detailed Human Anatomy, various body part, detailed structure

detailed human anatomy

1. Welcome

2. Human Anatomy By : Dr. Vandana Sharma Professor & Head Department of Anatomy GMC Bhopal

3. Definition - It is a science of structure of human body. The term Anatomy is derived from a Greek word “anatome” meaning “cutting up” [ana–up ; tomy-to cut]. The term dissection is the latin equivalent of the Greek term anatome.

4. Anatomical position — It’s a position of body when a person is standing straight with his eyes looking forward both arms by the side of body palms facing forward & both feet together .

5. REGIONAL ANATOMY Human body is divided into 6 regions Head & neck Brain Thorax Abdomen Upper limb Lower limb

6. Human body consists of following structures from out side inwards- 1. Skin - outer covering of our body 2. Superficial fascia contains blood vessels nerves & lymphatics in it. 3. Muscles – Is a contractile tissue which carry movements of body. 4. Bones &Joints - it forms a skeletal framework of body 5. Nervous system -consist of Brain & spinal cord

7. SYSTEMIC ANATOMY Skeletal System- consists of bones, cartilages and joints. (a) Axial skeleton[ bones &cartilages lies close to central axis such as skull &vertebral column (b) Appedndicular skeleton [mainly consist of bones of upper &lower extremities] * Total no of bones in our body are 206 [in adult] *At birth the skeleton has 270 bones[ no decreses because of fusion of bones]

8. FUNCTIONS OF SKELETAL SYSTEM It forms rigid framework,protect imp. Viscera such as heart lung &brain It gives attachment to muscles ligaments &tendons Is a store house of calcium &phosphorus It contains bone marrow[ a factory of blood cells]

9. Muscular system- [contractile tissue] consisting of 3 types of muscles- (a). Skeletal muscle .[voluntary] are attached to the bones. supplied by somatic nerves. Basic function is to move the body as in walking, running. (b). Smooth muscle .[involantary] present in wall of GIT, respiratory tract, urogenital tract&, blood vessels. (c). Cardiac muscle .[involuntary] present in the myocardium of heart. Smooth & cardiac muscles are supplied by autonomic nerves.

10. 3. Cardio vascular system- consists of heart & blood vessels which are of two types – (a). Arteries - which carries pure blood from the heart to various organs. (b). Veins - which brings impure blood from various organs back to the heart.

11. 4. Nervous system – It is divided into 2 parts - CNS - It includes (a) Brain & Spinal cord PNS – Includes – (1) Peripheral nerves (a) 12 pairs of cranial nerves (b) 31 pairs of spinal nerves (2) Ganglia - [autonomic& sensory ] (3) Autonomic nervous system—It controls involuntary activities of body such as smooth muscle cardiac muscle & glands .

12. AUTONOMIC NERVOUS SYSTEM This system is divided into 2 parts Sympathetic nervous system Parasympathetic nervous system In general sympathetic stimulation mobilizes body energy for flight & fright. Where as parasympathetic stimulation slows down the body processes to conserve & restore energy. Sympathetic system is said to have vasomotor,sudomotor& pilomotor effect while parasympathetic do not have any such effect

13. CLINICAL CORELATION The sympathetic system is stimulated at the time of stress & strain. Its over activity causes rise in B.P., increase heart rate, increase respiratory rate, sweating, dilatation of pupil, dryness of mouth. Overactivity of parasympathetic causes constriction of pupil, decreased heart rate, increase motality of gut.

14. 5. Respiratory System - consists of nose, nasal cavity, larynx, trachea, bronchus & lungs .

15. 6. Gastro intestinal system – Starts from mouth cavity, tongue, pharynx, esophagus, stomach, duodenum, small & large intestine, rectum & anal canal. Associated glands with GIT are salivary glands (parotid, sub-mandibular and sub lingual), liver, gall-bladder & pancreas.

