A: Forearm + hand Flashcards
What muscles are responsible for pronation?
Pronator teres + pronator quadratus
Supination muscle
Biceps brachii + Supinator
What are the superficial muscles in forearm?
Pronator teres, Flexor carpi radialis, Palmaris longus, Flexor carpi ulnaris.
Intermediate muscles in forearm?
Flexor digitorum superficialis
Deep muscles in forearm?
Flexor digitorum profundus- flexes fingers
Flexor pollicus longus - flexes thumb
Pronator quadratus
Innervation of muscles in forearm
Median nerve innervates all muscles in anterior forearm, except flexor carpi ulnaris & flexor digitorum profundus (medial half). These are both innervated by the ulnar nerve.
Dupuytren’s contracture syndrome
When palmar aponeurosis tightens
Carpal tunnel structure
Roof = flexor retinaculum
Floor + side = carpal bones
What is in the carpal tunnel
Carpal tunnel contains:
- 4 tendons from flexor digitorum superficialis
- 4 tendons from flexor digitorum profundus
- Tendon of flexor pollicus longus
- Median nerve
Flexor digitorum superficialis movement
Flexor digitorum superficialis can flex wrist, knuckle, and proximal interphalangeal joint on finger but not the distal interphalangeal joint.
Flexor digitorum profundus movement
Can flex wrist, knuckle and both finger joints.
Short muscles of thumb
- Abductor pollicis brevis
- Flexor pollicis brevis
- Opponens pollicis
How are short muscles of thumb innervated?
Median nerve
Muscles for little finger
- Abductor digiti minimi
- Flexor digiti minimi brevis
- Opponens digiti minimi
How are muscles for little finger innervated
ulnar nerve
Injury to median nerve in carpal tunnel:
- Numbness to lateral 3.5 digits.
- Palm skin not affected
- Thenar muscles paralysed, so loss of opposition.
- Flexion + abduction of thumb weakened.
Injury to median nerve due to wrist laceration
- Numbness to lateral 3.5 digits + posterior distal parts of digits + skin of palm
- Thenar muscles paralysed, so loss of opposition.
- Flexion + abduction of thumb weakened.
- Paralysis of lateral two lumbricals –> impaired fine control movements of index + middle fingers.
Injury to median nerve in elbow
- Pronation is weak or lost.
- Wrist flexion is weak & associated with ulnar deviation (flexor carpi ulnaris is unopposed). – Wrist abduction is weak.
- Flexion of index & middle fingers is absent, & flexion is weakened in ring & little fingers grip is weak.
- Thumb: Opposition & flexion of distal phalanx are lost; thumb abduction is weak.
What muscles in anterior compartment + skin does ulnar nerve supply?
flexor carpi ulnaris + medial half of flexor digitorum profundus.
Supplies skin on medial 1.5 digits, medial part of back of hand + medial side of palm
Superficial branch of ulnar nerve innervation?
Supplies skin on anterior surface of medial 1.5 digits.
Deep branch of ulnar nerve?
innervates all small muscles of hand except 3 thenar muscles, lateral 2 lumbricals.
Injury to ulnar at wrist from laceration superficial to flexor retinaculum
Numbness over palmar aspect of medial 1.5 digits + medial palm.
- Paralysis of adductor pollicis = cannot adduct thumb.
- paralysis of palmar + dorsal interossei = cannot adduct or abduct fingers.
Where is the ulnar nerve vulnerable to injury?
Posterior to medial epicondyle - fracture
Wrist - laceration
Why is skin of the palm not affected in Carpal Tunnel Syndrome?
Palmar cutaneous branch of median nerve arises in the forearm & enters hand by passing superficial to flexor retinaculum (i.e. not through carpal tunnel).
Injury to ulnar nerve at elbow
Sensory loss: Both palmar and dorsal aspects of the little finger and medial 1⁄2 ring finger and of those parts of the hand proximal to them.
Motor: loss of adduction/abduction of fingers (hollowing between metacarpals with time); loss of thumb adduction (Frommet’s sign).
Injury to ulnar nerve at elbow
Sensory loss: Both palmar and dorsal aspects of the little finger and medial 1⁄2 ring finger and of those parts of the hand proximal to them.
Motor: loss of adduction/abduction of fingers (hollowing between metacarpals with time); loss of thumb adduction (Frommet’s sign).
A ‘claw hand’ deformity may result from a lesion of which nerve? Explain how?
Paralysis of medial 2 lumbricals: affects ring & little fingers —> hyperextension of MP joints (long flexors unopposed) & flexion of IP joints (extensors unopposed).
Name this vessel and identify its main source of blood
Superficial palmar arch, ulnar artery
Carpal tunnel syndrome?
Sensory loss: anterior aspect of lateral 3 1⁄2 fingers and nail beds (not palm). Motor: paralysis of thenar muscle of thumb (tying shoes/clumsy), loss of opposition. Flattening of thenar eminence with time. ‘Ape Hand (Simian Hand) deformity’.
What is the action of palmar interosseous muscle? How to test for it?
Adduction of fingers
Put a piece of paper between adjacent fingers and ask the patient to squeeze them together with sufficient force to hold the paper.
What is precision grip? What muscles?
Precision Grip where there is a change in position of object that is held (fine control of movements of digits) e.g. writing, buttoning shirt.
