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Peripheral Nerve Injuries in the Upper Extremity

Peripheral nerve damage affecting the upper extremities is a common occupational injury and also occurs in individuals who participate in recreational sports. Injuries can affect Affect The feeling-tone accompaniment of an idea or mental representation. It is the most direct psychic derivative of instinct and the psychic representative of the various bodily changes by means of which instincts manifest themselves. Psychiatric Assessment the axillary, musculocutaneous, median, ulnar, or radial nerves. The most common causes of these injuries are overuse, compression Compression Blunt Chest Trauma or entrapment, or nerve trauma; degenerative or demyelinating disorders Demyelinating disorders Conditions characterized by loss or dysfunction of myelin in the brain, spinal cord, or optic nerves secondary to autoimmune mediated processes. This may take the form of a humoral or cellular immune response directed toward myelin or oligodendroglia associated autoantigens. Posterior Cord Syndrome; radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma therapy; and mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast lesions. Clinical presentation is with motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology and/or sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology deficits. Diagnosis is made clinically and based on electrodiagnostic and imaging studies. Treatment in most cases is conservative, although surgical intervention may occasionally be necessary.

Last updated: Jun 8, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Overview

Anatomy

The brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region is a network of nerves that originates in the posterior triangle Posterior triangle Triangles of the Neck: Anatomy of the neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess and passes to the axilla Axilla The axilla is a pyramid-shaped space located between the upper thorax and the arm. The axilla has a base, an apex, and 4 walls (anterior, medial, lateral, posterior). The base of the pyramid is made up of the axillary skin. The apex is the axillary inlet, located between the 1st rib, superior border of the scapula, and clavicle. Axilla and Brachial Plexus: Anatomy. The brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region is formed by the spinal nerve roots C5 to T1, which then divides and branches to provide all of the somatic innervation and some sympathetic innervation to the upper extremities.

  • Formed from the anterior rami of spinal nerve roots C5 to T1
  • Divided into trunks → divisions → cords, branches, and nerves
    • Upper trunk: formed by the C5 and C6 roots
    • Middle trunk: formed by the C7 root
    • Lower trunk: formed by the C8 and T1 roots
  • Divisions: Each trunk divides into an anterior and posterior part.
  • Cords, branches, and nerves
    • Lateral cord branches into:
      • Musculocutaneous nerve Musculocutaneous Nerve A major nerve of the upper extremity. The fibers of the musculocutaneous nerve originate in the lower cervical spinal cord (usually C5 to C7), travel via the lateral cord of the brachial plexus, and supply sensory and motor innervation to the upper arm, elbow, and forearm. Axilla and Brachial Plexus: Anatomy
      • Median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy
    • Posterior cord branches into:
    • Medial cord branches into:
      • Median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy
      • Ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy
      • Medial cutaneous nerves of the arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy and forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy
    • Suprascapular nerve Suprascapular nerve Axilla and Brachial Plexus: Anatomy: arises from the upper trunk
    • Dorsal scapular nerve Dorsal scapular nerve Axilla and Brachial Plexus: Anatomy: arises from the C5 root
    • Long thoracic nerve Long thoracic nerve Axilla and Brachial Plexus: Anatomy: arises from the C5, C6, and C7 roots

Classification

  • Grade I injury:
    • Usually mild
    • Involves damage to the myelin sheath without the involvement of the axon of the nerve
    • Symptoms improve in a few days.
  • Grade II–IV injury:
    • Based on the extent of nerve tissue damage
    • Involves injury to the axon itself
    • Regeneration Regeneration The physiological renewal, repair, or replacement of tissue. Wound Healing is possible, but may require months.
  • Grade V injury:
    • Most severe
    • Involves complete disruption of the axon of the nerve
    • Clinical recovery is not likely.
Sunderland classification of nerve injuries

Sunderland classification of nerve injuries

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Pathophysiology

Peripheral nerve damage affecting the upper extremities is a common occupational injury that can also occur in individuals who participate in recreational sports. Several mechanisms are involved in nerve injury Nerve Injury Surgical Complications.

