Teres minor muscle
The teres minor is a narrow, elongated muscle of the rotator cuff. The muscle originates from the lateral border and adjacent posterior surface of the corresponding right or left scapula and inserts at both the greater tubercle of the humerus and the posterior surface of the joint capsule; the primary function of the teres minor is to modulate the action of the deltoid, preventing the humeral head from sliding upward as the arm is abducted. It functions to rotate the humerus laterally; the teres minor is innervated by the axillary nerve. It arises from the dorsal surface of the axillary border of the scapula for the upper two-thirds of its extent, from two aponeurotic laminae, one of which separates it from the infraspinatus muscle, the other from the teres major muscle, its fibers run obliquely upwards and laterally. The teres minor originates at the lateral border and adjacent posterior surface of the scapula, it inserts at the greater tubercle of the humerus. The tendon of this muscle passes across, is united with, the posterior part of the capsule of the shoulder-joint.
The muscle is innervated by the posterior branch of axillary nerve. A pseudoganglion has no nerve cells but nerve fibres are present. Damage to the fibers innervating the teres minor is clinically significant. Sometimes a group of muscle fibres from teres minor may be fused with infraspinatus; the infraspinatus and teres minor attach to head of the humerus. They work in tandem with the posterior deltoid to externally rotate the humerus, as well as adduction. Teres Minor can produce only small scapular plane adduction during maximal contraction with adductor moment arm of 0.2 cm at 45° of shoulder internal rotation and 0.1 cm at 45° of shoulder external rotation. There are two types of rotator cuff injuries: chronic tears. Acute tears occur as a result of a sudden movement; this might include throwing a powerful pitch, holding a fast moving rope during water sports, falling over onto an outstretched hand at speed, or making a sudden thrust with the paddle in kayaking. A chronic tear develops over a period of time.
They occur at or near the tendon, as a result of the tendon rubbing against the underlying bone. The teres minor is normal following a rotator cuff tear. Atrophy of the teres minor muscle is a consequence of a rotator cuff tear, but common isolated teres minor atrophies have been found. A quadrangular space syndrome causes excessive and or chronically compression of the structures which pass through this anatomical tunnel; the axillary nerve and the posterior humeral circumflex artery pass through the space. People affected note shoulder pain and paresthesia down the arm first and foremost in abduction, external rotation and overhead activity. Selective atrophy of the teres minor muscle has been seen and pulled together directly with compression of the corresponding axillary nerve branch or posterior humeral circumflex artery. Fibrous bands, cysts of the glenoid labrum, lipoma or dilated veins can occupy the quadrilateral space pathologically. Similar symptoms are common with anterior shoulder dislocation, humeral neck fracture, brachial plexus injury and thoracic outlet and inlet syndrome.
It is important to include those pathologies for a complete as possible differential diagnosis. Ultrasonography is a tool to detect a fatty degenerative atrophy of the teres minor and shows in affected muscles increased echogenicity and betimes a slight reduction in muscle bulk. MR imaging helps to consolidate the diagnosis of neurogenic muscle atrophy. Extracellular edema after traumatic events causing neural damage show an increased signal intensity on T2-weighted MRI sequences and normal intensity on T1-weighted sequences. Posterior humeral circumflex artery compression and reduced blood flow in stressful arm positions and or maneuvers can be diagnosed by a Doppler ultrasonography; the nerve should be detected adjacent to the vessel. In an elevated arm position the axillary neurovascular bundle can be seen at the posterior axillary fold just before it perforates the deltoideus, while the posterior course is well visible in the neutral position. For a detailed assessment of the artery, a MR angiography is required.
