UPPER EXTRIMITIES
All Upper Limb 1st Volume Important Questions Completed:
- Brachial plexus
- Cubital fossa
- Axilla
- Shoulder joint
- Mammary gland
- Muscles of pectoral region
- Deltoid muscle
- Elbow joint
- Carpal bones
- Axillary artery
- Serratus anterior
1)## Brachial Plexus
Definition
- Brachial plexus is a network of nerves supplying the upper limb.
- It is formed by anterior rami of spinal nerves.
Formation
- Formed by anterior rami of C5, C6, C7, C8 and T1.
- May receive contribution from C4 → Prefixed plexus.
- May receive contribution from T2 → Postfixed plexus.
Situation
- Present in lower part of neck and axilla.
- Extends from root of neck to axilla.
Parts of Brachial Plexus
- Roots – 5
- Trunks – 3
- Divisions – 6
- Cords – 3
- Branches – 5 terminal branches
Roots
- C5, C6, C7, C8, T1
Branches from Roots
- Dorsal scapular nerve
- Long thoracic nerve
Trunks
- Upper trunk – formed by C5 and C6
- Middle trunk – continuation of C7
- Lower trunk – formed by C8 and T1
Branches from Trunks
- Suprascapular nerve
- Nerve to subclavius
Divisions
- Each trunk divides into anterior and posterior division.
- Total 3 anterior and 3 posterior divisions.
Cords
- Named according to relation with 2nd part of axillary artery.
Lateral Cord
- Formed by anterior divisions of upper and middle trunks.
Medial Cord
- Formed by anterior division of lower trunk.
Posterior Cord
- Formed by union of all three posterior divisions.
Branches of Cords
From Lateral Cord
- Musculocutaneous nerve
- Lateral root of median nerve
- Lateral pectoral nerve
From Medial Cord
- Ulnar nerve
- Medial root of median nerve
- Medial pectoral nerve
- Medial cutaneous nerve of arm
- Medial cutaneous nerve of forearm
From Posterior Cord
- Axillary nerve
- Radial nerve
- Upper subscapular nerve
- Lower subscapular nerve
- Thoracodorsal nerve
Terminal Branches
- Musculocutaneous nerve
- Axillary nerve
- Radial nerve
- Median nerve
- Ulnar nerve
Applied Anatomy
Erb’s Palsy
- Injury to upper trunk (C5, C6).
- Causes waiter’s tip deformity.
- Arm adducted and medially rotated.
Klumpke’s Palsy
- Injury to lower trunk (C8, T1).
- Causes claw hand.
Saturday Night Palsy
- Radial nerve compression.
-
Cubital Fossa
Definition
- Cubital fossa is a triangular depression present in front of elbow joint.
- It is an important anatomical space.
Situation
- Present on anterior aspect of elbow between arm and forearm.
Boundaries
- Base (Superior) – Imaginary line joining medial and lateral epicondyles of humerus.
- Medial – Pronator teres.
- Lateral – Brachioradialis.
- Apex – Where brachioradialis crosses pronator teres.
Roof
- Skin.
- Superficial fascia – Median cubital vein, cephalic vein, basilic vein, medial and lateral cutaneous nerves of forearm.
- Deep fascia.
- Bicipital aponeurosis.
Floor
- Brachialis (medial).
- Supinator (lateral).
Contents (Medial to lateral – M B T R)
- Median nerve.
- Brachial artery (divides into radial and ulnar arteries).
- Tendon of biceps brachii.
- Radial nerve (divides into superficial and deep branch).
Applied Anatomy
- Site for venepuncture.
- Brachial artery pulse felt here.
- Supracondylar fracture may injure brachial artery.
3)## Axilla
Definition
- Axilla is a pyramidal space between upper limb and thoracic wall.
- It acts as a passage for vessels and nerves to upper limb.
Situation
- Present below shoulder joint.
- Between arm and side of chest.
Shape
- Pyramidal in shape.
- Has apex, base and four walls.
Apex (Cervico-axillary canal)
- Bounded by clavicle (anterior), 1st rib (medial), upper border of scapula (posterior).
- Transmits axillary vessels and brachial plexus.
Base
- Formed by skin, superficial fascia and axillary fascia.
Anterior Wall
- Pectoralis major.
- Pectoralis minor.
- Subclavius.
- Clavipectoral fascia.
Posterior Wall
- Subscapularis (above).
- Latissimus dorsi and teres major (below).
Medial Wall
- Serratus anterior.
- Upper ribs and intercostal muscles.
