The hand Flashcards
How are the thumb and digits named?
Thumb Index Finger Middle Finger Ring Finger Little Finger
Name the carpal bones.
Scaphoid, Lunate Triquetrum, Pisiform
Trapezium, Trapezoid, Capitate, Hamate
What other bones make up the hand?
Metacarpals
Proximal, Middle + Distal Phalanges
How many radio-ulnar joints are there?
2: proximal + distal
Describe the distal articulation of the radius and ulna with the carpal bones.
Radius: articulates with scaphoid + lunate
Ulna: articulates with an articular disc
What separates the anterior and posterior compartments of the forearm?
Interosseous membrane
What type of bone is the pisiform bone?
Sesamoid: it is encased within flexor carpi ulnaris tendon
What are the four parts of the metacarpals?
Head (distal), tubercle, shaft + base
Which two carpal bones have bone protrusions?
Hook of Hamate
Tubercle of Trapezium
What type of skin do you get on the palms of your hands?
Palmar-plantar skin
Which muscle forms the palmar aponeurosis? (If present)
The distal end of palmaris longus
What is the palmar aponeurosis distally and proximally continuous with?
Distal: fibrous digital sheaths
Proximal: flexor retinaculum
What is contained within the fibrous digital sheaths?
Flexor tendons + their synovial sheaths
Which muscle tendons are found within the fibrous digital sheaths? Describe their attachments.
Flexor digitorum superficialis
Flexor digitorum profundus
FDS lies superficial to FDP + splits in 2 about midway up the proximal phalanx
FDP then runs between the 2 divisions of FDS
The 2 branches of FDS attach to the middle phalanx + FDP attaches to the distal phalanx
Which small quadrate muscle is found proximal to the hypothenar compartment?
Palmaris brevis
What is another name for the flexor retinaculum?
Transverse carpal ligament
Name the 4 compartments of the hand.
Thenar
Hypothenar
Adductor
Central
What separates the compartments of the hand?
Fibrous septa
From palmar aponeurosis to little finger metacarpal medially
From palmar aponeurosis to middle finger metacarpal laterally
What are the two main spaces found within the hand?
Midpalmar
Thenar
What structures do the septa form within the hand?
Channels that contain structures e.g. long flexors passing from the wrist into the digits
What does ‘carpi’ mean?
Acting on the wrist
What does ‘digitorum’ mean?
Acting on >1 finger
State the muscles in the superficial anterior compartment of the forearm.
Pronator teres (PT) Flexor carpi radialis (FCR) Palmaris longus (PL) Flexor digitorum superficialis (FDS) Flexor carpi ulnaris (FCU)
What is the name given to the proximal attachment of all of the superficial muscles of the forearm?
Common flexor origin (at medial epicondyle of the humerus)
What muscles are in the deep anterior compartment of the forearm?
Flexor digitorum profundus (FDP) Flexor pollicis longus (FPL) Pronator quadratus (FQ)
Where do the muscles in the deep anterior compartment of the forearm attach?
Flexor digitorum profundus (FDP)
Posterior + medial borders of ulna + interosseous membrane
To the distal phalanges of the 4 fingers
Flexor pollicis longus (FPL)
Interosseous membrane + anterior surface of radius
To palmar side of the distal phalanx of the thumb
Pronator quadratus (PQ)
Anterior surface of distal ulna
To anterior surface of distal radius
Which muscles of the anterior compartment do not cross the wrist?
Pronator quadratus + pronator teres
State the 12 muscles of the posterior compartment of the forearm.
Extensor carpi radialis longus (ECRL) Extensor carpi radialis brevis (ECRB) Extensor carpi ulnaris (ECU) Extensor indicis (EI) Extensor digitorum (ED) Extensor digiti minimi (EDM) Abductor pollicis longus (APL) Extensor pollicis longus (EPL) Extensor pollicis brevis (EPB) Brachioradialis Supinator Extensor retinaculum (not a muscle)
What is the common proximal attachment of most of the posterior forearm muscles?
Common extensor origin (just distal to the lateral epicondyle)
Which muscles have a proximal attachment along the ulna rather than the common extensor tendon?
Abductor pollicis longus (APL) Extensor pollicis longus (EPL) Extensor pollicis brevis (EPB) Extensor indicis (EI)
Describe the attachment of brachioradialis.
Distal lateral side of the humerus
To the lateral part of the styloid process of the radius
Name the intrinsic muscles of the hand.
