Hand Flashcards
what joint type is thumb
first carpo-metacarpal joint which belongs to the thumb. this joint is a saddle-type joint
type of joints knuckles are and associated movements
The metacarpo-phalangeal (M-P) or knuckle joints are condyloid joints permitting flexion/extension, adduction/abduction, and some rotation.
The interphalangeal (IP) joints joint type and movements
drawing
pure hinge joints permitting flexion/extension only.
First carpometacarpal (thumb) joint
Movements
permits flexion / extension, abduction / adduction and a small amount of rotation. (this enables the thumb to ‘oppose’ the
fingers)
like a saddle on a horuse and legs of rider
-rider rolls in saddle could be flexion/extension
-rider leans back and foward adduction/abduction
-legs are far enough apart and saddle is narrow enough can be rotation
Hand anatomy
label diagram
Lecture slide
interphalangeal joints
-movement
-label
permits flexion / extension only
because 2 condyles cant adduct/abduct
Lecture slide
where are the deep transverse metacarpal ligaments and purpose
Note the deep transverse metacarpal ligaments between the heads of 2nd and 3rd, 3rd and 4th, and 4th and 5th metacarpals which stop the bones spreading too widely.
They are attached to the edges of the palmar ligaments of the metacarophalangeal joints. Palmar ligaments are also present at the IP joints and are crucial structures for their functional integrity.
label areas of metaCARPAL with ligaments, joint etc
Lecture Slide
Location of interossei muscles
The interossei muscles pass on the dorsal side of the transverse ligaments, the lumbrical muscles on the palmar side, to reach their insertion into the extensor hood.
Lecture Slide
Palmer aponeurosis and palmaris location
The palmar aponeurosis is a triangular fibrous sheet fanning out from the distal edge of the flexor retinaculum. The tendon of palmaris longus, when present, inserts into it after having crossed over the flexor retinaculum.
Fibrious septa location and form what 3 major compartments of the palm
From the medial and lateral edges of the aponeurosis, fibrous septa are sent dorsally to the bones and thus create three major compartments of the palm: a central one housing the long flexor tendons, lumbricals, etc., a lateral one housing the thenar muscles, and a medial one housing the hypothenar muscles
Spreading the fingers:
movement type
what allows this movement
Abduction (abducting from the hands midline = a line running down the length of the middle
digit)
- dorsal interossei (DI) acting on the 2nd, 3rd and 4th digits, and abductor digiti minimi (AbDM) on the little finger and abductor policis on thumg.
Extensor pollicis brevis and longus extend the thumb in the same plane as the palm, thus completing the spread of the hand.
**(“digits” includes thumb, “fingers” does not)
Abduction of thumb involves what?
Abduction of the thumb is in a plane at right angles to the palm and is accomplished by Abductor pollicis longus (AbPL) and Abductor pollicis brevis (AbPB) AND in order to abduc in same plane as fingers, need Extensor pollicis brevis/longus.
HAND abduction
DI: 2,3,4
abductor digiti minimi: 5
Extensor pollicis brevis/longus and Abductor pollicis longus/brevis: thumb
Adduction of digits is accomplished by what
Adduction of the digits is accomplished by the palmar interossei (PI) acting on the 1st, 2nd, 4th and 5th digits
The DI are responsible for moving the 3rd digit if required and Adductor pollicis (AdP, over page) will also act on the thumb adding strength to this movement.
PI: 1,2,4,5
DI: 3
Adductor pollicis - thumb
Neumonic to learn for abduction and adduction
DIMAB: Dorsal interossei insert Into Midline therefore they ABduct the fingers
**only act on middle 3 digits
** 2 origins, 2 metacarpals
POMAD = Palmar interossei insert Out from Midline therefore they ADduct the fingers
** 1 origin, 1 metacarpal
Label diagram showing abduction and adduction of the hand
Lecture Slide
Label the dorsal digitital expansion (extensor hood)
Lecture Slide
What allows flexion of intraphalnageal joints
via the insertion of the tendons of FDS and FDP into the bases of the middle and distal phalanges
How are metacarpophalangel joint flexed?
It is partially accomplished by FDS and FDP maximally shortening (eg making a tight fist) but fine control of MCP flexion is done by interossei and lumbricals, with their insertions into edges of the dorsal digital expansion hood (= aponeurosis) as this narrows over the proximal phalanx.
