The foot is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made up of one or more segments or bones, generally including claws and/or nails.
The lumbricals are intrinsic muscles of the hand that flex the metacarpophalangeal joints, and extend the interphalangeal joints.
The flexor digitorum 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.
Flexor digitorum superficialis is an extrinsic flexor muscle of the fingers at the proximal interphalangeal joints.
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 arm, forearm and hand, and is primarily used for climbing, lifting and manipulating objects.
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.
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 palmar or volar interossei are four muscles, one on the thumb that is occasionally missing, and three small, unipennate, central muscles in the hand that lie between the metacarpal bones and are attached to the index, ring, and little fingers. They are smaller than the dorsal interossei of the hand.
A mallet finger, also known as hammer finger or PLF finger or Hannan finger, is an extensor tendon injury at the farthest away finger joint. This results in the inability to extend the finger tip without pushing it. There is generally pain and bruising at the back side of the farthest away finger joint.
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 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.
The interphalangeal joints of the hand are the hinge joints between the phalanges of the fingers that provide flexion towards the palm of the hand.
Within each osseo-aponeurotic canal, the tendons of the flexor digitorum superficialis and flexor digitorum profundus are connected to each other, and to the phalanges, by slender, tendinous bands, called vincula tendina.
The interphalangeal joints of the foot are between the phalanx bones of the toes in the feet.
Jammed finger is a colloquialism referring to a variety of injuries to the joints of the fingers, resulting from axial loading beyond that which the ligaments can withstand. Common parts of the finger susceptible to this type of injury are ligaments, joints, and bones. The severity of the damage to the finger increases with the magnitude of the force exerted by the external object on the fingertip. Toes may become jammed as well, with similar results.
In the human hand, palmar or volar plates are found in the metacarpophalangeal (MCP) and interphalangeal (IP) joints, where they reinforce the joint capsules, enhance joint stability, and limit hyperextension. The plates of the MCP and IP joints are structurally and functionally similar, except that in the MCP joints they are interconnected by a deep transverse ligament. In the MCP joints, they also indirectly provide stability to the longitudinal palmar arches of the hand. The volar plate of the thumb MCP joint has a transverse longitudinal rectangular shape, shorter than those in the fingers.
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).
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).
Acquired hand deformity refers to the structural or functional abnormalities that develop in the hand. There are multiple varying causes of acquired hand deformity, triggering significant consequences and complications. Trauma, including blunt force, penetrating injuries, burns, and sports-related incidents, is a primary cause of acquired hand deformities. Inflammatory conditions such as rheumatoid arthritis, gouty arthritis, and systemic lupus erythematosus can also contribute to hand deformities by affecting the joints. Degenerative arthritis, specifically osteoarthritis, functions to evoke impaired hand function due to the gradual deterioration of cartilage. Neurological disorders like cerebral palsy can result in hand contractures due to increased muscle tone and stiffness. There are different types of acquired hand deformities, each with distinct characteristics and underlying causes, such as boutonnière deformity, Dupuytren's contracture, gamekeeper's thumb, hand osteoarthritis deformity, mallet finger, swan-neck deformity, ulnar claw hand, among many others.
