i want 30 multiple choice questions with their model answer below each question that covers all of the different aspects of the following information: The radioulnar joints locations
in which
the radius and ulna articulate in the forearm (proximal, middle & distal RUJ):
• Proximal radioulnar joint: located near the elbow. It is articulation between the head of the radius and the radial notch of the ulna.• The radial head is held in place by the annular
radial ligament, which forms a ‘collar’ around
the joint. The annular radial ligament is lined with
a synovial membrane, reducing friction during
movement.
• Movement is produced by the head of the radius
rotating within the annular ligament. There are
two movements possible at this joint; pronation
and supination.
• Pronation: Produced by the pronator quadratus
and pronator teres.
• Supination: Produced by the supinator and biceps
brachii.• Distal radioulnar joint: located near
the wrist. It is an articulation between
the ulnar notch of the radius and the
ulnar head.
• Both of these joints are classified as
pivot
joints,
responsible
for pronation and supination of the
forearm.• In addition to anterior and posterior ligaments
strengthening the joint, there is also a fibrocartilaginous
ligament present, called the articular disk.
• It serves two functions:
1. Binds the radius and ulna together, and holds them
together during movement at the joint.
2. Separates the distal radioulnar joint from the wrist joint.
• Like the proximal radioulnar joint, this is a pivot joint,
allowing for pronation and supination.
• Pronation: Produced by the pronator quadratus and
pronator teres
• Supination: Produced by the supinator and biceps brachiiMiddle RUJ)Interosseous Membrane)
• The interosseous membrane is a sheet of connective
tissue that joins the radius and ulna.
• It spans the distance between the medial radial border,
and the lateral ulnar border. There are small holes in the
sheet, as a conduit for the forearm vasculature.
• This connective tissue sheet has three major
functions:
1. Holds the radius and ulna together during pronation and
supination of the forearm, providing addition stability.
2. Acts as a site of attachment for muscles in the anterior
and posterior compartments of the forearm.
3. Transfers forces from the radius to the ulna.The wrist joint
• Def: also known as the radiocarpal
joint: is an articulation between the
radius and the carpal bones of the
hand.
• Type:
It
is
condyloid-
type(ellipsoid) synovial joint which
marks the area of transition between
the forearm and the hand.Articulating Surfaces
• The wrist joint is formed by an articulation
between:
1. Distal end of the radius and the articular disk.
2. Proximal row of the carpal bones (except the
pisiform).
• Together,
the
carpal
bones
form
a convex surface, which fits into the concave
shape of the radius and articular disk.
• The ulna is prevented from articulating with the
carpal bones by the presence of a
fibrocartilaginous ligament, the articular disc.Joint Capsule
• The joint capsule of the wrist joint is
attached to the radius, ulna and the
proximal row of the carpal bones.
• It is lined internally by a synovial
membrane, which produces synovial
fluid to reduce friction between the
articulating structures.Ligaments
• There are four main ligaments located at the wrist joint: • Palmar radiocarpal: located on the palmar (anterior) side of the joint. It passes from the radius to both rows of carpal bones. Its function, apart from increasing stability, is to ensure that the hand follows the forearm during supination.
• Dorsal radiocarpal: Found on the dorsum (posterior) side of the hand. It passes from the radius to both rows of carpal bones. It contributes to the stability of the wrist, but also ensures that the hand follows the forearm during pronation.
• Ulnar collateral: Runs from the ulnar styloid process to the triquetrum and pisiform. It acts to prevent excessive radial (lateral) deviation of the hand.
• Radial collateral: Runs from the radial styloid process to the scaphoid and trapezium. It acts to prevent excessive ulnar (medial)Movements
• The wrist is an ellipsoidal (condyloid) type synovial joint,
allowing for movement along two axes. This means that
flexion, extension, adduction and abduction can all occur at
the wrist joint.
• All the movements of the wrist are performed by the
muscles of the forearm.
• Flexion: Produced mainly by the flexor carpi ulnaris, flexor
carpi radialis, with assistance from the flexor digitorum
superficialis.
