Hand & Structures Flashcards
What are the compartments of the hand?
Thenar, hypothenar, central, and adductor interosseous
What are the muscles of the thenar compartment? What innervate them?
Abductor pollicis Brevis, flexor pollicis Brevis, and opponens pollicis
Movement/positioning of the 1st digit
Median nerve
What are the muscles of the hypothenar compartment muscles? What innervate it?
abductor digiti minimi, flexor digiti minimi, and opponens digiti minimi
Positioning/movement of 5th digit
Ulnar nerve
What are the muscles of the central compartment? What innervates it?
Lumbricals, tendons of flexor digitorum superficialis, tendons of flexor digitorum profundus
What is the function of the lumbricals?
Flexion at MCP joints and extension at IP joints (1st and 2nd innervated by median and 3rd and 4th innervated by ulnar nerve)
What limits the central compartment anteriorly?
Palmar aponeuroses
What limits the central compartment laterally?
Thenar septum
What limits the central compartment medially?
hypothenar septum
What limits the central compartment inferiorly?
Palmar interousseus fascia
What are the muscles of the adductor-interosseous compartment?
Adductor pollicis
Palmar interossei (3 muscles)
Dorsal interossei (4 muscles)
ALL innervated by ulnar nerve
What is the function of the adductor pollicis?
Adducts/positions 1st digit
Ulnar nerve
What is the function of the 3 palmar interossei muscles?
Adducts digits 2, 4, 5
Ulnar nerve
What is the function of the 4 dorsal interossei muscles?
Abducts digits 2, 3, 4
Ulnar nerve
Describe the flexor retinaculum
Inelastic connective tissue band extending laterally from scaphoid to trapezium and medially from pisiform to hammate
What does the flexor retinaculum form the root of?
Carpal Tunnel
What is the extensor retinaculum?
connective tissue band present on posterior wrist
What do retinacula prevent?
Bowing of tendons when muscles contract
What are synovial sheaths?
Enclose tendons of the flexor and extensor muscles to reduce friction during movement
What are the digital fibrous sheaths?
Fibrous bands superficial to synovial sheaths in fingers that prevent bowing of tendons during muscle contraction
What is the carpal tunnel?
Passageway between flexor retinaculum & carpal bones containing tendons
Which tendons are in the carpal tunnel? What innervates them?
Flexor digitorum superficialis, flexor digitorum profundus, flexor pollicis longus
Median nerve
Describe carpal tunnel syndrome
Compression of median nerve
Burning, tingling, itching, and numbness in thumb, middle, and index fingers
Progresses to decrease in grip strength, motor loss, and thenar eminence muscle waste
3x more likely in women
Treatment: rest, decrease activity, anti-inflammatory medication, and surgery
What forms the palmar arch?
Radial aa and ulnar aa superficial to flexor retinaculum and anastomose
What is the purpose of the palmar arch?
To continue blood supply to hand if either ulnar aa or radial aa is blocked
Where do common palmar digital arteries originate?
Superficial palmar arch
Where do proper palmar digital arteries branch from?
Branches from common palmar digital aa and supplies contiguous sides of 2nd-5th digits
Where does deep palmar arch anastomosis between?
Radial and ulnar artery branches
What are the branches of deep palmar arch that supplement superficial palmar arch by way of anastomoses with common palmar digital aa?
Palmar metacarpal aa
What is the principal blood supply for thumb and radial side of index fingers, respectively?
Princeps pollicis a. And radial indices a.
What is the anatomical snuffbox (radial fossa) bounded by?
Tendon of extensor pollicis longus posteriorly
Tendons of extensor pollicis Brevis
Abductor pollicis longus anteriorly
What artery passes through the anatomical snuff box?
Radial - can take pulse here
What bones form the floor of the snuff box?
Scaphoid and trapezium
What is the most commonly broken carpal bone?
Scaphoid
