Kidney

Kidney :  

Defination : The kidneys are a pair of excretory organs situated at the posterior abdominal wall, one on each side of vertebral column , behind the peritoneum. 

Description of kidney : 

• The kidneys are two bean-shaped organs found in vertebrates.
• They are located on the left and right in the retroperitoneal space. 
• They receive blood from the paired renal arteries; blood exits into the paired renal veins.
• Each kidney is attached to a ureter, a tube that carries excreted urine to the bladder.
• In the fetus the kidney is lobulated and is made up of about 12 lobules , After birth lobules are fused so that kidney is uniformly smooth.  

Structure : 

• In humans, the kidneys are located high in the abdominal cavity, one on each side of the spine, and lie in a retroperitoneal position at a slightly oblique angle.
• Right kidney is lower than left kidney due to presence of liver.
• The left kidney is approximately at the vertebral level T12 to L3, and the right is slightly lower.  
• The right kidney sits just below the diaphragm and posterior to the liver.
• The left kidney sits below the diaphragm and posterior to the spleen.
• On top of each kidney is an adrenal gland. 
• The upper parts of the kidneys are partially protected by the 11th and 12th ribs. 
• 
• kidney measures , length (11 cm), broad (6 cm), thick (3 cm) .
• Weight in both male and female is varies i.e in Male (150 g) , in Female (135 g) 
• Kidney are reddish brown in colour.  

Location :

• The kidney occupy the epigastric , hypochondric, lumbar, umbilical region. 
• Vertically it extended from 12th thoracic to 3rd lumbar .
• Left kidney is little nearer to median plane than left kedney. 

External features : Each kidney is bean shaped. It has upper and lower poles, medial and lateral borders, and anterior and posterior borders. 

• Two poles of kidney : The upper pole is in close contact with SUPRARENAL  GLAND . The lower end is POINTED . 
• Two surfaces : Anterior surface and posterior surface . Anterior surface is irregular, Posterior surface is flat.
• Two borders : Lateral border and Medial border . Lateral border is  convex, Medial border is concave 
• Hilum : The following structures seen in the hilum from anterior to posterior side. 1. renal vain 2.The renal artery , and 3. The renal pelvis, which is expanded upper end of the ureter.   

Clinical anatomy : 

• The common diseases of kidney is nephrities, pyeloneprities , tuberculosis of kidney, renal stone, and tumours. 
• The common manifestations of a kidney diseases are renal oedema and hypertention. 
• Raised blood urea indicate suppressed kidney function and renal failure. Kidney transplantation is done in selected cases.
• In cases of chronic renal failure dialysis needs to be done. 
• Kidney is likely to have stone as urine gets concentrated here.
• One common congenital condition of kidney is polycystic kidney which leads to hypertention .  

ARCHES OF FOOT

Arches of foot  

• Arches of the foot helps in fast walking, running , and jumping. In addition these help in weight bearing and in providing upright posture.
• The arches pf foot, formed by the tarsal and metatarsal of bone, Strengthened by ligaments and tendons, allow the foot to support the weight in the body in the erect posture with the least weight. 
• 

Classification of the arches : 

• Longitudinal : Medial , Lateral .
• Transverse :  Anterior, Posterior .

Formation Or Structure Of Arches : 

Medial Longitudinal Arch .

• This arch is considerably higher , more mobile and resilient than the lateral. 
• It is considered as a big arch of a small circle. 
• Its constitution is as follow : 

1. Ends : The anterior end is formed by the head of the first second , and third metatarsals. The phalanges do not take part in forming the arches. The posterior end of this arch is formed by the medial tubercle  of the calcaneum.
2. Summit : The summit of the arch is formed by the talus.
3. Pillars : the anterior pillar is long and weak. it is formed by the talus , the navicular, the three cuneiform bone , and the first three metatarsal bones. The posterior pillar is short and strong . It is formed by the medial part of the calcaneum . The main joint of the arch is the talocalcaneonavicular joint . 
   
4. 
   

Lateral Longitudinal Arch :  

• This arch is characteristically low, has limited mobility, and is buit to transmit weight and thrust to ground . It is built to transmit weight and thrust to the ground. it is considered as a small arch of  a big circle . This is in contrast o the medial longitudinal arch which acts as a shock absorber. the constitution of the lateral longitudinal arch is as follows.

