Maximus Gage
Our hands and wrists are a complex network of bones, muscles, nerves, connective tissue, and blood vessels. While the fingers themselves do not contain muscles, the muscles responsible for finger movement are located in the forearm and palm. The muscles in the forearm end as tendons in the hand, which transmit movement to the fingers. The fingers have two long flexors, located on the underside of the forearm, which allow for the bending of the fingers. The extensors, located on the back of the forearm, are connected in a more complex way than the flexors to the dorsum of the fingers.
| Characteristics | Values |
|---|---|
| Are there muscles in fingers? | No |
| Muscles that move the fingers | Located in the forearm |
| Tendons | Connect muscles to bones |
| Types of tendons | Extensor and flexor |
| Extensor tendons | Used for stretching the hand |
| Flexor tendons | Used for bending the fingers |
| Types of muscles | Extrinsic and intrinsic |
| Extensor muscles | Straighten the digits |
| Flexor muscles | Allow for the actual bending of the fingers |
| Interossei muscles | Allow us to spread our fingers away from each other |
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What You'll Learn
- Muscles in the forearm become tendons in the hand, allowing finger movement
- There are two types of muscles in the hand: extrinsic and intrinsic
- The fingers have two long flexors, located on the underside of the forearm
- The primary function of the extensors is to straighten the fingers
- The human hand is made up of 27 individual bones
Muscles in the forearm become tendons in the hand, allowing finger movement
The human hand is a complex network of bones, muscles, nerves, tendons, ligaments, blood vessels, and parts of the lymphatic system. The muscles in the forearm become tendons in the hand, allowing for finger movement. Tendons generally connect muscle to bone, and the tendons that control the bones in the fingers are attached to 17 muscles in the palm of the hand and 18 in the forearm.
The fingers have two long flexors, located on the underside of the forearm, which insert by tendons to the phalanges of the fingers. The deep flexor attaches to the distal phalanx, and the superficial flexor attaches to the middle phalanx. The flexors allow for the actual bending of the fingers. The thumb has one long flexor and a short flexor in the thenar muscle group. The human thumb also has other muscles in the thenar group (opponens and abductor brevis muscle), which allow for the thumb to move in opposition, making grasping possible. The extensors are located on the back of the forearm and are connected in a more complex way than the flexors to the dorsum of the fingers. The tendons unite with the interosseous and lumbrical muscles to form the extensorhood mechanism. The primary function of the extensors is to straighten out the digits.
The flexor digitorum profundus arises from the ulna and interosseous membrane in the forearm. Four tendons emerge from the muscle, which pass through the carpal tunnel and insert into the tips of the index, middle, ring, and small fingers. Its primary action is to bend these fingers, and due to its insertion past the last joint of the finger, it is able to bend all three finger joints. The flexor digitorum superficialis arises from the medial epicondyle (an elbow bone) between the palmaris longus and the flexor carpi ulnaris muscles. In the forearm, the FDS has four independent muscle bellies from which four tendons arise. The FDS's primary function is to bend the middle joint of each finger (except the thumb). The independence of each finger's FDS contributes to the hand's skill in performing tasks, such as using chopsticks.
The intrinsic muscles inside the hand work with extrinsic muscles near the outside of the hand and in the forearm to give the hand its strength and dexterity. There are 34 muscles in each hand, which can be categorized into groups, including thenar muscles, hypothenar muscles, interossei muscles, and lumbrical muscles.
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There are two types of muscles in the hand: extrinsic and intrinsic
There are no muscles in the fingers themselves, but the muscles that control the finger joints are located in the palm and forearm. Tendons connect the muscles in the forearm to the bones in the fingers. The muscles that close the hand are called flexors, and the ones that open the hand are extensors. The flexors are located on the underside of the forearm and attach by tendons to the phalanges of the fingers. The extensors are located on the back of the forearm and are connected to the dorsum of the fingers.
The muscles of the hand are subdivided into two groups: extrinsic and intrinsic. The extrinsic muscles are located in the anterior and posterior compartments of the forearm and control crude movements, producing a forceful grip. The intrinsic muscles, on the other hand, are located within the hand itself and are responsible for fine motor functions. These muscles are smaller and are found within the various hand osseofascial compartments within the anatomic confines of the wrist and phalanges. The intrinsic muscles are crucial for various hand functions, such as pinch and grip strength.
The thenar muscles are an example of intrinsic muscles. They consist of three short muscles located at the base of the thumb and are responsible for the thumb's fine movements. The opponens pollicis is the largest of the thenar muscles and lies underneath the other two. The median nerve innervates all the thenar muscles.
The extrinsic muscles, on the other hand, originate in the forearm. An injury to the proximal median nerve can result in paralysis of the extrinsic flexors of the hand, leading to partial flexion of the fourth and fifth digits while the other digits remain extended.
