what is the coracoid plexus

The choroid plexus, or plica choroidea, is a plexus of cells that arises from the tela choroidea in each of the ventricles of the brain. Regions of the choroid plexus produce and secrete most of the cerebrospinal fluid (CSF

) of the central nervous system.

Full Answer

What does the choroid plexus do?

The choroid plexus is part of the blood - brain barrier that protects the central nervous system from harmful chemicals, and is the primary source of the various components of cerebrospinal fluid. The choroid plexus or plica choroidea borders the membrane of the pia mater and the ventricles of the brain.

Is there a choroid plexus in the cerebral aqueduct?

The cerebral aqueduct is void of choroid plexus. The choroid plexus is located in the posterior medullary velum which partially forms the roof of the fourth ventricle. The choroid plexus is supplied by the branches of the posterior inferior cerebellar arteries. Choroid plexus of fourth ventricle (axial view)

What is the coracoid process?

The coracoid process is a hook-shaped bone structure projecting anterolaterally from the superior aspect of the scapular neck.

What is a choroid plexus fissure?

A choroid plexus fissure (choroidal fissure) is a natural anatomical structure. It is at this point that the choroid plexus attaches to either lateral ventricle.

What is the Coronoid plexus?

The choroid plexus is a complex network of capillaries lined by specialized cells and has various functions. One of the primary functions is to produce cerebrospinal fluid (CSF) via the ependymal cells that line the ventricles of the brain.

What is a choroid plexus and what is its role?

The choroid plexus (CP) is a highly vascularized complex found within each of the four ventricles of the brain. It is comprised of a monolayer of polarized secretory epithelial cells whose primary role is the production and secretion of 60–75% of total cerebrospinal fluid (CSF) [1].

What is the choroid plexus composed of?

cuboidal epithelial cellsChoroid plexus is composed of cuboidal epithelial cells resting on a basal lamina which are adjacent to highly fenestrated blood vessels separated by the stroma. The tight junctions located between the apical parts of the choroid plexus epithelial cells form the blood–cerebrospinal fluid barrier (Kaur et al., 2016).

What does the choroid plexus carry?

The choroid plexus (CP) is an epithelial tissue primarily responsible for the secretion of the cerebrospinal fluid (CSF). Choroid plexuses are found in each of the four brain ventricles: two laterals, third and fourth.

What is choroid plexus tumor symptoms?

A noncancerous tumor of this area is called a choroid plexus papilloma. As the tumor grows, it can affect the function of nearby structures in the brain, causing excess fluid in the brain (hydrocephalus), irritability, nausea or vomiting, and headaches.

Is choroid plexus harmful?

Choroid plexus cysts are usually considered normal and do not harm your baby. These cysts can also be found in some healthy children and adults. A choroid plexus cyst happens when a small amount of the cerebrospinal fluid gets trapped in the layer of cells as your baby's brain grows and develops.

What plexus is found in the brain?

The choroid plexus, or plica choroidea, is a plexus of cells that arises from the tela choroidea in each of the ventricles of the brain. Regions of the choroid plexus produce and secrete most of the cerebrospinal fluid (CSF) of the central nervous system.

What is choroid plexus tumor?

Choroid plexus tumors are primary central nervous system (CNS) tumors. This means they begin in the brain or spinal cord. To get an accurate diagnosis, a piece of tumor tissue will be removed during surgery, if possible. A neuropathologist should then review the tumor tissue.

What are the 3 layers of choroid?

Choroid StructureHaller's layer – outermost layer of the choroid, comprising large diameter blood vessels.Sattler's layer – region of medium diameter blood vessels.Choriocapillaris – this layer has capillaries.Bruch's membrane – it forms the choroid's innermost layer.

What does it mean to have fluid in your brain?

Hydrocephalus is an abnormal buildup of fluid in the ventricles (cavities) deep within the brain. This excess fluid causes the ventricles to widen, putting pressure on the brain's tissues. Cerebrospinal fluid (CSF) is the clear, colorless fluid that protects and cushions the brain and spine.

