Anatomy & Branchial Arches Flashcards

Question

PTERYGOPALATINE Ganglion   Branches

Answer 1

**Branches of the Pterygopalatine Ganglion:** **1. Nasopalatine N - SP foramen** - Septum + incisive gum of hard palate (descends down incisive foramen) **2. Lat Post Sup Nasal Ns - SP foramen** - Postersup quadrant of LNW **3. Greater Palatine N - GP foramen/canal** (junction of maxilla and palatine bone) - Mucosa of hard palate - Nasal branches - posteroinf quadrant LNW + med wall max sinus 4. **Lesser Palatine Ns** - Lesser palatine foramina (behind GPN) - Soft palate and tonsil mucosa 5. **Pharyngeal N - Palatovaginal canal** - Nasopharynx mucous membrane 6. **Orbital branches - IOF** - Orbital periosteum, orbitalis muscle - Sphenoid/ethmoid sinuses

Answer 2

Mass of skeletal muscle with midline fibrous septum covered by mucous membrane - Keratinising stratified squamous epithelium Parts of the tongue: - Dorsum, tip, ventral surface, base (BOT is oropharynx not oral cavity) **Papillae**: 1. Filiform- velvety appearance 2. Fungiform- discrete pink pinheads (bears the taste buds) 3. Circumvallate- 12, form a V in front of sulcus terminalis (marks division of oral cavity and oropharynx **Folds**: Median glossoepiglottic, lateral glossoepiglottic **Muscles**: 1. Intrinsic x4 shape no bony attachments - longitudinal (sup/inf), vertical, transverse 2. Extrinsic x 4 position - Genioglossus - bulk of tongue. Genial tub to mucous memb + hyoid (i.e. geniohyoglossus) - Hyoglossus - length of greater horn/body of hyoid (free ant + post borders) - Styloglossus - low/ant styloid to interdig with hyoglossus - Palatoglossus - undersurface of palate to interdig with styloglossus

Answer 3

Mass of skeletal muscle with midline fibrous septum covered by mucous membrane - Keratinising stratified squamous epithelium Parts of the tongue: - Dorsum, tip, ventral surface, base (BOT is oropharynx not oral cavity)

Answer 4

**Papillae**: 1. Filiform- velvety appearance 2. Fungiform- discrete pink pinheads (bears the taste buds) 3. Circumvallate- 12, form a V in front of sulcus terminalis (marks division of oral cavity and oropharynx

Answer 5

**Folds**: Median glossoepiglottic, lateral glossoepiglottic **Muscles**: 1. Intrinsic x4 shape no bony attachments - longitudinal (sup/inf), vertical, transverse 2. Extrinsic x 4 position - Genioglossus - bulk of tongue. Genial tub to mucous memb + hyoid (i.e. geniohyoglossus) - Hyoglossus - length of greater horn/body of hyoid (free ant + post borders) - Styloglossus - low/ant styloid to interdig with hyoglossus - Palatoglossus - undersurface of palate to interdig with styloglossus

Answer 6

**Blood supply:** Lingual A. - above greater horn of hyoid - Dorsal lingual branches to posterior tongue Asc Pharyngeal, tonsil branches of Facial- small contributions Lingual v. - tributaries run with Lingual a. Deep Lingual v. (visible in FOM) + sublingual v. --- vena comitants of XII **Nerve supply:** Anterior 2/3 - sensation- Lingual N., Taste- chorda tympani Posterior 1/3 - IX (sensation + taste), X (internal branch of SLN- ant valleculla) Motor - all CN XII except palatoglossus (pharyngeal plexus) \*\* taste travels to nucleus tractus solitarius

Answer 7

**Embryology**: Appears during Week 4 - as the tuberculum impar. 2 lateral swellings appear either side of the tuberculum —\> fuse to form the midline fibrous septum (Arch I) Base of tongue is formed from the hypobranchial eminence (Arch III). This joins with the lateral swellings at the sulcus terminalis to form the tongue Tongue muscles derived from suboccipital myotomes (ie not supplied by branchial arch nerves - XII instead) Migrate forward into the sac of mucous membrane derived from arches I, III, IV

Answer 8

BOS to C6 (12cm), open anteriorly Divided to Naso-, Oro-, Hypo- - Free edge of soft palate - Tip of epiglottis (level of hyoid) **Layers of Pharynx** 1. Mucosa 2. Submucosa- thickened superiorly as the Pharyngobasilar Fascia 3. Muscle - 3 constrictors, 3 other 4. Buccopharyngeal Fascia (thickening of the epimysium of the muscle layer)

Answer 9

**Attachments of the Pharyngobasilar Fascia** - Pharyngeal tubercle (occipital bone) - Laterally across longus colli, anterior to carotid canal/foramen lacerum, drapes off ET - Medial Pterygoid plate down to hamulus

Answer 10

Constrictor muscles insert to the pharyngeal raphe (midline posteriorly) and fan out from there to the following attachments: - Superior - Hamulus, pterygomandibular raphe, mandible - Middle - Angle between Stylohyoid (at lesser horn) and hyoid bone - Inferior - 2 parts: - Thyropharyngeus - Oblique line of thyroid and fibres spanning CT muscle - Cricopharyngeus - Cricoid cartilage (full ring of muscle) - Killian's dehiscence between TP and CP