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The fingers have two long flexors, located on the underside of the forearm
The muscles in our fingers are responsible for their movement. These muscles can be divided into two groups: the extrinsic and intrinsic muscle groups. The extrinsic muscles are the long flexors and extensors, and they are called extrinsic because the muscle belly is located on the forearm. The intrinsic muscles are the smaller muscles located within the hand itself.
The extensors are located on the back of the forearm and are connected to the dorsum of the fingers. The primary function of the extensors is to straighten out the digits. The thumb has two extensors in the forearm, and the tendons of these form the anatomical snuff box. The index finger and the little finger have an extra extensor, used for pointing. The extensors are situated within six separate compartments. The first four are located in the grooves on the dorsum of the inferior side of the radius, while the fifth is between the radius and ulna. The sixth compartment is in the groove on the dorsum of the inferior side of the ulna.
The muscles of the hand are innervated by the radial, median, and ulnar nerves from the brachial plexus. The radial nerve innervates the finger extensors and the thumb abductor. The median nerve innervates the flexors of the wrist and digits, the abductors and opponens of the thumb, and the first and second lumbricals.
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The primary function of the extensors is to straighten the fingers
While fingers do not contain muscles, the muscles that move the finger joints are in the palm and forearm. The muscles that close your hand are known as flexors, and the ones that open your hand are extensors. The extensors are located on the back of the forearm and are connected to the dorsum of the fingers. The primary function of the extensors is to straighten the fingers.
The extensors are extrinsic muscles, which means that the muscle belly is located in the forearm. The extensors include the extensor carpi radialis longus (ECRL), extensor carpi radialis brevis (ECRB), extensor digitorum (ED), extensor digiti minimi (EDM), extensor carpi ulnaris (ECU), abductor pollicis longus (APL), extensor pollicis brevis (EPB), extensor pollicis longus (EPL), and extensor indicis (EI).
The extensors are situated within six separate compartments. The first four compartments are located in the grooves on the dorsum of the inferior side of the radius, while the fifth compartment is between the radius and ulna. The sixth compartment is in the groove on the dorsum of the inferior side of the ulna.
The thumb has two extensors in the forearm, and the index finger and little finger have an extra extensor, which allows for more independent movement of these fingers. The tendons of the thumb extensors form the anatomical snuff box. The radial nerve innervates the finger extensors and the thumb abductor.
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The human hand is made up of 27 individual bones
The human hand is a complex structure made up of 27 individual bones. These bones are supported by an intricate network of muscles, tendons, ligaments, nerves, and blood vessels. The hand consists of three types of bones: phalanges, metacarpal bones, and carpal bones.
The phalanges are the 14 bones found in the fingers and thumb of each hand, with each finger containing three phalanges, and the thumb containing two. These bones form the segments of the fingers and thumb, with the distal phalanx being the bone at the tip of the finger, the middle phalanx in the middle, and the proximal phalanx closest to the palm.
The metacarpal bones are the five bones that make up the middle part of the hand. These bones provide a foundation for the fingers and thumb to attach to and allow for a wide range of movements. The metacarpal bones are also the site of attachment for many muscles and tendons that control the hand's dexterity and grip strength.
The carpal bones consist of eight bones arranged in two rows, forming the wrist. These bones articulate with the ulna and radius bones of the forearm, allowing for complex movements of the wrist, such as flexion, extension, and rotation. The carpal tunnel, a space within the wrist formed by the carpal bones, allows for the passage of vital structures, including nine tendons, four ligaments, and one nerve, which provide function and sensation to the hand.
While the fingers themselves do not contain muscles, the movement of the finger joints is controlled by muscles located in the palm and forearm. These muscles, including flexors and extensors, allow for the bending, straightening, and spreading of the fingers. Tendons, strong, flexible structures, connect these muscles to the bones of the hand, enabling the translation of muscular contractions into precise finger movements. The intricate interplay between the 27 bones, supporting structures, and muscles allows the human hand to achieve an impressive range of motion and dexterity.
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Frequently asked questions
No, the fingers do not contain muscles. The muscles that move the finger joints are in the palm and forearm.
Tendons, which are fibrous connective tissues that attach muscles to bones, play a crucial role in finger movement. The muscles in the forearm transmit movements to the tendons in the hand, enabling finger motion.
There are two types of tendons in the hand: extensor tendons and flexor tendons. Extensor tendons help to straighten and extend the fingers, hand, and wrist, while flexor tendons enable finger, hand, and wrist flexion and curling.
The fingers are moved by the flexor digitorum profundus and flexor digitorum superficialis muscles. The flexor digitorum profundus arises from the ulna and interosseous membrane, with four tendons inserting into the tips of the index, middle, ring, and small fingers. The flexor digitorum superficialis, on the other hand, originates from the medial epicondyle (elbow bone) and has four independent muscle bellies.
Tendon injuries in the fingers can occur, with tendonitis being a common condition. Tendon repair surgery may be required in severe cases, followed by physical therapy for rehabilitation.
