Wrist and Hand
Damage to ulnar nerve at wrist (in Guyon's canal)
"ulnar claw hand" at rest but preservation of flexion of DIP joints of digits 4 and 5 when making a fist. Paralysis of finger abduction and adduction. Loss of sensation on dorsal and palmar surface of digit 5 and half of 4.
2 sets of interosseous muscles
Arise from bodies of metacarpals and attach distally to extensor hood and bases of proximal phalanges. Produce opposite actions on abduction and adduction of digits 205. Through attachment of all interossei on extensor hood, these muscles also produce flexion of MP joints and extension of IP joints.
Opponens pollicis
Attaches distally along lateral margin of body of thumb. Pulls thumb toward longitudinal midline of hand and rotates it medially.
Proximal bases of metacarpal bones
Bound together with ligaments and joint capsules while heads of metacarpals held in position by superficial and deep transverse metacarpal ligaments.
Dermatomes and hand
C6 dermatome = innervates thumb C7 dermatome = innervates middle finger C8 dermatome = innervates pinky
Carpal tunnel
Contains flexor digitorum and flexor pollicis longus tendons as well as median nerve
Palmar carpal ligament
Continuation of deep antebrachial fascia on anterior surface of wrist
Deep fascia of hand
Covers hand and digits. Extension of antebrachial deep fascia. Deep fascia of dorsum is thin and covers dorsal interossei and bones. Palmar deep fascia is thin over thenar and hypothenar muscles. Deep fascia of rest of palm is thickened and called palmar aponeurosis.
Cartilaginous disc attachments
Disc is also called triangular ligament. It attaches between distal ends of radius and ulnar, thereby reinforcing distal radioulnar joint.
Wrist joint
Distal radius and ulna and proximal row of carpal bones form this joint
Fascial septa extend from deep fascia to metacarpals
Divide hand into compartments and spaces. Thenar compartment contains thumb muscles. Adductor pollicis compartment is recognized as separate space deep to thenar compartment. Hypothenar contains pinky muscles. Central (midpalmar) compartment is between thenar/hypothenar and contains flexor tendons, lumbricals, and superficial palmar arterial arch. Metacarpal bones and interosseous muscles contained in space bounded by deep fascia covering palmar/dorsal interosseous muscles.
DAB
Dorsal interosseous muscles ABduct fingers
Damage to ulnar nerve at elbow or above
Extension of MP joint and flexion of IP joints of digits 4 and 5 when hand is at rest (producing "ulnar claw"). Paralysis of flexion of DIP of digits 4 and 5 when making a fist. Paralysis of finger abduction and adduction. Loss of sensation over palmar and dorsal surfaces of medial hand and palmar surface of digit 5 and half of 4.
Which two flexor tendons pass through separate fibrous tunnels superficial to carpal tunnel as they cross the wrist?
Flexor carpi radialis tendon Flexor carpi ulnaris tendon
Nerves, vessels and tendons are ordered on anterior surface of wrist I
Flexor carpi ulnaris tendon is most medial (attaches to pisiform and through pisometacarpal ligaments to base of 5th metacarpal) Ulnar nerve is next to ulnaris tendon. Ulnar artery lies lateral to nerve (and both pass in a CT tunnel called Guyon's canal between palmar carpal ligament and flexor retinaculum). Palmaris longus tendon and flexor carpi radialis tendon also pass between palmar carpal ligament and flexor retinaculum
Radial bursa
Flexor pollicis longus tendon lies laterally in separate synovial sheath.
Flexor retinaculum attaches to these bones
Hook of Hamate bone Tubercle of Trapezium Tubercle of Scaphoid
Extended distal end of radius
Makes direct articulation with scaphoid and lunate bones (this is the radiocarpal joint)
What is the only nerve to pass through carpal tunnel?
Median nerve
Ulnar nerve for hand I
Motor to intrinsic muscles of hand but has significant sensory compartment as well. Palmar branch arises proximal to wrist and provides sensory innervation to medial palm. Dorsal branch provides sensation to posterior lateral dorsum of hand and dorsum of digits 4 and 5.
Ulnar bursa
One continuous synovial sheath encases all the flexor digitorum tendons at wrist. Usually continuous with sheath that surrounds 5th digit flexor tendons in finger.
