Anatomy
MBBS Anatomy question bank: general anatomy and osteology, regional gross anatomy (upper limb, lower limb, thorax, abdomen, pelvis, head and neck), neuroanatomy, histology and embryology.
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Definition
The neck is divided by the sternocleidomastoid into anterior and posterior triangles, each subdivided, to aid description of its contents.
Anterior Triangle (subdivisions)
- Submental & submandibular (digastric)
- Carotid
- Muscular
Posterior Triangle (subdivisions)
- Occipital
- Supraclavicular (subclavian)
Boundaries
- Anterior triangle: midline, mandible, SCM
- Posterior triangle: SCM, trapezius, clavicle
The SCM splits the neck into an anterior and a posterior triangle. Triangle Key contents Carotid Carotid vessels, IJV, vagus Submandibular Submandibular gland Posterior Accessory nerve, brachial plexus Applied
- Cervical lymph nodes
- Accessory nerve injury (posterior triangle)
🔑KEY POINTS TO REMEMBER- SCM divides neck into anterior + posterior triangles.
- Anterior: submental, submandibular, carotid, muscular.
- Posterior: occipital, supraclavicular (accessory nerve).
📚SOURCES: BD Chaurasia’s Human Anatomy; Gray’s Anatomy; Snell’s Clinical Anatomy.Definition
The face contains the muscles of facial expression (facial nerve) with a rich blood supply; the parotid region houses the parotid gland.
Muscles of Facial Expression
- Supplied by the facial nerve (VII)
- Orbicularis oculi & oris, buccinator, etc.
- Develop from the 2nd pharyngeal arch
Blood Supply
- Facial artery (from the external carotid)
- Rich anastomosis → heals well
- ‘Danger area’ connects to cavernous sinus
Parotid Region
- Parotid gland (largest salivary gland)
- Structures within (superficial→deep): facial nerve, retromandibular vein, external carotid
The facial nerve moves the face and runs through the parotid gland. Structure Detail Muscles Facial nerve (VII) Artery Facial artery Parotid Largest salivary gland Applied
- Bell’s palsy (facial nerve)
- Facial ‘danger area’ (infection spread)
🔑KEY POINTS TO REMEMBER- Muscles of expression = facial nerve (VII); 2nd arch.
- Facial artery supply; danger area → cavernous sinus.
- Parotid contains VII, retromandibular vein, external carotid.
📚SOURCES: BD Chaurasia’s Human Anatomy; Gray’s Anatomy; Snell’s Clinical Anatomy.Definition
The cranial cavity houses the brain, covered by three meninges; the dural venous sinuses drain its venous blood.
Meninges (outer → inner)
- Dura mater — tough outer layer
- Arachnoid mater — middle
- Pia mater — delicate inner
Dural Folds
- Falx cerebri
- Tentorium cerebelli
Venous Sinuses
- Lie between the dural layers
- Superior sagittal, transverse, sigmoid, cavernous
- Drain into the internal jugular vein
Three meninges cover the brain; dural sinuses drain to the internal jugular vein. Space Location Extradural Above the dura Subdural Dura–arachnoid Subarachnoid Arachnoid–pia (CSF) Applied
- Extradural (middle meningeal) vs subdural (bridging veins) haematoma
- Venous sinus thrombosis
🔑KEY POINTS TO REMEMBER- Meninges: dura, arachnoid, pia.
- Dural folds: falx cerebri, tentorium cerebelli.
- Sinuses drain to internal jugular vein.
📚SOURCES: BD Chaurasia’s Human Anatomy; Gray’s Anatomy; Snell’s Clinical Anatomy.Definition
There are 12 pairs of cranial nerves arising from the brain, each passing through a specific skull foramen.
The Twelve Nerves
- I Olfactory, II Optic, III Oculomotor, IV Trochlear
- V Trigeminal, VI Abducens, VII Facial, VIII Vestibulocochlear
- IX Glossopharyngeal, X Vagus, XI Accessory, XII Hypoglossal
Functional Types
- Sensory: I, II, VIII
- Motor: III, IV, VI, XI, XII
- Mixed: V, VII, IX, X
Twelve cranial nerves leave through set foramina to supply the head and neck. Nerve Foramen Optic (II) Optic canal V2 Foramen rotundum V3 Foramen ovale Facial (VII) Stylomastoid foramen Applied
- Cranial nerve palsies localise lesions
- Foramen involvement in fractures / tumours
🔑KEY POINTS TO REMEMBER- 12 cranial nerves; mnemonic On Old Olympus’ Towering Tops…
- Sensory (I, II, VIII), motor (III, IV, VI, XI, XII), mixed (V, VII, IX, X).
