingers at the metacarpophalangeal joints
Dorsal (Bipennate) Interosseous muscles (4)•Origin•Adjacent sides of metacarpals•Insertion•Extensor hood and base of proximal phalanges of index, middle, and ring fingers•Innervation•Deep Branch of ulna nerve (C8, T1)•Function•Abduction of index, middle, and ring fingers at the metacarphphalangeal joints
Lumbricals (4 Muscles)•Origin•Tendons of flexor digitorum profundus•Insertion•Extensor hoods of index, ring, middle, and little fingers•Innervation•Medial 2 by the deep branch of the ulna nerve; lateral 2 by digital branches of the median nerve•Function•Flex metacarpophalangeal joints while extending interphalangeal joints
Common Digital branches •Lateral 4 Branches are from the Median n.•Medial 2 Branches are from the Ulna n.
Proper Digital Nerves•Note that the Proper Digital Nerves in the ring finger are branched from both the ulna and medial nerve