Launch the next step in your career. Hire the next generation of talent. Bring the best jobs to your students. Arthritis of the Wrist and Hand Arthritis is the progressive wearing down of cartilage between joints to the point that bone begins wearing against bone. Read about who is affected, what the symptoms are, how arthritis is diagnosed, treated and what surgical options might be available. Definition of hand in the Idioms Dictionary. What does hand expression mean? Definitions by the largest Idiom Dictionary. Hand - Idioms by The Free.
A Patient’s Guide to Hand Anatomy
Introduction
Few structures of the human anatomy are as unique as the hand. The hand needs to be mobile in order to position the fingers and thumb. Adequate strength forms the basis for normal hand function. The hand also must be coordinated to perform fine motor tasks with precision. The structures that form and move the hand require proper alignment and control in order for normal hand function to occur.
In addition to reading this article, be sure to watch ourHand Anatomy Animated Tutorial Video.
This guide will help you understand
- what parts make up the hand
- how those parts work together
Important Structures
The important structures of the hand can be divided into several categories. These include
- bones and joints
- ligaments and tendons
- muscles
- nerves
- blood vessels
The front, or palm-side, of the hand is referred to as the palmar side. The back of the hand is called the dorsal side.
Bones and Joints
There are 27 bones within the wrist and hand. The wrist itself contains eight small bones, called carpals. The carpals join with the two forearm bones, the radius and ulna, forming the wrist joint. Further into the palm, the carpals connect to the metacarpals. There are five metacarpals forming the palm of the hand. One metacarpal connects to each finger and thumb. Small bone shafts called phalanges line up to form each finger and thumb.
The main knuckle joints are formed by the connections of the phalanges to the metacarpals. These joints are called the metacarpophalangeal joints (MCP joints). The MCP joints work like a hinge when you bend and straighten your fingers and thumb.
The three phalanges in each finger are separated by two joints, called interphalangeal joints (IP joints). The one closest to the MCP joint (knuckle) is called the proximal IP joint (PIP joint). The joint near the end of the finger is called the distal IP joint (DIP joint). The thumb only has one IP joint between the two thumb phalanges. The IP joints of the digits also work like hinges when you bend and straighten your fingers and thumb.
The joints of the hand, fingers, and thumb are covered on the ends with articular cartilage. This white, shiny material has a rubbery consistency. The function of articular cartilage is to absorb shock and provide an extremely smooth surface to
facilitate motion. There is articular cartilage essentially everywhere that two bony surfaces move against one another, or articulate.
facilitate motion. There is articular cartilage essentially everywhere that two bony surfaces move against one another, or articulate.
Profind 1 7 2 full. Ligaments and Tendons
Ligaments are tough bands of tissue that connect bones together. Two important structures, called collateral ligaments, are found on either side of each finger and thumb joint. The function of the collateral ligaments is to prevent abnormal sideways bending of each joint.
Hand Emoji
In the PIP joint (the middle joint between the main knuckle and the DIP joint), the strongest ligament is the volar plate. This ligament connects the proximal phalanx to the middle phalanx on the palm side of the joint. The ligament tightens as the joint is straightened and keeps the PIP joint from bending back too far (hyperextending). Finger deformities can occur when the volar plate loosens from disease or injury.
The tendons that allow each finger joint to straighten are called the extensor tendons. The extensor tendons of the fingers begin as muscles that arise from the backside of the forearm bones. These muscles travel towards the hand, where they eventually connect to the extensor tendons before crossing over the back of the wrist joint. As they travel into the fingers, the extensor tendons become the extensor hood. The extensor hood flattens out to cover the top of the finger and sends out branches on each side that connect to the bones in the middle and end of the finger.
The place where the extensor tendon attaches to the middle phalanx is called the central slip. When the extensor muscles contract, they tug on the extensor tendon and straighten the finger. Problems occur when the central slip is damaged, as can happen with a tear.
Muscles
Many of the muscles that control the hand start at the elbow or forearm. They run down the forearm and cross the wrist and hand. Some control only the bending or straightening of the wrist. Others influence motion of the fingers or thumb. Many of these muscles help position and hold the wrist and hand while the thumb and fingers grip or perform fine motor actions.
Most of the small muscles that work the thumb and pinky finger start on the carpal bones. These muscles connect in ways that allow the hand to grip and hold. Two muscles allow the thumb to move across the palm of the hand, an important function called thumb opposition.
The smallest muscles that originate in the wrist and hand are called the intrinsic muscles. The intrinsic muscles guide the fine motions of the fingers by getting the fingers positioned and holding them steady during hand activities.
Nerves
All of the nerves that travel to the hand and fingers begin together at the shoulder: the radial nerve, the median nerve, and the ulnar nerve. These nerves carry signals from the brain to the muscles that move the arm, hand, fingers, and thumb. The nerves also carry signals back to the brain about sensations such as touch, pain, and temperature.
The radial nerve runs along the thumb-side edge of the forearm. It wraps around the end of the radius bone toward the back of the hand. It gives sensation to the back of the hand from the thumb to the third finger. It also supplies the back of the thumb and just beyond the main knuckle of the back surface of the ring and middle fingers.
The median nerve travels through a tunnel within the wrist called the carpal tunnel. This nerve gives sensation to the thumb, index finger, long finger, and half of the ring finger. It also sends a nerve branch to control the thenar muscles of the thumb. The thenar muscles help move the thumb and let you touch the pad of the thumb to the tips each of each finger on the same hand, a motion called opposition.