Lateral Wall
- Intertubercular sulcus of humerus.
Contents
- Axillary artery and its branches.
- Axillary vein and its tributaries.
- Cords and branches of brachial plexus.
- Axillary lymph nodes.
- Fat and loose connective tissue.
Applied Anatomy
- Axillary lymph nodes enlarge in carcinoma breast.
- Injury to long thoracic nerve causes winged scapula.
- Important area during breast surgery.
4)## Shoulder Joint
Definition
- Shoulder joint is a synovial ball and socket joint.
- It is the most movable joint of the body.
Articular Surfaces
- Head of humerus.
- Glenoid cavity of scapula.
- Glenoid cavity is deepened by glenoid labrum.
Type
- Synovial joint.
- Multiaxial joint.
Capsule
- Thin and loose.
- Attached to margin of glenoid cavity and anatomical neck of humerus.
Ligaments
- Capsular ligament.
- Glenohumeral ligaments (superior, middle, inferior).
- Coracohumeral ligament.
- Transverse humeral ligament.
- Coracoacromial ligament (forms arch above joint).
Relations
- Above – Supraspinatus and coracoacromial arch.
- Below – Long head of triceps.
- Anterior – Subscapularis.
- Posterior – Infraspinatus and teres minor.
Movements
- Flexion.
- Extension.
- Abduction.
- Adduction.
- Medial rotation.
- Lateral rotation.
- Circumduction.
Muscles Producing Abduction
- 0–15° – Supraspinatus.
- 15–90° – Deltoid.
- Above 90° – Trapezius and serratus anterior (rotation of scapula).
Blood Supply
- Anterior and posterior circumflex humeral arteries.
- Suprascapular artery.
Nerve Supply
- Axillary nerve.
- Suprascapular nerve.
- Lateral pectoral nerve.
Applied Anatomy
- Dislocation common (inferior dislocation).
- Axillary nerve may be injured.
- Frozen shoulder (adhesive capsulitis).
-
Mammary Gland
Definition
- Mammary gland is a modified sweat gland present in superficial fascia of chest wall.
- It is well developed in females.
Situation and Extent
- Extends from 2nd to 6th rib.
- From lateral border of sternum to mid-axillary line.
- Axillary tail of Spence extends into axilla.
Structure
- Composed of 15–20 lobes.
- Each lobe has lobules.
- Each lobe drained by lactiferous duct.
- Lactiferous ducts open on nipple.
- Lactiferous sinus present near nipple.
Nipple
- Present at level of 4th intercostal space.
- Contains openings of lactiferous ducts.
Areola
- Pigmented area around nipple.
- Contains sebaceous glands (Montgomery glands).
Supports
- Suspensory ligaments of Cooper.
- Skin.
- Fibrous septa.
Blood Supply
- Internal thoracic artery.
- Lateral thoracic artery.
- Intercostal arteries.
Venous Drainage
- Axillary vein.
- Internal thoracic vein.
Lymphatic Drainage
- Mainly to axillary lymph nodes.
- Some to parasternal nodes.
- Few to opposite breast.
Nerve Supply
- 4th, 5th and 6th intercostal nerves.
Applied Anatomy
- Carcinoma breast common in upper outer quadrant.
- Spread through lymphatics to axillary nodes.
- Retraction of nipple due to fibrosis.
- Peau d’orange appearance due to lymph obstruction.
-
Muscles of Pectoral Region
Classification
- Superficial group.
- Deep group.
Superficial Muscles
- Pectoralis major.
- Pectoralis minor.
Deep Muscles
- Subclavius.
- Serratus anterior.
Pectoralis Major
Origin
- Medial half of clavicle.
- Sternum.
- Upper 6 costal cartilages.
- Aponeurosis of external oblique muscle.
Insertion
- Lateral lip of intertubercular sulcus of humerus.
Nerve Supply
- Medial and lateral pectoral nerves.
Action
- Adduction of arm.
- Medial rotation of arm.
- Flexion of arm.
Pectoralis Minor
Origin
- 3rd, 4th and 5th ribs near costal cartilages.
Insertion
- Coracoid process of scapula.
Nerve Supply
- Medial pectoral nerve.
Action
- Draws scapula forward and downward.
- Stabilizes scapula.
Subclavius
Origin
- 1st rib at costochondral junction.
Insertion
- Inferior surface of clavicle.
Nerve Supply
- Nerve to subclavius.
Action
- Depresses clavicle.
- Stabilizes sternoclavicular joint.