The major task of an ultrasonographic examination is to rule out any space occupying mass. Additional electromyography is helpful to reveal any decelerated nerve conduction velocity, thus denervation of the concerned muscle. Accessory muscles of the scapula This article incorporates text in the public domain from page 441 of the 20th edition of Gray's Anatomy Anatomy figure: 03:03-05 at Human Anatomy Online, SUNY Downstate Medical Center ExRx
A nerve tract is a bundle of nerve fibers connecting nuclei of the central nervous system. In the peripheral nervous system this is known as a nerve; the main nerve tracts in the central nervous system are of three types: association fibers, commissural fibers, projection fibers. A tract may be referred to as a commissure, fasciculus or decussation. A commissure connects the two cerebral hemispheres at the same levels. Examples are the corpus callosum. A decussation is a connection made by fibres that cross at different levels, such as the sensory decussation. Examples of a fascicle are the lenticular fasciculus; the nerve fibers in the central nervous system can be categorized into three groups on the basis of their course and connections. The tracts that connect cortical areas within the same hemisphere are called association tracts. Long association fibers connect different lobes of a hemisphere to each other whereas short association fibers connect different gyri within a single lobe. Among their roles, association tracts link memory centers of the brain.
The cingulum is a major association tract. The cingulum forms the white matter core of the cingulate gyrus and links from this to the entorhinal cortex. Commissural tracts connect corresponding cortical areas in the two hemispheres, they cross from one cerebral hemisphere to the other through bridges called commissures. The great majority of commissural tracts pass through the corpus callosum. A few tracts pass through the much smaller posterior commissures. Commissural tracts enable the left and right sides of the cerebrum to communicate with each others. Projection tracts connect the cerebral cortex with the corpus striatum, diencephalon and the spinal cord; the corticospinal tract for example, carries motor signals from the cerebrum to the spinal cord. Other projection tracts carry signals upward to the cerebral cortex. Superior to the brainstem, such tracts form a broad, dense sheet called the internal capsule between the thalamus and basal nuclei radiate in a diverging, fanlike array to specific areas of the cortex.
Nerve fascicle Mammillotegmental tract Neuromodulation
Hematoxylin and eosin stain or haematoxylin and eosin stain is one of the principal stains in histology. It is the most used stain in medical diagnosis and is the gold standard. A combination of hematoxylin and eosin, it produces blues and reds; the staining method involves application of hemalum, a complex formed from aluminium ions and hematein. Hemalum colors nuclei of cells blue, along with a few other objects, such as keratohyalin granules and calcified material, which turns blue when exposed to alkaline water; the nuclear staining is followed by counterstaining with an aqueous or alcoholic solution of eosin Y, which colors eosinophilic structures in various shades of red and orange. The staining of nuclei by hemalum is ordinarily due to binding of the dye-metal complex to DNA, but nuclear staining can be obtained after extraction of DNA from tissue sections; the mechanism is different from that of nuclear staining by basic dyes such as thionine or toluidine blue. Staining by basic dyes occurs only from solutions that are less acidic than hemalum, it is prevented by prior chemical or enzymatic extraction of nucleic acids.
There is evidence to indicate that co-ordinate bonds, similar to those that hold aluminium and hematein together, bind the hemalum complex to DNA and to carboxy groups of proteins in the nuclear chromatin. The eosinophilic structures are composed of intracellular or extracellular protein; the Lewy bodies and Mallory bodies are examples of eosinophilic structures. Most of the cytoplasm is eosinophilic. Red blood cells are stained intensely red; the structures do not have to be basic to be called basophilic and eosinophilic. Other colors, e.g. yellow and brown, can be present in the sample. Some structures do not stain well. Basal laminae need to be stained by PAS stain or some silver stains, if they have to be well visible. Reticular fibers require silver stain. Hydrophobic structures tend to remain clear. Hematoxylin is a dark blue or violet stain, basic/positive, it binds to basophilic substances. DNA/RNA in the nucleus, RNA in ribosomes in the rough endoplasmic reticulum are both acidic because the phosphate backbones of nucleic acids are negatively charged.
