Tuesday, January 22, 2008

7 - anatomy mcqs - 35 to 45

PICK THE TRUE STATEMENTS .

Question 35 : Regarding gluteus medius

A.is supplied by the inferior gluteal nerve- FALSE
B.acting from the pelvis adduct the thigh-FALSE
C.arises from the outer surface of the pelvis--TRUE
D.in unilateral paralysis trendelenberg sign becomes positive--TRUE
E.with gluteus minimus maintain the poise and balance of the body when the foot of the opposite side is raised from the ground--TRUE

Question 36: Regarding the hypoglossal nerve

A.arises from the floor the 3rd ventricle-FALSE
B.is the motor nerve of the tongue--TRUE
C.supplies all the muscles of the tongue-FALSE
D.supplies the thyrohyoid muscle--TRUE
E.in unilateral paralysis protruded tongue deviates to the normal side-FALSE

Question 37: Regarding the root of the lung

A.lie opposite the bodies of the 5, 6 , 7 thoracic vertebrae--Right
B.includes bronchial arteries--Right
C.that of right lung lies behind the inferior vena cava-FALSE
D.that of left lung lies behind the arch of aorta--Right
E.vagus nerve runs anterior to it-FALSE

Question 38 : Regarding the spleen

A.its long axis lies in the line of the 8th rib-FALSE
B.anteriorly reaches as far as the mid-axillary line * * Right
C.its hilum is related to the tail of the pancreas-FALSE
D.one or two notches are present in the posterior border * * Right
E.costodiapharmatic recess extends as far as the inferior border * * Right

Question 39 : Regarding the kidney

A. hilum of the right kidney lies just above the transpyloric plane.-FALSE
B. right kidney rests on the twelfth rib-TRUE
C. related posteriorly to subcostal vessels and the last thoracic, iliohypogastric and ilioinguinal nerves-TRUE
D. left colic vessels are related the left kidney-TRUE
E. at the hilum renal vein is anterior to the renal artery-TRUE

Question 40 : Regarding the caecum

A. lies on the iliacus and psoas major muscles * * Right
B. lateral cutaneous nerve of the thigh is anterior to it-FALSE
C. entirely enveloped by the peritoneum * * right
D. situated in the right iliac fossa above the medial half of the inguinal ligament E. may herniate down the right inguinal canal * * Right

Question 41 : Regarding the appendix

A. arises from the posterolateral aspect of the caecum-FALSE
B. commonly lies below the caecum-FALSE
C. mesentery of the appendix contains appendicular branch of the ileocolic artery--Right
D. lumen of the appendix is frequently completely obliterated in the elderly--Right
E. the lumen of the appendix is relatively narrow in infants-FALSE

Question 42 : Regarding the clavicle

A. it has a medullary cavity-FALSE
B. it is a long bone-TRUE
C. it is the most commonly fractured bone in the body-TRUE
D. it develops in membrane and not in cartilage-TRUE
E. it is the 1st bone to ossify in the foetus-TRUE

Question 43 : Regarding the shoulder joint

A. Capsule extend down onto the diaphysis on the medial aspect of the neck humerus-TRUE
B. Stability of the joint is related to the short muscles of the rotator cuff-TRUE
C. Least commonly dislocated joint-TRUE
D. the humeral head is likely to dislocate inferiorily-TRUE
E. Circumflex nerve may be damaged in dislocation of the shoulder joint-FALSE

Question 44 : Regarding the inguinal canal all are tue except

A. Anteriorily over its lateral one third is related to the internal oblique muscle-TRUE
B. Floor is formed by the inguinal ligament-TRUE
C. The conjoint tendon forms the posterior wall of the canal medially-FALSE
D. An indirect inguinal hernia passes through the internal ring-TRUE
E. A direct inguinal hernia lies lateral to the inferior epigastric artery-FALSE