Where is the choroid plexus function?

The choroid plexus (ChP) is a secretory tissue found in each of the brain ventricles, the main function of which is to produce cerebrospinal fluid (CSF).

Where is choroid plexus found in the body?

A network of blood vessels and cells in the ventricles (fluid-filled spaces) of the brain. The blood vessels are covered by a thin layer of cells that make cerebrospinal fluid.

What is the function of the choroid plexus quizlet?

What is the function of the choroid plexus? The choroid plexus produces cerebrospinal fluid.

What is choroid short answer?

(KOR-oyd) A thin layer of tissue that is part of the middle layer of the wall of the eye, between the sclera (white outer layer of the eye) and the retina (the inner layer of nerve tissue at the back of the eye).

What is the main function of choroid quizlet?

Nourishes the retina and assists with absorption of light to prevent its scattering within the eye. What is the primary function of the choroid layer? space between the lens and cornea filled with aqueous humor.

What does choroid plexus mean in medical terms?

The choroid plexus is the part of the brain that makes cerebrospinal fluid, the fluid that normally bathes and protects the brain and spinal column.

Where is the choroid plexus located?

The cerebral aqueduct is void of choroid plexus. The choroid plexus is located in the posterior medullary velum which partially forms the roof of the fourth ventricle.

What is the most common treatment for choroid plexus papilloma?

A solid mass, with some calcifications, is generally evident on imaging. The most common treatment for choroid plexus papilloma is complete surgical excision.

What is the opening between the lateral and third ventricles?

As previously mentioned, the lateral ventricles are connected to the third ventricle by a twin opening called the interventricular foramen (or foramen of Monro ). At the junction of the anterior horn and the inferior portion of the body of the lateral ventricles, the choroid plexus continues along the interventricular foramen on both sides.

What type of cell is the choroid plexus?

a fourth ventricle. These ventricles are lined by a specialized type of glial cell called ependymal cells, or the ependyma. The choroid plexus is formed by these vascularized invaginations, bordered by the ependyma.

How big are cysts in pregnancy?

Ranging from a few mm to 1-2cm in size, these cysts generally occur in approximately 2% of all pregnancies. They are described as pockets or bubbles of choroid plexus filled with CSF and cellular material. These cysts are typically visible during ultrasound in the 2nd trimester.

What is the innermost layer of the meninges called?

The innermost layer of the meninges, called the pia mater, forms invaginations in some parts of the ventricles. These vascularized invaginations, are lined by a plexus of specialised cells that produce our CSF. This plexus of cells is called the choroid plexus.

What is the opening in the anterior ventricle?

The anterior end of the body of the lateral ventricle (before the beginning of the anterior horn) is demarcated by a twin opening called the interventricular foramen (foramen of Monro), which both connect and open into the third ventricle.

What are the two things that help prevent CNS infections?

Infections. . The CSF and the choroid plexus help prevent CNS infections, and while CNS infections aren't common, they may occur. Infections of the CNS include meningitis (infection of the meninges) and encephalitis (infection of the brain).

What are the structural issues that arise from the choroid plexus?

5  And a number of neurological conditions affect and are impacted by the choroid plexus and/or CSF flow. 1 

What is the blood CSF barrier?

Blood-CSF barrier: The blood-CSF barrier, which is created by the choroid plexus and the meninges, helps protect the brain from infectious organisms and helps maintain control of the nourishment and waste in and out of the brain. 2  The permeability of this structure affects the ability of medications, drugs, and other substances to enter the brain.

What are the anatomical variations of the choroid plexus?

Anatomical Variations. Variations in the function or structure of the choroid plexus can be associated with cysts and other congenital (from birth) malformations. 3  If they block CSF flow, choroid plexus cysts can lead to hydrocephalus and other brain malformations.

What is the choroid plexus?