Serratus Anterior
Origin
- Upper 8 ribs.
Insertion
- Medial border of scapula.
Nerve Supply
- Long thoracic nerve.
Action
- Protraction of scapula.
- Upward rotation of scapula.
- Holds scapula against chest wall.
Applied Anatomy
- Injury to long thoracic nerve causes winged scapula.
-
Deltoid Muscle
Origin
- Lateral one third of clavicle.
- Acromion process.
- Spine of scapula.
Insertion
- Deltoid tuberosity of humerus.
Nerve Supply
- Axillary nerve (C5, C6).
Action
- Main abductor of arm from 15° to 90°.
- Anterior fibers – Flexion and medial rotation.
- Posterior fibers – Extension and lateral rotation.
Applied Anatomy
- Intramuscular injection given in deltoid region.
- Injury to axillary nerve causes inability to abduct arm.
-
Elbow Joint
Definition
- Elbow joint is a synovial hinge joint.
Articulations
- Humerus with ulna.
- Humerus with head of radius.
Type
- Synovial hinge joint.
Ligaments
- Capsular ligament.
- Ulnar collateral ligament.
- Radial collateral ligament.
- Annular ligament.
Movements
- Flexion.
- Extension.
Muscles Producing Movements
- Flexion – Biceps brachii, brachialis, brachioradialis.
- Extension – Triceps brachii, anconeus.
Blood Supply
- Branches from brachial artery.
Nerve Supply
- Musculocutaneous nerve.
- Radial nerve.
- Median nerve.
- Ulnar nerve.
Applied Anatomy
- Dislocation common in children.
- Tennis elbow (lateral epicondylitis).
-
Serratus Anterior (Boxer’s Muscle)
Definition
- Serratus anterior is a muscle of pectoral region.
- Called boxer’s muscle because it helps in punching action.
Origin
- Upper 8 ribs on lateral side.
Insertion
- Medial border of scapula on costal surface.
Nerve Supply
- Long thoracic nerve (C5, C6, C7).
Action
- Protraction of scapula.
- Upward rotation of scapula.
- Holds scapula against chest wall.
Applied Anatomy
- Injury to long thoracic nerve causes winged scapula.
- Patient cannot raise arm above head properly.
-
Axillary Artery and its Branches (Short Revision Format for Exam)
Extent
- Outer border of 1st rib to lower border of teres major.
- Continuation of subclavian artery.
- Continues as brachial artery.
Divided Into 3 Parts by Pectoralis Minor
First Part
- Superior thoracic artery.
Second Part
- Thoracoacromial artery.
- Lateral thoracic artery.
Third Part
- Subscapular artery.
- Anterior circumflex humeral artery.
- Posterior circumflex humeral artery.
Applied
- Compressed to control bleeding.
- Injured in shoulder dislocation.
Posterior Triangle of Neck ⭐
II. HEAD AND NECK (IIIrd Volume)
- Posterior triangle ⭐ (V. Important)
- Anterior triangle ⭐ (V. Important)
- Tongue ⭐ (V. Important)
- Lacrimal apparatus ⭐ (V. Important)
- Scalp (layers)
- Black eye
- Little's area ⭐
- Nasal Septum
- Parotid gland
- Lateral wall of nose
- External carotid artery
- Carotid triangle
- Mandible
- Blood supply and nerve supply of face
- Masseter muscle
- Sternocleidomastoid muscle ⭐ (Important)
- Extraocular muscle
- Eyeball with internal structure
- Thyroid gland
- Circle of Willis
Posterior Triangle
Definition
- Posterior triangle is a triangular space on the side of neck.
Boundaries
- Anterior – Posterior border of sternocleidomastoid.
- Posterior – Anterior border of trapezius.
- Base – Middle one third of clavicle.
- Apex – Meeting point of SCM and trapezius at superior nuchal line.
Roof
- Skin.
- Superficial fascia.
- Platysma.
- Investing layer of deep cervical fascia.
Floor
- Splenius capitis.
- Levator scapulae.
- Scalenus medius.
Subdivision
-
Divided by inferior belly of omohyoid into:
- Occipital triangle.
- Supraclavicular triangle.
Contents
- Spinal accessory nerve.
- Cutaneous branches of cervical plexus.
- Roots of brachial plexus.
- Subclavian artery (3rd part).
- External jugular vein.
Applied Anatomy
- Injury to spinal accessory nerve causes drooping of shoulder.
- Lymph node enlargement common.
- Important for central venous access.