  • Overuse injury Overuse Injury Osgood-Schlatter Disease:
    • Caused by a combination of individual factors:
      • Genetics Genetics Genetics is the study of genes and their functions and behaviors. Basic Terms of Genetics
      • Previous trauma
      • Age-related musculoskeletal changes
      • Conditioning and lifestyle
    • Types:
  • Compression Compression Blunt Chest Trauma injury:
  • Transection:
    • Occurs with severe trauma → complete disruption of the axon of the nerve
    • Complete loss of sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology and motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology responses
    • Variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables levels of clinical recovery with regeneration Regeneration The physiological renewal, repair, or replacement of tissue. Wound Healing
  • Nerve ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage/ infarct Infarct Area of necrotic cells in an organ, arising mainly from hypoxia and ischemia Ischemic Cell Damage:
    • Ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage occurs due to atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis → occlusion of small intraneural vessels due to:
      • Inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation
      • Radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma
      • Metabolic abnormalities (e.g., diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus)
    • Nerve infarction can occur with vasculitis Vasculitis Inflammation of any one of the blood vessels, including the arteries; veins; and rest of the vasculature system in the body. Systemic Lupus Erythematosus → axonal injury pattern → entire distal segment of the nerve degenerates within a few days
    • Nerve conduction velocity does not decrease.
    • Nerve repair:
      • After nerve injury Nerve Injury Surgical Complications, nerve growth factor promotes the proliferation of Schwann cells.
      • Production of neurotrophic factors by Schwann cells in the myelin sheath is crucial to axonal regeneration Regeneration The physiological renewal, repair, or replacement of tissue. Wound Healing.
  • Infection due to various viral, microbial, and parasitic causes:
    • EBV EBV Epstein-barr virus (EBV) is a linear, double-stranded DNA virus belonging to the herpesviridae family. This highly prevalent virus is mostly transmitted through contact with oropharyngeal secretions from an infected individual. The virus can infect epithelial cells and B lymphocytes, where it can undergo lytic replication or latency. Epstein-Barr Virus
    • Herpes zoster Herpes Zoster Varicella-zoster virus (VZV) is a linear, double-stranded DNA virus in the Herpesviridae family. Shingles (also known as herpes zoster) is more common in adults and occurs due to the reactivation of VZV. Varicella-Zoster Virus/Chickenpox virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology
    • Coxsackie B virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology
    • Mumps Mumps Mumps is caused by a single-stranded, linear, negative-sense RNA virus of the family Paramyxoviridae. Mumps is typically a disease of childhood, which manifests initially with fever, muscle pain, headache, poor appetite, and a general feeling of malaise, and is classically followed by parotitis. Mumps Virus/Mumps
    • HIV HIV Anti-HIV Drugs
    • Human parvovirus B19 Parvovirus B19 Primate erythroparvovirus 1 (generally referred to as parvovirus B19, B19 virus, or sometimes erythrovirus B19) ranks among the smallest DNA viruses. Parvovirus B19 is of the family Parvoviridae and genus Erythrovirus. In immunocompetent humans, parvovirus B19 classically results in erythema infectiosum (5th disease) or “slapped cheek syndrome.” Parvovirus B19
    • Lyme disease Lyme disease Lyme disease is a tick-borne infection caused by the gram-negative spirochete Borrelia burgdorferi. Lyme disease is transmitted by the black-legged Ixodes tick (known as a deer tick), which is only found in specific geographic regions. Patient presentation can vary depending on the stage of the disease and may include a characteristic erythema migrans rash. Lyme Disease
    • Leprosy Leprosy Leprosy, also known as Hansen’s disease, is a chronic bacterial infection caused by Mycobacterium leprae complex bacteria. Symptoms primarily affect the skin and peripheral nerves, resulting in cutaneous manifestations (e.g., hypopigmented macules) and neurologic manifestations (e.g., loss of sensation). Leprosy
  • Metabolic disorders:
    • Hypothyroidism Hypothyroidism Hypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism: distal sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology polyneuropathy Polyneuropathy Polyneuropathy is any disease process affecting the function of or causing damage to multiple nerves of the peripheral nervous system. There are numerous etiologies of polyneuropathy, most of which are systemic and the most common of which is diabetic neuropathy. Polyneuropathy possibly due to demyelination Demyelination Multiple Sclerosis or axonal degeneration
    • Vitamin B12 Vitamin B12 A cobalt-containing coordination compound produced by intestinal microorganisms and found also in soil and water. Higher plants do not concentrate vitamin B 12 from the soil and so are a poor source of the substance as compared with animal tissues. Intrinsic factor is important for the assimilation of vitamin B 12. Folate and Vitamin B12 deficiency causes demyelination Demyelination Multiple Sclerosis.
    • Vitamin B6 Vitamin B6 Vitamin B 6 refers to several picolines (especially pyridoxine; pyridoxal; & pyridoxamine) that are efficiently converted by the body to pyridoxal phosphate which is a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, and aminolevulinic acid. During transamination of amino acids, pyridoxal phosphate is transiently converted into pyridoxamine phosphate. Although pyridoxine and vitamin B 6 are still frequently used as synonyms, especially by medical researchers, this practice is erroneous and sometimes misleading. Most of vitamin b6 is eventually degraded to pyridoxic acid and excreted in the urine. Water-soluble Vitamins and their Deficiencies deficiency causes decreased nerve fiber density and increased axon-to-myelin ratio.
    • Vitamin B6 Vitamin B6 Vitamin B 6 refers to several picolines (especially pyridoxine; pyridoxal; & pyridoxamine) that are efficiently converted by the body to pyridoxal phosphate which is a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, and aminolevulinic acid. During transamination of amino acids, pyridoxal phosphate is transiently converted into pyridoxamine phosphate. Although pyridoxine and vitamin B 6 are still frequently used as synonyms, especially by medical researchers, this practice is erroneous and sometimes misleading. Most of vitamin b6 is eventually degraded to pyridoxic acid and excreted in the urine. Water-soluble Vitamins and their Deficiencies toxicity Toxicity Dosage Calculation causes loss of large myelinated Myelinated Internuclear Ophthalmoplegia fibers.
  • Medications:
  • Malignancy Malignancy Hemothorax: direct nerve invasion by cancer cells

