The hand Flashcards
What are the names of the digits and thumb?
Named NEVER by their numbers: Thumb, index finger, middle finger, ring finger and little finger.
What are the bones of the wrist and hand?
The radius
The ulna
The carpus (carpal bones): Proximal row (scaphoid, lunate, triquetrum, pisiform) and distal row (trapezium, trapezoid, capitate and hamate).
The metacarpal bones.
The phalanges (proximal, intermediate and distal bones).
What is the anatomy and articulations of the carpal bones?
Scaphoid – boat shaped.
Lunate – crescent shaped.
Triquetrum – three sided.
Pisiform – sesamoid bone in the tendon of the flexor carpi ulnaris.
Trapezium – irregular, thumb.
Trapezoid – four-sided, index finger.
Capitate – has a head, middle finger.
Hamate – has a hook, little and ring fingers.
What are the attachments of the flexor retinaculum?
Attached to the pisiform, hook of hamate, tubercle of the scaphoid and ridge of the trapezium.
Why is the blood supply of the scaphoid clinically important?
Its blood vessels tend to pass from distal to proximal. They can be interrupted by fracture of the waist of the bone, which can cut off the blood supply to its proximal portion causing a condition called avascular necrosis.
What does palmar and dorsal refer to in the hand?
Palmar = anterior surface in the anatomical position. Dorsal = posterior.
What are the compartments and spaces of the hand? (x5 and x2) What forms these compartments?
Thenar compartment
Adductor compartment
Hypothenar compartment
Central compartment
Interossei compartments.
There are also thenar and midpalmar spaces.
Compartments are separated by SEPTA – medial and lateral. The septa originate from the palmar aponeurosis. Medial septa extend to little finger metacarpal; lateral septa extend to middle finger metacarpal.
[Revision] Nomenclature of forearm muscles?
Flexors (anterior) and Extensors (posterior)
- Movers of the wrist (the “carpi” muscles) act on the radial (radialis) or ulnar (ulnaris) aspects of the forearm.
- Movers of the digits: act on GROUPS of digits (digitorum muscles) or on INDIVIDUAL digits (pollicis (thumb), indicis (index finger) digiti minimi (little finger)) (THESE MUSCLES ALSO CONTRIBUTE TO WRIST MOVEMENTS).
- Also note that if there’s a longus, there’s a brevis – meaning that if two muscles are named the same (because they have the same attachments), longus denotes that it’s the longest of the two, and brevis denotes it’s the shortest.
- If two muscles have the same name again, they can also be differentiated because one may be called superficialis (meaning it’s a superficial muscle), and one is called a profundus (meaning it’s deep).
- The main exceptions to this nomenclature are the muscles involved in pronation (anterior) and supination (posterior).
What do interossei refer to?
Interossei refer to compartments/muscles BETWEEN bones.
What are the intrinsic muscles of the hand for each compartment? !!!
THENAR MUCSLES Abductor pollicis brevis Flexor pollicis brevis Opponens pollicis ADDUCTOR MISCLES Adductor pollicis. HYPOTHENAR MUSCLES Abductor digiti minimi Flexor digiti minimi Opponens digiti minimi INTEROSSEI Lumbricals. Palmar interossei – adduct the digits (PAD). Dorsal interossei – abduct the digits (DAB).
What are the movements of the thumb? (x6)
Abduction, adduction, extension, flexion, opposition, reposition.
What are the attachments of the abductor pollicis brevis? Function?
PROXIMAL: trapezium/flexor retinaculum.
DISTAL: proximal phalanx of the thumb.
FUNCTON: abduct the thumb.
What are the attachments of the Flexor pollicis brevis? Function?
PROXIMAL: trapezium/flexor retinaculum. DISTAL: proximal phalanx of the thumb. FUNCTON: flexes the thumb.
What are the attachments of the Opponens pollicis? Function?
PROXIMAL: trapezium/flexor retinaculum.
DISTAL: palmar surface of metacarpal I.
FUNCTON: medially rotates the thumb – OPPOSITION.
What are the attachments of the adductor pollicis? Function?
PROXIMAL: TRANSVESE HEAD – metacarpal III (middle finger); OBLIQUE HEAD – capitate.
DISTAL: sesamoid bone of the MCP joint of the thumb.
FUNCTON: adducts the thumb.
What are the attachments of the abductor digiti minimi? Function?
PROXIMAL: pisiform/flexor carpi ulnaris tendon.
DISTAL: proximal phalanx of the little finger.
FUNCTON: abducts the little finger.
