GA Exam 2 - Wrist + Hand

Proximal radioulnar joint

• Synovial joint

• Head of the radius
  articulates with the radial
  notch of the ulna

• Radius is held in place by
  the anular ligament

Movements of radioulnar joint

During pronation and supination the radial head rotates within the anular ligament

pronator teres

look at lab practical quizlet

interosseous membrane

• connects radius and ulna along their diaphysis

• Forms the radioulnar syndesmosis joint
  

Distal radioulnar joint

• Head of Ulna articulates
  with the ulnar notch on
  the radius

• Fibrocartilagenous articular disc (a.k.a. triangular ligament)
  connects

Volar

palkm

Thenar

base of thumb

Hypothenar

base of pinkie

Muscles of Pronation and Supination

• Supination: supinator and biceps brachii (esp during resistance)

• Pronation: pronator quadratus and pronator teres

Pisiform is a _____ bone

sesamoid bone

Carpals Lateral to medial

Metacarpals and Phalanges

Wrist complex contains 2 proximal-distal joints:

• Radiocarpal

• Midcarpal

Proximal and Distal components of the Radiocarpal joint

Proximal components:
Radius, articular disc (triangular ligament)

Distal components:
Scaphoid, lunate, triquetrum

Proximal and Distal components of the Midcarpal joint

Distal components:
Trapezium, trapezoid, capitate, hamate

Proximal components:
Scaphoid, lunate, triquetrium

The carpal tunnel

• A large, fibrous ligament stretches over the volar side of the wrist—transverse carpal ligament or flexor retinaculum

• Forms a tunnel with the carpals (carpal tunnel) through which tendons pass

Intercapal joints

Joints between carpals

Carpometacarpal joints

Joints between carpals and metacarpals

***All carpometacarpal joints are capable of flexion/extension***

• for the thumb,

  • has it’s own synovial joint and a greater ROM (abduction, adduction, flexion, extension, opposition)

• For the fingers

  • share one synovial cavity

• Metacarpals of the third and fourth fingers

  • have limited ROM,

• fifth metacarpal have more ROM than 3rd + 4th.

• The relatively immobile second and third joints

  • provide a stable axis for opposition

Wrist flexors

Muscles with tendons that cross the anterior of the wrist can assist in flexion

• Flexor carpi radialis
• Flexor carpi ulnaris
• Flexor digitorum superficialis
• Flexor digitorum profundis

• Flexor pollicis longus

• pronator teres

Antebrachial muscles (superficial anterior forearm)

• Pronator teres

• Flexor carpi radialis

• palmaris longus

• flexor carpi ulnaris

Antebrachial muscles (intermediate anterior forearm)

Antebrachial muscles (Deep anterior forearm)

Median nerve

supplies the majority of the anterior compartment of the forearm

• exceptions:

  • brachioradialis b/c it is lateral → radial nerve

  • flexor carpi ulnaris, and flexor digitorum profundi b/c = medial → ulnar nerve

Wrist extensors

Muscles with tendons that cross the posterior aspect of the wrist can assist in extension

• Extensor carpi radialis longus
• Extensor carpi radialis brevis
• Extensor carpi ulnaris
• Extensor digitorum
• Extensor indicis
• Extensor digiti minimi

Antebrachial muscles (superficial posterior forearm)

Antebrachial muscles (Deep posterior forearm)

Wrist Adductors and Abductors

ADDuctors

• Muscles with tendons that cross the ULNAR side of the wrist ADDuct

  • Flexor carpi ulnaris

  • Extensor carpi ulnaris

ABDuctors

• Muscles with tendons that cross the RADIAL side of the wrist ABDuct

  • Flexor carpi radialis

  • Extensor carpi radialis

• Thumb (pollicis) muscles with tendons that cross the RADIAL side of the wrist assist in ABDuction
  • Abductor pollicis longus
  • Extensor pollicis longus
  • Extensor pollicis brevis

Wrist motion in general

No muscular forces are applied directly to the proximal carpals

• (scaphoid, lunate, triquetrium)

These bones essentially serve as a mechanical link between the radius
and distal carpals

They tend to collapse anteriorly when force is applied, but are
stabilized by the intercarpal ligaments

What things passes via carpal tunnel

Tendons of:
• Flexor digitorum profundus
• Flexor digitorum superficialis
• Flexor pollicis longus

Median nerve
- Pass through the carpal tunnel

Flexor carpi radialis is embedded within the tendon

Palmaris longus

Flexor carpi ulnaris are outside the tendon

Anterior Palmar aponeurosis

• Distally, the flexor retinaculum gives way to the palmar aponeurosis

• This fascia covers the tendons, blood supply, nerves and muscles

• It connects on it’s distal side to the superficial transverse metacarpal ligament

Posterior palmar aponeurosis

• Similarly on the posterior side, the ligaments of all of the extrinsic finger extension muscles pass through the extensor retinaculum

• Its function is to hold the tendons in place and not let them wander medially/laterally

Carpometacarpal joints

****All carpometacarpal joints are capable of flexion/extension*****

For the thumb

• has it’s own synovial joint and a greater ROM

• ex movem → (abduction, adduction, flexion, extension, opposition)
  

For the fingers

• share one synovial cavity
  

Metacarpals of the third and fourth fingers have

• limited ROM but fifth metacarpal have more ROM

The relatively immobile second and third joints

• provide a stable axis for opposition

Finger joint layout basics

Metacarpophalangeal joints

Components:

• Volar plate → prevents hyperextension

• Collateral ligament connects metacarpal to proximal phalanx

• Accessory collateral ligament connects metacarpal to volar plate

Metacarpophalangeal joints are connected to each other by the deep transverse metacarpal ligament

• Deep transverse metacarpal ligament passes connects the volar plates of the metacarpophalangeal joints

• Flexor tendons pass over it

Interphalangeal joints

Movements of finger and thumb

Flexing the fingers

Extending the fingers

Intrinsic muscles of the hands:
• Lumbricals insert on the extensor hoods, aiding in extension

Interossei muscles:

• insert onto the extensor hoods and contributing to finger extension and ab/adduction

Finger abduction and adduction

• The dorsal interossei muscles contribute to abduction

• The palmar interossei contribute to adduction

DAB/ PAD

Intrinsic muscles of the thumb and little finger:

Intrinsic muscles of the thumb:

• Abductor pollicus brevis

• Flexor pollicus brevis

• Opponens pollicus

• Adductor pollicus

Intrinsic muscles of the little finger:
• Abductor digiti minimi
• Flexor digiti minimi
• Opponens digiti minimi