Answer 11

**Structures enter pharynx from outside:** Above SC - Eustachian tube Between SC/MC - IX, Lingual N, Stylopharyngeus Between MC/IC - IBSLN, SL vessels (thyrohyoid membrane) Under IC - RLN

Answer 12

**Innervation** - All pharyngeal plexus (IX, X, SNS fibres) - SNS fibres are vasoconstrictor - Arise in Nucleus Ambiguus - Except Stylopharyngeus - IX

Answer 13

Paired lymphoid aggregates in the lateral oropharyngeal wall forming part of Waldeyer's Ring - Specialized lymphoid aggregates with external lining of stratified squamous epithelium **2 borders** - Anterior - Palatoglossal arch - Posterior - Palatopharyngeal arch **2 poles** - Upper - Soft palate - Lower - Tongue base **2 surfaces** - Medial - Pharyngeal mucosa (stratified squamous epithelium) with crypts (up to 20 in number) - Lateral - Covered by capsule ( a thickening of the submucosa/extension of PB fascia) - Connective tissue septae extend to tonsil from capsule (not easily separated)

Answer 14

**Relations of the tonsil** - SC - Stylopharyngeus, Styloglossus, Stylohyoid lig, Styloid process - ICA (2cm posterolateral to tonsil bed) - IX

Answer 15

**Blood supply**: 5 arterial sources, tonsillar branches of 1. Ascending pharyngeal a. 2. Lesser palatine a. (3rd part IMA) 3. Ascending palatine a. (branch of Facial a.) 4. Facial a. 5. Lingual a. **Venous drainage** 1. Venous plexus forms around capsule then drain to tonsil branch of Lingual v. 2. Accessory Tonsil v. (drains to pharyngeal plexus) 3. External palatine v. (superior pole)

Answer 16

**Embryology**: Begins 12 weeks Derived from 2nd pharyngeal pouch endoderm Lymphocytes migrate into the area (mesoderm) 8-10 buds of pharyngeal squamous epithelium grow into the pharyngeal walls —\> crypts formed

Answer 17

**Embryology**: Begins 12 weeks Derived from 2nd pharyngeal pouch endoderm Lymphocytes migrate into the area (mesoderm) 8-10 buds of pharyngeal squamous epithelium grow into the pharyngeal walls —\> crypts formed

Answer 18

**Zones**: 1. **Specialised squamous epithelium** (epithelium invaginates as the crypts- increase surface area to compensate for lack of afferents) - Lymphoepithelium = epithelium + lymphocytes + macrophages + dendritic cells (APC) - Captures foreign material from the epithelial surfaces 2. **Parafollicular** (T-cell rich) - Dendritic cells present antigens on their cell surface via MHC-II molecules, interacting with CD4+ T cells (assisted by co-stimulatory molecules e.g. CD80) 3. **Mantle zone** = lymphocytic cap around the germinal centre (B-cell predominant) - Primed T cells interact with naive B cells with co-stimulatory CD-40 —\> B cell proliferation and differentiation - B cells migrate to the lymphoid follicle (forming germinal centres) 4. **Germinal centres** (B-cell rich) - B cell proliferation, high affinity mutation, isotype switching and maturation - Produces Plasma cells and memory B cells

Answer 19

**Differences from lymph nodes:** 1. Non-encapsulated 2. No afferent lymphatic channels Front-line defense at mucosal site - Secretory Ig regulation

Answer 20

**Innervation** - All pharyngeal plexus (IX, X, SNS fibres) - SNS fibres are vasoconstrictor - Arise in Nucleus Ambiguus - Except TVP - Nerve to Medial Pterygoid (V3) **Palatopharyngeal sphincter:** Level of hard palate (C1) Forms Passavant's ridge

Answer 21

**Made up of 5 paired muscles:** 1. Tensor Veli Palatini Arises outside pharynx - 2 triangles converge on the pterygoid hamulus - Vertical (muscular) - arises from scaphoid fossa (med pterygoid plate), lateral cartilagenous ET, spine of sphenoid - Horizontal (aponeurotic) - attaches to other side, hard palate. Posterior edge is free 2. Levator Veli Palatini Arises inside pharynx - Arises from petrous apex (ant. to ICA) and medial cartilagenous ET - Inserts to nasal surface of aponeurosis (interdigitates with other side to form a V-shaped sling) 3. Palatopharyngeus (Palatolaryngeus) post faucial pillar - Arises from 1. nasal surface of aponeurosis and 2. hard palate - Inserts to superior horn of thyroid cartilage and thyroid lamina 4. Palatoglossus Ant faucial pillar - Arises from under surface of aponeurosis - Interdigitates with Styloglossus 5. Musculus uvulae - unimportant

Answer 22

**Histology**: Oral surface = stratified squamous epithelium Nasal surface = respiratory epithelium

Answer 23

**Palatopharyngeal sphincter:** Level of hard palate (C1) Forms Passavant's ridge

Answer 24

**Cricoid cartilage to cardiac orifice of stomach (C6-T10), 25cm long** **2 portions** **Cervical** - Slightly to L of midline, then enters thorax in midline **Thoracic** - Slightly to L of midline against vertebral bodies, behind L main bronchus, passes in front of descending aorta (i.e. off vertebrae) in contact with pericardium (L atrium) **Relations in thorax** Crossed by aortic arch on left and azygos vein on right Crossed anteriorly by L main bronchus and R pulmonary artery Thoracic duct crosses behind oesophagus (R to L) L atrium