Thenar: Abductor pollicis brevis (APB), Flexor pollicis brevis (FPB), Opponens pollicis (OP)
Hypothenar: Abductor digiti minimi (ADM), Flexor digiti minimi (FDM), Opponens digiti minimi (ODM)
Adductor: Adductor pollicis (AP)
Interossei + Lumbricals: Palmar interossei, Dorsal interossei, Lumbricals
What movements are the lumbricals responsible for?
Flexion of metacarpophalangeal joint (MCP)
Extension of the interphalangeal joints (IPJs)
What movements are the palmar and dorsal interossei responsible for?
PAD + DAB
Palmar = ADduction of fingers
Dorsal = ABduction of fingers
Which muscles are responsible for the following thumb movements:
Abduction: APL + APB Adduction: AP + 1st dorsal interosseus Extension: EPL, EPB, APL Flexion: FPL, FPB Opposition: Opponens pollicis
Why is adductor pollicis in a different compartment to the other pollicis muscles?
It is innervated by the ulnar nerve whereas the thenar muscles are all innervated by the median nerve
How many lumbricals, dorsal interossei and palmar interossei are there?
Lumbricals: 4
Dorsal interossei: 4
Palmar interossei: 3
Describe the attachments of the dorsal interossei and explain why they cause abduction of the fingers.
Attached proximally to adjacent metacarpals
They attach distally to the base of the proximal phalanx + extensor expansion towards the axial line (towards middle finger) of the hand
Dorsal interossei 2 + 3 are attached to opposite sides of the middle finger, fixing middle finger in the midline while dorsal interossei 1 + 4 cause abduction of the index + little fingers
Describe the attachments of the palmar interossei.
Attached to extensor expansion away from the axial line (no palmar interossei attached to the middle finger)
Cause adduction of the fingers whilst the middle finger remains still
Describe the attachments of the lumbricals.
Attached proximally to tendons of flexor digitorum profundus
Wrap around lateral side of the digits + insert into a hood of connective tissue: the extensor expansion, at the proximal interphalangeal joint
Describe the sheaths that that the tendons of flexor digitorum superficialis and flexor digitorum profundus travel in after passing under the flexor retinaculum.
Pass under flexor retinaculum in the carpal tunnel then enter a common synovial sheath
Those going to the middle 3 fingers enter digital synovial sheath, within its own digital sheath
Describe how the little finger and thumb sheaths are different to the other three fingers.
Their digital synovial sheaths are continuous with the common synovial sheath
Describe the arrangement and attachment of flexor digitorum superficialis and flexor digitorum profundus as it runs along the fingers.
FDS splits around FDP around the middle of the proximal phalanx
FDS then attaches to the middle phalanx
FDP attaches to the distal phalanx
What are the two types of pulley that hold the tendons down to the bone?
Annular
Cruciform
Describe the posterior tendinous anatomy of the hand.
Extensor retinaculum
Synovial tendon sheaths
Inter-tendinous bands
At the end of the long extensors there are extensor expansions
Which muscles attach to the extensor expansions?
Lumbricals + some interossei
What are the two fibrous capsules found at the wrist joint?
Radio-carpal joint
Distal radio-ulnar joint
Which two ligaments are found on the radial and ulnar sides of the wrist?
Radial Collateral Ligament
Ulnar Collateral Ligament
Which muscles are important for the following wrist movements:
Flexion:
Flexor carpi radialis
Flexor carpi ulnaris
(+ long flexors of the thumb + fingers + palmaris longus + abductor pollicis longus)
Extension: Extensor carpi radialis longus Extensor carpi radialis brevis Extensor carpi ulnaris (+ long extensors of the thumb + fingers)
Radial Deviation: Flexor carpi radialis Extensor carpi radialis longus Extensor carpi radialis brevis Abductor pollicis longus
Ulnar Deviation:
Flexor carpi ulnaris
Extensor carpi ulnaris
What is the name given to the joint between the proximal + distal row of carpal bones?
Midcarpal joint
Which carpal bone does the thumb metacarpal articulate with?
Trapezium
What movements are the metacarpophalangeal joints capable of?
Flexion + Extension
Abduction + Adduction
What ligament prevents hyperextension of the interphalangeal joints?
Palmar plates (AKA volar plates)
Which ligaments prevent abduction and adduction of the interphalangeal joints?
Collateral ligaments
What are the two main arteries of the hand and what do they divide into?