Axillary Nerve Injury

The axillary nerve Axillary nerve Axilla and Brachial Plexus: Anatomy carries cutaneous sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology fibers to the area over the lateral shoulder and innervates the deltoid muscle for shoulder abduction Abduction Examination of the Upper Limbs and teres minor for external rotation Rotation Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. X-rays.

  • Causes of injury:
    • Trauma:
      • Shoulder dislocation
      • Fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures of the surgical neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess of the humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy
    • Compression Compression Blunt Chest Trauma:
      • Sleeping prone with arms raised above the head
      • Positioning of the individual while under general anesthesia General anesthesia Procedure in which patients are induced into an unconscious state through use of various medications so that they do not feel pain during surgery. Anesthesiology: History and Basic Concepts
      • Hypertrophy Hypertrophy General increase in bulk of a part or organ due to cell enlargement and accumulation of fluids and secretions, not due to tumor formation, nor to an increase in the number of cells (hyperplasia). Cellular Adaptation of the muscles of the quadrangular space (e.g., in weight lifters)
      • Compression Compression Blunt Chest Trauma in the axilla Axilla The axilla is a pyramid-shaped space located between the upper thorax and the arm. The axilla has a base, an apex, and 4 walls (anterior, medial, lateral, posterior). The base of the pyramid is made up of the axillary skin. The apex is the axillary inlet, located between the 1st rib, superior border of the scapula, and clavicle. Axilla and Brachial Plexus: Anatomy from the improper use of crutches
  • Clinical presentation:
    • Inspection Inspection Dermatologic Examination: atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation of the deltoid/loss of rounded shoulder contour
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss: lateral shoulder
    • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology weakness:
      • Loss of abduction Abduction Examination of the Upper Limbs beyond 15 degrees
      • Variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables; seldom severe, as other muscles assist in shoulder abduction Abduction Examination of the Upper Limbs and external rotation Rotation Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. X-rays
  • Diagnosis: electromyography Electromyography Recording of the changes in electric potential of muscle by means of surface or needle electrodes. Becker Muscular Dystrophy (EMG) and nerve conduction studies (nerve conduction velocity)
  • Management:
    • Conservative:
      • PT and exercise to preserve range of motion Range of motion The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate muscle strength exercises. Examination of the Upper Limbs
      • Recovery: usually within 3–4 months with incomplete nerve injury Nerve Injury Surgical Complications
    • Surgical intervention, if failure to improve with conservative management:
Posterior view of the proximal end of the humerus

Posterior view of the proximal end of the humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy featuring the surgical neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess, a frequent site of fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures:
A fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures at the site may injure the axillary nerve Axillary nerve Axilla and Brachial Plexus: Anatomy and/or posterior circumflex artery.

