510 hand

the carpal tunnel is formed by...

the deep arch is formed by the carpal bones and the flexor retinaculum Borders: Medially: hook of hamate and pisiform Laterally (thumb): tubercle of scaphoid and trapezium

Adductor Pollicis

Origin: Oblique head: 2nd and 3rd metacarpals and capitates Transverse head: 3rd metacarpal Insertion: Proximal 1st phalange Innervation: Ulnar nerve Main action: Adduction of the thumb

the interphalangeal joint is specific to which finger?

thumb

Which nerve innervates all intrisince muscles (except the 3 thenar muscles and the lateral 2 lumrbicals)?

ulnar nerve

what is the clinical importance of the anatomical snuffbox?

we can palpate the scaphoid bone here!

Metacarpophanangeal(MCP) joints are what type of joint?

Condylar Joints - which allow for flex, ex, ab, adduction, and circumduction

Which ligament is also known as the transverse carpal ligament Attachments: Medially: pisiform and hook of the hamate Laterally: scaphoid and trapezium Forms the covering over the carpal tunnel.

Flexor Reticulum

Main function of extensor hood

Serve as attachments for many of the intrinsic muscles of the hand. By inserting into the extensor hood, these intrinsic muscles are responsible for deliciated movements of the digits that could not be accomplished with the long flexor and extensor tendons alone. Because force from the small intrinsic muscles of the hand is applied to the extensor hood distal to the fulcrum of the metacarpophalangeal joints, the muscles flex these joints. Simultaneously, the force is transferred dorsally through the hood to extend the interphalangeal joints. This ability to flex the metacarpophalangeal joints, while at the same time extending the interphalangeal joints, is entirely due to the intrinsic muscles of the hand working through the extensor hoods

What movements can Carpometacarpal(CMC) Joint I perform?

flexion, extension, abduction, adduction, rotation, circumduction

what is the main function of the fibrous digital sheath?

hold the tendons to the bony plane and prevent the tendons from bowing when the digits are flexed

What are the symptoms of a fracture scaphoid?

pain in anterior snuff box with movement or palpatation

which ligament is a triangular condensation of deep fascia that covers the palm and is anchored to the skin in distal regions?

palmar aponeurosis

The capsule of each MCP joint is reinforced by which ligaments?

palmar ligament + medial and collateral ligaments

Entrapment syndrome is caused by ...

pressure on median nerve within the carpal tunnel

the dorsal Radiocarpal ligament runs from...

runs between the distal radius and the scaphoid, lunate, and triquetrum on the dorsal aspect of the wrist

Which arteries supply blood to the hand?

the radial and ulnar arteries, which form two interconnected vascular arches (superficial and deep) in the palm. Vessels to the digits, muscles, and joints originate from the two arches and the parent arteries.

What structures make up the anatomical snuffbox

- abductor pollicis -extensor pollicis brevis -extensor pollicis longus

T or F: the radial nerve only innervates skin of the dorsal side of the hand

F: the radial nerve only innervates skin of the dorsolateral side of the hand

What is the main action of the lumbricals?

Flexion of the MCP, extension of DIO and PIP

why does scaphoid fracture result in avascular necrosis? How does this affect healing time?

In approximately 10% of individuals, the scaphoid bone has a single blood supply from the radial artery, which enters through the distal portion of the bone to supply the proximal portion. When a fracture occurs across the "waist" of the scaphoid, the proximal portion therefore undergoes avascular necrosis. Can take up to 3 months to fully heal due to poor vascularization. Complete healing often requires surgery

Which nerve innervates the 3 thenar muscles (opponenes pollicis, abductor pollicis, flexor pollicis brevis) and 2 lateral lumbricals (lateral to 2nd-3rd digit)?

Median

Dorsal Interossei (4 muscles)

Origin: Adjacent side of metacarpals Insertion: Dorsal expansion and base of 2-4 proximal phalanges Innervation: Ulnar nerve Main action: Abduction of the digits, flexion of MCP and extension of IP joint

Palmaris Brevis

Origin: Flexor reticulum Insertion: Dermis on the ulnar border Innervation: Ulnar nerve Main action: Wrinkles the skin of the palm

What is the fibrous digital sheath formed by?

cruciate, annular, and distal extensions of the palmar aponeurosis

Which finger does not have a palmar interosseous muscle?

3rd

Name all the carpal bones. How many are there?

8

After exiting the carpal tunnel, the tendons of the ______ ______ _______ (1) and _______ _______ (2) cross the palm and enter the fibrous sheaths on the palmar aspect of the digits Within each tunnel, the tendons are surrounded by a __________ _________ (3). The ____________ ___________ (3)of the thumb and little finger are continuous with the sheaths associated with the tendons in the carpal tunnel.

After exiting the carpal tunnel, the tendons of the Flexor digitorum superficialis (1) and profundus muscles (2) cross the palm and enter the fibrous sheaths on the palmar aspect of the digits Within each tunnel, the tendons are surrounded by a synovial sheaths (3). The synovial sheaths(3) of the thumb and little finger are continuous with the sheaths associated with the tendons in the carpal tunnel. tendons of flexors muscles, thumb, and little finger--> synovial sheaths--> fibrous digital sheath (cruciate, annular, digital extensions of aponeurosis)

what are the attachement and functions of the Extensor Retinaculum Ligament?

Attachments: radius, pisiform, and triquetrum Functions: holds the extensor tendons in place and protects them

__________and ___________veins continue and connect to the superficial and deep venous palmar arch that run along side the arteries. A network of veins continue through the fingers and the dorsum of the hand that will drain into the arches.