Monday, January 21, 2008

6 - skull foramen and structures passing through them

1- HYPOGLOSSAL CANAL - hypoglossal nerve

2- INTERNAL CAROTID ARTERY - passes thru both carotid canal and foramen lacerum

3- GREATER PALATINE FORAMEN - anterior palatine nerve

4- LESSER PALATINE FORAMEN - posterior palatine nerve

5- NASOPALATINE NERVE - incisive foramen

6- SUPRA ORBITAL FORAMEN OR NOTCH - supraorbital nerve

7- SUPRA ORBITAL FISSURE - inferior opthalmic vein

8- INFRA ORBITAL FORAMEN - infra orbital nerve

9- ZYGOMATIC NERVE - infra orbital fissure

10- ZYGOMATICO FACIAL FORAMEN - zygomatico facial branch of the sixth nerve

11- OPTIC CANAL - central retinal vein

12 - FORAMEN ROTUNDUM - maxillary division of the trigeminal nerve

13- FORAMEN OVALE - Mandibular nerve, Accessory meningeal artery, Lesser petrosal nerve and Emissary veins (mnemonic : MALE).

14- FORAMEN SPINOSUM - middle meningeal artery

15- JUGULAR FORAMEN - 9 , 10 , 11 th cranial nerves

16- MASTOID FORAMEN - meningeal branch of occipital artery

17- TYMPANO MASTOID FISSURE - auricular branch of vagus ( vidian r alderman n )

18- FACIAL NERVE - stylomastoid foramen

19- CHORDA TYMPANI NERVE - petro tympanic fissure.


Go to this page to know the complete anatomy of the inferior part of skull and all the foramina with images.

Monday, January 14, 2008

5 - anatomy mcqs - 23 to 34


23) All are seen in the medial wall of middle ear except
a. Promontory
. Oval window
c. Facial canal
d. Chorda tymphani
Answer : D) Chorda tympani
Reference: Gray 38th Edition Page 1373

24) Blood supply of the submandibular gland is by
a. Facial Artery and Lingual Artery
b. Superior Thyroid Artery and Ascending Pharyngeal Artery
c. Lingaul Artery and Internal Maxillary Artery abd
d. Facial Artery and Superficial temporal Artery
Answer : A) Facial Artery and Lingual Artery
Reference: Gray 38th Edition Page 1693

25) Frontal Sinus are generally well developed at appears on
a. Birth
b. 1 year
c. 5 years
d. 8 years
Answer : d) 8 years
Reference: Gray 38th Edition Page 1636

26) Posterior most structure of ankle is
a. Flexor retinaculam
b. Posterior Tibial Artery
c. Tibialis posterior
d. Talus
Answer : d) Flexor Retinaculum
Reference: Gray 38th Edition Page 720

27) Muscle supplied by Nerve of III pharyngeal arch is
a. Cricothyroid
b. Stapedius
c. Stylohoid
d. Sylopharyngeus
Answer : d)Stylopharyngeus
Reference: Gray 38th Edition Page 281

28) All of the following develop from Neural crest except
a. Melanoblast
b. Odentoblast
c. Adrenal medulla
d. Spinal Cord
Answer : d) Spinal Cord
Reference: Dutta Embryology Page 255

29) Cone of Light Is seen in which part of Tympanic membrane
a. Antero superior
b. Antero inferior
c. Postero Superior
d. Postero Inferior
Answer : b) Antero inferior
Reference: Gray 38th Edition Page 1370

30) Posterior relation of lower part of manubrium sterni is
a. Subclavian vein
b. Brachocephalic artery
c. Left Brochocephalic vein
d. Arch of Aorta
Answer : d) Arch of Aorta
Reference: Gray 38th Edition Page 538

31) Lines of Gennari are seen in
a. Auditory cortex
b. Sensory cortex
c. Motor cortex
d. Visual Cortex
Answer : d) Visual Cortex
Reference: Gray 38th Edition Page 1142

32) Correct statement about a Superior mesenteric vessel is
a. arises from aorta at the level at L3
b. runs in front of the transverse part of diaphragm
c. the vein drains into IVC and
d. Supplies foregut
Answer : runs in front of the transverse part of diaphragm
Reference: Gray 38th Edition Page 1553