1. Ends : The anterior end of the arch is formed by the head of the 4th and 5th metatarsal bones. The posterior end is formed by the lateral tubercle of the calcaneum .
2. Summit : The summit is lie at the level of the articular facets on the superior surface of the calcaneum at the level of the subtalar joint . 
3. Pillars : The anterior pillar is long and weak . it is formed by the cuboid bone and by the 4th and 5th metatarsals. The posterior pillar is short and strong . it is formed by the lateral half of the calcaneum. 

Main joint : The  main joint of the arch is the calcaneocuboid joint. 

1. Anterior Transverse Arch : The anterior transverse  arch is formed by the head of the five metatarsal bones. It is complete because the head of the first and fifth metatarsals both come in contact with the ground , and form the two end of the arch. 
2. Posterior Transverse Arch : The posterior transverse arch is formed by the greater part of the tarsus and metatarsus . It is incomplete because  only lateral end  come in contact with the ground, the "half dome" which is completed by a similar half dome of the opposite foot.

Clinical Anatomy : 

• Absence or collapse of the arches leads to flat foot , which may congenital or acquired. the effect of a flat foot are as follows,

1.   Loss of spring in the foot leads to a clumsy, shuffling gait.
2. loss of shock absorbing function make the foot more liable to trauma and osteoarthritis. 

• A person with a low longitudinal arch, or flat feet will likely stand and walk with their feet in a pronated position, where the foot everts or rolls inward. This makes the person susceptible to heel pain, arch pain and plantar fasciitis. 
•  high or low arches can increase the risk of shin splints as the anterior tibialis must work harder to keep the foot from slapping the ground.
• Other deformities of the foot are as follows,
• 

1. Talipes equinus in which the patient walk on the toes, with the heel raised .
2. Talipes calcaneus in which the patient walk on the heel, with the fore foot raised. 
3. Talipes varus in which the patient walk on the outer border of the foot which is inverted and adducted.
4. Talipes valgus in which the patient walks on inner border of foot which is inverted and  abducted.   

Arches of foot   

 

Brachial Plexus

Brachial Plexus 

• The brachial plexus is a network (plexus) of nerves (formed by the anterior rami of the lower four cervical nerves and first thoracic nerve (C5, C6, C7, C8, and T1).
• This plexus extends from the spinal cord, through the cervicoaxillary canal in the neck, over the first rib, and into the armpit. It supplies afferent and efferent nerve fibers to the chest, shoulder, arm, forearm, and hand. 
• 

Structure :  

• The brachial plexus is divided into five roots, three trunks, six divisions (three anterior and three posterior), three cords, and five branches. 

Roots : The roots are the five anterior primary rami of the spinal nerves, after they have given off their segmental supply to the muscles of the neck. 

The brachial plexus emerges at five different levels; 

1. C5  (C5 and C6 merge to establish the upper trunk,)
2. C6  ( C5 and C6 merge to establish the upper trunk,)
3. CC7  (C7 continuously forms the middle trunk)
4. C8   (C8 and T1 merge to establish the lower trunk)
5. T1   (C8 and T1 merge to establish the lower trunk) 

Trunks : These roots merge to form the Trunks 

1. "superior" or "upper" (C5-C6)
2. "middle" (C7)
3. "inferior" or "lower" (C8, T1) 
   
4. 

Divisions : Each trunk then splits in two, to form six Divisions   : i.e. anterior, posterior. 

1. anterior divisions of the upper, middle, and lower trunks.
2. posterior divisions of the upper, middle, and lower trunks.

Cords : These six divisions regroup to become the three Cords .  The cords are named by their position with respect to the axillary artery. 

1. The posterior cord is formed from the three posterior divisions of the trunks (C5-C8, T1)
2. The lateral cord is formed from the anterior divisions of the upper and middle trunks (C5-C7)
3. The medial cord is simply a continuation of the anterior division of the lower trunk (C8, T1)

Clinical Anatomy :

• The injuries to different part of brachial plexus may leads to characteristic clinical features.
• Injury to the brachial plexus may affect sensation or movement of different parts of the arm.
• Injury can be caused by the shoulder being pushed down and the head being pulled up, which stretches or tears the nerves. 
• For the upper brachial plexus injuries, paralysis occurs in those muscles supplied by C5 and C6 like the deltoid, biceps, brachialis, and brachioradialis. 