Image by BioDigital, edited by Lecturio

Musculocutaneous Nerve Injury

The musculocutaneous nerve Musculocutaneous Nerve A major nerve of the upper extremity. The fibers of the musculocutaneous nerve originate in the lower cervical spinal cord (usually C5 to C7), travel via the lateral cord of the brachial plexus, and supply sensory and motor innervation to the upper arm, elbow, and forearm. Axilla and Brachial Plexus: Anatomy arises from the lateral cord of the brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region and contains fibers from the C5, C6, and C7 nerve roots. The musculocutaneous nerve Musculocutaneous Nerve A major nerve of the upper extremity. The fibers of the musculocutaneous nerve originate in the lower cervical spinal cord (usually C5 to C7), travel via the lateral cord of the brachial plexus, and supply sensory and motor innervation to the upper arm, elbow, and forearm. Axilla and Brachial Plexus: Anatomy innervates the coracobrachialis Coracobrachialis Arm: Anatomy, biceps Biceps Arm: Anatomy, and brachialis Brachialis Arm: Anatomy muscles and provides sensation to the lateral forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy via the lateral cutaneous nerve.

  • Causes of injury:
    • Direct trauma Direct Trauma Toddler’s Fractures
    • Shoulder dislocation
    • Strenuous exercise Strenuous exercise Physical activity which is usually regular and done with the intention of improving or maintaining physical fitness or health. Contrast with physical exertion which is concerned largely with the physiologic and metabolic response to energy expenditure. Cardiovascular Response to Exercise
    • Malposition of the arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy during anesthesia Anesthesia A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures. Anesthesiology: History and Basic Concepts
  • Clinical presentation:
    • Weakness of elbow flexion Flexion Examination of the Upper Limbs
    • Weakness of forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy supination Supination Applies to movements of the forearm in turning the palm forward or upward. When referring to the foot, a combination of adduction and inversion movements of the foot. Examination of the Upper Limbs
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss over the lateral forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy via the lateral cutaneous nerve
  • Diagnosis:
  • Management:

Median Nerve Injury

The median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy innervates the flexor muscles of the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy (except the flexor carpi ulnaris Flexor carpi ulnaris Forearm: Anatomy and ulnar head of the flexor digitorum profundus Flexor digitorum profundus Forearm: Anatomy (FDP)), the thenar muscles Thenar muscles Hand: Anatomy, and the 2 radial lumbricals Lumbricals Hand: Anatomy in the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy. The median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy supplies sensation to the thumb, index, middle, and lateral half of the 4th fingers.

Causes of injury

Carpal tunnel Carpal Tunnel The carpal tunnel is formed by the transverse carpal ligament (flexor retinaculum) superiorly and the carpal bones inferiorly. Carpal Tunnel Syndrome syndrome

  • Epidemiology:
    • Most common upper extremity mononeuropathy Mononeuropathy Disease or trauma involving a single peripheral nerve in isolation, or out of proportion to evidence of diffuse peripheral nerve dysfunction. Mononeuropathy multiplex refers to a condition characterized by multiple isolated nerve injuries. Mononeuropathies may result from a wide variety of causes, including ischemia; traumatic injury; compression; connective tissue diseases; cumulative trauma disorders; and other conditions. Mononeuropathy and Plexopathy due to compression Compression Blunt Chest Trauma
    • Prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency: approximately 3% of the general population
    • Annual incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: 1.1–3 and 2.2–5.4 per 1000 person-years in men and women, respectively
  • Risk factors:
    • Obesity Obesity Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Obesity
    • Female gender Gender Gender Dysphoria
    • Pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care
    • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
    • Hypothyroidism Hypothyroidism Hypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism
    • Repetitive use of hands at work
  • Clinical presentation:
    • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways in the thumb, 2nd and 3rd digits, and the adjacent palm
    • Thenar weakness
    • Numbness and paresthesia in the 1st 3 and a ½ fingers
    • Burning pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways in the median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy distribution
    • Symptoms worsen at night (awakens individuals).
  • Diagnosis:
    • Provocative maneuvers:
      • Tinel test Tinel test Firm percussion over the course of the median nerve proximal to or on top of the carpal tunnel . A positive test is defined as pain and/or paresthesia in median innervated fingers on percussion over the median nerve. Carpal Tunnel Syndrome: Tapping over the course of the median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy on top of the carpal tunnel Carpal Tunnel The carpal tunnel is formed by the transverse carpal ligament (flexor retinaculum) superiorly and the carpal bones inferiorly. Carpal Tunnel Syndrome in the volar wrist causes pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways and paresthesias Paresthesias Subjective cutaneous sensations (e.g., cold, warmth, tingling, pressure, etc.) that are experienced spontaneously in the absence of stimulation. Posterior Cord Syndrome.
      • Phalen test Phalen Test Examination of the Upper Limbs: Holding wrists fully flexed with the elbows bent for 30 seconds reproduces symptoms.
      • Compression Compression Blunt Chest Trauma test: applying pressure over the transverse carpal ligament
      • Hand elevation test Hand elevation test Raising hands above the head for 1 minute. Deemed positive if pain and/or paresthesia noted in median innervated fingers within 30 seconds of elevation Carpal Tunnel Syndrome: raising hands above the head for 1 minute
    • EMG/nerve conduction velocity testing
  • Management:

Pronator teres Pronator teres Forearm: Anatomy syndrome

  • Clinical presentation:
    • Forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss over the entire lateral palm
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss over the thenar eminence
  • Diagnosis: EMG/nerve conduction velocity
  • Management:
Median nerve as it passes through the anterior forearm

Median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy passing through the anterior forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy, featuring the innervated muscles

Image by BioDigital, edited by Lecturio.

Anterior interosseous neuropathy Anterior Interosseous Neuropathy Mononeuropathy and Plexopathy

  • Branches off from the median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy in the region of the elbow
  • Descends the anterior forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy to innervate:
  • Does not provide sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology innervation to the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions
  • Injury to the nerve is characterized by weakness of the above muscles.
  • The affected individual cannot make a standard “O” (as in “okay”) with the thumb and forefinger.
  • Isolated injury is very rare.

Recurrent branch of the median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy injury

Sensory innervation of the hand

Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology innervation of the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy

Image by Lecturio.

Ulnar Nerve Injury

Ulnar neuropathy Ulnar neuropathy Disease involving the ulnar nerve from its origin in the brachial plexus to its termination in the hand. Clinical manifestations may include paresis or paralysis of wrist flexion, finger flexion, thumb adduction, finger abduction, and finger adduction. Sensation over the medial palm, fifth finger, and ulnar aspect of the ring finger may also be impaired. Common sites of injury include the axilla, cubital tunnel at the elbow, and guyon’s canal at the wrist. Mononeuropathy and Plexopathy at the elbow is the 2nd-most diagnosed focal neuropathy Neuropathy Leprosy. The incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency of ulnar neuropathy Ulnar neuropathy Disease involving the ulnar nerve from its origin in the brachial plexus to its termination in the hand. Clinical manifestations may include paresis or paralysis of wrist flexion, finger flexion, thumb adduction, finger abduction, and finger adduction. Sensation over the medial palm, fifth finger, and ulnar aspect of the ring finger may also be impaired. Common sites of injury include the axilla, cubital tunnel at the elbow, and guyon’s canal at the wrist. Mononeuropathy and Plexopathy at the wrist is much lower than that at the elbow, but can be caused by injury at either location.

Ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy function

Ulnar neuropathy Ulnar neuropathy Disease involving the ulnar nerve from its origin in the brachial plexus to its termination in the hand. Clinical manifestations may include paresis or paralysis of wrist flexion, finger flexion, thumb adduction, finger abduction, and finger adduction. Sensation over the medial palm, fifth finger, and ulnar aspect of the ring finger may also be impaired. Common sites of injury include the axilla, cubital tunnel at the elbow, and guyon’s canal at the wrist. Mononeuropathy and Plexopathy at the elbow

  • Causes of injury:
  • Clinical presentation:
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology symptoms of numbness or paresthesias Paresthesias Subjective cutaneous sensations (e.g., cold, warmth, tingling, pressure, etc.) that are experienced spontaneously in the absence of stimulation. Posterior Cord Syndrome in the ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy distribution:
      • Palmar aspect of the 4th and 5th digits
      • Dorsal and palmar medial (ulnar) aspects of the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy
    • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology deficits: intrinsic hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy muscles → loss of dexterity
    • Deficits → severe muscle wasting Muscle Wasting Duchenne Muscular Dystrophy and claw hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy deformity Deformity Examination of the Upper Limbs