Tests. The choroid plexus is a thin structure that lines most of the the ventricles of the brain. It is a protective barrier that produces cerebrospinal fluid (CSF), a fluid that provides nourishment and cushioning for the brain and spinal cord. 1 . Cysts or tumors can form in the choroid plexus, and the cysts are not usually as dangerous as ...

Which layer of the meninges surrounds the CNS?

The choroid plexus is part of the pia mater, which is the deepest layer of the three layers of meninges that surround and protect the central nervous system (CNS). The CNS is composed of the brain and spinal cord.

Which structure helps direct the material of the CSF?

The lining of the choroid plexus also has villi, which are small hairlike structures that help direct the material of the CSF. 3 

What is the coracohumeral ligament?

The coracohumeral ligament originates from the coracoid process with variable insertion into the rotator interval or anterior rotator cuff, and in conjunction with the SGHL it limits inferior translation and external rotation of the adducted shoulder. The coracoacromial ligament extends from the undersurface of the medial acromion to the superolateral border of the coracoid process, although several types have been described.2 It acts as a tension band supporting the acromion and coracoid and has an important role in transmitting force from the surrounding muscles. Along with the acromion, it acts as a roof over the subacromial space under which the rotator cuff tendons slide, with the subacromial bursa lying between. This structure has been implicated in the pathology of impingement of the shoulder. The transverse humeral ligament runs between the greater and lesser tuberosities and covers the long head of the biceps tendon ( Fig. 73.3 ).

What muscle pulls the coracoid process?

The pectoralis minor muscle pulls the coracoid process anterior and downward, producing a protracted shoulder position (Ferguson & Gerwin 2005 ). TrPs within the pectoralis minor muscle refer pain to the anterior part of the chest, the anterior part of the shoulder (coracoid process) and usually to the ulnar aspect of the arm and forearm ( Fig 32.4 ). Since the brachial plexus runs anatomically under the pectoralis minor muscle, an increased tension of this muscle can entrap the lower trunk (C7–C8 nerve trunks) of the brachial plexus, simulating an ulnar radiculopathy ( Simons 1991 ). Langley (1997) suggested that patients with symptoms of brachial plexus irritation and other compression neuropathies should be examined for the presence of TrPs within the pectoralis minor muscle. Hong & Simons (1993) demonstrated that patients with chronic whiplash showed active TrPs in the pectoralis minor muscle reproducing their arm pain symptomatology.

How long is a coracoid incision?

The skin incision is made approximately 10 to 15 cm long, marked from the tip of the coracoid proximally to the deltoid tuberosity distally, and it is centered over the interval between the deltoid laterally and the pectoralis major medially.

How to expose the brachialis?

Over the humeral diaphysis, extend the deltopectoral interval to the anterolateral approach to the arm. Retract the biceps (musculocutaneous nerve) medially to expose the brachialis overlying the humerus ( Fig. 23-4 ). Split the brachialis between its medial (musculocutaneous nerve) and lateral (radial nerve) halves to allow access to the length of the shaft ( Fig. 23-5 ).

What is the function of the glenoid labrum?

The glenoid labrum is a fibrocartilaginous structure that surrounds the glenoid fossa and functions to deepen the glenoid cavity, thereby being essential to stabilization of the glenohumeral joint.

Where is the axillary nerve located?

The musculocutaneous nerve enters the undersurface of the conjoint tendon approximately 5 to 8 cm distal to the coracoid process and can be digitally palpated, whereas the axillary nerve should be palpated just below the inferior border of the subscapularis tendon as it heads posteriorly through the quadrilateral space. The anterior humeral circumflex vessels also run along the inferior edge of the subscapularis and are clamped, cut, and tied off or coagulated once exposed ( Fig. 6-7 ).

Where does the conjoined tendon originate?

The conjoined tendon originates from the coracoid process. It is composed of the short head of the biceps and the coracobrachialis (both supplied by the musculocutaneous nerve).

Why is hydrocephalus not caused by obstruction?

It is usually the result of subarachnoid bleeding or infection, or the presence of a choroid plexus papilloma that makes the ependymal cells produce much higher quantities of CSF.