These backbones form salts with basic dyes containing positive charges. Therefore, dyes stain them violet. Eosin is a red or pink stain, acidic and negative, it binds to acidophilic substances such as positively charged amino-acid side chains. Most proteins in the cytoplasm of some cells are basic because they are positively charged due to the arginine and lysine amino-acid residues; these form salts with acid dyes containing negative charges, like eosin. Therefore, eosin stains them pink; this includes cytoplasmic filaments in muscle cells, intracellular membranes, extracellular fibers. So, in optical microscopy, one can observe: Nuclei in blue/purple Basophils in purplish red Cytoplasm in red Muscles in dark red Erythrocytes in cherry red Collagen in pale pink Mitochondria in pale pink Papanicolaou stain, another popular staining technique Cytopathology Acid-fast Baker JR Experiments on the action of mordants. 2. Aluminium-haematein. Quart. J. Microsc. Sci. 103: 493–517. Kiernan JA Histological and Histochemical Methods: Theory and Practice.
4th ed. Bloxham, UK: Scion. Lillie RD, Pizzolato P, Donaldson PT Nuclear stains with soluble metachrome mordant lake dyes; the effect of chemical endgroup blocking reactions and the artificial introduction of acid groups into tissues. Histochemistry 49: 23–35. Llewellyn BD Nuclear staining with alum-hematoxylin. Biotech. Histochem. 84: 159–177. Marshall PN, Horobin RW The mechanism of action of "mordant" des – a study using preformed metal complexes. Histochemie 35: 361–371. Puchtler H, Meloan SN, Waldrop FS Application of current chemical concepts to metal-haematein and -brazilein stains. Histochemistry 85: 353–364. SIGMA-ALDRICH H&E Informational Primer Routine Mayer's Hematoxylin and Eosin Stain Hematoxylin & Eosin Staining Protocol Rosen Lab, Department of Molecular and Cellular Biology, Baylor College of Medicine) Step by step protocol
A nerve plexus is a plexus of intersecting nerves. A nerve plexus is composed of afferent and efferent fibers that arise from the merging of the anterior rami of spinal nerves and blood vessels. There are five spinal nerve plexuses, except in the thoracic region, as well as other forms of autonomic plexuses, many of which are a part of the enteric nervous system; the nerves that arise from the plexuses have both sensory and motor functions. These functions include muscle contraction, the maintenance of body coordination and control, the reaction to sensations such as heat, cold and pressure. There are several plexuses in the body, including: Spinal Plexuses Cervical plexus - serves the head and shoulders Brachial plexus - serves the chest, shoulders and hands Lumbar plexus - serves the back, groin, thighs and calves Sacral plexus - serves the pelvis, genitals, thighs and feet Coccygeal plexus - serves a small region over the coccyx Autonomic Plexuses Celiac plexus - serves internal organs Auerbach's plexus - serves the gastrointestinal tract Meissner's plexus - serves the gastrointestinal tract Pharyngeal plexus of vagus nerve - serves the palate and pharynx Cardiac plexus - serves the heart The following table shows the nerves that arise from each spinal plexus as well as the spinal level each plexus arises from.
The Cervical plexus is formed by the ventral rami of the upper four cervical nerves and the upper part of fifth cervical ventral ramus. The network of rami is located deep to the sternocleidomastoid within the neck; the cervical plexus innervates muscles of the neck and areas of skin on the head and chest. The deep branches innervate muscles. A long branch innervates muscles of the diaphragm; the cervical plexus communicates with the cranial nerves vagus nerve and hypoglossal nerve. The Brachial plexus is formed by the ventral rami of C5-C8-T1 spinal nerves, lower and upper halves of C4 and T2 spinal nerves; the plexus extends toward the armpit. The roots of C5 and C6 form upper trunk, the ramus C7 forms the middle trunk, the rami C8 and T1 join to form the lower trunk of the brachial plexus. Under the clavicle, the trunks reorganize to form cords around the axillary artery; the lateral cord is formed by the upper and middle trunk, all three trunks join to form the posterior cord, the lower trunk continues to the medial trunk.