33) The hernia occurring in Bochadelak's foramen is
a. Diaphragmatic hernia
b. Hiatus Hernia
c. Femoral hernia
d. Lumbar hernia
Answer : a) Diphragmatic Hernia
Reference: Gray 38th Edition Page 817

34) False about Golgi cells of cerebellum is
a. Inhibitory,
b. GABAergic interneurons,
c. Their somata are located in the granular layer.
d. Golgi cell dendritic trees are flattened,
Answer : D) Golgi cell dendritic trees are not flattened,
Reference: Gray 38th Edition Page 1042

Sunday, January 13, 2008

4 - Anatomy Mcqs - 11 to 22

11. Internal spermatic fascia is derived from
a. Transversalis facia
       b. Internal abdominis muscle
       c. External Oblique Abdominis Muscle
       d. Internal Oblique Abdominis Muscle
Answer a. Transversalis Fascia
Reference: Grays’ Anatomy 38th Edition Page 829
The spermatic cord in the male, or the round ligament of the uterus in the female, pass through the transversalis fascia at the deep inguinal ring (see below). This opening is not visible externally since the transversalis fascia is prolonged on these structures as the internal spermatic fascia
Layers of Anterior Abdominal Wall
Layers of Scrotum
Mnemonic
Skin
Skin
S
Some
Superficial Fascia
Dartos Muscle
D
Decent
External Oblique Abdominis
External Spermatic Fascia
E
Englishmen
Internal Oblique Abdominis
Cremateric Muscle and Fascia
C
Call
Transversalis Fascia
Internal Spermatic Fascia
I
It
Process Vaginalis
Tunica Vaginalis Testis
T
Testis

12) Length of Ureter is
a. 25 cms
b. 18 cms
c. 10 cms.
d. 5 cm
Answer 25 cm
Reference : Grays 38th Edition Page 1828
Ureter measures 25 to 30 cm

13) External laryngeal nerve supplies
a. Superior Constrictor.
b. Middle Constrictor.
c. Inferior constrictor.
d. None of the above
      Answer : Inferior Constrictor
Reference: Gray 38th Edition Page 1253
The external laryngeal nerve, smaller than the internal, descends posterior to the sternothyroid with the superior thyroid artery but on a deeper plane; it lies at first on the inferior pharyngeal constrictor and then, piercing it, curves round the inferior thyroid tubercle to reach and supply the cricothyroid. It also supplies the pharyngeal plexus and inferior constrictor; behind the common carotid artery it connects with the superior cardiac nerve and superior cervical sympathetic ganglion.

14) Vidian Nerve is formed by
a. Deep Petrosal & Greater Superficial Petrosal nerve
b. Greater Superficial Petrosal Nerve and Lesser Superficial Petrosal Nerve.
c. Deep Petrosal Nerve and Lesser Superficial Petrosal Nerve
d. None of the above
Answer Deep Petrosal & Greater Superficial Petrosal nerve
Reference: Gray 38th Edition Page 1245
Greater Petrosal Nerve is joined by the deep petrosal nerve from the internal carotid sympathetic plexus to become the Vidian nerve or nerve of the pterygoid canal which traverses the pterygoid canal to end in the pterygopalatine ganglion.

15) Superficial Surface of Parotid is related to
a. Great auricular nerve
b. Mastoid Process
c. Posterior Belly of Digastri
d. External Carotid Artery
Answer a. Greater Auricular Nerve
Reference Gray 38th Edition Page 1691

16) The communicating vein responsible for spread of infection from the Dangerous area of the face.
a. Superior ophthalmic Vein
b. Inferior Ophthalmic Vein
c. Maxillary Vein
d. Lingual Vein
Answer : Superior Ophthalmic Vein
Reference: Gray 38th Edition Page 1577
Near its beginning the facial vein connects with the superior ophthalmic directly and via the supraorbital; it is thus connected to the cavernous sinus.

