The median nerve is a nerve in humans and other animals in the upper limb. It is one of the five main nerves originating from the brachial plexus.
The lumbricals are intrinsic muscles of the hand that flex the metacarpophalangeal joints, and extend the interphalangeal joints.
The flexor digitorum profundus or flexor digitorum communis profundus is a muscle in the forearm of humans that flexes the fingers. It is considered an extrinsic hand muscle because it acts on the hand while its muscle belly is located in the forearm.
In anatomy, flexor carpi radialis is a muscle of the human forearm that acts to flex and (radially) abduct the hand. The Latin carpus means wrist; hence flexor carpi is a flexor of the wrist.
The ulnar nerve is a nerve that runs near the ulna, one of the two long bones in the forearm. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest in the human body unprotected by muscle or bone, so injury is common. This nerve is directly connected to the little finger, and the adjacent half of the ring finger, innervating the palmar aspect of these fingers, including both front and back of the tips, perhaps as far back as the fingernail beds.
The upper limbs or upper extremities are the forelimbs of an upright-postured tetrapod vertebrate, extending from the scapulae and clavicles down to and including the digits, including all the musculatures and ligaments involved with the shoulder, elbow, wrist and knuckle joints. In humans, each upper limb is divided into the shoulder, arm, elbow, forearm, wrist and hand, and is primarily used for climbing, lifting and manipulating objects. In anatomy, just as arm refers to the upper arm, leg refers to the lower leg.
The ulnar artery is the main blood vessel, with oxygenated blood, of the medial aspects of the forearm. It arises from the brachial artery and terminates in the superficial palmar arch, which joins with the superficial branch of the radial artery. It is palpable on the anterior and medial aspect of the wrist.
The extensor digitorum muscle is a muscle of the posterior forearm present in humans and other animals. It extends the medial four digits of the hand. Extensor digitorum is innervated by the posterior interosseous nerve, which is a branch of the radial nerve.
In human anatomy, the extensor pollicis longus muscle (EPL) is a skeletal muscle located dorsally on the forearm. It is much larger than the extensor pollicis brevis, the origin of which it partly covers and acts to stretch the thumb together with this muscle.
The flexor pollicis longus is a muscle in the forearm and hand that flexes the thumb. It lies in the same plane as the flexor digitorum profundus. This muscle is unique to humans, being either rudimentary or absent in other primates. A meta-analysis indicated accessory flexor pollicis longus is present in around 48% of the population.
In human anatomy, the dorsal interossei (DI) are four muscles in the back of the hand that act to abduct (spread) the index, middle, and ring fingers away from the hand's midline and assist in flexion at the metacarpophalangeal joints and extension at the interphalangeal joints of the index, middle and ring fingers.
In human anatomy, the abductor digiti minimi is a skeletal muscle situated on the ulnar border of the palm of the hand. It forms the ulnar border of the palm and its spindle-like shape defines the hypothenar eminence of the palm together with the skin, connective tissue, and fat surrounding it. Its main function is to pull the little finger away from the other fingers.
In human anatomy, the extensor indicis (proprius) is a narrow, elongated skeletal muscle in the deep layer of the dorsal forearm, placed medial to, and parallel with, the extensor pollicis longus. Its tendon goes to the index finger, which it extends.
The anterior interosseous nerve is a branch of the median nerve that supplies the deep muscles on the anterior of the forearm, except the ulnar (medial) half of the flexor digitorum profundus. Its nerve roots come from C8 and T1.
The anterior compartment of the forearm contains the following muscles:
The posterior compartment of the forearm contains twelve muscles which primarily extend the wrist and digits. It is separated from the anterior compartment by the interosseous membrane between the radius and ulna.
In the human body, the carpal tunnel or carpal canal is a flattened body cavity on the flexor (palmar/volar) side of the wrist, bounded by the carpal bones and flexor retinaculum. It forms the passageway that transmits the median nerve and the tendons of the extrinsic flexor muscles of the hand from the forearm to the hand. The median artery is an anatomical variant. When present it lies between the radial artery, and the ulnar artery and runs with the median nerve supplying the same structures innervated.
An ulnar claw, also known as claw hand or ‘Spinster’s Claw’, is a deformity or an abnormal attitude of the hand that develops due to ulnar nerve damage causing paralysis of the lumbricals. A claw hand presents with a hyperextension at the metacarpophalangeal joints and flexion at the proximal and distal interphalangeal joints of the 4th and 5th fingers. The patients with this condition can make a full fist but when they extend their fingers, the hand posture is referred to as claw hand. The ring- and little finger can usually not fully extend at the proximal interphalangeal joint (PIP).
Injuries to the arm, forearm or wrist area can lead to various nerve disorders. One such disorder is median nerve palsy. The median nerve controls the majority of the muscles in the forearm. It controls abduction of the thumb, flexion of hand at wrist, flexion of digital phalanx of the fingers, is the sensory nerve for the first three fingers, etc. Because of this major role of the median nerve, it is also called the eye of the hand. If the median nerve is damaged, the ability to abduct and oppose the thumb may be lost due to paralysis of the thenar muscles. Various other symptoms can occur which may be repaired through surgery and tendon transfers. Tendon transfers have been very successful in restoring motor function and improving functional outcomes in patients with median nerve palsy.
The extrinsic extensor muscles of the hand are located in the back of the forearm and have long tendons connecting them to bones in the hand, where they exert their action. Extrinsic denotes their location outside the hand. Extensor denotes their action which is to extend, or open flat, joints in the hand. They 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).