Superficial branch of radial nerve
Only sensory. Supplies sensation to dorsum of lateral hand and digits 1, 2, and 3.
PAD
Palmar interosseous muscles ADduct fingers
Damage to radial nerve at or above elbow
Paralysis of wrist and finger extension thus producing "wrist drop" with inability to extend fingers. Loss of sensation to dorsum of lateral hand and dorsum of thumb and digits 2 and 3 to the nail bed. Damage to superficial branch of radial nerve in forearm would result in only sensory deficits in hand.
Radial artery
Passes latearlly around radius, crosses floor of anatomical snuffbox, and passes through 1st dorsal interosseous, then between the 2 heads of adductor pollicis. Gives rise to superficial palmar brach that anastomoses with superficial palmar arterial arch.
Veins of hand
Prominent in superficial space of dorsum. These form the dorsal venous arch; cephalic and basilic veins are derived from this plexus.
Anatomical snuff box
Shorthand for space between extensor pollicis longus and brevis tendons at wrist. Scaphoid and trapezium lie in bottom of snuff box and radial artery crosses snuffbox as it winds around wrist.
Extensor expansion (hood)
Specialized CT structure. Found on posterior surface of digits 2-5. Extensors of digits and most of intrinsic hand muscles have attachments to extensor hood.
Ulnar nerve for hand II
Superficial branch in hand supplies sensation to palmar surface of medial half of digit 4 and 5. Deep branch of ulnar innervates hypothenar muscles, adductor pollicis, lumbricals 3 and 4, and all interossei.
Dorsal surface of hand
Supplied by small branches from both radial and ulnar arteries. These contribute to a dorsal carpal arterial arch. From this arch will arise dorsal metacarpal arteries that pass distally toward fingers. Dorsal metacarpal arteries branch into dorsal digital arteries. Penetrating arteries from deep palmar arterial arch pass between metacarpal bones to anastomose with this dorsal arterial system.
Median nerve for hand I
Supplies both sensory and motor function to hand. Superior palmar branch arises from median proximal to carpal tunnel and supplies palm sensation. Median divides into 3 common palmar digital nerves which each divides into proper palmar digital branches that pass along side of digits 1 to half of 4. Median supplies sensation to palmar surfaces of digits 1 to half of 4 as well as to dorsum of tips of same fingers.
Distal branches of median, ulnar, and radial nerves
Supply cutaneous sensation to hand. These pass in superficial space.
Skin of dorsum of hand
Thin and pliable. But, skin of palmar surface is specialized. Superficial fascia of dorsum is also quite thin and free of fat.
Flexor retinaculum
Transverse carpal ligament. Not a component of deep fascia. It spans the anterior arch of carpal bones and forms CT roof of carpal tunnel.
Cartilaginous disc between ulna and wrist
Ulna doesnt articulate directly with carpal bones. Cartilaginous disc is located between ulna head and pisiform and triquetrum.
Damage to median nerve at or above elbow
Will compromise all sensory and motor functions supplied by the nerve. Relative to hand function: complete paralysis of flexion of digits 1-3 (producing "hand of benediction" when attempting to make a fist), paralysis of lumbricals 1 and 2, paralysis of thenar muscles (inability to oppose thumb), and loss of sensation over lateral palm and palmar surface of digits 1-3 and half of 4.
Anastomosis between common palmar digital arteries and palmar metacarpal arteries
Will give rise to proper palmar digital arteries that pass on either side of most fingers
Ulnar artery
enters hand lateral to pisiform bone. Gives rise to superficial palmar arch. From this arch will arise common palmar digital arteries that pass toward fingers. Superficial palmar branch anastomoses with deep palmar arch from radial artery.
Lumbrical muscles
Arise proximally from tendons of flexor digitorum profundus. Attach distally to lateral sides of extensor hood of digits 2-5. Contraction pulls on extensor hood; this produces flexion of MP joints and extension of IP joints.