17) Para thyroid Develops from
a. 1st and 2nd Arch
b. 2nd and 3rd Arch
c. 3rd and 4th Arch
d. 4th and 5th Arch
Answer : 3rd and 4th Arch
Reference: Gray 38th Edition Page 1897

18) Preganglionic fibres of of Otic Ganglion travels in
a. Lesser Petrosal nerve
b. Auriculotemporal nerve
c. Greater Superficial Petrosal Nerve
d. None of the above
Answer : Lesser Petrosal Nerve
Reference: Gray 38th Edition Page 1377

19) Left common Cardinal Vein forms
a. Oblique Vein of Left Atrium
b. SVC
c. Coronary Sinus
d. None of the above
Answer : (A) Oblique Vein of the Left Atrium
Reference: Gray 38th Edition Page 324
Embryological part
Adult Part
Right Horn of Sinus Venosus
Posterior smooth part or the sinus venarum of the right atrium
Left Horn of Sinus Venosus and Body of Sinus Venosus
Coronary Sinus
Right duct of Cuvier or Right Common Cardinal Vein
Intrapericardial part of the Superior Vena Cava
Left duct of Cuvier or Left Common Cardinal Vein
Oblique vein of Left Atrium
Oblique cross connection between the right and the left anterior cardinal veins
Left Brachocephalic Vein
Caudal part of the Right Anterior Cardinal Vein
Extrapericardial part of the superior vena cava
Caudal part of the Left Anterior Cardinal Vein
Fibrous thread within the ligament of the left vena cava
Supra hepatic part of the Right Vitelline Vein
Terminal part of the Inferior Vena Cava

20) Auditory cortex area is Area
a. Area 14
b. Area 24
c. Area 34
d. Area 44
Answer : D) Area 44
Reference: Gray 38th Edition Page 1158 Figure 8.262

21) Which Law states that the Dorsal roots are Sensory Ventral roots are motor –
a. Bell magendie law
b. Starling’s law.
c. Both of the above
d. None of the above
Answer A)Bell magendie law
Reference: Ganong 22nd Edition Page 129

22) Superior oblique muscle is supplied by
a. Trochlear nerve.
b. Abducens Nerve
c. Oculomotor Nerve
d. None of the above
Answer (A) Trochlear Nerve
Reference: Gray 38th Edition Page 1230


3 - Anatomy Mcqs - 1 to 10

1. The diaphragm

(a) Develops from the septum transversum and cervical myotomes
(b) Receives a nerve supply from both the phrenic and intercostal nerves
(c) An opening in the central tendon transmits the left phrenic nerve
(d) The inferior vena cava passes through the diaphragm at the level of the T12 vertebra
(e) The aorta passes through the diaphragm at the level of the T8 vertebra

-------------------------

only a and b are true . The diaphragm develops in the neck and hence receives its nerve supply from the cervical spinal cord (C4-C5). It is made up of structures arising from the septum transversum, pleuroperitoneal membranes, the dorsal mesentery and body wall. The septum transversum forms the central tendon. The motor nerve supply arises from the phrenic nerve. The sensory nerve supply is from the lower six intercostal nerves. The IVC, oesophagus and aorta pass through the diaphragm at the levels of T8, T10 and T12 respectively. an opening in the central tendon transfers the right phrenic nerve .

