Abdominal reflex

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An abdominal reflex is a superficial neurological reflex stimulated by stroking of the abdomen around the umbilicus. It can be helpful in determining the level of a central nervous system (CNS) lesion. Being a superficial reflex, it is polysynaptic (involving multiple connections between nerves). [1]

Contents

Test

The abdomen is mentally divided into four quadrants, and the skin in each quadrant is gently stroked, on the diagonal, towards the navel. [2] The navel should twitch towards the stimulus. [2]

Roots involved

Thoracic 8th – 12th segments are involved. [1]

Absent abdominal reflex

Abdominal reflex is noted as either present or absent. An absent response can be physiological. Physiological absent response can be due to obesity, frailty, or muscle laxity after multiple pregnancies or abdominal surgery. [1] It is not unusual for this reflex to be absent in children. [2]

If the reflex is absent, or especially if it is asymmetric, it can indicate a neurological problem somewhere above the lower thoracic spine. [1]

Pathological absence can be due to: [3]

Evolutionary significance

The local contraction of the abdominal muscles to an abdominal sensory stimulus was to protect the internal viscera from damage. [4]

Related Research Articles

Abdominal cavity Body cavity in the abdominal area

The abdominal cavity is a large body cavity in humans and many other animals that contains many organs. It is a part of the abdominopelvic cavity. It is located below the thoracic cavity, and above the pelvic cavity. Its dome-shaped roof is the thoracic diaphragm, a thin sheet of muscle under the lungs, and its floor is the pelvic inlet, opening into the pelvis.

Thoracic diaphragm Sheet of internal skeletal muscle

The thoracic diaphragm, or simply the diaphragm, is a sheet of internal skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavity. The diaphragm is the most important muscle of respiration, and separates the thoracic cavity, containing the heart and lungs, from the abdominal cavity: as the diaphragm contracts, the volume of the thoracic cavity increases, creating a negative pressure there, which draws air into the lungs. Its high oxygen consumption is noted by the many mitochondria and capillaries present; more than in any other skeletal muscle.

In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous movement in response to a stimulus. A reflex is made possible by neural pathways called reflex arcs which can act on an impulse before that impulse reaches the brain. The reflex is then an automatic response to a stimulus that does not receive or need conscious thought.

Cremasteric reflex

The cremasteric reflex is a superficial reflex observed in human males.

Myoclonus Medical condition

Myoclonus is a brief, involuntary, irregular twitching of a muscle or a group of muscles. It describes a medical sign and, generally, is not a diagnosis of a disease. These myoclonic twitches, jerks, or seizures are usually caused by sudden muscle contractions or brief lapses of contraction. The most common circumstance under which they occur is while falling asleep. Myoclonic jerks occur in healthy people and are experienced occasionally by everyone. However, when they appear with more persistence and become more widespread they can be a sign of various neurological disorders. Hiccups are a kind of myoclonic jerk specifically affecting the diaphragm. When a spasm is caused by another person it is known as a provoked spasm. Shuddering attacks in babies fall in this category.

Patellar reflex Monosynaptic reflex

The patellar reflex, also called the knee reflex or knee-jerk, is a stretch reflex which tests the L2, L3, and L4 segments of the spinal cord.

The crossed extensor reflex or crossed extensor response or crossed extension reflex is a reflex in which the contralateral limb compensates for loss of support when the ipsilateral limb withdraws from painful stimulus in a withdrawal reflex. During a withdrawal reflex, the flexors in the withdrawing limb contract and the extensors relax, while in the other limb, the opposite occurs as part of the crossed extensor reflex. Besides shifting the body weight to the other side, the reflex pathway is also associated with leg coordination when walking by flexing muscle on one side, while extending muscle on the other side. This crossed extensor response is properly part of the withdrawal reflex.

Caridoid escape reaction Innate escape mechanism by crustaceans

The caridoid escape reaction, also known as lobstering or tail-flipping, refers to an innate escape mechanism in marine and freshwater crustaceans such as lobsters, krill, shrimp and crayfish.

Acoustic reflex Small muscle contraction in the middle ear in response to loud sound

The acoustic reflex is an involuntary muscle contraction that occurs in the middle ear in response to loud sound stimuli or when the person starts to vocalize.

The jaw jerk reflex or the masseter reflex is a stretch reflex used to test the status of a patient's trigeminal nerve and to help distinguish an upper cervical cord compression from lesions that are above the foramen magnum. The mandible—or lower jaw—is tapped at a downward angle just below the lips at the chin while the mouth is held slightly open. In response, the masseter muscles will jerk the mandible upwards. Normally this reflex is absent or very slight. However, in individuals with upper motor neuron lesions the jaw jerk reflex can be quite pronounced.