Tendons of flexor digitorum profundus
Arranged in 1 layer (not 2 like superficiales)
Tendons of flexor digitorum superficiales
Arranged with tendons 3 and 4 superficial (anterior) to tendons 2 and 5
Nerves, vessels and tendons are ordered on anterior surface of wrist II
Median nerve is located just lateral to palmaris longus tendon (if that tendon is missing, median nerve is located in middle of anterior wrist). Radial artery emerges from underneath brachioradialis just lateral to flexor carpi radialis tendon. Radial artery at wrist passes laterally around radius and deep to extensor/abductor pollicis tendons where it passes across floor of anatomical snuff box.
Extensor digitorum tendons (includes minimi and extensor indicis tendons)
Attach to extensor hood and to phalanges. Central band of each extensor tendon attaches to base of middle phalanx. Lateral bands pass on either side of PIP and reunite to attach to base of distal phalanx. Extensor tendon merges with extensor hood. Extensor tendons have interconnections with each other as they pass through dorsum. No synovial sheaths on extensor tendons distal to wrist.
Fibrous digital sheath
Located on anterior surface of each digit. Attached to phalangeal bones and retains flexor digitorum tendons.
Thenar muscles
Move thumbs. 3 muscles. All 3 have proximal attachment to flexor retinaculum and tubercles of scaphoid and trapezium. Abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis.
Flexor pollicis longus tendon attachments
Base of distal phalanx. Housed inside digital sheath and protected inside separate synovial sheath.
Median nerve for hand II
Just distal to carpal tunnel, median gives rise to recurrent (motor) branch that innervates thenar muscles. Median also innervates lateral 2 lumbrical muscles.
Hypothenar muscles
Moves pinky. Muscles have common proximal attachment to flexor retinaculum, hamate, and pisiform. Each attach distally so as to accomplish the function described as their name. Abductor digiti minimi, Flexor digiti minimi brevis, and Opponens digiti minimi.
Palmaris brevis
Superficial muscle spreading transversely across hypothenar muscles
What are the 3 posterior compartment muscles tendons that attach to the thumb?
Abductor pollicis longus (attaches on anterior surface of base of 1st metacarpal). Extensor pollicis brevis tendon lies immediately posterior to abductor tendon and attaches on lateral part of base of proximal phalanx of thumb. Extensor pollicis longus tendon passes medial to dorsal tubercle of radius, passes along posterior surface of thumb to attach to base of distal phalanx. Synovial sheaths of these tendons dont extend past extensor retinaculum
Lymph from hand
Accompany both superficial and deep venous drainage to cubital nodes, to lateral (humeral) axillary nodes, or to those found adj to cephalic vein where it empties into axillary vein.
Abductor pollicis brevis
Attaches distally to anterior surface of base of 1st metacarpal.
Flexor pollicis brevis
Attaches distally to base of proximal phalanx of thumb
Extensor retinaculum
Extension of deep antebrachial fascia; spans dorsum of wrist and forms 6 separate tunnels through which pass extensor/abductor tendons
Adductor pollicis
Fan shaped muscle with 2 heads. Adducts thumb. Oblique head arises from middle carpal bones and adj metacarpal bases. Transverse head arises from middle of body of 3rd metacarpal. Both heads converge to single tendon that attaches distally to medial side of base of proximal phalanx of thumb.
Radial artery at base of thumb
Gives rise to 3 arteries: princeps pollicis artery (supplies thumb) radiailis indicis artery (supplies lateral side of 2nd digit) deep palmar arterial arch (continues medially across midpalmar compartment and will give rise to palmar metacarpal arteries that pass toward fingers)
Extensor retinaculum
Immediately adj to wrist bones and helps retain extensor/abductors tendons in place. CT septa extending from extensor retinaculum to wrist bones divides out 6 separate compartments
Cephalic and basilic veins distal origin
In dorsal venous plexus of hand. Deep veins of hand will drain to deep veins that accompany the branches of radial and ulnar arteries.
Anastomosis between radial and ulnar arteries in hand
Integrity of this anastomosis can be assessed with Allen's test.
Flexor digitorum tendons attachments
Superficiales tendons pass within fibrous digital sheath of each finger, split and attach on either side of middle phalanx. Profundus tendons pass within fibrous digital sheath deep (posterior) to superficiales tendons and attach to base of distal phalanx. Both tendons for each finger are contained in a single synovial sheath inside fibrous digital sheath.