How many square meters are there in the choroid plexus?

If all of the microvilli were stretched flat, the surface area of the choroid plexus would be around five square meters. Ependymal cells have high numbers of mitochondria that provide the energy for these many active transport channels. Microvilli of the gut increase the total surface area.

Why do cerebrospinal fluids have high volumes?

High volumes are caused by sympathetic nervous system disorders that encourage the ependymal cells to produce high levels of CSF. Other causes are infection and choroid plexus cancer. Some causes are idiopathic (unknown). A further function of cerebrospinal fluid is its role as a waste-disposal system.

How much CSF is in the ventricles?

Although an adult only has approximately 25 ml of CSF in the ventricles at any one time, another 115 to 245 ml flows through the subarachnoid space of the spinal cord. The fluid constantly drains through the lining of the spinal arachnoid membrane and is absorbed into the venous blood circulation and lymph nodes. This means the choroid plexus must produce approximately 650 ml CSF every 24 hours. How quickly CSF is absorbed back into the blood supply depends on the pressure within the subarachnoid space. When the pressure of the cerebrospinal fluid is higher than the venous pressure, it will be absorbed into the arachnoid until these pressures equalize.

What is the choroid plexus?

The choroid plexus is composed of ependymal cells, a type of glia. It is a specialized area within the ventricular membrane. To better place the location of the choroid plexus, we should look at the surrounding anatomy. The soft tissue of the brain is surrounded by three membranes called the meninges.

Why is the choroid plexus important?

This is very important, as the choroid plexus is part of the blood-brain barrier (BBB) that protects the brain from harmful chemicals. The tight junctions between adjacent cells (red circles in the below image) let very little into the brain and most chemicals require transporter proteins to move through the ependyma.

What is the outermost layer of the choroid plexus?

When picturing the choroid plexus, you should also know how its tissue is arranged. The outermost layer (epithelium) consists of simple columnar ependymal cells (glia cells). These surround projections of pia mater tissue and have central capillaries.

What is the coracoid process?

The coracoid process is a hook-shaped bone structure projecting anterolaterally from the superior aspect of the scapular neck. Surgeons often refer to the coracoid process as the "lighthouse of the shoulder" given its proximity to major neurovascular structures such as the brachial plexus and the axillary artery and vein, its role in guiding surgical approaches, and its utility as a landmark for other important structures in the shoulder. The coracoid also serves as a critical anchor for many tendinous and ligamentous attachments. These include the tendons of the pectoralis minor, coracobrachialis, and short head of the biceps brachii muscles, and the coracoclavicular, coracohumeral, coracoacromial, and transverse scapular ligaments. Consequently, the coracoid and its associated structures are linked to numerous shoulder pathologic conditions. This article will detail the anatomy of the coracoid and its associated structures and review the clinical and radiologic findings of corresponding pathologic conditions in this region with original illustrations and multimodality imaging examples. Highlighted in this article are the coracoclavicular joint, the classification and management of coracoid fractures, subcoracoid impingement, the coracoacromial arch and subacromial impingement, the coracohumeral ligament and the biceps pulley, the coracoclavicular ligament and its surgical reconstruction, adhesive capsulitis, the suprascapular notch and suprascapular notch impingement, subcoracoid bursitis, coracoid transfer procedures, and coracoid tumors. A brief summary of the pathophysiology, potential causes, and management options for each of the pathologic entities will also be discussed. © RSNA, 2016.

Which of these structures is associated with shoulder path?

Consequently, the coracoid and its associated structures are linked to numerous shoulder pathologic conditions.

What are the symptoms of a choroid plexus tumor?