Ulnar neuropathy Ulnar neuropathy Disease involving the ulnar nerve from its origin in the brachial plexus to its termination in the hand. Clinical manifestations may include paresis or paralysis of wrist flexion, finger flexion, thumb adduction, finger abduction, and finger adduction. Sensation over the medial palm, fifth finger, and ulnar aspect of the ring finger may also be impaired. Common sites of injury include the axilla, cubital tunnel at the elbow, and guyon’s canal at the wrist. Mononeuropathy and Plexopathy at the wrist

  • Causes of injury:
    • Extrinsic:
      • Bone fractures Bone fractures Breaks in bones. Bones: Remodeling and Healing (e.g., hook of hamate fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures)
      • Lacerations
      • Direct repetitive trauma (e.g., work tools, propulsion of manual wheelchairs, cyclists)
    • Intrinsic:
      • Ganglion cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change
      • Tumors
  • Clinical presentation:
    • Hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy weakness and atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation
    • Loss of dexterity
    • Variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology involvement in the ulnar distribution depending on the small branches that are affected

Diagnosis and management of ulnar neuropathy Ulnar neuropathy Disease involving the ulnar nerve from its origin in the brachial plexus to its termination in the hand. Clinical manifestations may include paresis or paralysis of wrist flexion, finger flexion, thumb adduction, finger abduction, and finger adduction. Sensation over the medial palm, fifth finger, and ulnar aspect of the ring finger may also be impaired. Common sites of injury include the axilla, cubital tunnel at the elbow, and guyon’s canal at the wrist. Mononeuropathy and Plexopathy at both locations

  • Diagnosis:
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology assessment (pinprick, light touch Light touch Neurological Examination) of territories innervated by:
      • Superficial terminal branch
      • Palmar cutaneous nerve
      • Dorsal cutaneous nerve
    • Provocative tests: positive if pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways/ paresthesias Paresthesias Subjective cutaneous sensations (e.g., cold, warmth, tingling, pressure, etc.) that are experienced spontaneously in the absence of stimulation. Posterior Cord Syndrome is reproduced over the ulnar areas
      • Tinel test Tinel test Firm percussion over the course of the median nerve proximal to or on top of the carpal tunnel . A positive test is defined as pain and/or paresthesia in median innervated fingers on percussion over the median nerve. Carpal Tunnel Syndrome: percussion Percussion Act of striking a part with short, sharp blows as an aid in diagnosing the condition beneath the sound obtained. Pulmonary Examination of the ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy over the ulnar groove or cubital tunnel
      • Elbow flexion Flexion Examination of the Upper Limbs: sustained maximal elbow flexion Flexion Examination of the Upper Limbs for 1 minute with the wrist in a neutral position
      • Pressure test Pressure Test Urticaria (Hives): Apply sustained pressure over the ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy in the ulnar groove.
    • Palpation Palpation Application of fingers with light pressure to the surface of the body to determine consistency of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs. Dermatologic Examination for local nerve tenderness and nerve thickening
  • Tests:
    • EMG/nerve conduction velocity
    • MRI shows nerve enlargement.
  • Management:
    • Activity modification:
      • Avoid leaning on the elbows.
      • Use the other hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy or headset for the phone.
      • Soft elbow pad to reduce compression Compression Blunt Chest Trauma
      • Splints/wrap to limit Limit A value (e.g., pressure or time) that should not be exceeded and which is specified by the operator to protect the lung Invasive Mechanical Ventilation flexion Flexion Examination of the Upper Limbs at night
    • Surgery:
      • Ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy decompression
      • Ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy transposition

Radial Nerve Injury

The radial nerve Radial Nerve A major nerve of the upper extremity. In humans the fibers of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually C5 to T1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibers to extensor regions of the arm and hand. Axilla and Brachial Plexus: Anatomy is particularly predisposed to compression Compression Blunt Chest Trauma in the spiral groove Spiral groove Arm: Anatomy, where it runs adjacent to the humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy. The radial nerve Radial Nerve A major nerve of the upper extremity. In humans the fibers of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually C5 to T1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibers to extensor regions of the arm and hand. Axilla and Brachial Plexus: Anatomy provides motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology innervation to the extensors of the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy and extrinsic extensors of the wrists and hands, as well as sensation to the lateral half of the back of the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy.

