Carpal Tunnel and Hand Flashcards
How many bones are in each hand (including the wrist)
27
What are the components of each metacarpal
Proximal base, shaft, distal head
What types of bones are the metacarpals?
Long bones
How many phalanges does each digit have?
Digits 2-5 have proximal, middle, and distal phalanges
How many phalanges does the first digit have?
2 phalanges- proximal and distal
What are the parts of the phalanges?
- Proximal
- Shaft
- Distal heads
Describe the carpometacarpal joints
Synovial–> Plane
What is the one exception to the carpometacarpal joint?
The first digit is a saddle joint (trapezium and first metacarpal)
Describe the intermetacarpal joint
Synovial–> Planar
Describe metacarpophalangeal joint
Synovial –> Condyloid
Describe the interphalangeal joint
Synovial –> Hinge
What do the MCP and IP joints have to support the fibrous capsule?
Collateral ligaments
This is the main osseofibrous tunnel of the hand
Carpal Tunnel
What are the proximal row structures that create the carpal tunnel?
- Triquetrum
- Lunate
- Scaphoid
- Flexor retinaculum
Where does the flexor retinaculum span from (proximal row)?
Pisiform to the tubercle of the scaphoid
What are the distal row structures that make up the carpal tunnel
Hamate, capitate, trapezoid, trapezium, and flexor retinaculum
What is another name for the flexor retinaculum?
Transverse carpal ligament
Where does the flexor retinaculum span from (distal row)
The hoot of the hamate to the tubercle of the trapezium
How many tendons of the flexor digitorum superficialis are there?
4 (more superficial)
How many tendons of the flexor digitorum profundas are there?
4 (deeper)
What is the most superficial structure of the carpal tunnel?
The median nerve
What structure lies laterally to the median nerve?
Flexor pollicis longus
What structure lies superficially to flexor digitorum profundus but inferiorly to median nerve
Flexor digitorum superficialis
What structure superficial and medial to the flexor retinaculum?
Ulnar nerve and artery
Where is the radial artery located?
The anatomical snuff box
Where does the tendon of the flexor carpi radialis lie?
Between (NOT THROUGH) the tunnel and the trapezium on its way to attach to the base of the second metacarpal
Describe carpal tunnel syndrome
-Inflammation and swelling of the carpal tunnel due to overuse and repetitive motion that compress the MEDIAN nerve
What are some symptoms of carpal tunnel syndrome
- Always effect the median nerve
- paresthesis
- atrophy of thenar muscles
What is a nick name for the groove formed by the ulnar canal?
Guyon canal
The palmar fascia is a continuation of what?
The antebrachial fascia
What does the palmar fascia thicken into?
Palmar aponeourosis
Is the apex of the palmar aponeourosis proximal or distal?
Proximal
What does the apex fuse with?
The tendon of the palmaris longus muscle
What does the base of the palmar aponeosis do?
Sends 4 projections to the medial 4 digits
-Blend with fibrous tendon sheaths of the digits
What is the purpose for the sheaths?
They incase the bones and tendons of each finger and form more osseofibrous tunnels
These structures are continuous with the fascia
Fibrous septa
What is the purpose of the fibrous septa?
Compartmentalize the palm
What secure the skin of the palm to the palmar fascia and aponeuroisis?
Ligaments called retinacula cutis (they are very strong and prevent sliping of the skin of the palm
What does the hypothenar compartment contain?
Muscles that act on the 5th finger
-These muscles give rise to the hypothenar eminence on the medial palmar surface
What does the thenar compartment contain?
Muscles that act on the thumb
to place it in opposition
What does the central compartment contain?
Long flexor tendons of the digits
- lumbrical muscles
- arterial arches of the palm
What does the adductor compartment contain
-Adductor pollicis muscle
What does the interosseous compartment contain
The interossei muscle
What is the midpalmar space continuous with?
Carpal tunnel and the anterior compartment of the forearm
Does the third digit always adduct or abduct?
Abduct (it cant move to the midline cause it is the midline)
What plane are flexion and extension of the thumb in?
Coronal
What plane are abduction and adduction of the thumb in?
Saggital
This is continuous with the antebrachial fascia
-thickened to protect the deeper musculotendinous structures
Palmar Aponeuroisis
This is subcutaneous
- covers the guyon canal
- protects the deep branches of the ulnar nerve and artery
Palmaris brevis
These muscles act on the 1st digit
Thenar muscles
What are the thenar muscles?
- Abductor pollicis Brevis
- Flexor pollicis Brevis
- Opponens pollicis
What are the hypothenar eminence muscles?
- Abductor digiti minimi
- Flexor digiti minimi Brevis
- Opponens digiti minimi
This is a thickening part of the palmar fascia between the tubercles of the scaphoid/trapezium and pisiform/hamate
Flexor Retinaculum
What do flexor tendons go through?
The carpal tunnel
Where do flexor tendons insert?
Into distal (profundas) and middle phalanges (superficialis)
These are on digits 2-5 on the lateral side
Lumbricals
Are lumbricals 1 & 2 unipennate/bipennate?
Unipennate
Are lumbricals 3 and 4 unipennate/bipennate?
Bipennate
What are the 2 heads of the adductor pollicis?
Transverse and oblique
What structure splits the 2 heads of the adductor pollicis?
The radial artery
This is an abductor of digits 2, 3, and 4
Dorsal Interossei
Do digits 1 and 5 have their own abductors?
Yes um
What is special about abduction of the 3rd digit?
Being the midline, digit 3 abducts both laterally and medially so it requires 2 dorsal interossei muscles
What muscle adducts digits 2, 4, and 5?
Palmar Interossei (the thumb has its own adductor muscle
Due to the fibrous sheath, what happens when the extensor digitorum contracts?
The IP and MP joints all extend
Can the lumbricals flex the MP joints while extending the IP joints?
Yes- because…
- the lumbrical crosses the MP joint anteriorly
- distally, tension is placed on the sheath when the lumbrical pulls
Is the extensor mechanism opposite of the flexor arrangement?
Yes
Where does the split of the tendon run in an extensor mechanism?
To the distal phalanx
Where does the center continuation of the tendon run to?
The middle phalanx
What are the 2 ligaments of the fingers?
- Annular
- Cruciform
Describe the annular ligaments?
- Pulleys
- Extend over the flexor digitorum superficialis tendon
Describe cruciform ligaments
- They look like “x”
- Extend over the flexor digitorum superficialis tendon
Describe trigger finger
- Due to forcefully flexing fingers
- Thickens fiber sheaths
- Causes the flexed finger not to be able to extend actively since the tendon sheaths of the FDS and FSP cant return to the osseofibrous tunnel
Describe tenosynovitis
-inflammation of the sheaths of the flexor tendons
-causes pain and disrups movement
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