Anterior Triangle of Neck ⭐
Definition
- Anterior triangle is triangular area in front of neck.
Boundaries
- Anterior – Midline of neck.
- Posterior – Anterior border of sternocleidomastoid.
- Superior – Lower border of mandible.
- Apex – Jugular notch.
Roof
- Skin.
- Superficial fascia.
- Platysma.
- Investing layer of deep cervical fascia.
Floor
- Pharynx.
- Larynx.
- Thyroid gland.
Subdivision
- Submental triangle.
- Submandibular triangle.
- Carotid triangle.
- Muscular triangle.
Contents
- Common carotid artery.
- Internal jugular vein.
- Vagus nerve.
- Thyroid gland.
- Larynx and pharynx.
Applied Anatomy
- Carotid pulse felt in this region.
- Tracheostomy done in anterior triangle.
- Thyroid swelling visible here.
Tongue ⭐
Definition
- Tongue is a muscular organ situated in floor of mouth.
- It is organ of taste and speech.
Parts
- Apex.
- Body (anterior 2/3).
- Root (posterior 1/3).
Sulcus
- Sulcus terminalis divides anterior 2/3 and posterior 1/3.
- Foramen caecum present at its apex.
Papillae (Anterior 2/3)
- Filiform – most numerous, no taste.
- Fungiform – red, taste buds present.
- Circumvallate – 8–12, arranged in V shape.
- Foliate – rudimentary in humans.
Muscles
Intrinsic muscles
- Superior longitudinal.
- Inferior longitudinal.
- Transverse.
- Vertical. Function – Change shape of tongue.
Extrinsic muscles
- Genioglossus.
- Hyoglossus.
- Styloglossus.
- Palatoglossus. Function – Change position of tongue.
Nerve Supply
Motor
- All muscles by hypoglossal nerve.
- Palatoglossus by vagus nerve.
General sensation
- Anterior 2/3 – Lingual nerve.
- Posterior 1/3 – Glossopharyngeal nerve.
Taste
- Anterior 2/3 – Chorda tympani.
- Posterior 1/3 – Glossopharyngeal nerve.
Blood Supply
- Lingual artery.
Applied Anatomy
- Deviation of tongue in hypoglossal nerve palsy.
- Carcinoma common in lateral border.
Lacrimal Apparatus ⭐
Definition
- Lacrimal apparatus produces and drains tears.
Parts
- Lacrimal gland.
- Lacrimal canaliculi.
- Lacrimal sac.
- Nasolacrimal duct.
Lacrimal Gland
- Present in upper lateral part of orbit.
- Secretes tears.
Drainage of Tears
- Tears pass to conjunctival sac.
- Enter lacrimal puncta.
- Through canaliculi to lacrimal sac.
- From sac to nasolacrimal duct.
- Opens into inferior meatus of nose.
Blood Supply
- Lacrimal artery.
Nerve Supply
- Secretomotor from facial nerve (via greater petrosal nerve).
Applied Anatomy
- Blockage causes watering of eye.
- Infection of sac called dacryocystitis.
Scalp
Definition
- Scalp is soft tissue covering vault of skull.
Extent
- Anterior – Supraorbital margin.
- Posterior – Superior nuchal line.
- Lateral – Zygomatic arch.
Layers (S C A L P)
- Skin.
- Connective tissue (dense).
- Aponeurosis (epicranial).
- Loose areolar tissue.
- Pericranium.
Important Points
- Connective tissue layer is highly vascular.
- Loose areolar tissue is dangerous area of scalp.
Applied Anatomy
- Profuse bleeding in scalp injury.
- Spread of infection through emissary veins.
Black Eye
Definition
- Collection of blood in eyelids due to injury.
Cause
- Injury to forehead or scalp.
- Blood collects in loose areolar tissue.
Reason
- Gravity causes blood to collect in eyelids.
Little’s Area ⭐
Definition
- Little’s area is vascular area in anterior nasal septum.
Arterial Supply (Kiesselbach plexus)
- Anterior ethmoidal artery.
- Superior labial artery.
- Greater palatine artery.
- Septal branch of superior labial.
Applied
- Most common site of epistaxis.
Nasal Septum
Definition
- Partition dividing nasal cavity into two halves.
Parts
- Cartilage (anterior).
- Perpendicular plate of ethmoid.
- Vomer.
Blood Supply
- From Kiesselbach plexus.
Applied
- Deviated nasal septum (DNS).
- Epistaxis common anteriorly.
Parotid Gland
Definition
- Largest salivary gland.