Long flexor & extensor muscles hold wrist joint and joints of digits, Intrinsic hand muscles control fine movements of digits: interossei, lumbricals, opponens pollicis, thenar muscles.
Identify this nerve
Digital branch of median nerve
Following an injury to the elbow region, a patient complains of a tingling sensation of the skin of the little finger. You suspect a nerve injury. Weakness of which movement(s) will confirm the most likely diagnosis?
Wrist flexion is weak & associated with radial deviation (flexor carpi radialis is unopposed).
Distal phalanges of little and ring fingers cannot be flexed (FDP). Unable to adduct the thumb.
Unable to adduct or abduct the fingers (interrosei).
‘Claw hand’ deformity: hyperextension of MP joints of ring & little
fingers & flexion of IP joints (medial 2 lumbricals).
What is power grip?
Power Grip: entire hand is used e.g. holding a hammer.
Long flexor muscles (Flexor digitorum superficialis, Flexor digitorum profundus, Flexor pollicis longus) & wrist extensors (extensor carpi ulnaris, extensor carpi radialis) which hold wrist in extension.
Flexor digitorum superficialis (origin, insertion, action, nerve supply)
- Common flexor origin, upper radius + ulna
- Anterior surface of middle phalanges of index, middle, ring and little fingers
- Flexes fingers at PIP and MP joint, flexes wrist
- Median nerve
Flexor digitorum profundus (origin, insertion, action, nerve supply)
- Anterior surface of upper ulna adjacent interosseous membrane
- Anterior surface of base of distal phalanges of index, middle, ring and little fingers
- Flexes fingers at PIP and DIP joints, flexes MP joints, flexes wrist
- lateral half by interosseous branch of median nerve, medial half by ulnar nerve
Flexor pollicis longus (origin, insertion, action, nerve supply)
- Anterior surface of radius. and adjacent interosseous membrane
- Anterior surface of base of distal phalanx of thumb
- Flexes thumb at IP and MP joints
- Anterior interosseous branch of median nerve
Flexor carpi radialis (origin, insertion, action, nerve supply)
- common flexor origin
- Bases of 2nd and 3rd metacarpal bones
- Flexes wrist, aids in abuction of wrist
- Median nerve
Palmaris longus (origin, insertion, action, nerve supply)
- Common flexor origin
- Palmar aponeurosis
- Flexes wrist and wrinkles skin of palm of hand
- Median nerve
Flexor carpi ulnaris (origin, insertion, action, nerve supply)
- Common flexor origin, upper ulna
- Pisiform, through ligaments to hamate, base of 5th metacarpal
- Flexes wrist, aids in adduction of wrist
- Ulnar nerve
Pronator teres (origin, insertion, action, nerve supply)
- Common flexor origin & upper ulna
- Lateral surface of shaft of radius
- Pronates forearm
- Median nerve
Pronator quadratus (origin, insertion, action, nerve supply)
- Distal anterior surface of ulna
- Distal anterior surface of radius
- Pronates forearm
- Anterior interosseous branch of median nerve
Abductor pollicis brevis (origin, insertion, action, nerve supply)
- Flexor retinaculum, scaphoid + trapezium
- Proximal phalanx of thumb
- Abducts thumb at MP joint
- Median nerve
Flexor pollicis brevis (origin, insertion, action, nerve supply)
- Flexor retinaculum, trapezium
- Proximal phalanx of thumb
- Flexes thumb at MP joint
- Median nerve
Opponens pollicis (origin, insertion, action, nerve supply)
- Flexor retinaculum + trapezium
- 1st metacarpal
- Opposition of thumb
- Median nerve
Adductor policis (origin, insertion, action, nerve supply)
- Oblique head: wrist bones. Transverse head: 3rd metacarpal
- Proximal phalanx of thumb
- Adducts thumb
- ulnar nerve
Abductor digiti minimi (origin, insertion, action, nerve supply)
- Wrist bones
- Proximal phalanx of little finger
- Abducts little finger at MP joint
- Ulnar nerve
Flexor digiti minimi (origin, insertion, action, nerve supply)
- Flexor retinaculum, wrist bones
- Proximal phalanx of little finger
- Flexes little finger at MP joint
- Ulnar nerve
Opponens digiti minimi (origin, insertion, action, nerve supply)
- Flexor retinaculum, wrist bone
- 5th metacarpal
- Opposition of little finger
- Ulnar nerve
4 Palmar interossei (origin, insertion, action, nerve supply)
- Sides of metacarpal bones
- Extensor hoods
- Adduct thumb, index, ring and little finger, assist lumbricals
- Ulnar nerve
4 Dorsal interossei (origin, insertion, action, nerve supply)
- Adjacent sides of metacarpal bones
- Extensor hoods
- Abduct index, middle + ringer fingers, assist lumbricals
- Ulnar nerve
4 Lumbricals
- Tendons of flexor digitorum profundus
- Extensor hoods
- Flexion of MP joint and extension of IP joint
- Median nerve: 2 lateral lumbricals. Ulnar nerve = 2 medial lumbricals.
List the muscles that cause adduction at shoulder
Pectoralis major, Latissimus dorsi, Teres major, Coracobrachialis, Triceps.
Where would you find the ulnar artery pulse
Lateral to tendon of flexor carpi ulnaris