Cephalic and Basilic (cephalic on lateral side- i remember by seeing the the letter "c" formed by my thumb and index finger)

what thick bands of connective tissue connect palmar ligaments of the MCP joints of the fingers to each other, restricting the movement of these bones relative to eachother and helping form a unified skeletal framework for the palm of the hand?

Deep and Superficial Transverse Metacarpal Ligaments

What mechanical injury results in a scaphoid fracture?

FOOSH falling on out stretched hand

What is the main action of the oppones digiti minimi?

Lateral rotation of the 5th metacarpal (flexion, opposition to thumb as well)

MOI, risk factors, and symptoms of entrapment (carpal tunnel) syndrome

MOI: repetitive movements that lead to compression of the median nerve (swelling) ex: flexion of fingers, typing (why-flexor digitorum profundus, flexor digitorum superficialis, flexor pollicis longus tendon run through here) Risk factors: pregnancy, systemic health condition, job conditions Symptoms: Numbness, tingling (needles), and pain in hand and forearm. in 1st 2nd and 3rd digits and lateral side of 4th digit (course of median nerve)

What is the Guyon's canal made up of? Guyon's canal syndrome is the entrapement of what nerve?

Made up from the thickening of the antebrachial fascia (palmar carpar ligament) superiorly, and inferiorly by the flexor retinaculum and the hypothenar muscles. The medial wall of the canal is made up from the pisiform while the lateral wall is made up by the hook of the hamete bone. Clinical implicance: Guynon's canal syndrome- entrapment of Ulnar nerve

palmar aponeurosis: origin, insertion, function

O: extensor reticulum and palmaris longus I: base of metacarpophangeal joint and transversemetacarpal ligament

Lumbricals

Origin: 1st and 2nd: lateral tendons of flexor digitorum profundus 3rd and 4th: medial tendons of flexor digitorum profundus Insertion: Lateral side of the dorsal expansion of 2-5 Innervation: Median nerve (1st and 2nd lumbricals) Ulnar nerve (3rd and 4th lumbricals) Main action: Flexion of the MCP, extension of DIP and PIP

which ligament runs between the distal radius and the scaphoid, lunate, and triquetrum on the palmar aspect of the wrist?

Palmar radiocarpal ligament

Which artery supplies the thumb and the lateral side of the index finger?

Radial artery

Which ligament connects the radial styloid process to the side of the scaphoid. Limits ulnar deviation.

Radial collateral ligament

what type of joint is between metacarpal I and the trapezium?

Saddle Joint

what is the function of the deep and superficial transverse metacarpal ligaments?

The deep and superficial transverse metacarpal ligaments are thick bands of connective tissue connecting the palmar ligaments of the metacarpophalangeal joints of the fingers to each other. By linking the heads of the metacarpal bones together, they restrict the movement of these bones relative to each other. (2-5) As a result, they help form a unified skeletal framework for the palm of the hand. in contrast, thumb (1st metacarpal- trapezium) has lots of movement

why is the median nerve the most important sensory nerve of the hand?

The median nerve is the most important sensory nerve in the hand because it innervates skin on the thumb, index and middle fingers, and lateral side of the ring finger. The nervous system, using touch, gathers information about the environment from this area, particularly from the skin on the thumb and index finger. In addition, sensory information from the lateral three and one-half digits enables the fingers to be positioned with the appropriate amount of force when using precision grip.

What tendons from the extensor hoods (extensor expansion)

The tendons of the extensor digitorum and extensor pollicis longus muscles pass onto the dorsal aspect of the digits and expand over the proximal phalanges to form the extensor hoods. The tendons of the extensor digiti minimi, extensor indicis, and extensor pollicis brevis muscles join these hoods.

How to test for carpal tunnel syndrome?

Tinel's test. PT or clinican taps where median nerve passes through, quick and gental + produces symptoms, aggravation

Which artery mainly supplies digits 3-5 and the medial side of the index finger (digit 2)?

Ulnar artery

What ligaments run from the ulnar styloid process and divides to attach to the triquetrum and to the pisiform. Limits radial deviation.

Ulnar collateral ligament runs from the ulnar styloid process and divides to attach to the triquetrum and to the pisiform. Limits radial deviation.

clawing of hand is a result of a lesion in what nerve? At what two sites does this occur?

Ulnar nerve lesions are characterized by "clawing" of the hand, in which the metacarpophalangeal joints of the fingers are hyperextended and the interphalangeal joints are flexed because the function of most of the intrinsic muscles of the hand is lost. Clawing is most pronounced in the medial fingers because the function of all intrinsic muscles of these digits is lost while in the lateral two digits, the lumbricals are innervated by the median nerve. Function of the adductor pollicis muscle is also lost. In lesions of the ulnar nerve at the elbow, function of the flexor carpi ulnaris muscle and flexor digitorum profundus to the medial two digits is lost as well. The ulnar nerve is most commonly injured at two sites: the elbow and the wrist. At the elbow, the nerve lies posterior to the medial epicondyle. At the wrist, the ulnar nerve passes superficial to the flexor retinaculum and lies lateral to the pisiform bone.

how can the extensor retinaculum be used in surgical procedures?

it can be used as a graph for finger injuries that are not able to be repaired themeselves

what movements can CMC joint II-V do?

limited gliding movements

Which nerve innervates the flexor pollicis brevis muscle?

median

the thumb only has __ phalanges while the rest have ___. Since the thumb has no intermediate phalange, the joint in between the 2 phalanges is called ________.

the thumb only has (2)phalanges while the rest have (3). Since the thumb has no intermediate phalange, the joint in between the 2 phalanx is called the interphanangeal joint.

Distal Radioulnar Ligament (palmer and dorsal):

wraps around the distal end of the ulna to connect to the radius.