The nerves to the shoulder and to the upper limb emerge from the brachial plexus. Since the Lumbar plexus and Sacral plexus are interconnected, they are sometimes referred to as the Lumbosacral plexus; the intercostal nerves that give rami to the chest and to the upper parts of the abdominal wall efferent motor innervation and to the pleura and peritoneum afferent sensory innervation are the only ones that do not originate from a plexus. The ventral rami of L1-L5 spinal nerves with a contribution of T12 form Lumbar plexus; this plexus lies within the psoas major muscle. Nervi of the plexus serve the skin and the muscles of the lower abdominal wall, the thigh and external genitals; the largest nerve of the plexus is the femoral nerve. It supplies a part of skin distal to the inguinal ligament. Ventral rami of L4-S3 with parts of L4 and S4 spinal nerves form the Sacral plexus, it is located on the posterior wall of pelvic cavity. Nervi of the plexus innervate the perineal region and the lower limb.
The largest nerve of the human body, the sciatic nerve is the main branch, that give rami to the motor innervation of the muscles of the foot, the leg and the thigh. Common peroneal nerve and its branches innervate some part of the skin of the foot, the peroneal muscles of the leg and the dorsal muscles of the foot. Coccygeal plexus originate from S5, Co1 spinal nerves, it is interconnected with the lower part of Sacral plexus. The only nerve of the plexus is the coccygeal nerve, that serves sensory innervation of the skin in the coccygeal region. Autonomic plexuses can contain both parasympathetic neurons; the cardiac plexus is located near the carina of the trachea. The pulmonary plexus supplies innervation to the bronchial tree; the celiac, or solar plexus, contains the celiac ganglia. The solar plexus is the largest autonomic plexus and provides innervation to multiple abdominal and pelvic organs; the superior mesenteric plexus includes the superior mesenteric ganglia and is located around the superior mesenteric artery.
The inferior mesenteric plexus includes the inferior mesenteric ganglia and is located around the inferior mesenteric artery. Together, these plexuses innervate the intestines; some other plexuses include the superior and inferior hypogastric plexus, renal plexus, hepatic plexus, splenic plexus, gastric plexus, pancreatic plexus, testicular plexus / ovarian plexus. Henry Gray: Anatomy of the human body Richard S. Snell: Clinical neuroanatomy Philadelphia, New York, London. ISBN 978-963-226-293-2 Eldra P. Solomon - Richard R. Schmidt - Peter J. Adragna: Human anatomy & physiology ed. 2nd 1990 ISBN 0-03-011914-6 Jochen Staubesand. ISBN 3-541-72710-1 Saladin, Kenneth S. Anatomy & Physiology: The Unity of Form and Function. New York, NY: McGraw-Hill, 2007. Print. Instant Anatomy, 20
Autonomic nervous system
The autonomic nervous system the vegetative nervous system, is a division of the peripheral nervous system that supplies smooth muscle and glands, thus influences the function of internal organs. The autonomic nervous system is a control system that acts unconsciously and regulates bodily functions such as the heart rate, respiratory rate, pupillary response and sexual arousal; this system is the primary mechanism in control of the fight-or-flight response. Within the brain, the autonomic nervous system is regulated by the hypothalamus. Autonomic functions include control of respiration, cardiac regulation, vasomotor activity, certain reflex actions such as coughing, sneezing and vomiting; those are subdivided into other areas and are linked to ANS subsystems and nervous systems external to the brain. The hypothalamus, just above the brain stem, acts as an integrator for autonomic functions, receiving ANS regulatory input from the limbic system to do so; the autonomic nervous system has three branches: the sympathetic nervous system, the parasympathetic nervous system and the enteric nervous system.
Some textbooks do not include the enteric nervous system as part of this system. The sympathetic nervous system is considered the "fight or flight" system, while the parasympathetic nervous system is considered the "rest and digest" or "feed and breed" system. In many cases, both of these systems have "opposite" actions where one system activates a physiological response and the other inhibits it. An older simplification of the sympathetic and parasympathetic nervous systems as "excitatory" and "inhibitory" was overturned due to the many exceptions found. A more modern characterization is that the sympathetic nervous system is a "quick response mobilizing system" and the parasympathetic is a "more activated dampening system", but this has exceptions, such as in sexual arousal and orgasm, wherein both play a role. There are excitatory synapses between neurons. A third subsystem of neurons that have been named non-noradrenergic, non-cholinergic transmitters have been described and found to be integral in autonomic function, in particular in the gut and the lungs.