• Extension: Produced mainly by the extensor carpi radialis
longus and brevis, and extensor carpi ulnaris, with
assistance from the extensor digitorum.• Adduction:
Produced by
the
extensor carpi ulnaris and flexor
carpi ulnaris
• Abduction:
Produced by
the
abductor pollicis longus, flexor carpi
radialis, extensor carpi radialis longus
and brevis.Mobility and Stability
• The wrist joint is a highly mobile joint to
allow the hand to move in several directions.
• Because of this, the wrist joint is prone to injury.
• The wrist joint maintains some stability due
to intrinsic and extrinsic ligaments.
• Intrinsic carpal ligaments, the tiny ligaments
between the carpal bones, are short ligaments
that provide stability but are easily damaged
with excessive force or twisting due to their
small size.• The extrinsic ligaments, which
include
the
palmar/dorsal
radiocarpal ligaments and the radial
and ulnar collateral ligaments are
stronger and stabilise from the radius
and ulna to the carpal bones of the
wrist.Blood Supply
• The wrist joint receives blood
from branches of the dorsal and
palmar carpal arches, which are
derived
from
the ulnar and radial arteriesNerve supply
• by branches of three nerves: • Median nerve: Anterior interosseous branch.
• Radial nerve: Posterior interosseous branch.
• Ulnar nerve: deep and dorsalApplied anatomy
• Scaphoid Fracture • The scaphoid bone of the hand is the most commonly fractured carpal bone – typically by falling on an oustretched hand (FOOSH).
• In a fracture of the scaphoid, the characteristic clinical feature is pain and tenderness in the anatomical snuffbox.Hand anatomy
• The human hand, the most distal part
of the upper limb.
• The hand itself consists of specific bones
onto which various muscles are
attached,
and
a
collection
of
neurovascular structures responsible
for drainage and innervation.Bones Carpals:سعاد لازم تلعب بوكر تكسب تخسر كله هلس
scaphoid, lunate,triquetrum,pisiform,
trapezium, trapezoid, capitate, hamate
Metacarpals: base, shaft, head
Phalanges: proximal, middle, distal phalanges
except thumb(proximal&distal)
Muscles Thenar group: abductor pollicis brevis, flexor
pollicis brevis, opponens pollicis
Hypothenar group: abductor digiti minimi,
flexor digiti minimi, opponens digiti minimi
Metacarpal group: lumbircals, palmar
interossei, dorsal interosseiArteries All the branches originate from
the radial and ulnar arteries. They include:
1. palmar arches (superficial, deep),
2. palmar digital arteries (common, proper),
3. dorsal carpal arch,
4. dorsal metacarpal arteries,
5. dorsal digital arteries,
6. principal artery of the thumb.
Veins 1. Dorsal venous network of hand:
predominant drainage route of the hand (also
receiving palmar venous return via perforating
veins). Gives rise to cephalic and basilic
veins.
2. Palmar venous arches: Receives palmar
metacarpal and digital veins. Drain
into radial and ulnar veins.Nerves Median nerve and its branches (common and proper palmar digital nerves) predominantly supply the thenar muscles. Radial nerve provides cutaneous innervation along the outisde of the thumb. Ulnar nerve and its branches (superficial, deep and dorsal) innervate the hypothenar and metacarpal groups Mnemonic: Ulnar nerve supplies all intrinsic muscles of the hand except the LOAF muscles (Lateral two lumbricals, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis)The thenar muscles
• are three in total.
• They form the ‘ball’ or ‘fleshy’ part of the thumb known
as the thenar eminence, and are named as follows:
1. abductor pollicis brevis
2. flexor pollicis brevis, and
3. opponens pollicis
• A fourth muscle, the adductor pollicis, is also located in
this region, however is not part of the thenar muscle
group, but rather it is classified on it's own as the muscle
of the adductor compartment of the hand.• The last three groups of hand muscles,
that is the lumbricals, dorsal interossei,
and palmar interossei, are situated in
the deepest layer of the hand and are
commonly taken together as one big
group
called
the metacarpal
muscles of the hand.