• Injuries during birth      :  Brachial plexus injuries can occur during the delivery of newborns when after the delivery of the head, the anterior shoulder of the infant cannot pass below the pubic symphysis without manipulation. This manipulation can cause the baby's shoulder to stretch, which can damage the brachial plexus to varying degrees.

•  Erb's point  The nerve point of the neck, also known as Erb's point^[1] is a site at the upper trunk of the brachial plexus located 2–3 cm above the clavicle. 
• Injury to Erb's point is commonly sustained at birth or from a fall onto the shoulder. The nerve roots normally involved are C5 and partly C6.

Femoral Triangle

Femoral Triangle 

• The femoral triangle (or Scarpa's triangle) is an anatomical region of the upper third of the thigh. It is a subfascial space which appears as a triangular depression below the inguinal ligament when the thigh is flexed, abducted and laterally rotated.  

Boundaries : 

• superiorly (also known as the base) by the inguinal ligament.
• medially by the medial border of the adductor longus muscle.
• laterally by the medial border of the sartorius muscle. 
• Apex which is directed downward , is formed by the point where the medial and lateral boundaries cross.
• Apex is below with the adductor canal.
•  

Roof : The roof of femoral traingle formed by 

• Skin.
• Superficial Fascia. 
• Deep fascia. 

Floor : The floor of the triangle is formed  

• Medially by the addacture longus and pectinious.
• Laterly by the psoas major and iliacus. 
• 
• 
  
  

Contents : Are as follow 

• Femoral artery and its branches. 
• Femoral vein and its tributaries.
• Femoral sheath encloses the upper 4cm of the femoral vessels.

Nerves : 

• Femoral nerve 
• The femoral branch of genitofemoral nerve.
• Later cutaneous nerve of the thigh. 
• The nerve of pectineus. 

Cinical anatomy : 

• Femoral hernia : The femoral canal is an area of potential weakness in the abdominal wall through which abdominal contents may buldge out forming the femoral harnia.
• Abnormal obturator artery : The normal obturator artery is a branch of the internal iliac. 
• Swellings in the femoral triangle:
• 
  
• Can be caused by:
• 
  
• Femoral hernia
• Inflamed/ enlarged lymph nodes
• Abcess
• Lipoma
• Aneurisms of the vessels
• Neuromas
• Muscle tumors
• Psoas abcess, usually arising from TB spine 
• The artery can be pressed against the iliopubic eminence below the inguinal ligament at the mid-inguinal (femoral point), to reduce bleeding from a distal cut.
• 
  
• Lateral cutaneous nerve of thigh may get entangled in the inguinal ligament. This leds to the painon the lateral side of thigh. it is called "meralgia parasthetica". 
• 

Blood supply of long bone 

•  Blood supply of long bone accounts for 5 to 10 % of the cardiac output.
•   Long bone receives blood supply from various sources-  

1. Nutrient arteries
2.  Epiphy­seal arteries
3. Metaphyseal arteries
4. Periosteal arteries.   

   

  

Arterial Supply 

1. Nutrient artery :   

•  One or two diaphyseal nutrient arteries enter the shaft through nutrient foramina.
•   In the medullary cavity, the nutrient arteries divide into ascending and descending branches.
• Each branch divides into number of small parallel channels, after reaching the epiphysis they divide repeatedly into small rami which pursue spiral courses.
•  Near the epiphysis, they are joined by metaphyseal and epiphyseal arteries. 
•   Primary direc­tion of the blood flow is centrifugal. 

 2. Epiphyseal arteries  : 

•   When articular cartilage and epi­physeal cartilage are continuous, the epiphyseal arteries pierce the epiphyseal cartilage and supply the epiphysis.
•  If these arteries are damaged in epi­physeal separation, avascular necrosis of epiphysis may occur, e.g. head of the femur.
• In others, where the articular cartilage is not continuous with epi­physeal cartilage, the epiphyseal arteries enter the epiphysis without piercing it.
• In these cases, epi­phy­­seal separation will not cause avascular necrosis.
•   Epiphyseal arteries are derived from the peri­arti­­cular vascular arcades.
•  Out of many vascular foramina near epiphysis, very few admit arteries and rest are venous exits.
•  Epiphyseal arteries anasto­mose with metaphyseal and nutrient arteries after fusion of diaphysis and epiphysis.

3. Metaphyseal arteries : 

• Numerous small blood ves­sels arising from the anastomosis around the joint pierce the metaphysis along the attachment of the joint capsule.
• Metaphyseal arteries freely anas­to­­mose with spiral branches of nutrient arteries, so metaphysis is the most vascular area of the long bone.

