Anatomy books

Tuesday, November 1, 2016

Temporal bone: easy handout covering only important topics

Temporal: It is an important bone because
·        Whole internal ear
·        Whole middle ear
·        Bony part of external auditory meatus lies within it .
SN: Only cartilaginous part of external auditory meatus and auricle lies outside the temporal bone 
1.   Anatomical  point :
·        Convex squamous part is directed laterally
·        Apex of petrous part is directed medially , forward, and upward
·        Zygomatic process is directed anteriorly
2.   Morphological type : pneumatic irregular bone
3.   Ossification : both intramembranous and intracartilaginous
·        Squmous part and tympanic part is ossify from membrane
·        Rest of the temporal bone is ossify from cartilage
4.   Development :
     Petrous part of temporal bone is derived from paraxial mesoderm
    Rest of the part of temporal bone is derived from neural crest
5.   Parts: It has
Three parts:
                     i.        Squamous part
                    ii.        Petro-mastoid part
                   iii.        Tympanic part
Three processes:
It has three processes :
                     i.        Zygomatic process
                    ii.        Mastoid process
                   iii.        Styloid process

Squamous part : it has two surfaces
External surface: 
i)             whole external  surface is attached by origin of temporalis muscle except mandibular fossa and zygomatic process
ii)            external surface bears groove for middle temporal artery
iii)        Suprameatal triangle : this triangle situated just above and posterior part of  the external auditory meatus
iv)        Importance of suprameatal triangle : mastoid antrum lies 1.25 cm deep to it
Internal surface:
Impressions of temporal lobe of cerebrum
Groove for middle meningeal artery
Squamous part has two borders
·        Superior border articulate with inferior border of parietal bone
·        Antero-inferior border : articulate with greater wing of sphenoid bone



Petrous part:    It has
Apex: is directed medially, forward and upwards
Base: attached with squamous and mastoid part
Petrous part : 3 borders:
1.   Anterior border: articulate with greater wing of sphenoid   
2.   Superior border:  lodges superior petrosal sinus and attachment of tentorium cerebella except medial part
3.   Posterior border:
Medial part of posterior border is lodge by inferior petrosal sinus  and
Lateral part of posterior border forms jugular foramen by articulating with condylar part of occipital bone
3 surfaces of petrous part : anterior, posterior and inferior
Anterior surface of petrous part :
1.   This surface  is irregular for sulci and gyri of temporal lobe of cerebrum
2.   Trigeminal impression ( a depressed area near the apex ): lodge trigeminal ganglion
3.   Arcuate eminence: an elevated area behind the trigeminal impression, it is caused by superior semicircular canal of internal ear
4.   Tegmen tympani:  a thin plate of bone situated in between arcuate eminence and squamous part of temporal bone.
From antero- posteriorly , tegment tympani forms
1.   Roof of tensor tympani
2.   Roof of middle ear cavity
3.   Roof of mastoid antrum
Posterior surface of petrous part of temporal bone:
Bear orifice of internal auditory meatus :  Structure passing through the foramen
Structures entrance into internal auditory meatus :
·        Motor root of facial nerve
·        Labyrinthine artery
Structures exit from the internal auditory meatus:
·        sensory root of facial nerve
·        vestibulocochlear nerve
·        labyrinthine vein
Inferior surface of petrous part of temporal bone:
From antero posteriorly
1.   Near apex: attachment of levator veli palatine muscle and cartilaginous part of auditory tube
2.   External or lower opening of carotid canal
3.   Jugular fossa

Mastoid part
It forms the posterior part of temporal bone
It has
Two surfaces: external and internal
Two borders: superior and posterior
1 process: mastoid process
                                               External surface of mastoid part
It is attached with following muscles : muscles are arrange from above , downwards and forwards
                     i.        Auricularis posterior
                    ii.        Origin of occipital belly of occipito frontalis muscle
                   iii.        Insertion of sternocleidomastoid
                  iv.        Insertion of splenius capitis
                   v.        Insertion of longissimus capitis
internal surface of mastoid part
Sigmoid sulcus : a deep groove which lodge sigmoid sinus
Two borders of mastoid part  :
·        superior border articulate with inferior border of parietal bone
·        posterior border articulate with inferior border of squamous part of occipital bone

Tympanic part
·        A thin plate of bone lies between the squamous and mastoid parts
·        Anterior surface form non articular part of mandibular fossa
·        Posterior surface forms greater part of external auditory meatus