• They work in unison to help with the
extension, flexion, abduction, and
adduction of the phalanges.lumbricalsAction of the metacarpal muscles of
the hand.
• Lumbrical muscles: Writing
position(flexion of MCP joints&
extension of IP joints).
• Palmar interossei: adduction of
fingers
• Dorsal interossei: abduction of
fingers• Rule of 3s'
• 3 thenar muscles: abductor pollicis brevis,
flexor pollicis brevis, opponens pollicis
(+adductor pollicis)
• 3 hypothenar muscles: abductor digiti minimi,
flexor digiti minimi, opponens digiti minmi
(+palmaris brevis)
• 3 metacarpal muscles: dorsal interossei,
palmar interossei, lumbricals
• 3 abductors of digits: dorsal interossei,
abductor pollicis brevis, abductor digiti minimiCarpal tunnel
• Def: The carpal tunnel is a narrow
osteofibrous canal located on the palmar
side of the wrist, found deep to the flexor
retinaculum (transverse carpal ligament).
• The floor of the carpal tunnel is composed
of the carpal bones, which is how it got its
name.
• Func: The carpal tunnel serves as a
passageway for structures passing between
the anterior forearm and the hand.Contents
• It transmits
1. the median nerve and
2. the tendons of the flexor pollicis
longus,
3. flexor digitorum superficialis
4. and flexor digitorum profundus
muscles. (1n. & 3 ms)Definition
Passageway found on anterior wrist
for structures passing between
anterior forearm and hand
Boundaries Floor: Carpal groove
Roof: Flexor retinaculum
Contents
Flexor digitorum superficialis
tendons
Flexor digitorum profundus tendons
Flexor pollicis longus tendon
Median nerveCarpal tunnel syndrome
• Def: Carpal tunnel syndrome refers to a group of signs and
symptoms that result from the compression of the median
nerve as it travels through the carpal tunnel.
• Causes: It can be caused by any factor that narrows the tunnel,
such as a wrist fracture or swelling of the long tendons that pass
through the carpal tunnel.
• Risk factors for this condition include diabetes, obesity,
pregnancy, arthritis, trauma and occupational biomechanical
factors.
• Common symptoms include pain and paresthesia and, less
commonly, weakness in the median nerve distribution (sensory
innervation to the skin of the palmar side of the thumb, index
finger, middle finger and half of the ring finger; motor
innervation to the muscles of the thenar eminence).Anatomical snuff box
• Def: The anatomical snuffbox (also known as
the radial fossa), is a triangular depression
found on the lateral aspect of the dorsum of
the hand.
• Site: It is located at the level of the carpal
bones, and best seen when the thumb is
extended.
• In the past, this depression was used to hold
snuff (ground tobacco) before inhaling via the
nose – hence it was given the name ‘snuffbox’.Shape & Borders
• the snuffbox is triangularly shaped, it has three
borders, a floor, and a roof:
• Ulnar (medial) border: Tendon of the extensor
pollicis longus.
• Radial (lateral) border: Tendons of the extensor
pollicis brevis and abductor pollicis longus.
• Proximal border: Styloid process of the radius.
• Floor: Carpal bones; scaphoid and trapezium.
• Roof: Skin.Contents
• The main contents of the anatomical snuffbox: A N V 1. Radial artery: crosses the floor of the anatomical snuffbox, then turns medially and travels between the heads of the adductor pollicis muscle (The radial pulse can be palpated in some individuals by placing two fingers on the proximal portion of the anatomical snuffbox). 2. Superficial branch of the radial nerve: found in the skin and subcutaneous tissue of the anatomical snuffbox. It innervates the dorsal surface of the lateral three and half digits, and the associated area on the back of the hand. 3. Cephalic vein: arises from the dorsal venous network of the hand and crosses the anatomical snuffbox to the anterolateral aspect of the forearm.