4. Periosteal arteries : 

•  Many blood vessels anasto­mose beneath the periosteum and enter the Volkmann’s canal and supply the outer third of the compact bone.
• Periosteal arteries penetrate bone at these sites where fascial sheath or aponeurosis gain attachment to the shaft. 

                              Long bone blood supply 

Venous Drainage : 

 Valveless nutrient veins accompany the arteries.

·     In medullary cavity, a central venous sinus is present which is served by radial collecting sinuses.

·     The general layout is fan-shaped with cortical sinusoids radiating outwards towards periosteal surface.

·     Each haversian canal is supplied by a solitary sinusoid. 

Spinal chord

Spinal chord 

The Spinal chord is the long cylindrical lower part of central nervous system . It occupies upper (2/3) two-third of vertebral canal. And is enclosed in the three meninges.

 It gives rise to 31 pairs of spinal nerves and retains the basic structural pattern. 

               

Features : 

• The Spinal chord is 18 inches or 45 cm in male and 42 inches in female . 
• it extend from the upper border of the atlas vertebra to the lower border of first lumbar vertebra. In childrane it extents up to the L3 vertebra.
• Superiorly , it is continuous with medula oblengeta.
• inferiorly it terminates as conus medullaries .
• As the Spinal chord is much shorter than the length of the vertebral column.
• 
  
  

Meningeal covering : 

• The spinal chord is surrounded by the three meninges.

1. The outer is the Dura mater .
2. Middle is Arachnoid mater.
3. Inner most is Pia mater. 

• The space between the dura mater and arachnoid mater is called Subdural space 
• The arachnoid and pia mater is seperated by subarachnoid space which contain cerebrospinal fluid. 
  
  

External structure of spinal chord : 

• Anteriorly, the spinal chord reveal a deep anterior median fissure lodging the anterior spinal artery.
• posterior median sulcus is a thin thin longitudinal groove from which a septum runs in the depth of spinal chord.
• Each half is subdivided into anterior , lateral and posterior regions by by anterolateral and posterolateral sulci . 
• Ventral or motar nerves roots emerge from the anterolateral sulcus. 
• Dorsal or sensory nerve roots enter spinal cord from poserolateral sulcus.   
  

Internal Structure : 

• White matter, i.e. nerve fibers lie outside and gray matter lies inside. In the center of gray matter is the central canal containing CSF.
• The gray matter is in the form of "H" with ray commissure joning the gray matter of right and left sides.
• The gray matter comaprises one posterior horn and the oe anterior horn on  each side in the entire extent of the cord. 
• Shape and size of horn is differ in different segments due to functional reasons   

Function : 

• The spinal cord functions primarily in the transmission of nerve signals from the motor cortex to the body, and from the afferent fibers of the sensory neurons to the sensory cortex.
• It is also a center for coordinating many reflexes and contains reflex arcs that can independently control reflexes.

Clinical anatomy : 

• Conus medullaris syndrome : Due to injury to S2,S3,S4 segment of spinal chord . Fatures are :         a. Anaesthesia inthe perinium. The region is supplied by the three segments.                                   b. Sexual functions aremaffected as same nerves carry out sexual functions.
• Spinal tumours can occur in the spinal cord and these can be either inside (intradural) or outside (extradural) the dura mater.
• Spinal cord injuries can be caused by trauma to the spinal column (stretching, bruising, applying pressure, severing, laceration, etc.). The vertebral bones or intervertebral disks can shatter, causing the spinal cord to be punctured by a sharp fragment of bone.
• In milder cases, a victim might only suffer loss of hand or foot function.

• More severe injuries may result in paraplegia, tetraplegia (also known as quadriplegia), or full body paralysis below the site of injury to the spinal cord.

    

CEREBROSPINAL FLUID (CSF)

CEREBROSPINAL FLUID

The Cerebrospinal fluid is a modified tissue fluid.It is contained in the ventricular system of  the brain and in the subarachonoid space aroundthe brain and spinal chord. CSF replaces lymph in the CNS

CSF 

The cerebrospinal fluid fill the space between the arachnoid and the pia mater (subarachnoid space) and acts as a water cushion . 

The brain almost float in the cerebrospinal fluid without puting "its weight" onthe neck. The CSF forms watery cushions around the blood vessels to give them shock free enviornment.