16. 7. Urinary system- consist of kidney,ureter ,urinary bladder, urethra

17. 8. Genital system – (a) Male genital system – * External genital organs - scrotom & penis * Internal genital organs - testis, epididymus, vas deferens, seminal vesicles & prostate.

18. (b) Female genital system – * External genital organs - labia majora ,labia minora, clitoris & vagina. * Internal genital organs – ovary,fallopian tubes,uterus

19. 9. Endocrine system – Consists of endocrine glands such as pituitory gland, thyroid, parathyroid,& adrenal gland. These glands secretes various hormones which regulates the metabolism of the body. It is a important hormonal system of body helps in maintaining homeostasis of body. They are ductless glands which pour their secretion directly into blood.

20. Applied anatomy Skin– marks of pregnency can be identified on lower abdomen & thigh. In case of burn to know the extent of burn rule of 9 is usually applied. Absense of urine formation [ anuria ] after road accident,war injuries is common due to formation of av anastomosis .

21. Anatomy of Head & Neck Skeleton of head consist of skull. Skull consistrs of 20-22 flat bones which are joined by sutures. It has a cavity inside & it contains brain. Shape of the skull changes with growth by - fusion of sutures, eruption of teeth & enlargement of the paranasal sinuses. It also contains eye ball (in the orbit), nasal cavity, middle & internal ear in the temporal bone.

22. Base of Skull There are number of foramen present in the base of skull, through which 12 cranial nerves are coming out to supply the structures in the head & neck. Blood vessels coming from the heart passing upwards to supply the brain, are also passing through these foramina.

23. Skull is covered on the top by scalp. Skeleton of face is covered by muscles of face which are attached to skin .they are called muscles of facial expression.

24. Brain is covered by 3 layers called meninges – 1. Dura mater - outer tough layer having folds which further protect the brain. Outside the dura, lies a very important artery called middle meningeal artery, which is commonly ruptured causing extra-dural hematomas . 2. Archnoid mater- middle layer. Below this layer is a space which contains cerebro spinal fluid [C.S.F.].It acts like shock absorber. 3. Pia mater- inner vascular layer. This is the layer that directly covers the brain surface and contains blood vessels supplying the brain.

25. The space between dura & archnoid mater is subdural space. The space between archnoid & pia mater is subarchnoid space which contains cerebro spinal fluid which acts like shock absorber. The space outside the dura mater is extradural space .

26. BRAIN Is the highest controlling & coordinating system of body lying in the cranial cavity. It has 3 parts- (1) Prosencencephlon [ fore brain ] (a) cerebral hemispheres (b) thalamus (2) Mesencephlon [ mid brain ] (3) Rhombencephlon [ hind brain ] (a) Cerebellum (b) Pons (c) Medulla oblongata

27. All parts of our body are represented in the brain (cerebral cortex) upside down. Various functional areas such as- vision, speech, taste, smell, hearing & general sensations are represented in different parts of brain. Damage to that particular area will lead to loss of that particular function.

28. Cavity of cerebral hemisphere is Lateral ventricle. Cavity of midbrain is cerebral aqueduct. Cavity of hind brain is 4 th ventricle. 12 cranial nerves are attached to the base of brain.

29. Medulla oblongata continues as spinal cord. Spinal cord lies in the vertebral canal. It extends upto first Lumbar vertebra covered by same three meninges. 31 pairs of spinal nerves are attached to spinal cord.

30. CRANIAL NERVES 1 st olfactory 2 nd optic 3 rd occulomotor 4 th trochlear 5 th trigeminal 6 th abducent 7 th facial 8 th vestibulo cochlear 9 th glosso pharyngeal 10 th vagus 11 th accessary 12 th hypoglossal

31. APPLIED ANATOMY Head Injury is the major cause of death & disability. Incidences of death due to head injury in developing countries is increasing day by day. Half of them are by traumatic injury due to motor vehicle accidents. Head injury may be due to fracture of calvaria as occurs in direct blow on the head. Acceleration & Deceleration injuries can cause sudden death by damaging vital centers in the brain stem.