  • Causes of injury:
    • “Saturday night palsy Palsy paralysis of an area of the body, thus incapable of voluntary movement Cranial Nerve Palsies
    • Penetrating trauma (e.g., knife injury to the axilla Axilla The axilla is a pyramid-shaped space located between the upper thorax and the arm. The axilla has a base, an apex, and 4 walls (anterior, medial, lateral, posterior). The base of the pyramid is made up of the axillary skin. The apex is the axillary inlet, located between the 1st rib, superior border of the scapula, and clavicle. Axilla and Brachial Plexus: Anatomy)
    • Compression Compression Blunt Chest Trauma injuries at the humeral spiral groove Spiral groove Arm: Anatomy
    • Humeral fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures
  • Clinical presentation:
    • Radial neuropathy Radial neuropathy Disease involving the radial nerve. Clinical features include weakness of elbow extension, elbow flexion, supination of the forearm, wrist and finger extension, and thumb abduction. Sensation may be impaired over regions of the dorsal forearm. Common sites of compression or traumatic injury include the axilla and radial groove of the humerus. Mononeuropathy and Plexopathy at the spiral groove Spiral groove Arm: Anatomy:
      • Normal strength in triceps
      • Weakness of wrist extensors (i.e., wrist drop)
      • Weakness of finger extension Extension Examination of the Upper Limbs and thumb abduction Abduction Examination of the Upper Limbs
      • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss over the back of the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy extending to the posterior forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy, except for the back of the little finger and adjacent ½ of the ring finger
    • Posterior interosseous neuropathy Neuropathy Leprosy:
      • Brachioradialis Brachioradialis Forearm: Anatomy reflex is intact.
      • Radial deviation with wrist extension Extension Examination of the Upper Limbs, as the extensor carpi radialis is spared
      • Tenderness to palpation Palpation Application of fingers with light pressure to the surface of the body to determine consistency of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs. Dermatologic Examination of the proximal forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy with forceful supination Supination Applies to movements of the forearm in turning the palm forward or upward. When referring to the foot, a combination of adduction and inversion movements of the foot. Examination of the Upper Limbs (e.g., turning a doorknob)
      • Weak forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy supination Supination Applies to movements of the forearm in turning the palm forward or upward. When referring to the foot, a combination of adduction and inversion movements of the foot. Examination of the Upper Limbs (due to the brachioradialis Brachioradialis Forearm: Anatomy being affected)
  • Diagnosis:
    • Plain radiography to exclude fractures
    • MRI can precisely show pathological anatomical determinants.
    • EMG/nerve conduction velocity to differentiate between nerve and muscle injuries
    • Ultrasonography
  • Management: conservative treatment in individuals with a short-term injury (e.g., radial nerve Radial Nerve A major nerve of the upper extremity. In humans the fibers of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually C5 to T1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibers to extensor regions of the arm and hand. Axilla and Brachial Plexus: Anatomy compression Compression Blunt Chest Trauma due to “Saturday night palsy Palsy paralysis of an area of the body, thus incapable of voluntary movement Cranial Nerve Palsies”)
Radial nerve as it passes through the forearm

Radial nerve Radial Nerve A major nerve of the upper extremity. In humans the fibers of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually C5 to T1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibers to extensor regions of the arm and hand. Axilla and Brachial Plexus: Anatomy passing through the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy, featuring the innervated muscles

Image by BioDigital, edited by Lecturio.

References

  1. Doherty, T.J. (2021). Ulnar neuropathy at the elbow and wrist. UpToDate. Retrieved August 20, 2021, from https://www.uptodate.com/contents/ulnar-neuropathy-at-the-elbow-and-wrist
  2. Dydyk, A.M., Negrete, G., Cascella, M. (2021). Median Nerve Injury. StatPearls. Retrieved August 20, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK553109/
  3. Gragossian, A., Varacallo, M. (2021). Radial Nerve Injury. StatPearls. Retrieved August 20, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK537304/
  4. Rutkove, S.B. (2019). Overview of upper extremity peripheral nerve syndromes. UpToDate. Retrieved August 20, 2021, from: https://www.uptodate.com/contents/overview-of-upper-extremity-peripheral-nerve-syndromes

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