Formation 

1. The bulk of CSF is formed by the choroid plexuses of the lateral ventricales and lesser amount by the choroid plexus of the third and forth ventricles. 
2. Possily, it is also formed by the capillaries on the surface of the brain and spinal cord.    

The brain produces roughly 500 mL of cerebrospinal fluid per day, at a rate of about 25 mL an hour.

Circulation

1. CSF passes from each lateral ventrical to the third ventricle through the intervetricular foramen of Monro. From third ventricle,it passes to the fourth ventrical the cerebral aqueduct . From the forth ventrical,the CSF passes to the subarachnoid spaces of the cerebrum and the vertebral canal through the median and lateral apertures of the fourth ventricle .
2. Some of it passes down the central canal of the spinal chord. 

Absorption

1. CSF is absorbed chiefly through the arachnoid villi and granulations, and is thus drain into cranial venous sinuses.
2. It also absorbed partly by the perinural lymphatics around the first, secondand eighth cranial nerves.
3. It is also absorbed by veins related to spinal nerves.

Functions CSF 

1. CSF decreases the sudden pressure or forces on delicate nervous tissue.
2. CSF nourishes nervous tissue. Only CSF comes in contact with neurons . Even blood cannot directly comes in contact with neurons. It provides nourishment and returns products ofmetabolism to the venous sinuses.
3. Pineal gland secretions reach pituitary gland via CSF. 
4. Neurons cannot lives without glucose and oxygen for more than 3 to 5 minutes. These are constantly provided by CSF .
5. There is no CSF bain barrir, so drugs can rach the neurons through CSF
6. There is blood CSF barrier. There are no antibodies in CNS, making infections of brain very seriou entity.

  
Clinical anatomy 

1. Drainage of CSF at regular intervals is of therepeutic values in meningitis. certain intractable headaches of unknown  aetiology are also know to have been cured by a mere lumbar puncture with drainage of CSF.
2. Obstractin in  the vertribal canal produces Froin's syndrome or loculation syndrome . This is characterized by yellowish discolouration of CSF. 
3. Hydrocephalus : It is the dilatation of the ventricular system. and occurs due to obstruction of CSF circulation.                                                                                       

Meninges of Brain

Introduction 

The brain is very important delicate organ. it is protected by the following coverings. 

1. Bony covering of the cranium.
2. The middle arachnoid mater. (meninges) : 

     a. The outer dura mater (Pachymeninx)

     b. The middle arachnoid mater.

     c. The inner pia mater . 

Meninges

     Dura mater  : The dura mater is the outermost, thickest and toughest membrain covering the brain. (Dura = Hard) ( mater = mother) 

Dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. 

There are two layers of dura : 

a. An outer and endosteal layer which searves as an internal endoosteam and periosteum or endocranium for the skull bone.

b. An inner or meningeal layer which surrounds the brain. The meningeal layer is continuous with the spinal dura mater.

The two layers are fused to each other atall places, except wheren the cranial venous sinuses are enclosed between them. 

Dura mater. 

 

Arachnoid mater : The middle element of the meninges is the arachnoid mater, so named because of its spider web-like appearance.This thin, transparent membrane is composed of fibrous tissue and, like the pia mater, is covered by flat cells also thought to be impermeable to fluid.

Cerebrospinal fluid (CSF) flows under the arachnoid in the subarachnoid space.

Pia mater : The pia ( latin : loving mother) mater is a thin vascular membrain which closly investes the brain, diping into the various sulci and other irregularities of its surface. it comparises  epi-pia and pia-glia. On the cerebrum pia mater dips and forms fold in relation to larger fissures of cerebellum.

Functions of Pia mater : 

1.CSF production and circulation

2.Perivascular spaces (Pia mater allows for the formation of perivascular spaces that help serve as the brain’s lymphatic system.) 

3.Permeability (Due to the pia mater’s and the ependyma's high permeability, water and small molecules in the CSF are able to enter the brain interstitial fluid, so the interstitial brain fluid and the CSF are very similar in terms of composition)

Clinical anatomy

• Injuries involving the meninges, can result in a hemorrhage and two types of hematoma . 
• A subarachnoid hemorrhage is acute bleeding under the arachnoid; it may occur spontaneously or as a result of trauma
• An epidural hematoma, bleeding between the dura mater and the skull, may arise after an accident or spontaneously.