32. TRAUMATIC INJURY Blow on the side of skull /head ( usually leads to extradural haemorrhage) - due to rupture of meningeal vessels. Blow to front or back —[ usually in car accidents ] - antero-posterior displacement leading to tearing of cerebral veins.Blood accumulates between dura & arachnoid[ subdural haemorrhage.] Subarchnoid haemorrhage ( usually nontraumatic) -due to rupture of branches of circle of willis

33. DIFFERENCE BETWEEN EXTRADURAL & SUBDURAL HAEMORRHAGE S. No EXTRADURA L SUBDURAL 1 Unilateral Bilateral 2 Hematoma usually localised Hematoma usually extensive 3 Brain damage is slight Brain damage is severe 4 Slow onset Rapid onset 5 Lucid interval present absent 6 Paralysis occurs on opposite side & from above downwards no such order 7 Usually fracture of skull present Fracture may not be present 8 Lens shaped hyper-opacity Crescent shaped hyper-opacity 9 Usually arterial Usually venous

34. Subarchnoid haemorrhage Usually non traumatic Due to rupture of branches of circle of willis Cause is chronic hypertension Symptoms produded are severe headache,stiffness of neck & loss of consciousness Ct scan-hyperdensity in the cisterns.

35. ANATOMY OF NECK Region of neck consists of- 1.skin & superficial fascia 2. deep fascia of neck 3. muscles of neck 4. trachea & oesophagus in the midline covered by thyroid gland 5. blood vessels (carotid arteries & internal jugular vein on the side)

36. Injury to the lateral side of neck usually cuts the major blood vessels leading to severe blood loss. Injury to the front of the neck usually cuts the wind pipe (trachea). In hanging 2 nd cervical vertebra gets fractured & odontoid process separates and hits the vital centres in the medulla oblongata causing death.

37. ANATOMY OF THORAX Wall of thorax consists of following (from outside inwards) : Skin Superficial fascia Muscles attached to the thoracic cage which helps in respiration Thoracic cage is formed by thoracic vertebrae, ribs & sternum. Thoracic cage is also covered by muscles of upper limb. Inlet of thorax is formed by 1 st rib, manubrium, sternum & 1 st thoracic vertebrae. Outlet of thorax is formed by chief muscles of respiration called diaphragm which acts like a partition between thorax & abdomen Cavity of thorax contains important organs such as heart in the centre covered by pericardium & lungs on the sides are covered by pleura. Pleura & pericardium are double layered serous membranes which secretes watery fluid for lubricating the surface. It provides a dead space for expansion of these organs.

38. Applied aspects The upper 2 and lower 2 ribs are least involved in crushing injury of chest as upper 2 are covered by clavicle & lower 2 are the floating ribs. Fractured ribs are painful because fractured part moves during respiration, coughing & sneezing. Crushing injury breaks the rib & enters into the pleura (the outer covering of the lungs). Pleural cavity is a closed cavity which provides a dead space for expansion of lungs. If pleura is pierced, air enters into the pleural cavity & leads to collapse of lung. Foreign body may enter into the trachea,and then into the right bronchus commonly (as it is in line with trachea), & may lead to asphyxia.

39. HEART Human heart is a 4 chambered organ. It receives de-oxygenated blood through superior & inferior vena cava. It gives oxygenated blood through arch of aorta & its branches. Heart itself is supplied by the coronary arteries. Heart is covered by a layer called Pericardium.

40. APPLIED ASPECTS Narrowing of coronary artery leads to reduced blood flow & less oxygen supply to cardiac muscles, giving rise to pain in the left shoulder and left arm & fore-arm. This is called Angina Pectoris. If large branch of coronary artery is blocked, it leads to necrosis or death of that part of cardiac muscle. this will stop functioning of the heart and often is a common cause of death called as Heart-attack. The commonest branch of coronary artery involved is left anterior descending artery, also called as artery of sudden death. Slow & gradual blocking of coronary artery is less dangerous than sudden blockage, as in slow blocking the collaterals open up. Blockage of coronary artey in old age is less fatal than in young age because anastomosis increases and collateral channels opens with advancement of age .