Abdominal examination Physical examination of abdomen

An abdominal examination is a portion of the physical examination which a physician or nurse uses to clinically observe the abdomen of a patient for signs of disease. The physical examination typically occurs after a thorough medical history is taken, that is, after the physician asks the patient the course of their symptoms. The abdominal examination is conventionally split into four different stages: first, inspection of the patient and the visible characteristics of their abdomen. Auscultation (listening) of the abdomen with a stethoscope. Palpation of the patient's abdomen. Finally, percussion (tapping) of the patient's abdomen and abdominal organs. Depending on the need to test for specific diseases such as ascites, special tests may be performed as a part of the physical examination. An abdominal examination may be performed because the physician suspects a disease of the organs inside the abdominal cavity, or simply as a part of a complete physical examination for other conditions. In a complete physical examination, the abdominal exam classically follows the respiratory examination and cardiovascular examination.

Intercostal nerves

The intercostal nerves are part of the somatic nervous system, and arise from the anterior rami of the thoracic spinal nerves from T1 to T11. The intercostal nerves are distributed chiefly to the thoracic pleura and abdominal peritoneum, and differ from the anterior rami of the other spinal nerves in that each pursues an independent course without plexus formation.

Abdomen Part of the body between the chest and pelvis

The abdomen is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. The area occupied by the abdomen is called the abdominal cavity. In arthropods it is the posterior tagma of the body; it follows the thorax or cephalothorax.

Hypochondrium

In anatomy, the division of the abdomen into regions can employ a nine-region scheme. The hypochondrium refers to the two hypochondriac regions in the upper third of the abdomen; the left hypochondrium and right hypochondrium. They are located on the lateral sides of the abdominal wall respectively, inferior to (below) the thoracic cage, being separated by the epigastrium.

Lateral grey column

The lateral grey column is one of the three grey columns of the spinal cord ; the others being the anterior and posterior grey columns. The lateral grey column is primarily involved with activity in the sympathetic division of the autonomic motor system. It projects to the side as a triangular field in the thoracic and upper lumbar regions of the postero-lateral part of the anterior grey column.

Axillary lymph nodes Lymph nodes in the human armpit

The axillary lymph nodes or armpit lymph nodes are lymph nodes in the human armpit. Between 20 and 49 in number, they drain lymph vessels from the lateral quadrants of the breast, the superficial lymph vessels from thin walls of the chest and the abdomen above the level of the navel, and the vessels from the upper limb. They are divided in several groups according to their location in the armpit. These lymph nodes are clinically significant in breast cancer, and metastases from the breast to the axillary lymph nodes are considered in the staging of the disease.

Retching is the reverse movement (retroperistalsis) of the stomach and esophagus without vomiting. It can be caused by bad smells or choking, or by withdrawal from certain medications, or after vomiting has completed. Retching can also occur as a result of an emotional response or from stress, which produces the same physical reaction. The function is thought to be mixing gastric contents with intestinal refluxate in order to buffer the former and give it momentum in preparation of vomiting. Treatments include medication and correction of the fluid and electrolyte balance.

Axon reflex

The axon reflex is the response stimulated by peripheral nerves of the body that travels away from the nerve cell body and branches to stimulate target organs. Reflexes are single reactions that respond to a stimulus making up the building blocks of the overall signaling in the body's nervous system. Neurons are the excitable cells that process and transmit these reflex signals through their axons, dendrites, and cell bodies. Axons directly facilitate intercellular communication projecting from the neuronal cell body to other neurons, local muscle tissue, glands and arterioles. In the axon reflex, signaling starts in the middle of the axon at the stimulation site and transmits signals directly to the effector organ skipping both an integration center and a chemical synapse present in the spinal cord reflex. The impulse is limited to a single bifurcated axon, or a neuron whose axon branches into two divisions and does not cause a general response to surrounding tissue.

Anatomical terminology Scientific terminology used by anatomists, zoologists, and health professionals

Anatomical terminology is a form of scientific terminology used by anatomists, zoologists, and health professionals such as doctors.

Cutaneous reflex in human locomotion

Cutaneous, or skin reflexes, are activated by skin receptors and play a valuable role in locomotion, providing quick responses to unexpected environmental challenges. They have been shown to be important in responses to obstacles or stumbling, in preparing for visually challenging terrain, and for assistance in making adjustments when instability is introduced. In addition to the role in normal locomotion, cutaneous reflexes are being studied for their potential in enhancing rehabilitation therapy (physiotherapy) for people with gait abnormalities.

References

  1. 1 2 3 4 Shibasaki, Hiroshi; Hallett, Mark (2016-06-15). The Neurologic Examination: Scientific Basis for Clinical Diagnosis. Oxford University Press. p. 157. ISBN   978-0-19-024098-1.
  2. 1 2 3 AAOS; Armstrong, April; Hubbard, Mark C. (2018-06-26). AAOS Essentials of Musculoskeletal Care. Jones & Bartlett Learning. p. 1029. ISBN   978-1-284-16685-9.
  3. "Absent Abdominal Reflex" . Retrieved 5 February 2013.[ permanent dead link ]
  4. "Abdominal Reflex Evolutionary Significance" . Retrieved 5 February 2013.