Anatomy Of Wrist And Hand Pdf

anatomy of wrist and hand pdf

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Wrist ultrasound examination – scanning technique and ultrasound anatomy. Part 1: Dorsal wrist

The wrist block involves anesthesia of the median, ulnar, and radial nerves, including the dorsal sensory branch of the ulnar nerve. The wrist block is simple to perform, essentially devoid of systemic complications, and highly effective for a variety of procedures on the hand and fingers.

Wrist blocks can be used in the office or operating room setting. As such, skill in performing a wrist block should be in the armamentarium of every practitioner. A study comparing intra-articular and portal infiltration versus wrist block for analgesia after arthroscopy of the wrist has shown that wrist block provides better and more reliable analgesia in patients undergoing arthroscopy of the wrist without exposing patients to the risk of chondrotoxicity.

A wrist block is most commonly used for hand and finger surgery. The most common hand surgery in the United States is carpal tunnel release. Sir James Paget described carpal tunnel syndrome in Although Sir James Learmonth reported release of the carpal tunnel at the wrist in , it was not until the s that the surgery became popular through the efforts of George Phalen. Because of the ease of performing a wrist block, wrist blocks are used in a variety of settings including the emergency room, outpatient surgery centers, and office-based anesthesia practices.

Hand surgeons rely on the wrist block to perform minor procedures in their offices. A wrist block can be used in a patient with a full stomach requiring emergency surgery, thereby obviating the need for general anesthesia and reducing the risk of aspiration. Although there are only a few contraindications to wrist blocks, local infection at the site of needle insertion and allergy to local anesthetic are the most cited. Patients are usually able to tolerate a tourniquet on the arm without anesthesia for 20 minutes; a wrist tourniquet can be tolerated for about minutes.

Innervation of the hand is shared by the ulnar, median, and radial nerves Figure 1. The ulnar nerve innervates more intrinsic muscles than the median nerve, and supplies digital branches to the skin of the medial one and a half digits Figure 2. A corresponding area of the palm is innervated by palmar branches that arise from the ulnar nerve in the forearm.

The deep branch of the ulnar nerve accompanies the deep palmar arch and supplies innervation to the three hypothenar muscles, the medial two lumbrical muscles, all the interossei, and the adductor pollicis. The ulnar nerve also innervates the palmaris brevis muscle.

The median nerve traverses the carpal tunnel and terminates as digital and recurrent branches. The digital branches innervate the skin of the lateral three and a half digits and, usually, the lateral two lumbrical muscles. A corresponding area of the palm is innervated by palmar branches that arise from the median nerve in the forearm.

The recurrent branch of the median nerve supplies the three thenar muscles. In the palm, the digital branches of the ulnar and median nerves lie deep in the superficial palmar arch, but in the fingers, they lie anterior to the digital arteries that arise from the superficial arch.

Although the innervation of the ring and middle fingers may vary, the skin on the anterior surface of the thumb is always supplied by the median nerve and that of the little finger by the ulnar nerve. The palmar digital branches of the median and ulnar nerves also innervate the nail beds of their respective digits.

The radial nerve passes along the front of the radial side of the forearm. It arises first from the lateral side of the radial artery and beneath the supinator muscle. About 3 in. The superficial branch, the smaller of the two branches, supplies the skin of the radial side and base of the thumb and joins the anterior branch of the musculocutaneous nerve. The deep branch of the radial nerve communicates with the posterior branch of the musculocutaneous nerve.

On the dorsum of the hand, the deep branch of the radial nerve forms an arch with the dorsal cutaneous branch of the ulnar nerve. The superficial branch of the radial nerve runs along the medial aspect of the brachioradialis muscle see Figure 3.

It then passes between the tendon of the brachioradialis and radius to pierce the fascia on the dorsal aspect. Just above the styloid process of the radius, it gives off digital branches for the dorsal skin of the thumb, index finger, and lateral half of the middle finger. The palmaris longus tendon is usually the more prominent of the two tendons, and the median nerve passes just lateral to it.

The ulnar nerve passes between the ulnar artery and tendon of the flexor carpi ulnaris see Figures 2 and 4. The tendon of the flexor carpi ulnaris is superficial to the ulnar nerve. The patient is in the supine position with the arm abducted.

The wrist should be kept in slight dorsiflexion. Five milliliters of LA is injected subcutaneously just above the radial styloid while advancing the needle medially Figure 5. The infiltration is then extended laterally, using an additional 5 mL of LA. The dorsal sensory branch of the radial nerve is blocked by inserting the needle 1 cm proximal to the radial styloid, which is radial to the radial artery Figure 6. This branch of the radial nerve exits from between the brachioradialis and extensor carpi radialis longus 5—8 cm proximal to the radial styloid.

The needle is advanced to the Lister tubercle, and if there are no paresthesias, 5 mL of LA is injected subcutaneously throughout this area. The needle is advanced 5—10 mm to just past the tendon of the flexor carpi ulnaris. Three to 5 mL of LA solution is injected.

Subcutaneous injection of 2—3 mL of local anesthesia just above the tendon of the flexor carpi ulnaris is also advisable in blocking the cutaneous branches of the ulnar nerve, which often extend to the hypothenar area. The dorsal sensory branch of the ulnar nerve is blocked by inserting the needle at the level of the ulnar styloid because it travels from palmar to dorsal in the area of the ulnar styloid Figure 9. Start the injection at the flexor carpi ulnaris and extend subcutaneously dorsally toward the distal radioulnar joint.