Answer 25

**Constrictions** 15cm - Cricopharyngeus 22cm - Aortic arch 27cm - Left main bronchus 38cm - Diaphragm

Answer 26

**Structure** Epithelium- stratified squamous Muscularis mucosae- thick Submucosa- sparse mucous glands Muscular wall- inner circular, outer longitudinal - Skeletal in upper 1/3, visceral in lower 2/3 No serosa (except the short intra-abdominal course)

Answer 27

**Arterial supply** Upper- Inferior thyroid artery Middle- Oesophgeal branches of aorta Lower- Oesophageal branches of L gastric artery  Venous drainage Upper - Brachiocephalic veins Middle - Azygos veins Lower - L gastric vein (to Portal vein)

Answer 28

**Nerve supply** Upper - RLN Middle - Unnamed CN X branches Lower - Oesophageal plexus (CN X branches  Lymph Follows arteries

Answer 29

**Trachea** --- Mainstem Bronchi (Primary) --- Lobar Bronchi (Secondary) --- Segmental bronchi (Tertiary) --- Bronchioles --- Alveolar duct **Lobar bronchi:** - 3 on right - 2 on left (upper includes lingula segmental bronchi) **Segmental bronchi:** Each segmental bronchus enters a pyramid shaped bronchopulmonary segment with its apex pointing towards the hilum **Blood supply:** Artery - bronchial a. from aorta Venous - Right —\> Azygos, Left —\> Hemiazygos

Answer 30

**Left side:** ASIA ALPS (or ASIA SAMPL) 1. Upper - Apical - Sup Lingula - Inf Lingula - Anterior 2. Lower - Anterior - Lateral - Posterior - Superior

Answer 31

**Right side:** A PALM Seed Makes Another Little Palm (or A PALM SAMPL) 1. Upper - Apical - Posterior - Anterior 2. Middle - Lateral - Medial 3. Lower - Superior - Medial - Anterior - Lateral - Posterior

Answer 32

**2 symmetrical lobes +/- pyramidal lobe** - Joined by the isthmus which attaches to 2nd-4th tracheal rings Surrounded by visceral portion of MLDCF - Thickened as Berry's ligament (attachment to trachea) Upper pole is limited by sternothyroid thus goitre extends retrosternally rather than superiorly **3 Surfaces:** - Lateral - Under sternothyroid/sternohyoid - Medial - Against larynx/trachea - Posterior - Carotid sheath/parathyroids - Tubercle of Zuckerkandl (remnant of Ultimobranchial Body) - Posterolateral projection. RLN Nearly always behind this. - Sup PT nearly always cranio-posterior to TZ

Answer 33

**Recurrent Laryngeal Nerve:** Ascent - Left - in tracheo-oesophageal groove - Right - at an angle (20 degrees) to trachea Relationship to ITA - Left - more likely behind - Right - 50/50 in front/behind Always behind pretracheal fascia and therefore Berry's Ligament May divide above isthmus - anterior branch will be motor (larger)

Answer 34

**Non recurrent RLN** - Due to anomalies of branchial arteries - Come off ~ level with cricoid, behind CCA to CTJ - Right - 1% associated with retro-oesophageal subclavian artery (arises from left aortic arch) - Left - very rare - assoc with situs inversus & anomalous left SCA

Answer 35

**Arterial supply** - STA - 1st branch ECA - Divides on the gland (ant/post branches) - ITA - thyrocervical trunk, 1st part of SCA - Divides outside the fascia, then multiple branches enter capsule - Thyroid ima artery- present in 3% - Variably arises from Brachiocephalic a., R CCA, arch of Aorta Venous drainage - STV- drains to IJV or Facial v. - MTV- direct to IJV - ITV- Brachiocephalic v.

Answer 36

**Anatomy** - Arises from inferior (Nodose) Ganglion - Medial to ICA (bifurcates into ext (motor) & int (sensory & autonomic) branch) - Internal - Pierces thyrohyoid membrane (with SL artery & vein), divides into upper & lower branch - External runs inferiorly over inferior constrictor - EBSLN variable couse - Type 1 stays superficial to IC to CT, Type 2 pierces lower IC, Type 3 pierces upper IC - Type 3 rarely identified but is protected by IC - Type 1 commonly seen over superior pole thyroid (Cernea 2b) - most at risk

Answer 37

**Finding EBSLN (Friedman et al)** - Remove medial 5mm Sternothyroid to ecpose IC & CT - Nerve stimulator to identify EBSLN as inserts into CT - If runs over IC (type 1) it is followed to preserve it over superior pole (Cernea 2b) - If dives into IC low (type 2) no further dissection required (IC protects) - Type 3 usually not seen (~20%)

Answer 38

**Joll's Triangle:** 1. Lateral = superior thyroid pole and superior thyroid artery/vein 2. Superior = Hyoid bone (attachment of fascia and sternothyroid) 3. Medial = midline 4. Floor = cricothyroid membrane  Identifying the EBSLN within Joll's triangle: - Retract gland laterally and develop avascular plane between gland and larynx - EBSLN passes medialy across this space