41. ANATOMY OF ABDOMEN Cavity of abdomen is not bounded by bony framework as that of thorax. Cavity extends above from diaphragm below pelvic cavity on sides by ribs & anteriorly by muscles of abdominal wall Muscles of abdominal wall are strong & thin & arranged like a ply. (direction of muscle fibres is criss-cross). Cavity of abdomen mainly contains part of GIT & these organs are enclosed in a thin peritonial cavity.

42. Stomach is a storage organ for the food. It is well protected by ribs on its left side. However its large size makes it vulnerable for the gun-shot wounds. Pancreas is deeply placed so that it is well protected. however blunt trauma or sudden blow to abdomen as in sports injury or gun shot injury may damage it & causes release of pancreatic enzymes into the peritoneum and can cause acute peritonitis. Car accident with seat-belts on, may lead to tear of mesentery and leads to profuse bleeding.

43. SPLEEN Spleen is a haemolymph organ, situated at the left upper side of abdomen against 9 th , 10 th & 11 th ribs. So fracture of these ribs or any blunt trauma may rupture the spleen causing profuse internal bleeding. This may lead to death in few days.

44. LIVER Liver is a soft, friable organ of about 1.4 kg protected by ribs, present on the right upper side of abdomen. It may be injured in fracture of ribs or penetrating wounds or automobile accidents. Since it is a highly vascular organ, its injury causes profuse bleeding.

45. Passage of food into the mouth cavity with the help of teeth & tongue (Chewing &Mastication), the bolus passes from pharynx (voluntary process) into the oesophagus. Now onwards the process is involuntary. Food passes from the oesophagus & stored in the stomach & stomach. There occurs mixing of food with gastric juice. After 2-4 hours, it empties its contents into duodenum. Here pancreatic juice is added, then it enters into the small intestine where absorption of carbohydrate, protein and lipid starts. Remaining food passes through large intestine(where absorption of water occurs), rectum & anal canal.

46. Rupture of aorta due to aneurysm may cause severe pain in the abdomen. Person dies due to heavy blood-loss. Mortality rate is > 90 %. Kidney is an important organ for the formation of urine. It lies in the lumbar region (posteriorly) behind the peritoneum. It excretes most of the waste product of metabolism. This waste product is called as urine. It may be injured in stab injury or gun-shot injury leading to enormous rapid blood loss followed by death, as 25% of cardiac output goes to kidney.

47. ANATOMY OF PELVIS Wall of pelvis is well protected by bony pelvis (formed by hip-bone anteriorly & sacrum posteriorly). Cavity of pelvis contains lower part of GIT, Rectum & anal canal, lower part of urinary system (bladder & urethra) & genital system. In females, in between the bladder & rectum, is uterus which continues lower down as vagina, and onto the side are attached fallopian tubes & ovary. Male genital organ testis lies in the scrotm which continues as epidydymis (comma shaped structure) which continues as vas deferens. It opens along with the duct of seminal vesicle (present posterior to the base of bladder) into the prostate (accessory genital organ encircling the neck of bladder.

48. APPLIED ASPECTS Empty bladder lies in the pelvis, but full bladder may reach upto the abdominal cavity. It may be injured either in blunt injury to the lower part of abdomen or in accidents leading to leakage of urine into the peritoneal cavity. Normally uterus lies in the pelvic cavity, but gravid uterus extends upto the abdominal cavity. Pregnancy may occur in the fallopian tube which is known as ectopic pregnancy. Rupture of tube may lead to profuse bleeding. Common cause of bleeding during delivery is Placenta Previa (Abnormal Implantation of placenta). Male urethra is more prone to injury than female, as it lies outside .