Openings in the Diaphragm.—The diaphragm is pierced by a series of apertures to permit of the passage of structures between the thorax and abdomen. Three large openings—the aortic, the esophageal, and the vena caval—and a series of smaller ones are described.
The aortic hiatus is the lowest and most posterior of the large apertures; it lies at the level of the twelfth thoracic vertebra. Strictly speaking, it is not an aperture in the diaphragm but an osseoaponeurotic opening between it and the vertebral column, and therefore behind the diaphragm; occasionally some tendinous fibers prolonged across the bodies of the vertebræ from the medial parts of the lower ends of the crura pass behind the aorta, and thus convert the hiatus into a fibrous ring. The hiatus is situated slightly to the left of the middle line, and is bounded in front by the crura, and behind by the body of the first lumbar vertebra. Through it pass the aorta, the azygos vein, and the thoracic duct; occasionally the azygos vein is transmitted through the right crus.
The esophageal hiatus is situated in the muscular part of the diaphragm at the level of the tenth thoracic vertebra, and is elliptical in shape. It is placed above, in front, and a little to the left of the aortic hiatus, and transmits the esophagus, the vagus nerves, and some small esophageal arteries.
The vena caval foramen is the highest of the three, and is situated about the level of the fibrocartilage between the eighth and ninth thoracic vertebræ. It is quadrilateral in form, and is placed at the junction of the right and middle leaflets of the central tendon, so that its margins are tendinous. It transmits the inferior vena cava, the wall of which is adherent to the margins of the opening, and some branches of the right phrenic nerve.
Of the lesser apertures, two in the right crus transmit the greater and lesser right splanchnic nerves; three in the left crus give passage to the greater and lesser left splanchnic nerves and the hemiazygos vein. The gangliated trunks of the sympathetic usually enter the abdominal cavity behind the diaphragm, under the medial lumbocostal arches.
On either side two small intervals exist at which the muscular fibers of the diaphragm are deficient and are replaced by areolar tissue. One between the sternal and costal parts transmits the superior epigastric branch of the internal mammary artery and some lymphatics from the abdominal wall and convex surface of the liver. The other, between the fibers springing from the medial and lateral lumbocostal arches, is less constant; when this interval exists, the upper and back part of the kidney is separated from the pleura by areolar tissue only.

Variations.—The sternal portion of the muscle is sometimes wanting and more rarely defects occur in the lateral part of the central tendon or adjoining muscle fibers.

Nerves.—The diaphragm is supplied by the phrenic and lower intercostal nerves.

Actions.—The diaphragm is the principal muscle of inspiration, and presents the form of a dome concave toward the abdomen. The central part of the dome is tendinous, and the pericardium is attached to its upper surface; the circumference is muscular. During inspiration the lowest ribs are fixed, and from these and the crura the muscular fibers contract and draw downward and forward the central tendon with the attached pericardium. In this movement the curvature of the diaphragm is scarcely altered, the dome moving downward nearly parallel

--------------------------

2. The oesophagus

(a) Is 40 cm in length
(b) In the thorax passes behind the left main bronchus
(c) Is lined by stratified squamous epithelium in the upper two-thirds
(d) Is lined by transitional epithelium in the lower one-third
(e) Drains all of its blood into the azygos and hemiazygos veins

----------------------------

only b and c are right . The oesophagus is 25 cm in length. The oesophagogastric junction lies 40 cm from the incisors. The oesophagus is lined by both striated (upper two-thirds) and smooth (lower third) muscle. The lower third is line by columnar epithelium. The venous drainage is into the inferior thyroid, azygos and left gastric veins. The communication between the azygos and left gastric veins is an important portosystemic anastomosis that can be the site of oesophageal varices.

----------------------------

3. The radial nerve

(a) Is the principal branch of the posterior cord of the brachial plexus
(b) Is derived from the posterior primary rami of the C5 to T1 nerve roots
(c) Is the main nerve supply to the extensor compartments of the arm and forearm
(d) Gives rise to the anterior interosseous nerve
(e) Supplies sensation to the extensor aspect of the radial three and a half digits

------------------------------

a , c , e are the right answers . The radial nerve is the main branch of the posterior cord of the brachial plexus. Other branches of the posterior cord include the axillary, thoracodorsal and upper and lower subscapular nerves. All roots of the brachial plexus arise from the ""anterior"" primary rami. The radial nerve supplies the forearm and wrist extensors; A radial nerve palsy results in a classical 'wrist drop'. The anterior and posterior interosseus nerves are branches of the median and radial nerves respectively.

----------------------------------------

4. The thymus gland

(a) Lies within the posterior mediastinum
(b) Develops from the fourth pharyngeal pouch
(c) Decreases in size with age
(d) Is made up of cells of endodermal origin
(e) Descends anterior to the brachiocephalic vein

---------------------------------

The thymus lies within the anterior mediastinum. It develops with the inferior parathyroid gland from the third pharyngeal pouch. The cells of the thymus are of endodermal origin. It is at its largest in childhood and decreases in size with age.