Processes of temporal bone

                                                                                                          i.        Zygomatic process :
·        medial surface and lower border of zygomatic process give origin of masseter muscle
·        Superior border of zygomatic process attached with temporal fascia
·        Anterior end of zygomatic process articulate with temporal process of zygomatic bone
                                                                                                             ii.        Mastoid process :
External surface of mastoid process is attached with
a)   Insertion of sternocleidomastoid
b)   Insertion of splenius capitis
c)   Insertion of longissimus capitis
Mastoid notch : a deep notch at the medial surface of mastoid process gives origin of posterior belly of digastric muscle
Mastoid foramen near the posterior border of mastoid part of temporal bone : it transmit an emissary vein which connect sigmoid sinus with posterior auricular vein
                                                                                                              iii.        Styloid process
Muscles :
·        origin of styloglossus,  stylohyoid and stylopharyngeus
Ligaments :
·         stylohyoid and stylomandibular ligament
Stylomastoid foramen :
·        It is situated in between mastoid process and styloid process
It transmitted
·        Facial nerve exit
·        Entrance stylomastoid branch of posterior auricular artery 


 


Wednesday, October 26, 2016

Spinal nerve : handout for oral examination

Spinal nerve
How many Spinal nerves present in our body? Number: 31 pairs. 8 cervical spinal nerve, 12 thoracic spinal nerve, 5 lumbar spinal nerve, 5 sacral spinal nerve and 1 coccygeal spinal nerve
How a spinal nerve is formed? :  Spinal nerve form by union of ventral and dorsal nerve roots
Location of spinal nerve: within the intervertebral foramen
Exit : C1-C7 spinal nerves exit ABOVE C1-C7 vertebrae
                         C8 spinal nerve projects below C7 vertebra
                         T1-S5 spinal nerves project BELOW T1-S5 vertebrae
 Branches of a Spinal Nerve:
                        1. dorsal ramus – supply deep muscles and skin of back
                        2. ventral ramus – supply upper and lower extremities, ventrolateral trunk
                        3. meningeal branch - back into the spinal column
                        4. rami communicantes - for autonomic nerve fibers
Type of spinal nerves: they are mixed nerve (both sensory and motor ).
Component: GSA (general somatic afferent –carry impulse from periphery to CNS) and GSE( general somatic efferent- impulse goes from CNS to skeletal muscle)
Plexus of spinal nerve: plexus of spinal nerve is formed by ventral rami of different spinal nerves. There are four spinal nerve plexus  present within the body.
Name of plexus
Formation
Supplied area
Important nerve of the plexus
1. cervical plexus
ventral rami of C1-C4 with some C5
a. muscles/skin of head, neck, some shoulder
b. phrenic nerve - diaphragm muscle (breathing)
phrenic nerve -
2. brachial plexus
ventral rami of C5-C8 and T1
Upper limb and shoulder
Axillary N, musculocutanous
 N,
Radial N, median N, Ulnar N
3. lumbar plexus                       
- ventral rami of L1-L4
           
a. abdominal wall, genitals, part of lower limb      
Femoral N, Obturator N
4. sacral plexus
ventral rami of L4-L5 and S1-S4
a. buttocks, perineum, part of lower limb
b. sciatic nerve
Sacral n- largest nerve of body,
 pudendal n, Sup and inf
Gluteal n
                       
 Dermatomes: area of skin is supplied by single spinal nerve

            

Brief handout on spinal cord : helpful for oral examination

Spinal Cord & Nerves
This is the viscera of spinal cord and spinal meninges
1.         Anatomical points:
              I.         anteriror median fissure lies anteriorly
           II.      cauda equina lies inferiorly

2.         length : 45cm                    wide 2.5 cm
3.          Extension of spinal cord:
   Adult: start at the level of foramen magnum to lower border of 1st lumbar vertebra
   Children: at the level of the foramen magnum to the 3rd lumber vertebra
4.         Terminal part of sub-arachnoid space of the spinal cord : lower border of 2nd sacral vertebra
5.         termination of filum terminalis: at the 1st coccyx
External feature of spinal cord :
i)                    anteriorly : anterior median fissure
ii)                  posteriorly : posterior median septum
iii)                inferiorly : filum terminalis and cauda equine
iv)                two enlargement in cervical and lumbar region
v)                  external surface is covered by spinal meninges : outer meningeal dura mater, middle arachnoid mater and  inner pia mater
vi)                ventral roots, dorsal roots and dorsal root ganglia and spinal nerve
6.         How many enlargement present within the spinal cord and why?
i)                    Cervical enlargement: extend from the foramen magnum to 1st thoracic vertebra. Supply upper limb
ii)                  Lumbar enlargement: extend from thoracic 10th to 12th vertebra. Supply lower limb.
7.         What is spinal segment?
 Ans: Part of the spinal cord to which one pairs of spinal nerve is attached.
8.         How many spinal segments present in the spinal cord? – 31 spinal segments
9.         What is conus medullaris? – cone shaped terminal part of spinal cord
10.     What is filum terminalis ? – it is the prolongation of pia mater which extend from the cunus medullaris to 1st coccyx
11.     What is cauda equine: the lumbar and sacral roots below the termination of spinal cord continue as a leash of nerve roots known as cauda equine.
What is legamentum denticulate: it is the thickening of pia mater situated on either side of spinal cord between nerve roots.
Internal feature of spinal cord:
Inner grey matter contains a central canal. Parts of grey matter, ant horn and pos horn and lateral horn only in thoracic and lumbar region
Grey matter contain motor and internuncial neuron
Parts of outer white matter: 1. anterior (ventral) column
                        2. posterior (dorsal) column
                        3. lateral (intermediate) column
white matter contain ascending and descending tracts:
fasciculi/tracts –they are collection  axon bundles within the CNS. They are two types:                               
      a. ascending tracts – carry sensory impulse to the brain. Spinothalamic tract  
            b. descending tracts – carry motor impulse from brain to the effector organ (skeletal muscle). corticospinal tract
Important tract within the spinal cord :
ASCENDING TRACTS (SENSORY)

