Lecture 21: anterior forearm and hand Flashcards by Misha Gandhi

Define forearm

Antebrachium
Middle segment of free upper limb
Located between elbow and wrist joints

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Describe distal features of radius

Styloid process radius - projection, distally, Helps form bracketed joint - anterior
Dorsal tubercle - posterior

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Describe distal features of ulna

Head of ulna = at wrist (opposite of radial head)
Styloid process of ulna = projects from medial side, can be palpated medially, extends posteriorly

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Name radioulnar joints

Proximal
Middle
Distal

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Describe proximal radioulnar joint - gen

Synovial pivot
Has annular ligament = completes pivot joint, forms ring

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Describe distal radioulnar joint

Synovial, pivot joint
Hast anterior and posterior radioulnar ligaments = forms ring, contract = allows rotation

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Describe proximal and distal radioulnar joints specifically

Allows axial rotation of one bone = radius relative to the other = ulna
= motion known as pronation/supination

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Describe middle radioulnar joint

Syndesmosis - fibrous joint = 2 bones held together by stretch of tough ct = interosseus membrane
No articular cartilage or synovial capsule
Relatively immobile joint - v little movement

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Describe motion at radioulnar joints

Axis of rotation = along long axis of forearm
Pronation and supination

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Way to remember pronation/supination

Hold soup = supination - palms facing up in anatomical position
Pour out soups = pronation - thumbs together

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What moves during pronation and supination

Only radius moves during pronation and supination
Distal end pivots arounf ulnar head
Interosseous membrane twists to follow rotation of radial head and shaft
Ulna stays put, solidly anchored at hinge joint

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What increases pronation

If involve axial rotation of shoudler

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Describe wrist joint - gen

Made up of carpals

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Describe carpal bones - name all

2 rows = proximal to distal
Scaphoid
Linage
Triquetrum
Pisiform
Hamate (hook of hamate**)
Capitate
Trapezoids
Trapezium (articulates with thumb bone)

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Acronym for carpal bones

PROXIMAL ROW LATERAL TO MEDIAL - So long to pinky = scaphoid lunate triquetrum pisiform
DISTAL ROW FROM MEDIAL TO LATERAL - here comes the thumb = hamate capitate trapezoid trapezium

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Describe carpal bones - joints

Carpals = 8 tightly packed nodular bones that link forearm and hand
Between bones = synovial joints of a gliding type
Most allow limited movement bc presence of strong ligaments - stability of carpals

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What is tfcc

Triangular fibrocartilaginous complex tfcc wedge shaped triangle of fibrocartilage that fills in and provides support to ulnocarpal side of wrist joint
Ulnar head does not articulate with carpals
Medially

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What type of jont is wrist joint

Complex synovial
Condyloid joint
Elliptical in shape = one long axis and one short axis
Aka radiocarpal joint = involves radius and proximal row of carpals NOT ULNA DIRECTLY

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Describe tfcc for wrist joint

PROXIMAL SURFACE fills in space of articular surface of ulna and half lunate and triquetrum = indirect articulation

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Describe direct articulations wrist

Between distal radius and scaphoid and lunate in proximal row of carpals

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Describe indirect articulations wrist

On ulnar side between tfcc and triquetrum = outside radiocarpal synovial capsule

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Describe NO articulations wrist

Between pisiform and wrist joint

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DESCRIBE WRIST JOINT motions = Gen

Condylloid joints are biaxial = motion in 2 planes + combos
Flex ext = sagittal plane around. Transverse axis
Abduction and adduction
Circumduction = combo flex ext and abd add

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Describe wrist abduction and adduction

Carpal collateral ligaments restrict motion
Radial collateral = restricts ulnar deviation -adduction
Ulnar collateral = restricts radial deviation - abduction, MORE LIMITED ROM than ulnar deviation

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Wrist abduction

Radial deviation

Wrist adduction

Ulnar deviation

Describe bones of hand gen

5 hand manual digits = I-v Thumb = i pinky = v (lateral to medial) Digits - fingers = free portion consisting of phalanges, exclusive of metacarpals Pentadactyl

How many carpal bones

How many metacarpals and explains

5 Head, body and base

Describe phalanges

2-5 = proximal, middle, distal Thumb = proximal, distal (Head, body base too)

Name intrinsic hand joints

Metacarpophalangeal mcp joints i-v Carpometacarpal joint 1 Carpometacarpal joint ii-v Interphalangeal ip joints