Situation
- Below and in front of ear.
Structures Passing Through
- Facial nerve.
- External carotid artery.
- Retromandibular vein.
Duct
- Stensen’s duct opens opposite upper 2nd molar tooth.
Nerve Supply
- Parasympathetic from glossopharyngeal nerve.
Applied
- Parotitis (mumps).
- Facial nerve injury during surgery.
Lateral Wall of Nose
Features
- Three conchae – Superior, Middle, Inferior.
- Three meatus – Superior, Middle, Inferior.
Openings
- Maxillary sinus opens in middle meatus.
- Nasolacrimal duct opens in inferior meatus.
Applied
- Sinusitis common in maxillary sinus.
External Carotid Artery
Origin
- From common carotid at level of upper border of thyroid cartilage.
Branches (8 branches)
- Superior thyroid.
- Ascending pharyngeal.
- Lingual.
- Facial.
- Occipital.
- Posterior auricular.
- Maxillary.
- Superficial temporal.
Applied
- Pulse felt in carotid triangle.
Carotid Triangle
Boundaries
- Superior – Posterior belly of digastric.
- Inferior – Superior belly of omohyoid.
- Posterior – Anterior border of SCM.
Contents
- Common carotid artery.
- Internal jugular vein.
- Vagus nerve.
- Hypoglossal nerve.
Applied
- Carotid pulse felt here.
Mandible
Definition
- Largest and strongest facial bone.
Parts
- Body.
- Ramus.
- Angle.
Features
- Mental foramen.
- Mandibular foramen.
- Condylar process.
Applied
- Fracture common at angle.
Blood Supply of Face
Arterial
- Facial artery (main).
- Transverse facial artery.
Venous
- Facial vein drains into internal jugular vein.
Nerve Supply of Face
Motor
- Facial nerve.
Sensory
- Trigeminal nerve branches.
Masseter Muscle
Origin
- Zygomatic arch.
Insertion
- Lateral surface of ramus of mandible.
Nerve Supply
- Mandibular nerve (V3).
Action
- Elevation of mandible.
Sternocleidomastoid Muscle ⭐
Origin
- Manubrium sterni.
- Medial clavicle.
Insertion
- Mastoid process.
Nerve Supply
- Spinal accessory nerve.
Action
- Flexion of neck.
- Rotation of head to opposite side.
Applied
- Torticollis.
Extraocular Muscles
Muscles
- 4 Recti – Superior, Inferior, Medial, Lateral.
- 2 Oblique – Superior, Inferior.
Nerve Supply
-
All by oculomotor nerve except:
- Lateral rectus – Abducent.
- Superior oblique – Trochlear.
Applied
- Squint due to nerve palsy.
Eyeball
Coats
- Outer fibrous – Sclera, Cornea.
- Middle vascular – Choroid, Ciliary body, Iris.
- Inner nervous – Retina.
Chambers
- Anterior chamber.
- Posterior chamber.
Applied
- Cataract – lens opacity.
- Glaucoma – increased intraocular pressure.
Thyroid Gland
Situation
- In front of trachea.
Parts
- Two lobes.
- Isthmus.
Blood Supply
- Superior thyroid artery.
- Inferior thyroid artery.
Applied
- Goitre.
- Thyroidectomy complications.
Circle of Willis
Definition
- Arterial circle at base of brain.
Formed By
- Anterior cerebral arteries.
- Anterior communicating artery.
- Internal carotid arteries.
- Posterior cerebral arteries.
- Posterior communicating arteries.
Function
- Maintains collateral circulation of brain.
Applied
- Berry aneurysm common at circle.