Ulnar Artery (beside FCU in wrist):
Interosseous arteries of the forearm
Superficial palmar arch: palmar digital arteries
Deep palmar branch
Radial Artery (under brachioradialis + beside FCR in wrist)
Found in anatomical snuff box
Deep palmar arch
Palmar metacarpal arteries
What are the anterior and posterior interosseous arteries a branch of?
Ulnar Artery
What is the arch on the dorsal side of the hand called?
Dorsal carpal arch
Where do you find anastomoses in the hand?
Between the dorsal + palmar digital arteries
The arches + plexuses are also places of anastomoses between the radial + ulnar arteries
What are the two main superficial veins of the arm?
Cephalic (lateral border of arm)
Basilic (medial border of arm)
What happens to the basilic and cephalic veins as they pass into the upper arm?
Basilic vein joins venae comitantes to form axillary vein
Cephalic vein joins the axillary vein in the axilla
At what point does the axillary vein become the subclavian vein?
At the level of the first rib
What pattern do the deep veins from the hand follow?
They pass in the opposite direction to the arteries
What vein links the cephalic and basilic vein in the cubital fossa?
Median cubital vein
Which spinal nerves contribute to the Ulnar, Median and Radial nerve?
Ulnar Nerve : C8-T1
Median Nerve: C6-T1
Radial Nerve: C5-T1
What is the main motor nerve of the hand?
Ulnar nerve
What is the radial nerve responsible for in the hand?
Sensory innervation of the lateral half of the dorsum of the hand
What type of nerve are the digital nerves?
Purely sensory because motor innervation to muscles controlling fingers happens more proximally
What are the contents of the carpal tunnel?
4 tendons of flexor digitorum superficialis
4 tendons of flexor digitorum profundus
Flexor pollicis longus tendon
Median nerve
Where does the median nerve lie relative to the forearm muscles at the wrist?
In between FDP + FDS
Deep to PL
What intrinsic hand muscles does the median nerve provide motor supply to?
LOAF Lumbricals (1 + 2) Opponens pollicis Abductor pollicis brevis Flexor pollicis brevis
What does the median nerve provide sensory supply to?
Palmar surface of thumb Index finger Middle finger Half of the ring finger Some of the dorsal surface of those digits
Describe the position of the ulnar nerve at the wrist.
It lies by flexor carpi ulnaris
It runs over the flexor retinaculum, lateral to the pisiform
What are the two branches of the ulnar nerve in the hand and what are their roles?
Superficial branch sensory to: palmar surfaces of Little finger + medial half of right finger Deep branch motor to: Hypothenar muscles Adductor pollicis Lumbricals 3 + 4 All the interossei (all muscles except LOAF)
The radial nerve divides into two branches just above the elbow. What are the two branches of the radial nerve?
Superficial radial nerve (sensory)
Posterior interosseous nerve (motor, deep)
Which part of the hand does the radial nerve supply sensory innervation to?
Dorsum of the hand (mainly thumb, index finger + middle finger)
NO motor supply to hand
What sensory branches does the median nerve give off before passing under the flexor retinaculum?
Palmar cutaneous branch
Dorsal digital branches
What branches do the superficial radial nerve and dorsal branch of the ulnar nerve split into?
Dorsal digital nerves/branches
What are the bony attachments of the carpal tunnel that forms a gutter?
Scaphoid
Trapezium
Pisiform
Hamate
What is the roof of the carpal tunnel?
Flexor retinaculum
Through which canal do the ulnar nerve and artery pass through?
Guyon’s Canal
What are the three different types of grip and which muscles are involved in each type?
Power Grip:
Long flexors of the fingers + thumb
Intrinsic muscles of the palm
Extensors of the wrist joint
Precision Grip:
The wrist + fingers are held rigidly by the long flexors + extensors
The intrinsic muscles of the hand carry out the fine movements needed
Hook Grip:
Consumes little energy
Mainly involves long flexors of the digits (e.g. carrying briefcase)
What is the function of the flexor retinaculum and extensor retinaculum?
To hold tendons to bones
Prevent bow-stringing
What do you call the joints between the adjacent proximal carpal bones or distal carpal bones? What occurs here?
Intercarpal joints
Gliding occurs here
What movements are the carpometacarpal and intermetacarpal joints capable of?
Flexion + extension
Radial + ulnar deviation
Circumduction
What movements are the interphalangeal joints capable of?
Flexion + Extension
