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 the axillary, musculocutaneous, median, ulnar, or radial nerves. The most common causes of these injuries are overuse, compressionCompressionBlunt Chest Trauma or entrapment, or nerve trauma; degenerative or demyelinating disordersDemyelinating disordersConditions 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; radiationRadiationEmission 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 massMassThree-dimensional lesion that occupies a space within the breastImaging of the Breast lesions. Clinical presentation is with motorMotorNeurons which send impulses peripherally to activate muscles or secretory cells.Nervous System: Histology and/or sensorySensoryNeurons 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.
The brachial plexusBrachial PlexusThe 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 trianglePosterior triangleTriangles of the Neck: Anatomy of the neckNeckThe part of a human or animal body connecting the head to the rest of the body.Peritonsillar Abscess and passes to the axillaAxillaThe 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 plexusBrachial PlexusThe 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 nerveMusculocutaneous NerveA 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 nerveMedian NerveA 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
Radial nerveRadial NerveA 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
Medial cord branches into:
Median nerveMedian NerveA 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 nerveUlnar NerveA 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 armArmThe 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 forearmForearmThe 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
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 injuryNerve InjurySurgical Complications.
Carpal tunnelCarpal TunnelThe carpal tunnel is formed by the transverse carpal ligament (flexor retinaculum) superiorly and the carpal bones inferiorly.Carpal Tunnel Syndrome syndrome
As the nerve courses through a ligamentous canal (e.g., carpal tunnelCarpal TunnelThe carpal tunnel is formed by the transverse carpal ligament (flexor retinaculum) superiorly and the carpal bones inferiorly.Carpal Tunnel Syndrome)
Occurs with severe trauma → complete disruption of the axon of the nerve
Complete loss of sensorySensoryNeurons which conduct nerve impulses to the central nervous system.Nervous System: Histology and motorMotorNeurons which send impulses peripherally to activate muscles or secretory cells.Nervous System: Histology responses
VariableVariableVariables 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 regenerationRegenerationThe physiological renewal, repair, or replacement of tissue.Wound Healing
Nerve ischemiaIschemiaA 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/infarctInfarctArea of necrotic cells in an organ, arising mainly from hypoxia and ischemiaIschemic Cell Damage:
IschemiaIschemiaA 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 atherosclerosisAtherosclerosisAtherosclerosis 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:
InflammationInflammationInflammation 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
RadiationRadiationEmission 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., diabetesDiabetesDiabetes 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 vasculitisVasculitisInflammation 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
Production of neurotrophic factors by Schwann cells in the myelin sheath is crucial to axonal regenerationRegenerationThe physiological renewal, repair, or replacement of tissue.Wound Healing.
Infection due to various viral, microbial, and parasitic causes:
EBVEBVEpstein-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 zosterHerpes ZosterVaricella-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/ChickenpoxvirusVirusViruses 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 virusVirusViruses 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
MumpsMumpsMumps 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
Human parvovirus B19Parvovirus B19Primate 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 diseaseLyme diseaseLyme 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
LeprosyLeprosyLeprosy, 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:
HypothyroidismHypothyroidismHypothyroidism 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 sensorySensoryNeurons which conduct nerve impulses to the central nervous system.Nervous System: HistologypolyneuropathyPolyneuropathyPolyneuropathy 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 demyelinationDemyelinationMultiple Sclerosis or axonal degeneration
Vitamin B12 deficiencyVitamin B12 deficiencyA nutritional condition produced by a deficiency of vitamin B12 in the diet, characterized by megaloblastic anemia. Since vitamin B12 is not present in plants, humans have obtained their supply from animal products, from multivitamin supplements in the form of pills, and as additives to food preparations. A wide variety of neuropsychiatric abnormalities is also seen in vitamin B12 deficiency and appears to be due to an undefined defect involving myelin synthesis.Folate and Vitamin B12 causes demyelinationDemyelinationMultiple Sclerosis.
Vitamin B6 deficiencyVitamin B6 DeficiencyA nutritional condition produced by a deficiency of vitamin B 6 in the diet, characterized by dermatitis, glossitis, cheilosis, and stomatitis. Marked deficiency causes irritability, weakness, depression, dizziness, peripheral neuropathy, and seizures. In infants and children typical manifestations are diarrhea, anemia, and seizures. Deficiency can be caused by certain medications, such as isoniazid.Water-soluble Vitamins and their Deficiencies causes decreased nerve fiber density and increased axon-to-myelin ratio.
Vitamin B6Vitamin B6Vitamin 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 DeficienciestoxicityToxicityDosage Calculation causes loss of large myelinatedMyelinatedInternuclear Ophthalmoplegia fibers.