Metacarpophalangeal mcp joints i-v Type

Condyloid Between metacarpal and proximal phalanx

Metacarpophalangeal mcp joints i-v Movements

Abduction adduction Flexion extension

Carpometacarpal joint 1 Type

Saddle biaxial 1st metacarpal and trapezium

Carpometacarpal joint 1 Motions

Abduction adduction Flexion extension Opposition (abduct and flex thumb to reach to 5th digit)

Carpometacarpal joint ii-v type

Condyloid

Carpometacarpal joint ii-v Motions

Limited movement

Interphalangeal ip joints Type

Hinge Proximal - pip - and distal - dip - interphalangeal joints

Interphalangeal ip joints Motions

Flexion extension

Describe what radius/ulna and interosseous membrane do

Divides antebrachium into 2 tightly wrapped musculofascial compartments Dedicated to antagonistic movements of wrist and digital joints Innervated by own terminal branch of brachial plexus

Describe posterior compartment of forearm

Extensor compartment Extensors and supinations of wrist Extensors of digital joints

Describe posterior compartment of forearm innervation

Radial nerve C5-t1 Deep branch

Describe anterior compartment of forearm

Larger Flexor compartment Flexors and predators of wrist Flexors of digital joints

Describe anterior compartment of forearm Innervation

Medial c6-t1 Ulnar c8-t1

Name muscles of anterior compartment superficial layer

Pronator teres Flexor carpi radialis Palmaris longus Flexor carpi ulnaris (PFPF)

Pronator teres attachment

Medial humeral epicondyle to radius

Pronator teres functions

Pronation (It of elbow flexion and stabilization)

Flexor carpi radialis atthcments

Medial humeral epicondyle To metacarpals ii and iii

Flexor carpi radialis FUCNTION

Wrist flexion and abduction (radial deviation)

Palmaris longus attachment

Medial humeral epicondyle To palmar aponeurosis

Palmaris longus FUCNTION

Tenses palmar aponeurosis Assist in wrist flexion

Flexor carpi ulnaris attachment

Medial humeral epicondyle To pisiform, hamate, metacarpal v

Flexor carpi ulnaris FUCNTION

Wrist flexion and adduction (ulnar deviation)

What works together to flex wrist

Flexor carpi radialis, flexor carpi unalris, Palmaris longus = work together to flex wrist And since they cross elbow = weak elbow flexion too

Name muscles of anterior compartment intermediate layer

Flexor digitorum superficialis

Flexor digitorum superficialis Attachments

Medial humeral epicondyle, proximal ulna/radius To medial and lateral sides of middle phalanges of digits ii-v (4 tendons)

Flexor digitorum superficialis Functions

Flexion of wrist Metacarpophalangeal mcp and proximal interpahalangeal pip joints of digits ii-v

Flexor digitorum superficialis Tendons

Tendons split near mcp joint to allow passage of tendons of another muscle to distal phalanx of digits ii-v

What passes through Flexor digitorum superficialis Tendons split

Tendons of flexor digitorum profundus

Does Flexor digitorum superficialis Send tendons into all digits

NOOO Not to thumb Also not across distal interphalangeal joints - dip

Name anterior compartment deepest layer muscles

Flexor pollicis longus Flexor digitorum profundus Pronator quadratus

Flexor pollicis longus attachments

Radius, interosseus membrane to distal phalanx of thumb only digit 1

Flexor pollicis longus FUCNTION

Unique to humans Flexion of wrist and joints of thumb

Flexor digitorum profundus attachments

Ulna, interosseus membrane to base of distal phalanx ii-v

Flexor digitorum profundus Functions

Flexion of wrist, mcp joints, PIP AND DIP joints of digits ii-v

Describe Flexor digitorum profundus tendons

Tendons pass through split of flexor digitorum superficialis to attach to distal phalanx Flexor digitorum profundus tendons now superficial to flexor digitorum superficialis tendons

Describe and summarize Pronators of forearm - anterior compartment

Pronator teres and pronate quadratus = pull over radius in pronation Riot action fo radius at humeroradial and radioulnar joints, radius crosses over ulna = when muscles contract concentrically

Does everyone have Palmaris longus

Absent in 3 —> >60% of ppl, depends on population/study

Pronator quadratus attachments

Distal ulna to distal radius, deep to flexor digitorum profundus/flexor pollicis longus

Pronator quadratus functions

Pronation