What allows opposition of thumb?
Opposition of the thumb to the other digits is accomplished by the opponens pollicis (OP) and opponens digiti minimi (ODM) acting together with other intrinsic hand muscles
Label the key areas on the complex movement of hand (Ex and Flex at same time, eg pinch)
- explain how pinching is possible
Lecture Slide
interossei run in front of pivot point of metacarpophalangeal joint on their way to DDEH so if the interossei on both sides of joint
contract at same time they will cause MCP joint to flex , at the same time as they pull on the DDEH, The distal part of the hood gets pulled backwards So they can help extend the IP joint at the same time
lumbricals can contribute to this when they contract they can pull the FDP tendon distally creatign slack in the FDP tendon on anterior surface of fingers to assist the extension of IP joints when the interossei pull back
Feature about interosssei
If u stimulate the interossei on both sides of the same metacarpal, their add/ab cancel and they can add to the flexing metacarpophalngeal joint and extending interphalanheal joint
FDP contracting while interossei and lumbricals relaxed = flexion of MCP & IP joints
FDP contracting while interossei and lumbricals contract = flexion of MCP joint but extension of IP joints
Thenar muscles:
what are they
Attach to what nerve
Adductor pollicis brevis, flexor pollicis brevis, opponens pollicis (all attach to digital expansion hood)
Median nerve
Hypothenar muscles
- what are they
- - attach to what nerve
Adductor digiti minimi, flexor digiti minimi, opponens digiti minimi
Ulnar nerve
difference between thenar and hypothenar muscles
both groups have 3 muscles (flexor, opponens, abductor)
Only diff is that thumb has another abductor (Abductor pollicis longus) and another flexor (flexor pollicis longus)
Where does the following hypothenar and thenar muscles attach to?
Abductor
flexors
Opponens
Abductors and flexors attach onto DDEH of appropiate digit
Opponens attach oto anteior border of metacarpals
Label diagram of thenar and hypothenar muscles
Lecture SLide
How does the ulnar nerve supply the hand, from top to bottom
The Ulnar nerve passes over the flexor retinaculum at the wrist, lies on the ulnar side of the ulnar artery, and divides into superficial and deep branches in the hand. The superifical supplies innervation to the little finger and the ulnar side of the ring finger; the deep branch supplies the hypothenar muscles and then cross the palm with the deep branch of the ulnar artery, lying on the metacarpals, and supplies the interossei, the medial two lumbricals, adductor pollicis.
How does the median nerve supply the hand, from top to bottom
The median nerve passes under the flexor retinaculum, lies directly under the palmar aponeurosis, and immediately breaks up into three common digital nerves which supply innervation via proper digital nerves to each side of the thumb and adjacent sides of 3rd and 4th and 2nd and 3rd digits; and one proper digital nerve to the radial side of the index finger. A recurrent branch supplies the thenar muscles.
Cutaneous innervation of the palm is by
palmar branches of the median and ulnar nerves
Forearm Blood supply
The ulnar artery passes to the wrist on FDP, with the ulnar nerve on its medial side. It gives off a short common interosseous artery which splits to form anterior and posterior interosseous arteries. The anterior descends on the interosseous membrane and supplies the deep muscles. It passes through a gap in the membrane just above PQ to supplement the blood supply to the lower part of the extensor compartment and dorsal carpal anastomosis. The posterior interosseous artery passes backwards above the interosseous membrane to supply the posterior compartment. The radial artery passes to the wrist on FPL, under cover of brachioradialis, with the superficial branch of the radial nerve on its lateral side.
Hand blood supply:
Label diagram
Lecture Slide
Label nerve supply to hand
lecture slide
What are the synvovial sheaths in the hand
- Sheaths around the long flexor tendons (FDP/FDS)
- Common synvovial sheath surrounding tendons going through flexor reticulum
The tendons of flexor muscles on fingers run in along what tunnel/ligament of the phalanges?
At the joints palmar ligaments form the floor of the fibro-osseus tunnels which house the long flexor tendons.
The lumbrical muscles arise from the tendons of..
Lumbricals movement
The lumbrical muscles arise from the tendons of the flexor digitorum profundus muscle
They bring about flexion of the metacarpophalangeal joints and extension of the interphalangeal joints.