Answer 39

**Cernea EBSLN types:** Aina & Hisham ANZJ Surg, 2001 Type 1: \>1cm from upper pole (17%) Type 2a: \<1cm from upper pole (56%) Type 2b: in contact with upper pole (27%) **Asymmetry in 53%** - Increased Type 2a/2b configuration in MNG (superior enlargement of gland) - Preservation still results in 5% voice change (cricothyroid affects pitch) - Loss of high tone and pitch volume and fatigue after extensive use

Answer 40

**SLN Palsy** - Conflicting - up to 20% when not looked for - Bilateral CT paralysis rare (often needs EMG to confirm) **Symptoms** - Hoarse / breathy voice - Lack of projection / loudness - Vocal fatigue - Difficulty singing (loss of high pitch control) **Appearance** - Shortened cord - Bowing - Height mismatch (inferior displacement) - maybe compensatory muscle tension dysphonia

Answer 41

**Paired superior & inferior glands** 35-40mg, 3-8mm 87% 4 glands, 6% 3 glands, 6% 5 glands **Embryology** - starts in 5th week - Superior PT (PT IV)- 4th pouch endoderm with C cells of thyroid - Inferior PT (PT III)- 3rd pouch endoderm with thymus - Position more variable in ectopia, because of longer descent course **Location of the glands** Symmetrical in 80% - Inferior PT - superficial to RLN. within 1cm inf/post/lat to inferior pole (50%) - Carotid bifurcation to thymus - Identifying branches of ITA is an excellent technique - Superior PT - deep to RLN, in a 2cm diameter area centred above crossing of the ITA and RLN, within 1cm of CT joint - More likely to be intrathyroidal (joint origin with C cells) - Very rare to be below main trunk of ITA (i.e. cephalad to ITA) - On or just above RLN at junction of upper/middle 1/3s of gland (when thyroid retracted medially) **Blood Supply** - Both glands usually receive supply from ITA - Occ superior PT receives blood from STA

Answer 42

**Muscles of the FOM:** 1. Mylohyoid - Mylohyoid line to hyoid bone (only the posterior fibres) and midline raphe (most fibres) 2. Geniohyoid - midline, genial tubercle to hyoid body (lies on top of mylohyoid) Mylohyoid divides the neck and the mouth

Answer 43

**Structures between mylohyoid and hyoglossus:** **1.** SM duct - Passes fwd from superficial gland. Opens at sublingual papilla 2. CN XII - Passes fwd on lower border of hyoglossus - At the anterior border of hyoglossus it becomes flat and gives off branches to the tongue 3. Lingual Nerve - Enters mouth passing under sup constrictor (at its attachment to PM raphe) - Runs fwd on mylohyoid, dips under SM duct then runs fwd on hyoglossus above the duct - Lingual N runs lat-med, Wharton's duct runs med-lat - In the FOM the nerve is flattened rather than round

Answer 44

**Structures deep to hyoglossus**: 1. Lingual artery - Runs just above greater horn of hyoid (level with CN XII) 2. CN IX - Disappears under upper part of hyoglossus - Much thinner than CN XII 3. Stylohyoid ligament - Styloid process to lesser horn of hyoid - Angle between lig and hyoid is the origin of middle constrictor which fans out posteriorly

Answer 45

Part of temporal bone, ossifies in cartilage Embryologically derived from 2nd branchial arch 2 Ligs 3 Muscles **Stylohyoid ligament** - Runs from styloid tip to lesser horn of hyoid - Persistence of perichondrium of Reichert's cartilage - Styloid process has a variable length **Stylomandibular ligament** - Thickening of deep lamina of parotid fascia (SLDCF) - Vaginal process of tympanic bone to angle of mandible - Forms the stylomandibular tunnel (skull base and mandible) where parotid tumours dumb-bell

Answer 46

**Stylohyoid ligament** - Runs from styloid tip to lesser horn of hyoid - Persistence of perichondrium of Reichert's cartilage - Styloid process has a variable length **Stylomandibular ligament** - Thickening of deep lamina of parotid fascia (SLDCF) - Vaginal process of tympanic bone to angle of mandible - Forms the stylomandibular tunnel (skull base and mandible) where parotid tumours dumb-bell

Answer 47

**Muscles:** all have different innervation 1. Stylopharyngeus- Deepest (medial) and highest (CN IX) Inserts: posterior border of the thyroid lamina and side wall of pharynx 2. Stylohyoid- arises posteriorly, high up (CN VII) Inserts: splits around digastric tendon, inserts base of greater cornu 3. Styloglossus- Arises in front and low down (CN XII) Inserts: lateral aspect of tongue, interdigitates with hyooglossus

Answer 48

**Definition**: Synovial joint between mandibular head and mandibular fossa (squamous TB) **Features**: 1. Interarticular fibrocartilagenous disc (attaches to capsule) 2. Capsule 3. No Hyaline cartilage 4. Lateral TM lig - Oblique down and back - Tightened by movements away from resting position 5. Sphenomandibular lig axis of rotation - Spine of sphenoid to lingula of mandible Nerve supply: Auriculotemporal Nerve (Hilton's law)