FractureFractureA 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 neckNeckThe part of a human or animal body connecting the head to the rest of the body.Peritonsillar Abscess of the humerusHumerusBone in humans and primates extending from the shoulder joint to the elbow joint.Arm: Anatomy
Positioning of the individual while under general anesthesiaGeneral anesthesiaProcedure 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
HypertrophyHypertrophyGeneral 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)
CompressionCompressionBlunt Chest Trauma in the axillaAxillaThe 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:
InspectionInspectionDermatologic Examination: atrophyAtrophyDecrease 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
SensorySensoryNeurons which conduct nerve impulses to the central nervous system.Nervous System: Histology loss: lateral shoulder
MotorMotorNeurons which send impulses peripherally to activate muscles or secretory cells.Nervous System: Histology weakness:
VariableVariableVariables 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 abductionAbductionExamination of the Upper Limbs and external rotationExternal RotationExamination of the Upper Limbs
Diagnosis: electromyographyElectromyographyRecording 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 motionRange of motionThe 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
Surgical intervention, if failure to improve with conservative management:
Nerve grafting
Neurolysis
Neurotization (direct implantationImplantationEndometrial implantation of embryo, mammalian at the blastocyst stage.Fertilization and First Week of a nerve graftGraftA piece of living tissue that is surgically transplantedOrgan Transplantation into a denervated muscle)
Posterior view of the proximal end of the humerus featuring the surgical neck, a frequent site of fracture: A fracture at the site may injure the axillary nerve and/or posterior circumflex artery.
The musculocutaneous nerveMusculocutaneous NerveA 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 plexusBrachial PlexusThe 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 nerveMusculocutaneous NerveA 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 coracobrachialisCoracobrachialisArm: Anatomy, bicepsBicepsArm: Anatomy, and brachialisBrachialisArm: Anatomy muscles and provides sensation to the lateral forearmForearmThe 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.
Strenuous exerciseStrenuous exercisePhysical 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 armArmThe 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 anesthesiaAnesthesiaA 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
Weakness of forearmForearmThe 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: AnatomysupinationSupinationApplies 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
SensorySensoryNeurons which conduct nerve impulses to the central nervous system.Nervous System: Histology loss over the lateral forearmForearmThe 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
The median nerveMedian NerveA 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 forearmForearmThe 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 ulnarisFlexor carpi ulnarisForearm: Anatomy and ulnar head of the flexor digitorum profundusFlexor digitorum profundusForearm: Anatomy (FDP)), the thenar musclesThenar musclesHand: Anatomy, and the 2 radial lumbricalsLumbricalsHand: Anatomy in the handHandThe 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 nerveMedian NerveA 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.
Supracondylar humeral fractureFractureA 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
Degenerating and demyelinating disordersDemyelinating disordersConditions 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
Carpal tunnelCarpal TunnelThe 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 mononeuropathyMononeuropathyDisease 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 compressionCompressionBlunt Chest Trauma
PrevalencePrevalenceThe 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 incidenceIncidenceThe 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:
ObesityObesityObesity 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
PregnancyPregnancyThe 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
DiabetesDiabetesDiabetes 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
HypothyroidismHypothyroidismHypothyroidism 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:
PainPainAn 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 painPainAn unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons.Pain: Types and Pathways in the median nerveMedian NerveA 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 testTinel testFirm 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 nerveMedian NerveA 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 tunnelCarpal TunnelThe 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 painPainAn unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons.Pain: Types and Pathways and paresthesiasParesthesiasSubjective cutaneous sensations (e.g., cold, warmth, tingling, pressure, etc.) that are experienced spontaneously in the absence of stimulation.Posterior Cord Syndrome.
Hand elevation testHand elevation testRaising hands above the head for 1 minute. Deemed positive if pain and/or paresthesia noted in median innervated fingers within 30 seconds of elevationCarpal Tunnel Syndrome: raising hands above the head for 1 minute
Steroid injection into the “carpal tunnelCarpal TunnelThe carpal tunnel is formed by the transverse carpal ligament (flexor retinaculum) superiorly and the carpal bones inferiorly.Carpal Tunnel Syndrome”
ForearmForearmThe 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: AnatomypainPainAn unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons.Pain: Types and Pathways
SensorySensoryNeurons which conduct nerve impulses to the central nervous system.Nervous System: Histology loss over the entire lateral palm
SensorySensoryNeurons which conduct nerve impulses to the central nervous system.Nervous System: Histology loss over the thenar eminence
Branches off from the median nerveMedian NerveA 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 forearmForearmThe 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 sensorySensoryNeurons which conduct nerve impulses to the central nervous system.Nervous System: Histology innervation to the skinSkinThe 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.