- Each exits a specific foramen.
📚SOURCES: BD Chaurasia’s Human Anatomy; Gray’s Anatomy; Snell’s Clinical Anatomy.Definition
The thyroid gland lies in the front of the neck; the great vessels (carotid arteries, jugular veins) run in the carotid sheath.
Thyroid Gland
- Two lobes + isthmus (over 2nd–4th tracheal rings)
- Enclosed in pretracheal fascia → moves with swallowing
- Blood: superior (ext. carotid) & inferior (thyrocervical) thyroid arteries
Carotid Sheath
- Common / internal carotid artery
- Internal jugular vein
- Vagus nerve (between them)
Related Nerves
- Recurrent laryngeal (near inferior thyroid artery)
- External laryngeal (near superior thyroid artery)
The thyroid moves on swallowing; the carotid sheath runs alongside it. Structure Detail Thyroid 2 lobes + isthmus Carotid sheath Carotid artery, IJV, vagus Applied
- Goitre moves with swallowing
- Recurrent laryngeal injury in thyroidectomy
🔑KEY POINTS TO REMEMBER- Thyroid: 2 lobes + isthmus; moves on swallowing.
- Carotid sheath: carotid artery, IJV, vagus.
- Recurrent laryngeal nerve at risk in surgery.
📚SOURCES: BD Chaurasia’s Human Anatomy; Gray’s Anatomy; Snell’s Clinical Anatomy.Definition
The posterior triangle is a region on the side of the neck, bounded by the sternocleidomastoid, trapezius and clavicle.
Boundaries
- Anterior — sternocleidomastoid
- Posterior — trapezius
- Base — clavicle
- Apex — superior nuchal line
Contents
- Accessory nerve (XI)
- Roots / trunks of the brachial plexus
- Subclavian artery (3rd part)
- Cervical lymph nodes
A triangular region carrying the accessory nerve and brachial plexus. Boundary Structure Anterior SCM Posterior Trapezius Base Clavicle Applied
- Accessory nerve injury → trapezius palsy
- Cervical lymph-node biopsy
🔑KEY POINTS TO REMEMBER- Boundaries: SCM, trapezius, clavicle.
- Contents: accessory nerve, brachial plexus, subclavian artery.
- Accessory nerve injury → trapezius palsy.
📚SOURCES: BD Chaurasia’s Human Anatomy; Gray’s Anatomy; Snell’s Clinical Anatomy.Definition
The facial nerve (VII) is a mixed cranial nerve supplying the muscles of facial expression and carrying taste and secretomotor fibres.
Functions
- Motor — muscles of facial expression
- Taste — anterior 2/3 of the tongue (chorda tympani)
- Secretomotor — lacrimal & salivary glands
Course
- Internal acoustic meatus → facial canal
- Exits at the stylomastoid foramen
- Passes through the parotid gland
The facial nerve exits at the stylomastoid foramen and crosses the parotid. Component Function Motor Facial expression Taste Anterior 2/3 tongue Secretomotor Lacrimal, salivary Applied
- Bell’s palsy (LMN — whole side of face)
- UMN lesion spares the forehead
🔑KEY POINTS TO REMEMBER- Facial nerve (VII): motor to expression, taste (ant 2/3), secretomotor.
- Exits stylomastoid foramen; runs in parotid.
- Bell’s palsy (LMN) vs UMN (forehead spared).
📚SOURCES: BD Chaurasia’s Human Anatomy; Gray’s Anatomy; Snell’s Clinical Anatomy.Definition
The parotid gland is the largest salivary gland, situated below and in front of the ear.
Structures Within (superficial → deep)
- Facial nerve (most superficial)
- Retromandibular vein
- External carotid artery (deepest)
Duct
- Parotid (Stensen’s) duct
- Opens opposite the upper 2nd molar
Three structures run through the gland, facial nerve most superficial. Structure Depth Facial nerve Superficial Retromandibular vein Middle External carotid Deepest Applied
- Mumps (parotitis)
- Facial nerve at risk in parotid surgery
🔑KEY POINTS TO REMEMBER- Largest salivary gland; duct opposite upper 2nd molar.