Although the ANS is known as the visceral nervous system, the ANS is only connected with the motor side. Most autonomous functions are involuntary but they can work in conjunction with the somatic nervous system which provides voluntary control; the autonomic nervous system is divided into the sympathetic nervous system and parasympathetic nervous system. The sympathetic division emerges from the spinal cord in the thoracic and lumbar areas, terminating around L2-3; the parasympathetic division has craniosacral “outflow”, meaning that the neurons begin at the cranial nerves and sacral spinal cord. The autonomic nervous system is unique in; the preganglionic, or first, neuron will begin at the “outflow” and will synapse at the postganglionic, or second, neuron's cell body. The postganglionic neuron will synapse at the target organ; the sympathetic nervous system consists of cells with bodies in the lateral grey column from T1 to L2/3. These cell bodies are "GVE" are the preganglionic neurons. There are several locations upon which preganglionic neurons can synapse for their postganglionic neurons: Paravertebral ganglia of the sympathetic chain cervical ganglia thoracic ganglia and rostral lumbar ganglia caudal lumbar ganglia and sacral gangliaPrevertebral ganglia Chromaffin cells of the adrenal medulla These ganglia provide the postganglionic neurons from which innervation of target organs follows.
Examples of splanchnic nerves are: Cervical cardiac nerves & thoracic visceral nerves, which synapse in the sympathetic chain Thoracic splanchnic nerves, which synapse in the prevertebral ganglia Lumbar splanchnic nerves, which synapse in the prevertebral ganglia Sacral splanchnic nerves, which synapse in the inferior hypogastric plexusThese all contain afferent nerves as well, known as GVA neurons. The parasympathetic nervous system consists of cells with bodies in one of two locations: the brainstem or the sacral spinal cord; these are the preganglionic neurons, which synapse with postganglionic neurons in these locations: Parasympathetic ganglia of the head: Ciliary, Submandibular and Otic In or near the wall of an organ innervated by the Vagus or Sacral nerves These ganglia provide the postganglionic neurons from which innervations of target organs follows. Examples are: The postganglionic parasympathetic splanchnic nerves The vagus nerve, which passes through the thorax and abdominal regions innervating, among other organs, the heart, lungs and stomach The sensory arm is composed of primary visceral sensory neurons found in the peripheral nervous system, in cranial sensory ganglia: the geniculate and nodose ganglia, appen
An organ system is a group of organs that work together as a biological system to perform one or more functions. Each organ system does a particular job in the body, is made up of certain tissues; these specific systems are studied in anatomy. They are present in many types of animals. Respiratory system: the organs used for breathing, the pharynx, bronchi and diaphragm. Digestive system: digestion and processing food with salivary glands, stomach, gallbladder, intestines and anus. Cardiovascular system: and channeling blood to and from the body and lungs with heart and blood vessels. Urinary system: kidneys, ureters and urethra involved in fluid balance, electrolyte balance and excretion of urine. Integumentary system: skin, hair and nails. Skeletally system: structural support and protection with bones, cartilage and tendons. Endocrine system: communication within the body using hormones made by endocrine glands such as the hypothalamus, pituitary gland, pineal gland, thyroid and adrenal glands.