Ulnar neuropathyNeuropathyLeprosy at the elbow is the 2nd-most diagnosed focal neuropathyNeuropathyLeprosy. The incidenceIncidenceThe 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 neuropathyNeuropathyLeprosy at the wrist is much lower than that at the elbow, but can be caused by injury at either location.
Ulnar nerveUlnar NerveA 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
MotorMotorNeurons which send impulses peripherally to activate muscles or secretory cells.Nervous System: Histology innervation to:
Palmar aspect of the 5th finger and medial ½ of the 4th finger
Medial side of the dorsum of the handHandThe 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
MassMassThree-dimensional lesion that occupies a space within the breastImaging of the Breast lesions
SubluxationSubluxationRadial Head Subluxation (Nursemaid’s Elbow) of the ulnar nerveUlnar NerveA 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
Clinical presentation:
SensorySensoryNeurons which conduct nerve impulses to the central nervous system.Nervous System: Histology symptoms of numbness or paresthesiasParesthesiasSubjective cutaneous sensations (e.g., cold, warmth, tingling, pressure, etc.) that are experienced spontaneously in the absence of stimulation.Posterior Cord Syndrome in the ulnar nerveUlnar NerveA 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 handHandThe 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
MotorMotorNeurons which send impulses peripherally to activate muscles or secretory cells.Nervous System: Histology deficits: intrinsic handHandThe 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 wastingMuscle WastingDuchenne Muscular Dystrophy and claw handHandThe 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: AnatomydeformityDeformityExamination of the Upper Limbs
Direct repetitive trauma (e.g., work tools, propulsion of manual wheelchairs, cyclists)
Intrinsic:
Ganglion cystsCystsAny 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:
HandHandThe 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 atrophyAtrophyDecrease 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
VariableVariableVariables 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 VariablessensorySensoryNeurons 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 neuropathyNeuropathyLeprosy at both locations
Diagnosis:
SensorySensoryNeurons which conduct nerve impulses to the central nervous system.Nervous System: Histology assessment (pinprick, light touch) of territories innervated by:
Superficial terminal branch
Palmar cutaneous nerve
Dorsal cutaneous nerve
Provocative tests: positive if painPainAn unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons.Pain: Types and Pathways/paresthesiasParesthesiasSubjective 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 testTinel testFirm 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: percussionPercussionAct of striking a part with short, sharp blows as an aid in diagnosing the condition beneath the sound obtained.Pulmonary Examination of the ulnar nerveUlnar NerveA 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
Pressure testPressure TestUrticaria (Hives): Apply sustained pressure over the ulnar nerveUlnar NerveA 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.
PalpationPalpationApplication 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 handHandThe 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.
Ulnar nerveUlnar NerveA 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 nerveUlnar NerveA 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
Ulnar nerve passing through the medial aspect of the forearm
“Claw hand” due to ulnar nerve damage, resulting in atrophy and contractions on the denervated intrinsic hand muscles
Image: “Photograph of a healthy hand imitating an ulnar claw” by Mcstrother. License: CC BY 3.0
Hand distortions in nerve injuries
Image by Lecturio.
Radial Nerve Injury
The radial nerveRadial NerveA 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 compressionCompressionBlunt Chest Trauma in the spiral grooveSpiral grooveArm: Anatomy, where it runs adjacent to the humerusHumerusBone in humans and primates extending from the shoulder joint to the elbow joint.Arm: Anatomy. The radial nerveRadial NerveA 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 motorMotorNeurons which send impulses peripherally to activate muscles or secretory cells.Nervous System: Histology innervation to the extensors of the forearmForearmThe 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 handHandThe 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 palsyPalsyparalysis of an area of the body, thus incapable of voluntary movementCranial Nerve Palsies”
Penetrating trauma (e.g., knife injury to the axillaAxillaThe 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)
Humeral fractureFractureA 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
SensorySensoryNeurons which conduct nerve impulses to the central nervous system.Nervous System: Histology loss over the back of the handHandThe 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 forearmForearmThe 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
Tenderness to palpationPalpationApplication 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 forearmForearmThe 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 supinationSupinationApplies 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 forearmForearmThe 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: AnatomysupinationSupinationApplies 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 brachioradialisBrachioradialisForearm: 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 compressionNerve CompressionBrachial Plexus Injuries due to “Saturday night palsyPalsyparalysis of an area of the body, thus incapable of voluntary movementCranial Nerve Palsies”)
PainPainAn unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons.Pain: Types and Pathways management
Radial nerve passing through the forearm, featuring the innervated muscles