-------------------------------------

5. Scalenus anterior

(a) Is an accessory muscle of respiration
(b) Separates the subclavian vein from the subclavian artery and brachial plexus
(c) Is pierced by the phrenic nerve
(d) Inserts into the scalene tubercle on the second rib
(e) Lies anterior to the suprascapular artery

-------------------------------

only a and b are correct . Scalenus anterior arises from the transverse processes of the third to six cervical vertebrae. It inserts into the scalene tubercle of the first rib. The subclavian vein passes anteriorly. The subclavian artery and brachial plexus pass posteriorly. The phrenic nerve lies on the anterior surface.

------------------------------

6. The axilla contains

(a) The cords of the brachial plexus
(b) The superior thoracic artery
(c) The latissimus dorsi muscle in its medial wall
(d) The thoracodorsal nerve in its posterior wall
(e) The long thoracic nerve in its medial wall

-----------------------

a , b , d , e are the right answers . The axilla contains the cords of the brachial plexus. The latissimus dorsi muscle forms the posterior wall of the axilla. It is supplied by the thoracodorsal nerve. The long thoracic nerve supplies serratus anterior and lies on the medial wall.

------------------------------------

7. The common bile duct

(a) Lies in the free edge of the lesser omentum
(b) Lies anterior to the portal vein
(c) Lies to the right of the hepatic artery
(d) May open into the duodenum independent of the pancreatic duct
(e) Lies anterior to the first part of the duodenum

------------------------------

only e is false . The common bile duct lies in the free edge of the lesser omentum, anterior to the portal vein and to the right of the hepatic artery. It passes posterior to the first part of the duodenum before opening into the second part.

-----------------------------------

8. The following structures pass under the inguinal ligament

(a) The tendon of psoas major
(b) The femoral branch of the genitofemoral nerve
(c) The long saphenous vein
(d) The superficial epigastric vein
(e) The superficial femoral artery

-----------------------

only a and b are right . The tendon of psoas major and the femoral branch of the genitofemoral nerve both pass under the inguinal ligament. The long saphenous vein terminates in the femoral vein about 3 cm below the inguinal ligament. The external iliac becomes the common femoral artery at the inguinal ligament. The superficial epigastric vein passes in front of the inguinal ligament

-----------------------------

9. The pancreas gland

(a) Lies anterior to the left kidney
(b) Derives part of its blood supply from the splenic artery
(c) Has parts in both the supracolic and infracolic compartments
(d) Is pierced by the middle colic artery
(e) The junction of the splenic and superior mesenteric veins lies behind the gland

--------------------------

only d is wrong . The tail of the pancreas crosses the left kidney as it passes to the hilum of the spleen. The blood supply is from the splenic, superior and inferior pancreaticoduodenal arteries. The gland is pierced by the superior mesenteric artery. The middle colic arises from the lower border.

---------------------------------

10. A common peroneal nerve palsy

(a) Can occur following a fracture of the neck of the fibula
(b) Causes loss of extension of the big toe
(c) Causes a characteristic foot drop
(d) Causes loss of inversion of the foot
(e) Produces anaesthesia of the sole of the foot

----------------------------

a , b , c are right . The common peroneal nerve is a branch of the sciatic nerve. It winds around the neck of the fibula before dividing into the superficial and deep peroneal nerves. The latter is responsible for eversion of the ankle and dorsiflexion of the foot. Inversion is not lost as this is partially controlled by tibialis posterior supplied by the tibial nerve. Sensation to the sole of the foot is by the medial and lateral plantar branches of the tibial nerve.