- Contents (superficial→deep): VII, retromandibular vein, external carotid.
- Facial nerve at risk in surgery.
📚SOURCES: BD Chaurasia’s Human Anatomy; Gray’s Anatomy; Snell’s Clinical Anatomy.Definition
The cavernous sinus is a paired dural venous sinus beside the body of the sphenoid, with important nerves and the internal carotid artery passing through it.
Contents
- Internal carotid artery (with sympathetic plexus)
- Abducens nerve (VI) — within the sinus
- In the lateral wall: III, IV, V1, V2
Connections
- Drains the ophthalmic veins (facial ‘danger area’)
- Communicates across the midline
The internal carotid and CN VI run inside; III, IV, V1, V2 lie in the wall. Location Nerves Inside ICA, VI Lateral wall III, IV, V1, V2 Applied
- Cavernous sinus thrombosis (facial infection)
- Multiple cranial nerve palsies
🔑KEY POINTS TO REMEMBER- Inside: internal carotid artery + abducens (VI).
- Lateral wall: III, IV, V1, V2.
- Thrombosis from facial danger area.
📚SOURCES: BD Chaurasia’s Human Anatomy; Gray’s Anatomy; Snell’s Clinical Anatomy.Definition
The thyroid gland is an endocrine gland in the front of the neck, secreting thyroid hormones.
Anatomy
- Two lobes + isthmus
- Over the 2nd–4th tracheal rings
- Enclosed in pretracheal fascia → moves with swallowing
Blood Supply
- Superior thyroid artery (external carotid)
- Inferior thyroid artery (thyrocervical trunk)
The thyroid moves on swallowing and is supplied by two arterial pairs. Feature Detail Parts 2 lobes + isthmus Level 2nd–4th tracheal rings Applied
- Goitre moves on swallowing
- Laryngeal nerve injury in surgery
🔑KEY POINTS TO REMEMBER- Thyroid: 2 lobes + isthmus; moves with swallowing.
- Superior + inferior thyroid arteries.
- Goitre moves on swallowing.
📚SOURCES: BD Chaurasia’s Human Anatomy; Gray’s Anatomy; Snell’s Clinical Anatomy.Definition
The recurrent laryngeal nerve is a branch of the vagus supplying most laryngeal muscles and sensation below the vocal cords.
Course
- Right — hooks under the right subclavian artery
- Left — hooks under the arch of the aorta
- Ascends in the tracheo-oesophageal groove
- Runs near the inferior thyroid artery
Supplies
- All intrinsic laryngeal muscles (except cricothyroid)
- Sensation below the vocal cords
The nerve loops under a great vessel and ascends to the larynx. Side Hooks under Right Subclavian artery Left Arch of aorta Applied
- Injury in thyroidectomy → hoarseness
- Left affected by aortic / lung lesions
🔑KEY POINTS TO REMEMBER- Branch of vagus; supplies all intrinsic laryngeal muscles except cricothyroid.
- Right under subclavian; left under aortic arch.
- Injury → hoarseness.
📚SOURCES: BD Chaurasia’s Human Anatomy; Gray’s Anatomy; Snell’s Clinical Anatomy.Definition
The trigeminal nerve (V) is the largest cranial nerve, the main sensory nerve of the face and motor to the muscles of mastication.
Divisions
- V1 Ophthalmic — sensory (superior orbital fissure)
- V2 Maxillary — sensory (foramen rotundum)
- V3 Mandibular — mixed (foramen ovale)
Functions
- Sensory — face, cornea, mucosa
- Motor (V3) — muscles of mastication
Three divisions carry facial sensation; V3 also moves the jaw. Division Foramen Type V1 Superior orbital fissure Sensory V2 Foramen rotundum Sensory V3 Foramen ovale Mixed Applied
- Trigeminal neuralgia
- Corneal reflex (V1 afferent)
🔑KEY POINTS TO REMEMBER- Trigeminal (V): V1 ophthalmic, V2 maxillary, V3 mandibular.
- Sensory to face; V3 motor to mastication.
- Foramina: SOF, rotundum, ovale.
📚SOURCES: BD Chaurasia’s Human Anatomy; Gray’s Anatomy; Snell’s Clinical Anatomy.