III. NEUROANATOMY
- Internal capsule ⭐⭐ (V. Important)
- Lateral & IIIrd ventricle (V. Important)
- Corpus callosum (V. Important)
- Fourth ventricle ⭐ (V. Important)
- CSF (Cerebrospinal Fluid) ⭐
- Brainstem
- Cranial Nerves (Important): III, V, VII, IX, X
- Blood supply of Brain
- Basal ganglia
- Circle of Willis
- Brown-Séquard Syndrome
- Cisterna
1) Internal Capsule ⭐⭐
Definition
• Projection fibers cha compact band jo cerebral cortex la brainstem ani spinal cord shi connect karto
Situation
• Medially – Caudate nucleus ani thalamus • Laterally – Lentiform nucleus
Parts
• Anterior limb • Genu • Posterior limb • Retrolentiform part • Sublentiform part
Fibers
Anterior limb
• Frontopontine • Anterior thalamic radiation
Genu
• Corticonuclear (corticobulbar) fibers
Posterior limb
• Corticospinal tract • Sensory fibers (thalamocortical) • Optic radiation (retrolentiform) • Auditory radiation (sublentiform)
Blood Supply
• Lenticulostriate branches of middle cerebral artery • Anterior choroidal artery
Applied
• Most common site of stroke • Contralateral hemiplegia • Pure motor paralysis
2) Lateral Ventricle ⭐⭐
Parts
• Anterior horn • Body • Posterior horn • Inferior horn
Boundaries (Body)
• Roof – Corpus callosum • Floor – Thalamus
Communication
• Interventricular foramen (Monro) → Third ventricle
CSF Production
• Choroid plexus
Applied
• Hydrocephalus
3) Third Ventricle ⭐⭐
Definition
• Midline cavity of diencephalon
Boundaries
• Lateral – Thalamus & hypothalamus • Roof – Tela choroidea • Floor – Hypothalamus
Communication
• From lateral ventricle → Foramen of Monro • To fourth ventricle → Cerebral aqueduct
4) Corpus Callosum ⭐⭐
Definition
• Largest commissural fiber bundle
Parts
• Rostrum • Genu • Body • Splenium
Function
• Connects two cerebral hemispheres
Applied
• Split brain surgery • Agenesis → developmental delay
5) Fourth Ventricle ⭐
Situation
• Between pons & medulla anteriorly • Cerebellum posteriorly
Boundaries
• Floor – Rhomboid fossa • Roof – Cerebellum
Openings
• One median aperture (Magendie) • Two lateral apertures (Luschka)
Communication
• Cerebral aqueduct → Fourth ventricle • Fourth → Subarachnoid space
6) CSF (Cerebrospinal Fluid) ⭐
Formation
• Choroid plexus
Quantity
• ~150 ml
Circulation
Lateral ventricle → 3rd → Aqueduct → 4th → Subarachnoid space → Venous sinuses
Absorption
• Arachnoid villi
Functions
• Shock absorber • Nutrition • Waste removal
Applied
• Hydrocephalus • Lumbar puncture L3-L4
7) Brainstem
Parts
• Midbrain • Pons • Medulla oblongata
Functions
• Vital centers (respiration, cardiac) • Cranial nerve nuclei
Applied
• Brainstem lesion → coma • Decerebrate rigidity
8) Cranial Nerves (III, V, VII, IX, X)
III – Oculomotor
• Motor to most extraocular muscles • Parasympathetic to pupil • Lesion → ptosis, dilated pupil
V – Trigeminal
• Sensory to face • Motor to muscles of mastication • Lesion → loss of corneal reflex
VII – Facial
• Motor to facial muscles • Taste anterior 2/3 tongue • Bell’s palsy
IX – Glossopharyngeal
• Taste posterior 1/3 • Parotid gland secretomotor
X – Vagus
• Motor to larynx • Parasympathetic to thoracic & abdominal organs • Lesion → hoarseness
9) Blood Supply of Brain
Arteries
• Internal carotid • Vertebral arteries
Circle formation
• Anterior cerebral • Middle cerebral • Posterior cerebral
Applied
• Stroke common in middle cerebral artery
10) Basal Ganglia
Components
• Caudate nucleus • Putamen • Globus pallidus • Subthalamic nucleus • Substantia nigra
Function
• Control of voluntary movement
Applied
• Parkinson disease • Chorea
11) Circle of Willis
Formation
• Anterior cerebral arteries • Anterior communicating • Internal carotid • Posterior communicating • Posterior cerebral
Function
• Collateral circulation
Applied
• Berry aneurysm
12) Brown-Séquard Syndrome
Cause
• Hemisection of spinal cord
Features
• Ipsilateral paralysis • Ipsilateral loss of proprioception • Contralateral loss of pain & temperature
