Anatomy 29 Flashcards
How many bones make up the carpus?
8
What are the arrangement of bones in the carpus?
2 rows of 4 bones; 1 proximal, 1 distal
What forms the radiocarpal joint?
Distal radius articulating with the scaphoid and lunate
Which is the most commonly fractured carpal bone?
Scaphoid
What is the clinical relevance of the lunate bone?
An anterior dislocation of the lunate bone compresses the median nerve
Where do the metacarpals lie?
Distal to the carpus
In what order are the metacarpals numbered?
1 – 5 from the lateral (thumb) side to the
medial (little finger) side
What are the bones of the digits?
Phalanges
How many phalanges in digits 2-5?
3
How many phalanges in the thumb?
2
What are the names of the 3 phalanges of the fingers?
Proximal
Middle
Distal
What are the names of the 2 phalanges of the thumb?
Proximal
Distal
Where does the carpometacarpal joint lie?
Lies between the distal row of carpal bones and the proximal parts (the bases) of the metacarpals
Where does the metacarpophalangeal joint lie?
Lies between the distal parts (the heads) of the metacarpals and the proximal phalanges
Where does the interphalangeal joint lie?
Lies between the phalanges
How many interphalangeal joints are in the thumb?
1
How many interphalangeal joints are in the fingers?
2
* the proximal interphalangeal (PIP) joints lie between the proximal and middle phalanges
* the distal interphalangeal (DIP) joints lie between the middle and distal phalanges
What is the power grip used for?
To hold or squeeze objects tightly
What is the hook grip used for?
Carrying objects with handles, such as bags
What is the precision grip used for?
Allows us to hold objects between the pads of our thumb and index finger, such as a pen or needle.
This can be performed with or without power
What movements can occur at the fingers?
- Flexion
- Extension
- Abduction (moving the fingers apart)
- Adduction (bringing the fingers together)
What movements occur at the thumb?
- Flexion
- Extension
- Abduction
- Adduction
- Opposition
Where do the extrinsic muscles of the hand lie?
In the anterior and posterior forearm and their tendons travel into the hand
Where do the intrinsic muscles of the hand lie?
Within the hand
What are the muscles of the anterior forearm that are the prime flexors of the wrist?
Flexor carpi radialis
Flexor carpi ulnaris
Palmaris longus
What does the flexor carpi radialis insert onto?
2nd metacarpal
What does the flexor carpi ulnaris insert onto?
5th metacarpal
What does the palmaris longus insert onto?
Palmar fascia
Which anterior compartment muscles flex the digits?
- Flexor digitorum superficialis (FDS)
- Flexor digitorum profundus (FDP)
- Flexor pollicis longus (FPL)
What does the flexor digitorum superficialis (FDS) split into?
2 slips which insert on either side of the middle phalanx of digits 2-5
What does the flexor digitorum superficialis (FDS) flex?
The MCP joints and PIP joints of digits 2-5
Where does the flexor digitorum profundus (FDP) pass through?
The slit in the FDS tendon
What does the flexor digitorum profundus (FDP) insert onto?
The palmar aspect of the distal phalanx of digits 2-5
Which is the only muscle capable of flexing the DIP joint?
Flexor digitorum profundus (FDP)
Which joints does the Flexor digitorum profundus (FDP) flex?
DIP joint
PIP joint
MCP joint of digits 2-5
What does the tendon of flexor pollicis longus (FPL) insert onto?
Distal phalanx of the thumb
What does the flexor pollicis longus (FPL) flex?
IP joint of the thumb and is the only muscle that can do so
What is the function of fibrous sheaths?
Enclose the long flexor tendons.
They maintain the position of the flexor tendons in the midline of each finger
What are the tendons within the fibrous sheaths enclosed within?
A synovial sheath, which reduces friction and allows the tendons to slide freely within their fibrous sheath during flexion and extension
What is tenosynovitis?
Inflammation of the tendon and synovial sheath
What is the function of the thick palmar aponeurosis?
Protects the long flexor tendons, tendon sheaths and vessels in the central palm
What are the 4 groups of intrinsic muscles of the hand?
- thenar eminence
- hypothenar eminence
- lumbricals
- interossei
How many muscles does the thenar eminence contain?
3
How many muscles does the hypothenar eminence contain?
3
How many muscles do the lumbricals contain?
4
How many muscles do the interossei contain?
7
What is the adductor pollicis?
Remaining intrinsic muscle of the hand - muscle of the thumb
What are the intrinsic hand muscles innervated by?
Ulnar and median nerves
What is the thenar eminence?
This is the fleshy mass on the palm of the hand at the base of the thumb.
It contains 3 muscles that act upon the thumb
What 3 muscles are found in the thenar eminence?
- Flexor pollicis brevis (FPB)
- Abductor pollicis brevis (APB)
- Opponens pollicis - (OP)
What movement does the flexor pollicis brevis ( FPB) execute?
Flexes the thumb
What movement does the abductor pollicis brevis (APB) execute?
Abducts the thumb
What movement does the Abductor pollicis brevis (APB) execute?
Abducts the thumb
What movement does the Opponens pollicis - (OP) execute?
Opposes the thumb
Where does the opponens pollicis lie?
Lies deep to the flexor and abductor
What muscles are attached to the carpal bones proximally?
Thenar muscles
Where is the insertion point of the flexor pollicis brevis?
Proximal phalanx
Where is the insertion point of the abductor pollicis brevis?
Proximal phalanx, lateral aspect
Where is the insertion point of the opponens pollicis?
1st metacarpal
What is the innervation of the flexor pollicis brevis?
Recurrent branch of the median nerve
What is the innervation of the abductor pollicis brevis
Recurrent branch of the median nerve
What is the innervation of the opponens pollicis?
Recurrent branch of the median nerve