Answer 49

**Stability**: Greatest when occluded - Preventing forward movement: - Posterior temporalis fibres - Prominence of articular tubercle - Preventing backward movement: - Lateral pterygoid contraction - Obliquity of lateral ligament **Movements**: Protraction (LP) / Retraction (Temporalis) Depression (LP + Digastric) / Elevation (Masseter/MP/Temporalis) Side-to-side LP on one side, MP on the other

Answer 50

**Scalenus Anterior:** Key to the root of the neck - Anterior tubercles of transverse process - C3-6 —\> scalene tubercle (1st rib, upper surface) - In line with longus capitis **Relations**: 1. Anterior - Phrenic N (5) - Ascending Cervical A. (Branch of ITA or thyrocervical trunk (15) - Transverse cervical (4) / suprascapular aa (8) - CN X (incl RLN) (14) - IJV - Subclavian V. 2. Posterior - 2nd part SCA - Scalenus Medius 3. Lateral - 3rd part SCA - Brachial Plexus

Answer 51

**Scalenus Anterior:** Key to the root of the neck - Anterior tubercles of transverse process - C3-6 —\> scalene tubercle (1st rib, upper surface) - In line with longus capitis   **Scalenus Medius:** - Posterior tubercles of transverse process - all Cx vertebrae —\> quadrangular area btw neck + subclavian groove of 1st rib **Scalenus Posterior:** - Posterior tubercles of transverse process - C4-6 —\> 2nd rib

Answer 52

**Chassaignac's triangle:** Apex TP C6 - compress CCA here 1. Scalenus Anterior (lat) 2. Lower fibres of longus colli (med) 3. Subclavian Artery (base) Contents - Vertebral art, vein, Stellate Ganglion

Answer 53

**3 parts related to the Scalenus Anterior muscle:** Remember VITamin C + D 1st part before scalenus anterior 1. Vertebral a. 2. Thyrocervical trunk - Transverse cervical and suprascapular a. (laterally) - Inferior thyroid a. and Ascending Cervical a. (superiorly) 3. Internal Thoracic a. 2nd part behind scalenus anterior 4. Costocervical trunk - Superior Intercostal a. - Deep Cervical a. 3rd part beyond scalenus anterior 5. Dorsal Scapular a.

Answer 54

**Described in 3 parts related to Pec Minor:** - Before - Behind - Beyond **Mnemonic**: Sixties Teens Love Sex And Pot 1st part: 1. Superior Thoracic a. 2nd part: 1. Thoracoacromial a. --- pierces clavipectoral fascia --- clavicular/deltoid/acromial/pectoral branches 2. Lateral thoracic a. 3rd part: 1. Subscapular a. 2. Ant circumflex humeral a. 3. Post circumflex humeral a.

Answer 55

**Course**: - Ascends from thorax in front of prevertebral fascia - Medial to Vertebral a. and medial to CN X - Behind carotid sheath - Ends at superior cervical ganglion **Cervical ganglia:** 1. Superior - Lat mass of atlas (grey rami to C1-4) 2. Middle - Med to carotid tubercle (grey rami to C5-6) - In front of vertebral artery 3. Inferior - Behind commencement of Vertebral A. (grey rami to C7-8 ie brachial plexus) - Inf and middle connect via the ansa subclavia in front of SCA

Answer 56

**Visceral Efferents:** 1. Cardiac Plexus 2. Vascular - Superior - ICA (Int Carotid N, PPG and eyeball), ECA (pharyngeal plexus, otic/SM ganglia) - Middle - Subclavian a. (local branches), ITA (larynx, trachea, hypopharynx, upper oesophagus) - Inferior - Vertebral a. - to its branches

Answer 57

**Internal Carotid Artery System:** AEA - branch of Ophthalmic PEA - branch of Ophthalmic **External Carotid Artery System:** Facial artery branches - Superior labial artery Internal Maxillary artery branches - SPA. Divides to a septal branch and conchal branch - Greater Palatine artery - descends via GP foramen then ascends through Incisive foramen **Intranasal plexuses**: - Kiesselbach’s - anterior septum - Woodruff’s - posterior LNW **Septum distribution**: Upper septum - AEA + PEA Posterior / inferior septum - SPA Ant / inferior septum - GPA Caudal septum/columella - Sup labial art **Lateral nasal wall:** Superior - AEA Posterior - SPA Anterior - nasal br of facial a (check)

Answer 58

**Intranasal plexuses:** - Kiesselbach’s - anterior septum - Woodruff’s - posterior LNW

Answer 59

**Septum distribution:** Upper septum - AEA + PEA Posterior / inferior septum - SPA Ant / inferior septum - GPA Caudal septum/columella - Sup labial art

Answer 60

**Lateral nasal wall**: Superior - AEA Posterior - SPA Anterior - nasal br of facial a (check)

Answer 61

**Make-up:** 1. Palatal process of maxilla - Pitted surface are insertion of Sharpey's fibres) 2. Horizontal process of palatine bone (smooth surface) - Mucous glands between bone and mucosa **Foramina**: 1. Greater palatine - between palatine and maxilla 2. Lesser Palatine - multiple foramina behind GPF 3. Incisive - midline anteriorly (GPN/GPA enter nose)

