Interval 9: Hand and Foot Flashcards
At the wrist, the carpal bones articulate proximally with the radius and ulna at the _______ and _______ joints and distally with the metacarpals at the __________ joints.
- radio carpal
- ulnocarpal
- carpometacarpal
What forms the radiocarpal joint?
-distal end of the radius and the scaphoid and lunate
What forms the ulnocarpal joint?
-distal end of ulna, an articular disk, and the triquetrum
What movements do the radiocarpal and ulnocarpal joints permit?
-flexion, extension, abduction (radial deviation) and adduction (ulnar deviation)
Colles’ fracture
- fracture of the distal end of the radius resulting from a fall on the outstretched hands
- posterior placement of distal surface producing “dinner fork” deformity
Colles’ facture usually occurs in what patient population?
-patients older than 50
Name the proximal and distal carpal bones from lateral to medial
- scaphoid
- lunate
- triquetral
- pisiform
- trapezium
- trapezoid
- capitate
- hamate
The pisiform is really a sesamoid bone in the tendon of the _________.
-flexor carpi ulnaris
Any bone prominens on the proximal row of carpal bones?
-scaphoid tubercle
What is unique about the trapezium?
-characterized by an elongated tubercle on its palmar surface that the tendon of the flexor carpi radialis passes through
What is the largest carpal bone?
-capitate
The hamate is characterized by its flattened, hook like process, the _______.
-Hamulus
What is the most commonly dislocated carpal bone? What issues may arise from this?
- lunate
- typically dislocated anteriorly into the carpal tunnel
- dislocation may cause carpal tunnel syndrome
What forms the arch of the carpal tunnel?
-the flexor retinaculum
Describe the ulnar and radial attachments of the flexor retinaculum.
- ulnar proximal: pisiform
- ulnar distal: hook of hamate
- radial proximal: tubercle of scaphoid
- radial distal: medial side of trapezium
Contents of the carpal tunnel
- tendons of the flexor pollicis longus and its own synovial sheath
- tendons of the flexor digitorum superficialis
- tendpns of flexor digitorum profundus
- median nerve
Position of median nerve in the carpal tunnel
-lies superficial to the long flexor tendons against the deep surface of the flexor retinaculum
Where is the canal of Guyon and what passes through it?
- a space on the anterior surface of the flexor retinaculum covered by superficial slip of fascia lateral to pisiform
- ulnar nerve and artery pass through this just lateral to pisiform
In each of the 4 fingers, a metacarpal and the 3 phalanges form what 3 joints?
- metacarpophalangeal joint (MP joint)
- proximal interphalangeal joint (PIP joint)
- distal interphalangeal joint (DIP joint)
Metacarpophalangeal joints allows movement in what direction?
- flexion-extension
- abduction-adduction
- condyloid joints
What movements do the phalangeal joints permit?
- flexion and extension
- they are hinge joints
Insertion of flexor carpi ulnaris
-pisiform
At the PIP joints the ______ phalanges articulate with the ________ phalanges. At the DIP joints, the ______ phalanges articulate with the ________ phalanges.
- proximal; middle
- middle; distal
3 joints of the thumb
- carpometacarpal joint
- MP joint
- interphalangeal joint
What type of joint is the carpometacarpal joint of the thumb and what actions does it permit?
- saddle joint formed by first metacarpal and the trapezium
- flexion, extension, abduction, adduction, and rotation
Borders of the anatomical snuffbox
- lateral: extensor pollicis brevis and abductor pollicis longus
- medial: extensor pollicis longus
- floor: scaphoid and trapezium bones
The ________ travels through the snuffbox, and the ______________ innervates skin over the snuffbox
- radial artery
- superficial branch of the radial nerve
What is the most commonly fractured carpal bone? Signs exhibited in patients?
- scaphoid
- pain and tenderness localized over anatomic snuffbox
Avascular necrosis and the scaphoid
-proximal part may undergo avascular necrosis because the blood supply to the bone supplies the distal part first and then the proximal part
The wrist is an ________ joint conveying what movements?
- ellipsoid joint
- flexion, extension, abduction, adduction, and circumduction
Can the wrist rotate?
-no, but supination and pronation in the forearm compensate for this inability
___________ arise from the brachial artery in the cubital fossa and supply the forearm and the hand.
-Radial and ulnar arteries
The common interosseous artery arises from the __________ in the cubital fossa. What does it branch into and supply?
- ulnar artery
- branches into anterior and posterior interosseous artery which supplies deep muscles in anterior and posterior forearm
The ulnar artery and its branches supply ______.
-the medial side of the forearm and hand
Superficial arch
-continuation of the ulnar artery which forms the superficial palmar arch in the palm of the hand and branches into palmar metacarpal arteries which supply the hand and digits
Deep branch of the ulnar artery
-anastomoses with the medial part of the deep palmar arch
What does the radial artery supply?
-lateral side of the forearm and the hand
Superficial branch of the radial artery
- arises from radial artery at wrist
- anastomoses with lateral part of the superficial palmar branch
Distal part of the radial artery
- courses dorsal to the wrist and crosses the floor of the anatomic snuffbox
- enters the deep part of the palm after passing between the 2 heads of the first dorsal interosseous muscle
- forms the deep palmar arch that branches into dorsal metacarpal arteries, which supply the hand and digits
5 muscles/groups of muscles that are intrinsic to the hand
- adductor pollicis
- thenar muscles
- hypothenar muscles
- interossei
- lumbricals
Unlike the extrinsic muscles that originate in the forearm, insert in the hand, and function in forceful gripping, the intrinsic muscles _______.
-occur entirely in the hand and mainly execute precision movements with the fingers and thumb
All intrinsic muscles are innervated by the _________ EXCEPT for _________.
- deep branch of the ulnar nerve
- EXCEPT the three thenar muscles and 2 lateral lumbricals
3 thenar muscles and 2 lateral lumbricals are innervated by ______.
-median nerve
Name the muscles of the thenar compartment and their innervation
- abductor pollicis brevis
- flexor pollicis brevis
- opponens pollicis
- innervated by recurrent branch of the median nerve
Abductor pollicis brevis function and innervation
- abduction of the thumb at metacarpophalangeal joint
- recurrent branch of median nerve
Flexor pollicis brevis function and innervation
- flexion of thumb
- recurrent branch of median nerve
Opponens pollicis function and innervation
- opposes and flexes the thumb
- recurrent branch of median nerve
Lumbricals arise from and are innervated by what?
- take origin from tendons of the flexor digitorum profundus muscle
- 1st and 2nd lumbricals are innervated by median nerve
- 3rd and 4th by ulnar nerve
Muscles and innervation of hypothenar compartment
- abductor digiti minimi
- flexor digiti minimi brevis
- opponens digiti minimi
- deep branch of ulnar nerve
Abductor digiti minimi function and innervation
- abduction of digit 5 at MP joint
- deep branch of ulnar nerve
Flexor digiti minimi brevis
- flexion of digit 5 at MP joint
- deep branch of ulnar nerve