The ulnar nerve travels through a separate tunnel, called Guyon’s canal. This tunnel is formed by two carpal bones, the pisiform and hamate, and the ligament that connects them. After passing through the canal, the ulnar nerve branches out to supply feeling to the little finger and half the ring finger. Branches of this nerve also supply the small muscles in the palm and the muscle that pulls the thumb toward the palm.
The nerves that travel to the hand are subject to problems. Constant bending and straightening of the wrist and fingers can lead to irritation or pressure on the nerves within their tunnels and cause problems such as pain, numbness, and weakness in the hand, fingers, and thumb.
Blood Vessels
Traveling along with the nerves are the large vessels that supply the hand with blood. The largest artery is the radial artery that travels across the front of the wrist, closest to the thumb. The radial artery is where the pulse is taken in the wrist. The ulnar artery runs next to the ulnar nerve through Guyon’s canal (mentioned earlier). The ulnar and radial arteries arch together within the palm of the hand, supplying the front of the hand, fingers, and thumb. Other arteries travel across the back of the wrist to supply the back of the hand, fingers, and thumb.
Summary
The hand is formed of numerous structures that have an important role in normal hand function. Conditions that change the way these structures work can greatly impact whether the hand functions normally. When our hands are free of problems, it’s easy to take the complex anatomy of the hand for granted.
Muscles of the hand | |
---|---|
Details | |
Origin | Upper extremity |
Insertion | Hand and fingers |
Nerve | radial, median, and ulnar nerves (from C5–T1) |
Actions | Flexion, extension, adduction, abduction of the hand and fingers and oppossion of the thumb |
Identifiers | |
FMA | 42368 |
Anatomical terms of muscle [edit on Wikidata] |
The muscles of the hand are the skeletal muscles responsible for the movement of the hand and fingers. The muscles of the hand can be subdivided into two groups: the extrinsic and intrinsic muscle groups. The extrinsic muscle groups are the long flexors and extensors. They are called extrinsic because the muscle belly is located on the forearm. The intrinsic group are the smaller muscles located within the hand itself. The muscles of the hand are innervated by the radial, median, and ulnar nerves from the brachial plexus.[1] Bigasoft video downloader pro 3 22 1 730 gb.
Intrinsic[edit]
The intrinsic muscle groups are the thenar (thumb) and hypothenar (little finger) muscles; the interossei muscles (four dorsally and three volarly) originating between the metacarpal bones; and the lumbrical muscles arising from the deep flexor (and which are special because they have no bony origin) to insert on the dorsal extensor hood mechanism. Palmaris brevis which is a superficial muscle and adductor pollicis are also intrinsic muscles.[2]
Extrinsic[edit]
Extensor compartments of wrist (back of hand)
The fingers have two long flexors, located on the underside of the forearm. They 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), moving the thumb 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 thumb has two extensors in the forearm; the tendons of these form the anatomical snuff box. Also, the index finger and the little finger have an extra extensor, used, for instance, pointing. The extensors are situated within 6 separate compartments.
Compartment 1 (Most radial) | Compartment 2 | Compartment 3 | Compartment 4 | Compartment 5 | Compartment 6 (Most ulnar) |
---|---|---|---|---|---|
Abductor pollicis longus | Extensor carpi radialis longus | Extensor pollicis longus | Extensor indicis | Extensor digiti minimi | Extensor carpi ulnaris |
Extensor pollicis brevis | Extensor carpi radialis brevis | Extensor digitorum communis |
Handshake
The first four compartments are located in the grooves present on the dorsum of inferior side of radius while the 5th compartment is in between radius and ulna. The 6th compartment is in the groove on the dorsum of inferior side of ulna.
Nerve supply[edit]
The muscles of the hand are innervated by the radial, median, and ulnar nerves.
The radial nerve innervates the finger extensors and the thumb abductor; that is, the muscles that extend at the wrist and metacarpophalangeal joints (knuckles) and abduct and extend the thumb. The median nerve innervates the flexors of the wrist and digits, the abductors and opponens of the thumb, the first and second lumbrical. The ulnar nerve innervates the remaining intrinsic muscles of the hand.[3]
All muscles of the hand are innervated by the brachial plexus (C5–T1) and can be classified by innervation:[1]
Nerve | Muscles |
---|---|
Radial | Extensors: carpi radialis longus and brevis, digitorum, digiti minimi, carpi ulnaris, pollicis longus and brevis, and indicis. Other: abductor pollicis longus. |
Median | Flexors: carpi radialis, pollicis longus, digitorum profundus (half), superficialis, and pollicis brevis (superficial head). Other: palmaris longus. abductor pollicis brevis, opponens pollicis, and first and second lumbricals. |
Ulnar | Flexor carpi ulnaris, flexor digitorum profundus (half), palmaris brevis, flexor digiti minimi, abductor digiti minimi, opponens digiti minimi, adductor pollicis, flexor pollicis brevis (deep head), palmar and dorsal interossei, and third and fourth lumbricals. |
See also[edit]
References[edit]
Hand And Stone
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- ^'Medical mnemonics'. LifeHugger. Archived from the original on 2011-07-13. Retrieved 2009-12-19.
- ^Jones & Lederman 2006, pp. 16–18 harvnb error: no target: CITEREFJonesLederman2006 (help)
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