Answer 62

**Blood supply:** Greater Palatine A. **Nerve supply:** 1. Greater Palatine N. 2. Nasopalatine N. (anterior)

Answer 63

Torcular Herophili or Torcula is the confluence of the sinuses

Answer 64

Spindle-shaped dural venous sinus Volume = 1.5mL - No valves in the veins --- bidirectional blood flow possible Extends orbital apex —\> petrous apex Intersected by fibrous bands = tiny 'caves' (contrasts with all other dural venous sinuses) **Lies between 2 layers of dura** - Outer layer = periosteum of sphenoid bone - Inner layer = covering of temporal lobe

Answer 65

**Relationships**: Medial = sphenoid bone and pituitary fossa Lateral = Temporal lobe + Meckels' cave (post/inf) Anterior = orbital apex (medial end of SOF) Posterior = cerebral peduncle (PCF contents) Roof = ICA + uncus of temporal lobe Floor = greater wing of sphenoid

Answer 66

**3 sources:** - Orbit (sup/inf ophthalmic veins) - Bony vault (sphenoparietal sinus) - Cerebral hemispheres (superficial middle cerebral vein) **3 outputs:** - Superior petrous sinus - Inferior petrosal sinus - Vein of Vesalius (to pterygoid plexus either via FO or own foramen medial to FO) **Contents**: - ICA - III, IV, V1, V2 (lateral wall, top to bottom) - VI (medial side, below ICA)

Answer 67

**5 layers of the scalp:** **SCALP pnemonic** Skin- thickest in the body (3-7mm) - mostly firmly attached by the CT layer to aponeurosis/muscle Connective tissue - a dense layer Aponeurosis - includes muslce at either end (occipitalis/frontalis) Loose areolar tissue - really a subaponeurotic layer (scalping can occur through this layer) Pericranium - loosely applied to bone but firmly applied to the sutures - Carries blood supply to the cranium

Answer 68

**Blood supply:** free anastomosis between all branches **ECA branches** - Occipital a. (runs with greater occipital N, Post auricular a. runs with lesser occipital N.) - Superficial Temporal a. **ICA branches** branches of Ophthalmic a. - Supraorbital a. - Supratrochlear a.

Answer 69

**There are 3 fascial layers in the temporal region:** 1. Temporoparietal fascia (also known as superficial temporal fascia) - Continuous with SMAS below zygoma) 2. Deep Temporal fascia, subdivided to: - Superficial layer DTF - Deep layer DTF - These layers surround the temporal fat pad **Layers of the temporal region** Skin Subcutaneous tissue Temporoparietal fascia (aka superfical temporal fascia) - continuous with SMAS below, galea aponeurotica above superficial temporal line Loose areolar tissue Temporalis muscle fascia (aka deep temporal fascia) - continuous with pericranium. Has 2 lamina which fuse 2 cm above zygomatic arch. (superficial temporal fat pad between lamina) T emporal muscle Pericranium Bone

Answer 70

**Layers of the face:** Skin Subcutaneous fat SMAS - superficial musculoaponeurotic system Muscles Deep facial fascia (parotidomasseteric fascia - continuous with SLDCF in neck) Retaining ligaments **Key features of the SMAS:** 1. Divides subcutaneous fat of the face into 2 layers - Non-septate fat (muscles to SMAS) - Septate fat (SMAS to dermis) 2. Has a consistent relationship with neurovascular structures of the face 3. Acts as a distributor of force - Attaches to nasolabial fold, perioral and periorbital regions to transmit the forces of facial expression **Relationship of SMAS to VII branches:** - Lower face: VII branches are deep to SMAS - innervate facial muscles from undersurface (except levator anguli oris, buccinator and mentalis) - Upper face: nerves penetrate SMAS and thus run superficial to SMAS - sub-SMAS dissection to avoid nerves - Temporal branch of VII: runs within the SMAS \*\*\* NEW STUDY in PRS suggests all branches are deep to SMAS

Answer 71

Form part of the panniculus carnosus - attached in part to dermis, thus wrinkles the skin Consist of 3 functional groups- eyelid, nose, lips/cheeks

Answer 72

**Eyelid** - Sphincter = Orbicularis oculi - Palpebral - confined to lids. Med palpebral lig to lateral palpebral raphe - Orbital - anterior lacrimal crest and frontal process of maxilla - Dilator = Levator palpebrae superiorus and occipitofrontalis

Answer 73

**Nose** - Sphincter = compressor naris (transverse component of nasalis) - Dilator = dilator naris - Elevator = procerus, lev labii sup alequae nasi - Depressor = depressor septi

Answer 74

**Lips/cheeks** - Sphincter = orbicularis oris - Mental + incisive slips attach to bone, rest forms from Buccinator via the modiolus - Buccinator - upper to lower jaw + PM raphe + pterygomaxillary lig - Dilators = form the 'spokes of a wheel' - Lev labii sup alequae nasi = frontal process maxilla to LLCs + upper lips - Lev labii sup = inferior orbital margin to upper lip - Lev anguli oris = canine fossa to modiolus - Zygomaticus minor = zygomaticomaxillary suture to modiolus - Zygomaticus major = zygomatic bone to modoilus - Risorius = upward extension of platysma to modiolus - Depressor anguli oris = oblique line of mandible to modiolus - Depressor labii inferioris = deep to DAO to lower lip - Mentalis = mental symphysis to skin