Lymphatic system: the transfer of lymph between tissues and the blood stream. Includes the functions of immune responses and the development of antibodies. Our bodies consist of a number of biological systems that carry out specific functions necessary for everyday living; the job of the circulatory system is to move blood, oxygen, carbon dioxide, hormones, around the body. It consists of the heart, blood vessels and veins. Immune system: protects the organism from foreign bodies. Nervous system: collecting and processing information with brain, spinal cord, peripheral nervous system and sense organs. Sensory systems: visual system, auditory system, olfactory system, gustatory system, somatosensory system, vestibular system. Muscular system: allows for manipulation of the environment, provides locomotion, maintains posture, produces heat. Includes skeletal muscles, smooth muscles and cardiac muscle. Reproductive system: the sex organs, such as ovaries, fallopian tubes, vagina, mammary glands, testes, vas deferens, seminal vesicles and prostate
Anatomical terminology is a form of scientific terminology used by anatomists and health professionals such as doctors. Anatomical terminology uses many unique terms and prefixes deriving from Ancient Greek and Latin; these terms can be confusing to those unfamiliar with them, but can be more precise, reducing ambiguity and errors. Since these anatomical terms are not used in everyday conversation, their meanings are less to change, less to be misinterpreted. To illustrate how inexact day-to-day language can be: a scar "above the wrist" could be located on the forearm two or three inches away from the hand or at the base of the hand. By using precise anatomical terminology such ambiguity is eliminated. An international standard for anatomical terminology, Terminologia Anatomica has been created. Anatomical terminology has quite regular morphology, the same prefixes and suffixes are used to add meanings to different roots; the root of a term refers to an organ or tissue. For example, the Latin names of structures such as musculus biceps brachii can be split up and refer to, musculus for muscle, biceps for "two-headed", brachii as in the brachial region of the arm.
The first word describes what is being spoken about, the second describes it, the third points to location. When describing the position of anatomical structures, structures may be described according to the anatomical landmark they are near; these landmarks may include structures, such as the umbilicus or sternum, or anatomical lines, such as the midclavicular line from the centre of the clavicle. The cephalon or cephalic region refers to the head; this area is further differentiated into the cranium, frons, auris, nasus and mentum. The neck area is called cervical region. Examples of structures named according to this include the frontalis muscle, submental lymph nodes, buccal membrane and orbicularis oculi muscle. Sometimes, unique terminology is used to reduce confusion in different parts of the body. For example, different terms are used when it comes to the skull in compliance with its embryonic origin and its tilted position compared to in other animals. Here, Rostral refers to proximity to the front of the nose, is used when describing the skull.
Different terminology is used in the arms, in part to reduce ambiguity as to what the "front", "back", "inner" and "outer" surfaces are. For this reason, the terms below are used: Radial referring to the radius bone, seen laterally in the standard anatomical position. Ulnar referring to the ulna bone, medially positioned when in the standard anatomical position. Other terms are used to describe the movement and actions of the hands and feet, other structures such as the eye. International morphological terminology is used by the colleges of medicine and dentistry and other areas of the health sciences, it facilitates communication and exchanges between scientists from different countries of the world and it is used daily in the fields of research and medical care. The international morphological terminology refers to morphological sciences as a biological sciences' branch. In this field, the form and structure are examined as well as the changes or developments in the organism, it is functional.
It covers the gross anatomy and the microscopic of living beings. It involves the anatomy of the adult, it includes comparative anatomy between different species. The vocabulary is extensive and complex, requires a systematic presentation. Within the international field, a group of experts reviews and discusses the morphological terms of the structures of the human body, forming today's Terminology Committee from the International Federation of Associations of Anatomists, it deals with the anatomical and embryologic terminology. In the Latin American field, there are meetings called Iberian Latin American Symposium Terminology, where a group of experts of the Pan American Association of Anatomy that speak Spanish and Portuguese and studies the international morphological terminology; the current international standard for human anatomical terminology is based on the Terminologia Anatomica. It was developed by the Federative Committee on Anatomical Terminology and the International Federation of Associations of Anatomists and was released in 1998.
It supersedes Nomina Anatomica. Terminologia Anatomica contains terminology for about 7500 human gross anatomical structures. For microanatomy, known as histology, a similar standard exists in Terminologia Histologica, for embryology, the study of development, a standard exists in Terminologia Embryologica; these standards specify accepted names that can be used to refer to histological and embryological structures in journal articles and other areas. As of September 2016, two sections of the Terminologia Anatomica, including central nervous system and peripheral nervous system, were merged to form the Terminologia Neuroanatomica; the Terminologia Anatomica has been perceived with a considerable criticism regarding its content including coverage and spelling mistakes and errors. Anatomical terminology is chosen to highlight the relative location of body structures. For instance, an anatomist might describe one band of tissue as "inferior to" another or a physician might describe a tumor as "superficial to" a deeper body structure.
Anatomical terms used to describe location