13) Cisterna
Definition
• Subarachnoid space chi widened areas
Types
• Cisterna magna • Suprasellar cistern • Interpeduncular cistern • Pontine cistern
Importance
• CSF accumulation • Subarachnoid hemorrhage
IV. EMBRYOLOGY
- Placenta (structure and function) ⭐
- Development of heart ⭐
- Development of Kidney
- Germ layers and their derivatives ⭐
- Notochord ⭐
- Pharyngeal arches ⭐
- Fetal circulation
- Implantation
- Hypospadias and epispadias
1) Placenta ⭐
Definition
• Temporary fetomaternal organ for exchange between mother & fetus
Structure
Parts
• Fetal part – Chorion frondosum • Maternal part – Decidua basalis
Surface
• Fetal surface – Smooth, covered by amnion • Maternal surface – Rough, 15–20 cotyledons
Placental Barrier
• Syncytiotrophoblast • Cytotrophoblast • Connective tissue • Fetal capillary endothelium
Functions
Exchange
• Oxygen, CO₂ • Nutrients • Waste removal
Endocrine
• hCG • Progesterone • Estrogen • hPL
Protection
• IgG transfer • Partial barrier to infection
Applied
• Placenta previa • Abruptio placenta • Placental insufficiency
2) Development of Heart ⭐
Origin
• Mesoderm (cardiogenic area)
Timeline
3rd Week
• Two endocardial tubes form
Fusion
• Forms primitive heart tube
Parts of Heart Tube
• Truncus arteriosus • Bulbus cordis • Primitive ventricle • Primitive atrium • Sinus venosus
Septation
• Atrial septum (septum primum & secundum) • Ventricular septum (muscular + membranous)
Important Processes
• Cardiac looping • Neural crest role in outflow tract
Applied
• ASD • VSD • Tetralogy of Fallot
3) Development of Kidney
Three Stages
• Pronephros – rudimentary • Mesonephros – temporary • Metanephros – permanent kidney
Origin
• Intermediate mesoderm
Components
• Ureteric bud → ureter, pelvis, calyces • Metanephric blastema → nephrons
Applied
• Horseshoe kidney • Ectopic kidney • Polycystic kidney
4) Germ Layers & Derivatives ⭐
Ectoderm
• Epidermis • CNS & PNS • Enamel of teeth
Mesoderm
• Muscle • Bone • Heart • Kidney • Blood vessels
Endoderm
• GIT epithelium • Respiratory tract • Liver • Pancreas
Applied
• Teratoma contains all 3 germ layers
5) Notochord ⭐
Definition
• Midline mesodermal rod
Functions
• Induces neural tube formation • Forms nucleus pulposus
Fate
• Degenerates except nucleus pulposus
Applied
• Chordoma tumor
6) Pharyngeal Arches ⭐
Number
• 1 to 6 (5th regresses)
Each Arch Contains
• Cartilage • Muscle • Artery • Nerve
1st Arch
• Mandible • Muscles of mastication • Nerve – Trigeminal
2nd Arch
• Stapes • Facial expression • Nerve – Facial
3rd Arch
• Stylopharyngeus • Nerve – Glossopharyngeal
4th & 6th
• Laryngeal muscles • Nerve – Vagus
Applied
• Branchial cyst
7) Fetal Circulation
Important Shunts
• Ductus venosus • Foramen ovale • Ductus arteriosus
Pathway
Placenta → Umbilical vein → Ductus venosus → IVC → RA → LA (via foramen ovale) → LV → Aorta
After Birth
• Foramen ovale → Fossa ovalis • Ductus arteriosus → Ligamentum arteriosum
Applied
• Patent ductus arteriosus
8) Implantation
Time
• 6–7 days after fertilization
Site
• Posterior wall of uterus
Process
• Trophoblast differentiates into: • Cytotrophoblast • Syncytiotrophoblast
• Embeds into endometrium
Applied
• Ectopic pregnancy
9) Hypospadias & Epispadias
Hypospadias
Definition
• Urethral opening on ventral surface of penis
Cause
• Failure of urethral fold fusion
Types
• Glanular • Penile • Perineal
Features
• Ventral curvature (chordee) • Abnormal urinary stream
Epispadias
Definition
• Urethral opening on dorsal surface
Cause
• Abnormal genital tubercle positioning
Association
• Often with bladder exstrophy
V. GENERAL ANATOMY
- Type of joints ⭐
- Synovial joint ⭐
- Type of epithelium
- Tendon and ligament
- Bursa
- Epiphysis ⭐
- Sesamoid bone
- Aponeurosis ⭐
- Type of collagen fibers
- Classification of connective tissue with examples
- Type of epiphysis
- Pennate muscles
- Elastic cartilage
1) Types of Joints ⭐
Definition
Joint is junction between two or more bones.