---------------------------------------

2 - Diaphragm Mcq

1. The diaphragm (find true statements)

(a) Develops from the septum transversum and cervical myotomes
(b) Receives a nerve supply from both the phrenic and intercostal nerves
(c) An opening in the central tendon transmits the left phrenic nerve
(d) The inferior vena cava passes through the diaphragm at the level of the T12 vertebra
(e) The aorta passes through the diaphragm at the level of the T8 vertebra

-------------------------

only a and b are true . The diaphragm develops in the neck and hence receives its nerve supply from the cervical spinal cord (C4-C5). It is made up of structures arising from the septum transversum, pleuroperitoneal membranes, the dorsal mesentery and body wall. The septum transversum forms the central tendon. The motor nerve supply arises from the phrenic nerve. The sensory nerve supply is from the lower six intercostal nerves. The IVC, oesophagus and aorta pass through the diaphragm at the levels of T8, T10 and T12 respectively. an opening in the central tendon transfers the right phrenic nerve .

Openings in the Diaphragm.—The diaphragm is pierced by a series of apertures to permit of the passage of structures between the thorax and abdomen. Three large openings—the aortic, the esophageal, and the vena caval—and a series of smaller ones are described.
The aortic hiatus is the lowest and most posterior of the large apertures; it lies at the level of the twelfth thoracic vertebra. Strictly speaking, it is not an aperture in the diaphragm but an osseoaponeurotic opening between it and the vertebral column, and therefore behind the diaphragm; occasionally some tendinous fibers prolonged across the bodies of the vertebræ from the medial parts of the lower ends of the crura pass behind the aorta, and thus convert the hiatus into a fibrous ring. The hiatus is situated slightly to the left of the middle line, and is bounded in front by the crura, and behind by the body of the first lumbar vertebra. Through it pass the aorta, the azygos vein, and the thoracic duct; occasionally the azygos vein is transmitted through the right crus.
The esophageal hiatus is situated in the muscular part of the diaphragm at the level of the tenth thoracic vertebra, and is elliptical in shape. It is placed above, in front, and a little to the left of the aortic hiatus, and transmits the esophagus, the vagus nerves, and some small esophageal arteries.
The vena caval foramen is the highest of the three, and is situated about the level of the fibrocartilage between the eighth and ninth thoracic vertebræ. It is quadrilateral in form, and is placed at the junction of the right and middle leaflets of the central tendon, so that its margins are tendinous. It transmits the inferior vena cava, the wall of which is adherent to the margins of the opening, and some branches of the right phrenic nerve.
Of the lesser apertures, two in the right crus transmit the greater and lesser right splanchnic nerves; three in the left crus give passage to the greater and lesser left splanchnic nerves and the hemiazygos vein. The gangliated trunks of the sympathetic usually enter the abdominal cavity behind the diaphragm, under the medial lumbocostal arches.
On either side two small intervals exist at which the muscular fibers of the diaphragm are deficient and are replaced by areolar tissue. One between the sternal and costal parts transmits the superior epigastric branch of the internal mammary artery and some lymphatics from the abdominal wall and convex surface of the liver. The other, between the fibers springing from the medial and lateral lumbocostal arches, is less constant; when this interval exists, the upper and back part of the kidney is separated from the pleura by areolar tissue only.

Variations.—The sternal portion of the muscle is sometimes wanting and more rarely defects occur in the lateral part of the central tendon or adjoining muscle fibers.

Nerves.—The diaphragm is supplied by the phrenic and lower intercostal nerves.

Actions.—The diaphragm is the principal muscle of inspiration, and presents the form of a dome concave toward the abdomen. The central part of the dome is tendinous, and the pericardium is attached to its upper surface; the circumference is muscular. During inspiration the lowest ribs are fixed, and from these and the crura the muscular fibers contract and draw downward and forward the central tendon with the attached pericardium. In this movement the curvature of the diaphragm is scarcely altered, the dome moving downward nearly parallel.

Friday, January 4, 2008

1 - Retinal layers


From inside to outwards , the layers of the retina are :

1- internal limiting membrane--Müller cell footplates .

2- nerve fibre layer ( stratum opticum )

3- ganglion cell layer


4- inner plexiform layer


5- inner nuclear layer

6- outer plexiform layer-In the macular region ,
     this is known as the Fiber layer of Henle.

7- outer nuclear layer

8- external limiting membrane

9- rod and cone cell processes

10- pigment epithelium

---
refer gray's anatomy - 39 th edition - page 713

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