Presenting signs and symptoms of choroid plexus tumors include headaches, gait dysfunction, failure to thrive, macrocephaly, bulging fontanel, prominent scalp veins, and others. Generally, the most desirable outcome for CPP/CPC resection is gross total resection, a result that is only sometimes feasible. Due to the high vascularity of these tumors, aiming for initial control of the feeding vessels is prudent but not always possible. In choosing a surgical approach, the ideal route should be that which provides adequate control of the tumor and its associated vasculature, without causing significant harm to normal brain parenchyma. One effort to reduce the vascularity and increase the surgical resectability of CPCs, especially in infants, is a staged surgical approach. Following recovery from the initial surgery, neoadjuvant chemotherapy is administered to reduce blood supply and tumor burden and improve surrounding tumor-associated planes. Adjuvant therapy with chemotherapy or radiation therapy may be necessary for recurrent or inoperable cases, as well as for malignant CPCs ( Lafay-Cousin et al., 2010 ).

What is the choroid plexus?

The choroid plexus is a vascular convolute, consisting of epithelial cells (a type of microglia), fenestrated blood vessels, and stroma, which lie in the ventricular system of the brain. It is the main source of cerebrospinal fluid (CSF) and actively regulates the constituents in CSF. The choroid plexus epithelial cells and the tanycytes, special ependymal cells located in the floor of the third ventricle, constitute the blood-CSF-brain barrier that separates blood and CSF compartments.1 The choroid plexus begins to differentiate as a bulge of the pia mater into the ventricular ependyma in week 6 of gestation, shortly after closure of the neural tube. The choroid plexus is derived from an invagination of the neuroepithelium and is located within the brain substance, but in continuity with the meninges. It first appears on the roof of the fourth ventricle, then in the lateral ventricles, and finally in the third ventricle. 2,3 The two main components of the choroid plexus are the epithelium derived from the neural tube epithelium and mesenchyme derived from the meninges. 1,4

What are the morphologic changes of the choroid plexus?

The few morphologic alterations of the choroid plexus include atrophy of the epithelial cells and thickening of the basement membrane. In inflammatory and infectious diseases leukocytes and lymphocytes may migrate through the barrier made by the choroid plexus (Kaur et al., 2016 ). The role of the choroid plexus has been discussed in several disorders ( Kaur et al., 2016 ).

What is the role of the choroid plexus in the CNS?

The choroid plexus (CP) plays a central role in regulating inflammatory cells in the central nervous system (CNS), as well as in monitoring the synthesis, composition, and circulation of cerebrospinal fluid. The CP is a selective organ, containing blood vessels embedded within the stroma, enclosed in a wall of epithelial cells, secured by tight junction proteins. The endothelial cells in the CP stroma are unique, unlike the blood–brain barrier, in that these cells form relatively large, fenestrated capillaries allowing inflammatory cells to enter the CP stroma. However, the CP enables selective inflammatory populations to enter the CNS from the blood, based on specific adhesion molecules expressed on blood vessels, CP epithelial cells, and cytokines. The CP participates in immune surveillance, the development of CNS disease, and CNS trauma.

How early does the rat choroid plexus develop?

In the rat, the choroid plexus is present very early during development, by 14 to 16 days of gestation ( Keep and Jones, 1990; Keep et al., 1986 ), and its capacity for CSF secretion increases with age. From immunocytochemical studies, AQP1 protein is strongly expressed in the developing rat choroid plexus by 14 days of gestation ( Fig. 1a ), suggesting that AQP1 expression does not appear to represent the limiting factor for CSF secretion during early stages of development. The localized expression of AQP1 protein at the apical (lumen) side of the membrane is also retained in rat primary choroid plexus cell culture ( Fig. 1b,c ), which makes it a good in vitro model for investigating the mechanisms of modulation of CSF secretion.

What is a CP tumor?

Choroid plexus (CP) carcinomas are rare malignant central nervous system (CNS) tumors derived from the CP epithelium. The group of CP tumors is made up of CP papillomas (World Health Organization [WHO] grade I), atypical CP papillomas (WHO grade II), and CP carcinomas (WHO grade III). The average annual incidence of all CP tumors is 0.3 per 1,000,000 persons per year, and CP carcinomas account for less than 1% of all brain tumors and about 20%–40% of CP tumors [1]. The median age of all CP carcinoma patients is 3 years with an overall 80% of CP carcinomas occurring in children younger than 18 making up 20%–40% of CP tumors in this age group [1].