Five milliliters of LA is injected subcutaneously throughout the area. The median nerve is anesthetized by inserting the needle between the tendons of the palmaris longus and flexor carpi radialis Figures 10 and 11 ; see Figure 8. The needle is inserted until it pierces the deep fascia. Three to 5 milliliters of LA is injected. At that point, the needle is withdrawn 2—3 mm and the LA is injected. Figure 12 demonstrates the spread of the LA after injection of 5 mL using the described technique.

The median and ulnar nerves can also be blocked at the wrist using a nerve stimulator. These blocks may be used for finger flexor tendon repairs when the surgeon wishes to test their function intraoperatively the function of the forearm muscles is not affected. The median nerve is found in the carpal tunnel between the palmaris longus and the flexor carpi radialis tendons, and the ulnar nerve is found between the flexor carpi ulnaris and the ulnar artery.

Twitches are similar to elbow blocks except for the forearm pronation, which is missing. Two to 3 mL of LA is sufficient to block either nerve.

The choice of the type and concentration of LA for wrist blockade is based on the desired duration. Lidocaine is the most used anesthetic for wrist block, but bupivacaine can be used safely, also. Table 1 provides onset times and duration for some commonly used LAs. Clean the entire wrist area with a disinfectant solution. Aspirate prior to injection of LA to avoid intravascular injection. This technique is associated with moderate patient discomfort because multiple insertions and subcutaneous injections are required.

Typical onset time for a wrist block is 10—15 minutes, depending primarily on the concentration of LA used. Sensory anesthesia of the skin develops faster than the motor block. Placement of an Esmarch latex-free bandage or a tourniquet at the level of the wrist is well tolerated and does not require additional blockade.

Most common complications after wrist block are residual paresthesias due to an inadvertent intraneural injection. Systemic toxicity is rare because of the distal location of the blockade Table 2. Elbow blocks consist of blocks of the median, ulnar and radial nerves at the level at or about the elbow The wrist block is an effective method to provide anesthesia of the hand and fingers without the arm immobility that Describes the anatomy and practical approaches to the block of the brachial plexus at the interscalene space above the clavicle.

After the initial injection, the needle is withdrawn back to the skin level, redirected 30 degrees laterally, and advanced again to contact the bone. After pulling back 1—2 mm off the bone, an additional 2 mL of LA is injected. A similar procedure is repeated with a medial redirection of the needle. TABLE 1. Onset times and duration for commonly used local anesthetic mixtures.

Onset min Anesthesia h Analgesia h 1. Extra caution should, therefore, be used when advancing the needle and injecting LA. TABLE 2. Complications from wrist block. Infection This should be very rare with the use of an aseptic technique.

Hematoma Avoid multiple needle insertions for superficial blocks. Most superficial blocks can be accomplished with one or two needle insertions. Use gauge needle and avoid puncturing superficial veins. Vascular complications Do not use epinephrine with wrist and finger blocks. Nerve injury Do not inject when the patient complains of pain or high pressure on injection is detected. Do not reinject the median and ulnar nerves. Other Instruct the patient on the care of the insensate extremity.

Ultrasound-Guided Blocks at the Elbow Elbow blocks consist of blocks of the median, ulnar and radial nerves at the level at or about the elbow Ultrasound-Guided Wrist Nerve Block The wrist block is an effective method to provide anesthesia of the hand and fingers without the arm immobility that Ultrasound-Guided Interscalene Brachial Plexus Nerve Block Describes the anatomy and practical approaches to the block of the brachial plexus at the interscalene space above the clavicle.

Search for: Search Button. Avoid multiple needle insertions for superficial blocks. Do not inject when the patient complains of pain or high pressure on injection is detected.

Wrist Block – Landmarks and Nerve Stimulator Technique

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The median nerve is derived from the medial and lateral cords of the brachial plexus. It contains fibres from roots C6-T1 and can contain fibres from C5 in some individuals. After originating from the brachial plexus in the axilla , the median nerve descends down the arm, initially lateral to the brachial artery. Halfway down the arm, the nerve crosses over the brachial artery, and becomes situated medially. The median nerve enters the anterior compartment of the forearm via the cubital fossa. In the forearm, the nerve travels between the flexor digitorum profundus and flexor digitorum superficialis muscles. The median nerve gives off two major branches in the forearm:.

The Median Nerve

The anatomy of the hand is efficiently organized to carry out a variety of complex tasks. These tasks require a combination of intricate movements and finely controlled force production. The shape of the bony anatomy in conjunction with the arrangement of soft tissues contributes to the complex kinesiology of the hand. Injury to any of these structures can alter the overall function of the hand and therefore complicate the therapeutic management. The purpose of this article is to review the anatomy of the hand with special emphasis on structures that relate to management of hand injuries.

The wrist block involves anesthesia of the median, ulnar, and radial nerves, including the dorsal sensory branch of the ulnar nerve. The wrist block is simple to perform, essentially devoid of systemic complications, and highly effective for a variety of procedures on the hand and fingers. Wrist blocks can be used in the office or operating room setting. As such, skill in performing a wrist block should be in the armamentarium of every practitioner.

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