The hand part 2 Flashcards
List the joints of the hand region
Distal radio-ulnar joint Wrist joint Intercarpal joints Carpo-metacarpal and inter-metacarpal joints Metacarpo-phalangeal joints Interphalangeal joints
Describe the muscles involved in the different movements of the wrist joints
Flexion
FCR and FCU – important
Long flexors of thumb and fingers
(PL, APL)
Extension
ECRL, ECRB, ECU – important
Long extensors of the thumb and fingers
Radial deviation
APL, FCR, ECRL, ECRB
Ulnar deviation
ECU, FCU
Summarise the intercarpal joints
Joints between the proximal row
scaphoid, lunate, triquetral, pisiform
Joints between the distal row
trapezium, trapezoid, capitate, hamate
Joints between the proximal and distal rows
the midcarpal joint
“gliding occurs at these joints”
Describe the structure of the carpal joints and the movements that they facilitate
The synovial joints between the carpal bones share a common articular cavity. The joint capsule of the joints is reinforced by numerous ligaments.
Although movement at the carpal joints (intercarpal joints) is limited, the joints do contribute to the positioning of the hand in abduction, adduction, flexion, and, particularly, extension.
Summarise the carpometacarpal joints
CMC of the thumb – clinically important (trapezium to thumb metacarpal) CMC of digits Movements are; flexion and extension radial deviation and ulnar deviation circumduction
Describe the carpometacarpal joint of the thumb and its clinical importance
The saddle joint, between metacarpal I and the trapezium, imparts a wide range of mobility to the thumb that is not a feature of the rest of the digits. Movements at this carpometacarpal joint are flexion, extension, abduction, adduction, rotation, and circumduction.
The carpometacarpal joint of the thumb (pollex), also known as the first carpometacarpal joint, or the trapeziometacarpal joint (TMC) because it connects the trapezium to the first metacarpal bone, plays an irreplaceable role in the normal functioning of the thumb. The most important joint connecting the wrist to the metacarpus, osteoarthritis of the TMC is a severely disabling condition; up to twenty times more common among elderly women than in average.[1]
Pronation-supination of the first metacarpal is especially important for the action of opposition.[1] The movements of the first CMC are limited by the shape of the joint, by the capsulo-ligamentous complex surrounding the joint, and by the balance among involved muscles. If the first metacarpal fails to sit well ‘on the saddle’, for example because of hypoplasia, the first CMC joint tends to be subluxated (i.e. slightly displaced) towards the radius
Describe the carpometacarpal joints of the digits
There are five carpometacarpal joints between the metacarpals and the related distal row of carpal bones
The carpometacarpal joints between metacarpals II to V and the carpal bones are much less mobile than the carpometacarpal joint of the thumb, allowing only limited gliding movements. Movement of the joints increases medially, so metacarpal V slides to the greatest degree. This can be best observed on the dorsal surface of the hand as it makes a fist.
What joints are found between the metacarpals
Intermetacarpal joints
What are the metacarpophalangeal joints
The joints between the distal heads of the metacarpals and the proximal phalanges of the digits are condylar joints, which allow flexion, extension, abduction, adduction, circumduction, and limited rotation (Fig. 7.92). The capsule of each joint is reinforced by the palmar ligament and by medial and lateral collateral ligaments.
Describe the two parts of the lateral collateral ligaments of the MCP joints
Cord like part
Fan like part
Summarise the interphalangeal joints
Flexion and extension only Proximal Interphalangeal PIP Distal Interphalangeal DIP IP (thumb) volar plate
Summarise the interphalangeal joints of the hand
The interphalangeal joints of the hand are hinge joints that allow mainly flexion and extension. They are reinforced by medial and lateral collateral ligaments and palmar ligaments.
Explain why we don’t see abduction and adduction of the interphalangeal joints
The collateral ligaments are in place to prevent abduction or adduction of the interphalangeal joins as they are not stable on there own.
