Wrist joints and carpal joints

What is the wrist joint also called?

The radiocarpal joint.

What type of joint is the wrist/radiocarpal joint?

Synovial condyloid/ellipsoid joint.

What does the wrist joint connect?

Distal forearm to the proximal carpal bones.

What forms the proximal articular surface of the wrist joint?

Distal radius and articular disc/TFCC.

What forms the distal articular surface of the wrist joint?

Scaphoid, lunate, and triquetrum.

What movements occur at the wrist joint?

Flexion, extension, abduction/radial deviation, adduction/ulnar deviation, and circumduction.

What muscles flex the wrist?

Flexor carpi radialis, flexor carpi ulnaris, and palmaris longus.

What muscles extend the wrist?

Extensor carpi radialis longus/brevis and extensor carpi ulnaris.

What muscles cause radial deviation/abduction of the wrist?

Flexor carpi radialis + extensor carpi radialis longus/brevis

What muscles cause ulnar deviation/adduction of the wrist?

Flexor carpi ulnaris + extensor carpi ulnaris.

Which wrist ligament is stronger: palmar or dorsal radiocarpal ligament?

Palmar radiocarpal ligament.

What does the palmar radiocarpal ligament limit?

Excessive wrist extension.

What does the dorsal radiocarpal ligament limit?

Excessive wrist flexion.

What does the radial collateral ligament of the wrist limit?

Ulnar deviation/adduction.

What does the ulnar collateral ligament of the wrist limit?

Radial deviation/abduction.

Where does the radial collateral ligament attach?

Radial styloid to scaphoid/trapezium.

Where does the ulnar collateral ligament attach?

Ulnar styloid to triquetrum/pisiform.

What nerves supply the wrist joint?

• Anterior interosseous nerve & posterior interosseous nerve of median nerve

• deep branch of ulnar nerve.

What arteries supply the wrist joint?

From dorsal and palmar carpal arches, branches of:

• Radial artery

• Ulnar artery

• Anterior interosseous artery

• Posterior interosseous artery

What are intercarpal joints?

Joints between adjacent carpal bones within the same row

What type of joints are most intercarpal joints?

Synovial plane joints.

What movement occurs at intercarpal joints?

Small gliding movements.

What is the midcarpal joint?

The joint between the proximal and distal rows of carpal bones.

What type of joint is the midcarpal joint?

Compound synovial plane joint.

Which bones are involved proximally in the midcarpal joint?

caphoid, lunate, and triquetrum.

Which bones are involved distally in the midcarpal joint?

Trapezium, trapezoid, capitate, and hamate.

What movements does the midcarpal joint contribute to?

Wrist flexion, extension, radial deviation, and ulnar deviation.

What are carpometacarpal joints?

Joints between distal carpal bones and metacarpal bases.

What type of joints are CMC joints II–V?

Mostly synovial plane joints.

Which CMC joints are most stable?

2nd and 3rd CMC joints.

Which CMC joints are more mobile?

4th and 5th CMC joints.

Why are the 4th and 5th CMC joints more mobile?

They help with gripping.

What type of joint is the 1st carpometacarpal joint?

Synovial saddle joint.

What bones form the 1st CMC joint?

Trapezium and base of 1st metacarpal.

What movements occur at the 1st CMC joint?

Flexion, extension, abduction, adduction,, and circumduction

Why is the 1st CMC joint clinically/functionally important?

It allows thumb opposition.

Why is thumb opposition important?

It allows precision grip.

What are intermetacarpal joints?

Joints between the bases of metacarpals II–V.

What type of joints are intermetacarpal joints?

Synovial plane joints.

Does the 1st metacarpal form an intermetacarpal joint with the 2nd metacarpal?

No, the 1st metacarpal is independent.

What forms the floor and sides of the carpal tunnel?

Carpal Arch

• Concave on the palmar side, forming the base and sides of the carpal tunnel.

• Formed laterally by the scaphoid and trapezium tubercles

• Formed medially by the hook of the hamate and the pisiform

What forms the roof of the carpal tunnel?

Flexor retinaculum.

What are the contents of the carpal tunnel?

Median nerve + 9 tendons:

• 4 tendons of flexor digitorum superficialis

• 4 tendons of flexor digitorum profundus

• 1 tendon of flexor pollicis longus

Is flexor carpi radialis usually counted inside the carpal tunnel?

No, it runs in its own compartment.

Are the ulnar nerve and artery inside the carpal tunnel?

No, they pass through Guyon’s canal.

What forms the lateral border of the anatomical snuffbox?

• Abductor pollicis longus

• extensor pollicis brevis.

What forms the medial border of the anatomical snuffbox?

Extensor pollicis longus.

What bones form the floor of the anatomical snuffbox?

Scaphoid and trapezium.

What are the contents of the anatomical snuffbox?

• radial artery (passes inside)

• cephalic vein

• superficial branch of radial nerve

Tenderness in the anatomical snuffbox after FOOSH suggests what?

Scaphoid fracture.

What is the most commonly fractured carpal bone?

Scaphoid.

What is the typical mechanism of scaphoid fracture?

Fall on outstretched hand, FOOSH.

Which carpal dislocation can compress the median nerve?

Lunate dislocation.

What is a Colles fracture?

Fracture of the distal radius.

What deformity is seen in Colles fracture?

Dinner fork deformity.

What nerve is compressed in carpal tunnel syndrome?

Median nerve.

What sensory symptoms occur in carpal tunnel syndrome?

Numbness/tingling in lateral 3½ fingers

What motor problem occurs in carpal tunnel syndrome?

Thenar weakness/atrophy and weak thumb opposition.

What nerve supplies the LOAF muscles? (Lateral 2 lumbricals, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis.)

Median nerve.

What nerve is compressed in Guyon canal syndrome?

Ulnar nerve.

What sensory symptoms occur in Guyon canal syndrome?

Numbness/tingling in medial 1½ fingers.

What are the borders of Guyon’s canal?

• medial (ulnar): pisiform

• Lateral (radial): hook of hamate

• Roof: palmar carpal ligament

• Floor: flexor retinaculum

What are the contents of Guyon’s canal?

• ulnar nerve

• ulnar artery

• concomitant veins of ulnar artery

• lymphatic vesesels

What motor weakness occurs in Guyon canal syndrome?

Weak interossei and weak finger abduction/adduction.

What hand deformity may occur in Guyon canal syndrome?

Clawing.