Movements of the Hand Flashcards
Describe the muscles located in the forearm + their actions
Anterior Compartment (Flexor Group):
Flexor Carpi Radialis: Flexes and abducts the wrist.
Flexor Carpi Ulnaris: Flexes and adducts the wrist.
Flexor Digitorum Superficialis: Flexes the proximal interphalangeal joints of the middle phalanges of fingers 2-5.
Flexor Digitorum Profundus: Flexes the distal interphalangeal joints of fingers 2-5.
Flexor Pollicis Longus: Flexes the thumb at the interphalangeal joint.
Pronator Teres: Pronates and flexes the forearm.
Pronator Quadratus: Pronates the forearm.
Palmaris Longus (if present): Tenses the palmar aponeurosis and weakly assists in wrist flexion.
Posterior Compartment (Extensor Group):
Extensor Carpi Radialis Longus: Extends and abducts the wrist.
Extensor Carpi Radialis Brevis: Also extends and abducts the wrist.
Extensor Digitorum: Extends the phalanges of fingers 2-5.
Extensor Digiti Minimi: Extends the little finger.
Extensor Carpi Ulnaris: Extends and adducts the wrist.
Supinator: Supinates the forearm.
Abductor Pollicis Longus: Abducts the thumb.
Extensor Pollicis Brevis: Extends the proximal phalanx of the thumb.
Extensor Pollicis Longus: Extends the distal phalanx of the thumb.
Extensor Indicis: Extends the index finger.
Describe arrangement of long flexor tendons of the wrist + hand. How does this arrangement influence the movements they produce
Arrangement of Long Flexor Tendons:
Flexor Tendons of the Fingers: The primary flexor tendons for the fingers are the Flexor Digitorum Superficialis (FDS) and Flexor Digitorum Profundus (FDP). These tendons run from the forearm through the carpal tunnel at the wrist and into the hand. The FDS attaches to the middle phalanges, while the FDP extends further to attach to the distal phalanges.
Flexor Tendon of the Thumb: The Flexor Pollicis Longus (FPL) tendon functions similarly but is dedicated to the thumb. It also runs through the carpal tunnel and attaches to the distal phalanx of the thumb.
Arrangement in the Carpal Tunnel: These tendons pass through the carpal tunnel, a narrow passage in the wrist formed by carpal bones and the transverse carpal ligament. Within the tunnel, the tendons are accompanied by the median nerve.
Synovial Sheaths: The tendons are enclosed in synovial sheaths which reduce friction and allow smooth movement.
Influence on Movements:
Flexion of Fingers and Thumb: The primary movement facilitated by these tendons is flexion. The FDS and FDP allow bending of the fingers at the proximal and distal interphalangeal joints, respectively. The FPL facilitates flexion of the thumb.
Independent and Combined Finger Movement: The arrangement allows for both independent and combined movement of the fingers. For example, the FDP can flex the distal interphalangeal joints independently of the proximal interphalangeal joints, which is crucial for tasks requiring fine motor skills.
Force Distribution: The arrangement of these tendons, especially the way they run through the carpal tunnel and attach to the bones of the fingers, allows for efficient distribution of force across the hand. This enables both strong grip and precise movements.
Coordination with Extensors: These flexor tendons work in coordination with the extensor tendons on the back of the hand and forearm to facilitate complex hand movements.
Describe the contents of carpal tunnel + its boundaries
The ulnar nerve + ulnar artery enter the hand superficially to carpal tunnel so both are unaffected in carpal tunnel syndrome
hand contains approx ___ joints
hand contains approx 27 joints
which digit do we call 1 and which digit is 5
digit 1 is the thumb counting up to the pinky which is digit 5
what are the 3 most commonly fractured carpal bones of wrist
The most commonly fractured carpal bones in the wrist are:
Scaphoid Bone:
This is the most frequently fractured carpal bone. The scaphoid is located near the base of the thumb, and fractures here often occur due to a fall onto an outstretched hand. Because of its blood supply, scaphoid fractures can sometimes be slow to heal or lead to complications like avascular necrosis.
Triquetrum Bone:
The triquetrum is the second most commonly fractured carpal bone. Injuries to this bone typically occur from direct trauma to the wrist or a fall.
Lunate Bone:
Fractures of the lunate are less common compared to the scaphoid and triquetrum, but they can be significant due to the risk of lunate dislocation, which can lead to serious conditions like Kienböck’s disease.
What is the anatomical name for wrist joint and what movements does it permit
wrist joint= radiocarpal joint
movements it permits: flex, extend, abduct, adduct
the carpometacarpal joint of thumb is what kind of joint?
the carpometacarpal joint (of thumb) is a specialised saddle joint
In a saddle joint, the surfaces of the bones are shaped like a saddle and a rider, allowing for a range of movements. This specific type of joint is characterized by concave and convex areas. The CMC joint of the thumb allows for a wide range of movements, including flexion, extension, abduction, adduction, and circumduction, making the thumb highly versatile and dexterous.
what type of joint is
1)radiocarpal joint
2) mid-carpal joint
3) carpo-metacarpal joint
4) metacarpopharangeal joint (MCP)
5) proximal interpharangeal joint (PIP)
6) distal interpharangeal joing (DIP)
1) Radiocarpal Joint: This is a condyloid joint (also known as an ellipsoidal joint). It allows movement in two planes, including flexion, extension, abduction, and adduction.
2) Mid-Carpal Joint: This joint is also a condyloid type. It allows similar movements to the radiocarpal joint, contributing to the overall flexibility and range of motion of the wrist.
3) Carpometacarpal Joint (CMC): The type of this joint varies depending on the specific carpal and metacarpal bones involved. For the thumb (the first CMC joint), it’s a saddle joint, which allows a wide range of movements. The other CMC joints are generally plane type or slightly gliding.
4) Metacarpophalangeal Joint (MCP): These are condyloid joints. They allow movements such as flexion, extension, abduction, adduction, and circumduction, but not rotation.
5) Proximal Interphalangeal Joint (PIP): This is a hinge joint. It allows flexion and extension movements but no rotation.
6) Distal Interphalangeal Joint (DIP): Like the PIP, the DIP is a hinge joint. It allows primarily flexion and extension.
what age do most people develop a precision grip
precision grip is usually developed by 9 months of age
whereas we are born with a power grip already
what do we mean when we say extrinsic vs intrinsic muscles of the arm.
Describe the muscles and innervation of the anterior compartment and posterior compartment of the forearm
Extrinsic muscles found in forearm but they have long tendons that cross wrist and enter the hand to control/move fingers
Intrinsic muscles are within the hand and act on hand directly
We have both for coordination + control
ANTERIOR COMPARTMENT OF FOREARM
*flexors + pronators (originate from medial epicondyle of humerus which is why its such a large epicondyle as all those muscles attached)
* ulnar + median nerve
POSTERIOR COMPARTMENT OF FOREARM
* extensors + supinator
* radial nerve
define aponeurosis
Aponeurosis= a thin sheath of connective tissue that helps connect your muscles to your bones. Aponeuroses are similar to tendons. They support your muscles and give your body strength and stability. Aponeuroses absorb energy when your muscles move
what does pollicis mean anatomically
pollicis= thumb
so flexor pollicis longus muscle flexes the thumb
pronation of forearm is initiated by ____ and assisted by _____
(fill in blanks for muscles involved)
pronation of forearm is initiated by PRONATOR QUADRATUS and assisted by PRONATOR TERES
what is the function of a synovial sheath and what are synovial sheaths held in place by
the synovial sheath protects the long tendons of the flexor muscles in the hand.
synovial sheaths are held in place by fibrous digital tendon sheath