Answer 75

**Distribution of VII branches:** 1. Temporal --- Frontalis 2. Zygomatic - Upper —\> above eye (frontalis and upper 1/2 of orbicularis oculi) - Lower —\> below eye (lower 1/2 of orbicularis oculi and muscles below orbit 3. Buccal --- Buccinator and upper lip muscles (OO, LLSAN, LLS, ZMin, Zmaj, LAO, Ris) 4. Marginal mandibular --- Lower lip muscles (OO, DAO, DLI, Mentalis) 5. Cervical --- Platysma

Answer 76

**Motor Supply:** CN VII VII divides to temporozygomatic and cervicofacial divisions in parotid - Pes anserinus Emerges as 5 branches 1. Temporal- Frontalis 2. Zygomatic- - Upper branch- upper 1/2 of orbicularis oculi - Lower branch- lower half of orbicularis oculi and muscle below orbit 3. Buccal- buccinator and upper lip muscles (upper 1/2 orbicularis oris and elevators) 4. Marginal mandibular- Muscles of lower lip 5. Cervical- platysma

Answer 77

**Sensory supply:** CN V branches (except over Ao mandible - GAN) 1. **Ophthalmic** - Lacrimal - Upper lateral eyelid - Supraorbital - forehead and scalp to vertex - Supratrochlear - midline forehead - Infratrochlear - medial upper eyelid - External Nasal - middle of external nose down to tip 2. **Maxillary** - Infraorbital - - Palpebral- lower eyelid and cheek - Nasal- nasal sidewall and alar - Labial- upper lip and labialgum to 2nd premolar - Zygomaticotemporal - hairless part of the temple - Zygomaticofacial - over zygomatic arch 3. **Mandibular** - Auriculotemporal - - Auricular- EAM, surface of TM, pinna above EAM - Temporal- hairy skin over temple - Buccal - 'thumbprint' area of skin below zygomatic arch - Mental - skin/mucous membrane of lower lip/gum midline to 2nd premolar

Answer 78

**Venous drainage face** Supraorbital, supratrochlear veins → angular vein → facial vein → pierces investing layer of deep fascia → joined by anterior branch of retromandibular vein → IJV → brachiocephalic vein Superficial temporal vein → joined by maxillary veins (from pterygoid plexus) → becomes retromandibular vein → anterior branch joins facial vein, posterior branch joined by posterior auricular vein → EJV → subclavian vein **Deep venous anastomoses:** B/W facial vein and cavernous sinus (via ophthalmic veins at medial canthus) B/W facial vein and pterygoid plexus (via deep facial vein in front of masseter)

Answer 79

Paired glands on either side of face between ear and mandibular ramus Surrounded by thick capsule derived from SLDCF Superficial/deep portions arbitrarily divided by CN VII **Relations**: Superior - TMJ, zygomatic arch Inferior - upper border of SCM ('parotid tail') Lateral - subcutaneous, GAN - GAN branches to anterior and posterior (supplies ear lobe) Anterior - MP, ramus, masseter Deep - Mastoid tip (with assoc muscles esp SCM, PBD), styloid (assoc muscles- stylohyoid, stlyoglossus, stylopharyngeus), ECA

Answer 80

**Landmarks for CN VII in Parotid** 1. Posterior belly of digastric (just above its superior border, bisects digastric-mastoid angle) 2. Tympanomastoid suture 3. Tragal pointer- 1cm inferior, deep

Answer 81

**Stensen's duct:** 5cm long - along a line from intertragal notch to philtrum Passes fwd across masseter and turns to pierces buccinator - Passes submucosal in buccinator before pierces mucous membrane opposite upper 2nd molar - Provides a 'valve' function

Answer 82

**Histology**: predominantly a serous gland Serous secretory units (acini) drain to intercalated (terminal) ducts Intercalated ducts converge to form striated (intralobular) ducts which in turn converge to form secretory (interlobular) ducts Interlobular ducts empty to main parotid duct

Answer 83

SOF forms between greater and lesser wings of sphenoid, tendinous ring = Ligament of Zinn

Answer 84

**Lig of Zinn** attaches to bone, origin of recti LR separates SOF into medial & lateral compartments LPS arises from LWoS inserts sup tarsal plate & skin upper lid SO arises from narrow tendon body sphenoid, thru trochlea into postero-superior sclera IO - arises orbital floor beneath trochlea (maxilla) - passes obliquely back to post-inf sclera All nerves stay within / outside cone except anterior ethmoid / posterior ethmoid / infratrochlear (all branches of nasocilary (V1))

Answer 85

**Consists of:** 1. Lacrimal gland 2. Lacrimal canaliculi   3. Lacrimal sac  4. Nasolacrimal duct

Answer 86

**1. Lacrimal gland** - A serous gland made up of two components- orbital (large) and palpebral (small) - Lacrimal gland fossa sits in orbital portion of frontal bone - In the lateral part of orbital roof, supported by lateral edge of apopneurotic tendon of LPS - Approx 12 ducts lead from palpebral component to superior fornix of conjunctiva   **Nerve supply**: Sup Salivatory Nucleus —\> NI —\> GG --\> GSPN --\> Vidian Nerve --\> PPG v—\> Zygomatic Nerve (V2) —\> lacrimal nerve (v1) —\> lacrimal gland SNS - Sup cervical ganglion

