Lecture 6.1: Wrist and Hand Flashcards
Bones of Hand (3)
- Phalanges
- Metacarpals
- Carpals
Joints of the Hand (4)
- Distal Interphalangeal (DIP) Joint of Phalanges
- Proximal Interphalangeal (PIP) Joint Phalanges
- Metacarpophalangeal (Knuckle) Joint Phalanges and Metacarpals
- Carpometacarpal Joint Metacarpals and Carpals
Carpal Bones of the Hand
Scaphoid Lunate Triquetrum Pisiform - Hamate Capitate Trapezoid Trapezium
Straight line thumb to pinky, here comes the thumb
Starts at bottom carpals at thumb, travels to pinky, then upper carpals pinky to thumb
What type of Joint is the wrist?
Condyloid Synovial Joint
What bones make up the Wrist?
Articulation of the radius + Articular disc with the Scaphoid, Lunate & Triquetrum
Why is the Ulna not part of the Wrist Joint?
Separated from carpals by fibrocartilage disc
How many Extensor Compartments does the Wrist have?
6
What do the Extensor Compartments of the Wrist contain?
Specific posterior forearm tendons that are covered in common synovial sheaths
1st Extensor Compartments of the Wrist
EPB: Extensor pollicis brevis
ABL: Abductor pollicis longus
2nd Extensor Compartments of the Wrist
ECRB: Extensor carpi radialis brevis
ECRL: Extensor carpi radialis longus
3rd Extensor Compartments of the Wrist
EPL: Extensor pollicis longus
4th Extensor Compartments of the Wrist
ED: Extensor digitorum
EI: Extensor indicis
5th Extensor Compartments of the Wrist
EDM: Extensor digiti minimi
6th Extensor Compartments of the Wrist
ECU: Extensor carpi ulnaris
What problems are associated with the 1st Extensor Compartment of the Wrist?
EPB affected by painful De-Quervains tenosynovitis
What problems are associated with the 3rd Extensor Compartment of the Wrist?
EPL can wear on the dorsal radial tubercle and rupture
What problems are associated with the 6th Extensor Compartment of the Wrist?
ECU can wear on the ulnar styloid process and rupture
What is the Anatomical Snuffbox?
A triangular depression found on the lateral aspect of the dorsum of the hand
Scaphoid Fracture
Results in anatomical snuffbox tenderness
Possible avascular necrosis (AVN)
What anatomical structures can be found in the Anatomical Snuffbox?
- Radial artery (palpable pulse)
- Radial styloid process
- Scaphoid
- Trapezium
- Base of 1st metacarpal
- Cephalic (houseman’s) vein passes over snuffbox.
What is Carpal Tunnel Syndrome?
Involves the compression of the median nerve in the carpal tunnel
What forms the Carpal Tunnel? What passes through it?
Carpal tunnel is formed by the carpal bones & the flexor retinaculum
Nine tendons and the median nerve pass through the carpal tunnel:
• Flexor digitorum superficialis (x4)
• Flexor digitorum profundus (x4)
• Flexor pollicis longus
What is the Flexor Retinaculum?
A strong, fibrous band that covers the carpal bones on the palmar side of the hand near the wrist
How many Flexor Compartments does the Wrist have?
Where does the Ulnar Nerve run in the Wrist?
It runs above the carpal tunnel in Guyon’s canal
What is Tinel’s Test?
- Tap the median nerve near palmaris longus proximal to carpal tunnel
- Elicits tingling in CTS
What is the Phalen Test?
- Test for Carpal Tunnel Syndrome
- Put hands in prayer position, then flip them downwards
- Elicits pain/ tingling in CTS
Risk Factors for Carpal Tunnel (8)
- Female
- Increasing Age
- Pregnancy
- Obesity
- Previous Wrist Injury
- Diabetes Mellitus
- Rheumatoid Arthritis
- Hypothyroidism
Treatments for Carpal Tunnel: Conservative and Surgical
• Wrist Splint • Hand Physiotherapy • Corticosteroids Injections • Carpal tunnel release, cut through flexor retinaculum, decompresses carpal tunnel
What is the Palmar Aponeurosis?
It is a tough fibrous layer limiting movement of the palmar skin
Fibrous Digital Sheaths
• Tendons of Flexor Digitorum Superficialis (FDS) & Flexor Digitorum Profundus
(FDP) are surrounded by a synovial sheath
• They then cross palm and enter fibrous sheaths on the palmar aspect of the
digits
What is the purpose of Fibrous Digital Sheaths?
• Hold the tendons in place and prevent bowing
What are the 2 Palmar Spaces?
Thenar Space (Thumb-side) Midpalmar Space
What is Dupuytren’s Contracture?
Aponeurotic thickening leads to soft tissue contractures causing passive flexion of medial digits
What is Stenosing Tenosynovitis?
• Aka Trigger Finger
• Occurs when inflammation narrows the space within the sheath that
surrounds the tendon in the affected finger
• Inflammations leads to trapping of the flexor tendon
• If is severe, your finger may become locked in a bent position
What is Ulnar Claw Hand?
• Caused due to a lower ulnar nerve lesion (below elbow)
• Clawing and Flexion of 4th and 5th Fingers
• This is due to unopposed action of ulnar part of the flexor digitorum
profundus muscle
Intrinsic Hand Muscles supplied by the Ulnar Nerve
- Palmaris brevis
- Interossei muscles
- Adductor pollicis
- Hypothenar muscles
- Lumbrical muscles: Medial 2
Intrinsic Hand Muscles supplied by the Median Nerve
- Lumbrical muscles: Lateral 2
* Thenar muscles
What is a Fulcrum?
The point against which a lever is placed to get a purchase, or on which it turns or is supported
What are the Interossi?
They are hand muscles, situated between the metacarpal bones all innervated by ulnar nerve
What are the 2 types of Interosseous Muscles?
3 Palmar Interossi Muscles
4 Dorsal Interossi Muscles
What are the Lumbricles? What do they do?
They are hand muscles
The lumbricals flex the MCP joints & extend PIP & DIP joints
Hand Muscles of the Palm (7)
- Adductor Pollicis (Ulnar n.) - Thumb Side
- Flexor Pollicis Brevis - Thumb Side
- Abductor Pollicis Brevis (Median n.) - Thumb Side
- Opponens Pollicis - Thumb Side
- Abductor Digiti Minimi Brevis- Pinky Side
- Flexor Digiti Minimi Brevis - Pinky Side
- Opponens Digiti Minimi - Pinky Side
What is Froment Sign?
- Excess thumb flexion whilst pinching
* Due to Adductor Pollicis loss (e.g. in Ulnar nerve lesion)