What are the attachments of the flexor digiti minimi? Function?
PROXIMAL: hamate/flexor retinaculum.
DISTAL: proximal phalanx of the little finger.
FUNCTON: flexes the little finger.
What are the attachments of the opponens digiti minimi? Function?
PROXIMAL: hamate/flexor retinaculum.
DISTAL: medical aspect of metacarpal V.
FUNCTON: laterally rotates the little finger.
What are the attachments of the lumbricals? Function?
PROXIMAL: flexor digitorum profondus tendon.
DISTAL: extensor hoods of fingers – towards axial line. Explanation of extensor hoods in later flashcard.
FUNCTON: flex the metacarpophalangeal joints and extend the interphalangeal joints.
There are 4 lumbricals. I attaches to medial border of index finger (in anatomical position i.e. on the side closest to the thumb); IV attaches between ring and little finger.
What are the attachments of the palmar interossei? Function?
PROXIMAL: sides of metacarpals.
DISTAL: extensor hoods of fingers – towards the axial line. Explanation of extensor hoods in later flashcard.
FUNCTON: adduct digits.
What are the attachments of the dorsal interossei? Function?
PROXIMAL: sides of metacarpals.
DISTAL: extensor hoods of fingers – towards the axial line. Explanation of extensor hoods in later flashcard.
FUNCTON: abducts digits.
How can the long extensor tendons be palpated?
Extend the wrist against resistance.
What is the thenar eminence? Surface anatomy?
Refers to is group of muscles. Look at photo for photo.
What is the hypothenar eminence? Surface anatomy?
Refers to is group of muscles. Look at photo for photo.
What is the fascia of the hand?
PALMAR FASCIA.
PALMAR APONEUROSIS is found beneath this. It is a triangular condensation of deep fascia that overlies the long flexor tendons of the hand. It is proximally continuous with the flexor retinaculum (an extension of the palmar carpal ligament), and distally continuous with the fibrous digital sheaths.
FIBROUS DIGITAL SHEATH – wrap around and contain the flexor tendons and their synovial sheaths.
What are the components of the anterior tendinous anatomy of the hand?
- FDS, FDP and FPL tendons (the FLEXOR TENDONS) pass through the carpal tunnel beneath the flexor retinaculum and are surrounded by a COMMON SYNOVIAL SHEATH for lubrication. The FPL has its own synovial sheath at the flexor retinaculum – it then run to the distal phalanx of the thumb.
- The tendons of the index, middle and ring finger then leave the common synovial sheath and enter DIGITAL SYNOVIAL SHEATHS, each inside the FIBROUS DIGITAL SHEATHS of each finger.
- The tendons of the thumb and little finger are also contained within fibrous digital sheaths, but their synovial sheaths are CONTINUOUS with the common synovial sheath.
- The FDP tendon is longer and terminates at the distal phalanx; FDS at the middle phalanx.
- Fibrous digital sheaths have ANNULAR and CRUCIFORM pulleys – ligaments which together form an OSSEO-FIBROUS TUNNEL in each digit.
- Photo – purple indicates synovial sheath.
What are alternative names for the FDS and FDP tendons? What is their anatomy in this context? !!!
FDS is known as the SUPERIOR FLEXOR TENDON, and FDP as the DEEP FLEXOR TENDON. The FDP therefore lies under the FDS as it travels up the phalanges. However, as mentioned, the FDP is longer than the FDS – therefore, where the FDS terminates at the middle phalanx, the FDP pierces the FDS tendon and becomes superficial – see photo.
What are the components of the posterior tendinous anatomy of the hand?
EXTENSOR RETINACULUM, much like its flexor counterpart, is a fascial tissue, but on the dorsal side of the hand and not as tough. It holds the EXTENSOR TENDONS down and prevents bowstringing during extension (where the tendons become released from the ligaments holding them down).
The synovial structure is the same as the anterior tendinous anatomy.
On the dorsum of the hand, INTER-TENDINOUS BANDS join long extensor tendons to each other. These prevent free movement of one extensor tendon independently of the others.
At the metacarpophalangeal joint, the extensor tendons EXPAND and form a complex EXTENSOR HOOD across the proximal and middle phalanx (aka ETENSOR EXPANSION). This flattening and expansion of tendons forms APONEUROSIS.
The hood has bands which provide attachments for extensor tendons. Therefore, when extensor tendons extend the phalanges, they are not pulling on bone; they are pulling on the hood.
Lumbrical and interossei also attach to the extensor expansions.
What are the extensor tendons? Only remember the capitalised tendons.