Which tissue is the source of cerebrospinal fluid?

The single layer of epithelium is separated from numerous winding blood vessels by a thin band of connective tissue. Choroid plexus is the source of cerebrospinal fluid. (B) Human choroid plexus has a larger surface area and more abundant connective tissue relative to that of the mouse.

What is the coracoclavicular joint?

A rare anatomic variant, the coracoclavicular joint, is an accessory articulation between a prominent conoid tubercle of the inferior aspect of the lateral third of the clavicle and the superior aspect of the coracoid process ( Fig 5 ).

What is the coracoid process?

The coracoid process is a hook-shaped bone structure projecting anterolaterally from the superior aspect of the scapular neck. Surgeons often refer to the coracoid process as the “lighthouse of the shoulder” given its proximity to major neurovascular structures such as the brachial plexus and the axillary artery and vein, its role in guiding surgical approaches, and its utility as a landmark for other important structures in the shoulder. The coracoid also serves as a critical anchor for many tendinous and ligamentous attachments. These include the tendons of the pectoralis minor, coracobrachialis, and short head of the biceps brachii muscles, and the coracoclavicular, coracohumeral, coracoacromial, and transverse scapular ligaments. Consequently, the coracoid and its associated structures are linked to numerous shoulder pathologic conditions. This article will detail the anatomy of the coracoid and its associated structures and review the clinical and radiologic findings of corresponding pathologic conditions in this region with original illustrations and multimodality imaging examples. Highlighted in this article are the coracoclavicular joint, the classification and management of coracoid fractures, subcoracoid impingement, the coracoacromial arch and subacromial impingement, the coracohumeral ligament and the biceps pulley, the coracoclavicular ligament and its surgical reconstruction, adhesive capsulitis, the suprascapular notch and suprascapular notch impingement, subcoracoid bursitis, coracoid transfer procedures, and coracoid tumors. A brief summary of the pathophysiology, potential causes, and management options for each of the pathologic entities will also be discussed.

What is the coracoid in the shoulder?

In addition to serving as a palpable landmark in guiding surgical approaches, the coracoid serves as a critical attachment anchor for several tendons and ligaments. These include the tendons of the pectoralis minor, coracobrachialis, and short head of the biceps brachii muscles, and the coracoclavicular, coracohumeral, coracoacromial, and suprascapular ligaments ( 2 ). Thus, it comes as no surprise that among the litany of causes of anterior shoulder pain, the coracoid or one of its related structures is often implicated. Given the numerous key structures involving this relatively small region and the clinical reliance on imaging to confirm a diagnosis, detailed knowledge of coracoid process anatomy and its related structures is crucial in musculoskeletal radiologic practice yet challenging to attain.

What is the lighthouse of the shoulder?

One of the most fundamental principles of shoulder surgery is to embark on an approach that is lateral to the coracoid process, to avoid the vital neurovascular structures that run medially, such as the brachial plexus and branches of the axillary artery and vein. Therefore, the coracoid has been dubbed the “lighthouse of the shoulder” by some orthopedists ( 1 ).

Why is the coracoid process important?

The coracoid process is an important anatomic landmark and historically serves as a guide in shoulder surgical approaches. The spectrum of pathologic conditions involving the coracoid and its related structures is broad. As several of these pathologic conditions are significant sources of patient morbidity, detailed knowledge of the anatomy of the coracoid and its related structures is crucial in musculoskeletal radiology practice.

Where is the suprascapular notch?

Suprascapular Notch. The suprascapular notch is found just medial to the base of the coracoid and is bounded superiorly by the superior transverse scapular ligament, also referred to as the transverse scapular ligament or suprascapular ligament.

When does the coracoid base physeal plate fuse?

The coracoid base physeal plate usually fuses by 18 years of age; the normal unfused apophysis is more uniformly spaced from the scapula and frequently symmetric in appearance with the contralateral side ( 24 ).