anterior (ventral) spinothalamic       
touch and pressure to thalamus
lateral spinothalamic tract                
pain & temperature to thalamus
fasciculus gracilis                                          
touch, 2-pt. discrimination,
fasciculus cuneatus                                        
conscious proprioception,      vibration
posterior spinocerebellar                                 
anterior spinocerebellar
subconscious proprioception

DESCENDING TRACTS (MOTOR)

lateral corticospinal                                         
anterior corticospinal tract
Carry motor output from cortex to motor neuron of ant. Grey horn which stimulate the skeletal muscles
Blood supply: one ant and two posterior spinal arteries. Other branches: ascending cervical a, pos intercostals a, and the lumbar a
Vein: ant and pos spinal vein.
Development : caudal part of neural tube (neuroectodarm)

Tuesday, October 25, 2016

Scapula : Anatomical point with short answer questions

1.   Anatomical points:
-       Glenoid cavity directed upward, forward and laterally
-       Spinous process lies posteriorly
-        Coracoid process directs anteriorly
2.   Name of the three processes and their muscular attachment
3.   Name of the three border and muscular attachment
4.   Name of the three angle and muscular attachment
5.   Attachment of supra and infra glenoid tubercle
6.   Learn NS of following muscles
a)   deltoid and teres minor: axillary nerve
b)   Trapezius : spinal root of accessory nerve
c)   Lattissimus dorsi: thoracodorsal nerve
d)  Serratus ant : long thoracic nerve
e)   Supraspinatus and infraspinatus and subscapsularis
f)    Biceps brachii : musculocutanous nerve
Triceps brachii: radial nerve

Monday, October 24, 2016

Maxilla : easy and short handout for oral examination

Maxilla
1.       Anatomical points:
·         Frontal process of maxilla is directed upward and medially
·         Palatine process is directed medially
·         Alveolar process is directed inferiorly  
2.       Morphological type:  Pneumatic irregular bone
3.       Ossification : intra membranous ossification
4.       Development: neural crest
5.       Parts:
·         four processes :
·         Frontal process of maxilla : it is directed upward and articulate with nasal notch of frontal bone, situated in between nasal bone and lacrimal bone
·         Zygomatic process of maxilla: is directed laterally  and articulate with zygomatic bone
·         Palatine process of maxilla: lies horizontally and directed medially. it is articulated with opposite palatine process of maxilla and formed anterior 2/3 of hard palate
·           Alveolar process of maxilla : it is directed downward , by uniting opposite maxilla it is formed alveolar arch forms upper jaw
·         Body of maxilla:
·         Anterior surface
·         Posterior surface
·         Orbital surface
·         Nasal surface
·         Foramen : infra orbital foramen : transmit infra orbital nerve and vessels
·         Identify following bony impression : maxillary hiatus , ethmoidal  and conchal crest and nasolacrimal groove, maxillary tuberosity ,
·         Show the attachment   of buccinator muscle  
6.       How maxillary hiatus is reduced in size?
·         It is reduced by
·         From above : Uncinate process of ethmoid and Descending process of lacrimal bone
·         From below : maxillary process of inferior nasal concha
·         From behind: maxillary process of perpendicular plate of palatine bone
7.       Dentoalveolar joint: Gomphosis variety of fibrous joint
8.       Related questions :
9.       Maxillary sinus: lining epithelium, functions, in which nasal meatus it is open? 
10.   What is intermaxillary segment? Mention its derivatives