[MEDIALLY TO LATERALLY IN THE ANATOMICAL POSITION] Abductor pollicis longus, extensor pollicis brevis, extensor carpi radialis longus and brevis, extensor pollicis longus, EXTENSOR DIGITORUM (extends the ring, index, middle and little fingers), EXTENSO INDICIS extends the index finger, EXTENSOR DIGITI MINIMI (extends little finger) and extensor carpi ulnaris.
What is the anatomy of the metacarpophalangeal and interphalangeal joints?
MCP is found between metacarpal and proximal phalanx. IP is between phalanges – there is a proximal and distal – PIP and DIP. VOLAR PLATES (aka palmar ligament) are found at these joints on the palmar surface, as well as COLLATERAL LIGAMENTS, and reinforce the joint capsules. NB: volar plate is formed from condensation of collateral ligaments.
What are the arteries of the hand?
ULNAR ARTERY follows the FCU tendon at the wrist and gives off anterior and posterior interosseous branches in the forearm.
When the ulnar artery crosses the wrist, it divides to form the SUPERFICIAL PALMAR ARCH and deep palmar BRANCH on the palmar surface. The superficial palmar arch also receives a contribution from the superficial palmar branch of the radial artery.
The superficial palmar arch gives off three common palmar digital arteries which divide into palmar digital arteries.
Interosseus arteries of the ulnar supply the dorsal carpal arch (dorsal surface).
RADIAL ARTERY is found under the brachioradialis and besides the FCR at the wrist.
The radial artery anastomoses with the deep palmar BRANCH of the ULNAR ARTERY to form the DEEP PALMAR ARCH.
The deep palmar arch gives origin to the palmar metacarpal arteries.
Ulnar artery supplies mainly the index–>little finger.
Radial artery supplies mainly the index–>thumb.
The deep palmar is mainly supplied by the radial; the superficial palmar is mainly supplied by the ulnar.
What are the veins of the hand?
Superficial and deep systems.
SUPERFICIAL (most drainage): cephalic vein runs up lateral border of the arm and the basilic on the medial border, joining to form the dorsal venous network over the metacarpal bones. i.e. the superficial veins are formed from digital veins draining into a dorsal venous arch.
DEEP: run with arteries (ulnar and radial) to form deep venous arch – multiple of each vein running with a single artery i.e. there are many radial and ulnar veins.
What is the function and anatomy of the median nerve in the hand?
Lies between the FDS and FDP, deep to the PL (palmaris longus). Enters the carpal tunnel with the FDP, FDS and FPL.
MOTOR TO: thenar muscles (APB, FPB, OP) and lumbricals I and II.
SENSORY TO: index finger, middle finger, half the ring finger, and palmar surface of thumb.
What is the function and anatomy of the ulnar nerve in the hand?
At the wrist, lies by FCU and runs OVER the flexor retinaculum, lateral to the pisiform bone.
Divides into SUPERFICIAL BRANCH, SENSORY TO: palmar surfaces of little finger and half the ring finger.
And DEEP BRANCH, MOTOR TO: hypothenar muscles, adductor pollicis, lumbricals III and IV, and all interossei.
What is the function and anatomy of the radial nerve in the hand?
Divides just above the level of the elbow into
DEEP BRANCH – the interosseous nerve (motor) which does NOT go to the hand, and
SUPERFICIAL BRANCH – the superficial radial nerve (sensory) which is sensory of the dorsum (dorsal surface) of the hand.
SUMMARY: what is the cutaneous innervation of the hand?
Look at photo.
What is the anatomy of the carpal tunnel? Contents?
FLOOR: scaphoid, trapezoid, pisiform and hamate form the gutter.
ROOF: flexor retinaculum.
Contents: the median nerve and FLEXOR TENDONS (FPL tendon, 4 tendons of the FDP and 4 tendons of the FDS).
The ulnar nerve and ulnar artery are superior to the flexor retinaculum (go through the semi-rigid ulnar (Guyon’s) canal), while the extensor tendons lie below the carpal bones with the radial artery laterally.
What are the three types of grip? What muscles/tendons do they utilise?
POWER GRIP: long flexors of the finger and thumb, intrinsic muscles of the palm, and extensors of the wrist joint.
PRECISION GRIP: the wrist and fingers are held rigidly by the long flexors and extensors. The intrinsic muscles of the hand carry out fine movements needed.
HOOK GRIP: consumes little energy, mainly involves long flexors of digits.
What is the (i) proximal palmar skin crease, (ii) distal palmar skin crease, (iii) radial longitudinal crease?
See photo.