49. ANATOMY OF LIMBS Limbs mainly consist of long bones. Long bones has 3 parts epiphysis,diphysis,&metaphysis .[where growth plate is present]. Radiological examination of bones are helpful in determining the age. In x ray, growth plate appears dark incontrast tobone which appears white. In lower limb center of ossification of lower end of femur which appears just before birth i s used for medicolegal evidence whether the foetus is alive or not. Blood vessels of upper limb at the wrist are superficia l[ ulnar & radial arteries] so commen site for suicidal cuts.

50. ERRUPTION OF TEETH This is an important landmark in identifying the age. Teeth are the most indestructible bodily structure & it can provide identification when trauma & fire has rendered the face unrecognisable . Chronology of crown development, eruption & root formation can be used to estimate age until the 3 rd molar is completed, i.e. at about 21 years. The dental formula in adult is 2123 i.e. 2 incisors, 1 canine, 2 premolars & 3 molars In children dental formula is 2102. Saliva obtained from the bites of culprit is useful in DNA finger printing for precise identification of culprit.

51. AGE CHANGES IN MANDIBLE At birth the 2 halves of mandible are united by a fibrous joint. During 1 st three post natal years, 2 halves start joining from below upwards. The shape of body elongates (behind mental foramen) for providing space for additional teeth. Mental foramen alters its direction( it no longer faces forwards but faces backwards now). Increase in the height of body of mandible for the erupting teeth. In adults alveolar & sub-alveolar margins are equal in depth & mental foramen appears midway between upper & lower border. If teeth are lost as in old age, the mental foramen comes to lie near to the superior border.

52. AGE DETERMINATION BY SKULL Fontanelles are closed by middle of 2 nd year.posterolateral in 2 nd month after birth. Anterrior fontanelle in the middle of 2 nd year. Mastoid process appears in 2 nd year. Metopic suture between two frontal bones will close by 4 th year. Sphenoid & occipital bone will fuse between 11- 16 years in female and 13-18 years in male. Vomer & ethmoid fuses between 20-30 years. Closure of cranial suture begins early in the 3 rd decade from inside outwards. Determination of sex is predicted only with 80 % accuracy. In general male skull is more robust & female skull is more gracile. Determination of racial & genetic origin is very difficult.

53. AGE DETERMINATION BY BONES OF UPPER LIMB Clavicle is the first bone to ossify. Its Primary centre of ossification appears by 45 th day. Coracoid process of scapula appears by 1 st year & fuses with the rest of bone by 15 th year. Upper end of the humerus- Osification begins for the head in the greater tubercle at 1 st year in female & 2 nd year in male, and at 5 th year in the lesser tubercle. They all unites to form a single epiphysys by 6 th year. Lower end of humerus – medial epicondyle appears at 4 th year in female and 6 th year in male. Lateral epicondyle by 12 th year Each carpal bone ossifies by 1 centre, capitate in 2 nd month, hamate in 3 rd month, triquetral in 3 rd year & rest in 4–6 years and pisciform is the last bone to ossify by 9-10 years.

54. AGE DETERMINATION BY BONES OF LOWER LIMB Femur is the 1 st long bone to ossify other than clavicle. Secondary centres for the lower end appears at 9 th month of intrauterine life (just before birth). It is an important landmark for identifyinf whether the child is viable or not. Centre for greater trochanter 4 th year and lesser trochanter 12-14 years. Tibia upper end –ossification centre is present at birth. Rest of the centres appears at puberty & fuses by 18-20 years. Tarsal bones – single centre appears at 6 th month. Calcaneum & navicular -3 rd month.

55. DETERMINATION OF SEX As already mentioned, its difficult to identify the sex of an individual by skull. But pelvis which is formed by 2 hip bones & sacrum helps in identifying the sex. Female pelvis in general is wider than male pelvis. Distinction can be made even during fetal life particularly by sub-pubic arch. This distinction prevails in childhood, but difference is maximum by about 22 months. Sub-pubic arch is angular in male i.e. 50-60 degree. In female it is rounded & measures 80-85 degree. Female sacrum are broad, less curved but male are more evenly curved, long & narrow.

56. Thanks