Structural Classification
A) Fibrous Joints
• Bones joined by fibrous tissue • No joint cavity • Immovable (Synarthrosis)
Types • Suture – Between skull bones • Syndesmosis – Inferior tibiofibular joint • Gomphosis – Tooth in socket
B) Cartilaginous Joints
1. Primary (Synchondrosis) • Hyaline cartilage • Temporary • Example – Epiphyseal plate
2. Secondary (Symphysis) • Fibrocartilage • Slight movement • Example – Pubic symphysis
C) Synovial Joints
• Joint cavity present • Freely movable (Diarthrosis) • Most common type
2) Synovial Joint ⭐
Definition
Joint with cavity containing synovial fluid allowing free movement.
Essential Features
• Articular cartilage (Hyaline) • Joint cavity • Synovial membrane • Fibrous capsule • Synovial fluid
Accessory Structures
• Ligaments • Menisci / Articular disc • Bursa
Types with Examples
• Plane – Intercarpal • Hinge – Elbow • Pivot – Atlantoaxial • Condyloid – Wrist • Saddle – First carpometacarpal • Ball and socket – Shoulder
Movements
• Flexion and extension • Abduction and adduction • Rotation • Circumduction
Applied
• Arthritis • Dislocation
3) Types of Epithelium
Definition
Epithelium is avascular lining tissue covering surfaces and cavities.
A) Simple Epithelium
• Simple squamous – Alveoli • Simple cuboidal – Kidney tubules • Simple columnar – Intestine
B) Pseudostratified Epithelium
• Respiratory tract
C) Stratified Epithelium
• Stratified squamous keratinized – Skin • Stratified squamous non-keratinized – Esophagus • Transitional – Urinary bladder
Functions
• Protection • Secretion • Absorption
4) Tendon and Ligament
Tendon
• Connects muscle to bone • Dense regular connective tissue • Type I collagen • Less elastic • Example – Achilles tendon
Ligament
• Connects bone to bone • Slightly elastic • Stabilizes joint • Example – Cruciate ligament
Difference
• Tendon – Movement • Ligament – Stability
5) Bursa
Definition
Small synovial fluid filled sac.
Location
• Between tendon and bone • Between skin and bone
Function
• Reduces friction • Facilitates smooth movement
Example
• Prepatellar bursa
Applied
• Bursitis
6) Epiphysis ⭐
Definition
Expanded end of long bone.
Functions
• Participates in joint formation • Responsible for growth in length
Structure
• Spongy bone • Covered by articular cartilage
Blood Supply
• Epiphyseal arteries
Applied
• Epiphyseal injury affects growth
7) Types of Epiphysis
1. Pressure Epiphysis
• Transmits weight • Example – Head of femur
2. Traction Epiphysis
• Muscle attachment • Example – Greater trochanter
3. Atavistic Epiphysis
• Phylogenetically separate bone • Example – Coracoid process
4. Aberrant Epiphysis
• Occasional • Example – Base of first metacarpal
8) Sesamoid Bone
Definition
Bone embedded in tendon.
Functions
• Reduces friction • Changes direction of pull • Increases mechanical advantage
Example
• Patella
Applied
• Sesamoiditis
9) Aponeurosis ⭐
Definition
Broad, flat sheet-like tendon.
Structure
• Dense fibrous connective tissue • Type I collagen
Examples
• Palmar aponeurosis • External oblique aponeurosis
Functions
• Muscle attachment • Protects deeper structures
Applied
• Dupuytren’s contracture
10) Types of Collagen Fibers
Type I
• Bone • Tendon • Ligament
Type II
• Cartilage
Type III
• Reticular fibers
Type IV
• Basement membrane
Clinical Correlation
• Type I defect – Osteogenesis imperfecta • Type II defect – Cartilage disorders
11) Classification of Connective Tissue
A) Embryonic
• Mesenchyme • Mucous connective tissue
B) Adult
1. Loose Connective Tissue
• Areolar • Adipose
2. Dense Connective Tissue
• Dense regular – Tendon • Dense irregular – Dermis
3. Specialized Connective Tissue
• Cartilage • Bone • Blood
Functions
• Support • Protection • Storage • Transport
12) Pennate Muscles
Definition
Muscle fibers arranged obliquely to tendon.
Types
• Unipennate – One side (Extensor digitorum longus) • Bipennate – Two sides (Rectus femoris) • Multipennate – Many fascicles (Deltoid)
Advantage
• Greater power • Shorter range of movement
13) Elastic Cartilage
Definition
Cartilage containing elastic fibers.
Structure
• Chondrocytes in lacunae • Elastic fibers in matrix • Perichondrium present
Location
• Pinna • Epiglottis • Auditory tube
Function
• Maintains shape with flexibility
Difference from Hyaline Cartilage
• More flexible • Yellowish in color