Describe the transverse metacarpal ligaments
The three deep transverse metacarpal ligaments (Fig. 7.93) are thick bands of connective tissue connecting the palmar ligaments of the metacarpophalangeal joints of the fingers to each other. They are important because, by linking the heads of the metacarpal bones together, they restrict the movement of these bones relative to each other. As a result, they help form a unified skeletal framework for the palm of the hand.
Where does a deep transverse metacarpal ligament not occur
Significantly, a deep transverse metacarpal ligament does not occur between the palmar ligament of the metacarpophalangeal joint of the thumb and the palmar ligament of the index finger. The absence of this ligament, and the presence of a saddle joint between metacarpal I and the trapezium, are responsible for the increased mobility of the thumb relative to the rest of the digits of the hand.
What ligament prevents hyperextension of the interphalangeal joints?
Palmar plates (AKA volar plates)
What happens to the dorsal extensor expansion as it approaches the distal phalanx
It narrows out- allowing us to extend the digit
Summarise the arterial supply of the hand
The blood supply to the hand is by the radial and ulnar arteries, which form two interconnected vascular arches (superficial and deep) in the palm (Fig. 7.105). Vessels to the digits, muscles, and joints originate from the two arches and the parent arteries:
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The radial artery contributes substantially to the supply of the thumb and the lateral side of the index finger.
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The remaining digits and the medial side of the index finger are supplied mainly by the ulnar artery.
Describe the passage of the ulnar artery and its contribution to the superficial palmar arch
Lateral to FCU at wrist
The ulnar artery and ulnar nerve enter the hand on the medial side of the wrist (Fig. 7.106). The vessel lies between the palmaris brevis and the flexor retinaculum and is lateral to the ulnar nerve and the pisiform bone. Distally, the ulnar artery is medial to the hook of the hamate bone and then swings laterally across the palm, forming the superficial palmar arch, which is superficial to the long flexor tendons of the digits and just deep to the palmar aponeurosis. On the lateral side of the palm, the arch communicates with a palmar branch of the radial artery.
Describe the contribution of the ulnar artery to the deep palmar arch
One branch of the ulnar artery in the hand is the deep palmar branch (Figs. 7.105 and 7.106), which arises from the medial aspect of the ulnar artery, just distal to the pisiform, and penetrates the origin of the hypothenar muscles. It curves medially around the hook of the hamate to access the deep plane of the palm and to anastomose with the deep palmar arch derived from the radial artery.
Describe the branches from the superficial palmar arch
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a palmar digital artery to the medial side of the little finger, and
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three large, common palmar digital arteries, which ultimately provide the principal blood supply to the lateral side of the little finger, both sides of the ring and middle fingers, and the medial side of the index finger (Fig. 7.106); they are joined by palmar metacarpal arteries from the deep palmar arch before bifurcating into the proper palmar digital arteries, which enter the fingers.
Describe the passage of the radial artery
Under brachioradialis and medial to FCR at the wrist
The radial artery curves around the lateral side of the wrist and passes over the floor of the anatomical snuffbox and into the deep plane of the palm by penetrating anteriorly through the back of the hand (Figs. 7.105 and 7.107). It passes between the two heads of the first dorsal interosseous muscle and then between the two heads of the adductor pollicis to access the deep plane of the palm and form the deep palmar arch.
The deep palmar arch passes medially through the palm between the metacarpal bones and the long flexor tendons of the digits. On the medial side of the palm, it communicates with the deep palmar branch of the ulnar artery
Before penetrating the back of the hand- what vessels does the radial artery give off
Before penetrating the back of the hand, the radial artery gives rise to two vessels:
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a dorsal carpal branch, which passes medially as the dorsal carpal arch, across the wrist and gives rise to three dorsal metacarpal arteries, which subsequently divide to become small dorsal digital arteries, which enter the fingers; and
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the first dorsal metacarpal artery, which supplies adjacent sides of the index finger and thumb.
Which vessels arise form the radial artery in the plane between the first interosseous and the adductor pollciis
Two vessels, the princeps pollicis artery and the radialis indicis artery, arise from the radial artery in the plane between the first dorsal interosseous and adductor pollicis. The princeps pollicis artery is the major blood supply to the thumb, and the radialis indicis artery supplies the lateral side of the index finger.