Answer 87

**Lacrimal canaliculi**  puncta lie 6mm from medial canthus - Each canaliculus has a 2mm vertical portion and 8mm horizontal portion - Superior and inferior join to form the common canaliculus - Valved ducts (Valve of Rosenmuller) prevent reflux of tears from the lacrimal sac

Answer 88

3. **Lacrimal sac** 12mm x 5mm - Lies in its fossa formed by lacrimal grooves of maxilla and lacrimal bone - Relatively higher than previously appreciated --- affects surgical approach - 9mm above middle turbinate axilla - Crossed in front by medial palpebral ligament and palpebral fibres of OO - Muscle contraction causes tears to be 'sucked' through the puncta (i.e. during blinking) - When the muscle relaxes the lacrimal sac recoils and pumps its contents to the NLD

Answer 89

**Nasolacrimal duct** - 2cm long, slopes downward and laterally to open to inferior metaus - 2cm behind nostril, Hasner's valve - Internal diameter = 3.5mm - Mucous membrane is raised into several folds which act as valves to prevent air entering the NLD

Answer 90

**Structure of the eyelids:** superficial to deep 1. Loose skin 2. Orbicularis oculi muscle 3. Skeletal framework: orbital septum (thickened at the lid margins to form the tarsal plates) 4. Conjunctiva

Answer 91

**Tenon's Capsule:** **-** Applied to the back of the eye - Extends forward encasing the muscles - Thickenings lateral and medial: - Lateral/medial check ligaments - Joined as the suspensory ligament of Lockwood —\> supports the eye

Answer 92

**Orbital septum:** Attached to the anterior lacrimal crest and margins of the orbit - Wide 'buttonhole': the palpebral fissure between the lids Thickened superiorly and inferiorly - Superior/inferior tarsal plates (dense fibrous tissue) Septum thickened medially in its attachment to anterior lacrimal crest (medial palpebral ligament) - Lat palp lig is much thinner, fusing with lat palpebral raphe of OO Contain the tarsal (Meibomian) glands

Answer 93

**Epithelium** = pseudo stratified columnar neuroepithelium - 70microm thick vs 30microm for resp, Area = 1cm2 (cilia --- 22cm2) 10-15% of airflow reaches olfactory cleft **Olfactory epithelium - 5 cell types:** 1. Olfactory neurons- bipolar neurons - One end = knobs for detecting odour (immotile cilia- lack dynein arms) - Other end = projection to olfactory bulb. Synapses in glomerular layer 2. Microvillar cells - Receptor function (poorly understood) 3. Sustentacular cells - Maintains ionic milieu. Deactivates odourants. Insulates adjacent receptor cells from each other 4. Basal cells - deepest layer. Regenerative (3-7 weeks) - Globose cells —\> neuron replacement, Horizontal cells —\> replace all cell types 5. Bowman's glands - Mucus secretion for odour absorption

Answer 94

Unmyelinated axons converge into 15-20 fila (myelinated) to traverse cribriform plate - Synapse in glomerular layer (mitral + tufted cells). Convergence

Answer 95

**Olfactory bulb anatomy:** Divided into 2 layers 1. Internal plexiform layer = glomerular layer. Mitral/tufted cells 2. External plexiform layer = granular layer. Granular cells **Olfactory bulb cell types:** 1. Mitral - glomerular layer --- lateral olfactory tract 2. Tufted - glomerular layer. Function unclear 3. Periglomerular - relay between glomerular cells and granular cells for feedback loops 4. Granular - inhibitory cells 2nd order neurons project to ipsilateral olfactory cortex (temporal lobe)

Answer 96

**Olfactory physiology**: Largest gene family in the human genome Codes for \> 1000 G-protein receptor type. 7 transmembrane domains with binding site for specific odorants **Vomeronasal Organ:** - Anteroinferior septum. Reproductive behaviours in animals. Unknown function in humans **Accessory Inhalant Chemosensory Pathway** - V1 and V2 detect irritant stimuli —\> Substance P and Calcitonin GRP —\> nasal oedema and secretion

Answer 97

**Maxillary Sinus:** - Accessory ostium in 25% --- defect in mucosal coverage of posterior fontanelle - Haller cell most common additional cell **Ethmoid sinus:** - Roof thickness of bone (fovea ethmoidalis) - Lateral = 0.5mm (orbital plate of frontal bone) - Medial = 0.2mm thick (cribriform plate of ethmoid bone) - 0.05mm at site of AEA canal --- thinnest portion of skull base - Agger Nasi cell = 90% - Onodi cell = 30% - AEA on a mesentery + 35% - Suprabullar cell = Cell originating in suprabullar region but doesn't reach frontal sinus - Frontal bulla cell = Suprabullar cell that enters the frontal sinus

Answer 98

**Sphenoid sinus:** - ICA: 20% dehiscent, 40% septum inserts to its canal, \>50% have \>90 degrees bony exposure - Optic nerve: 15% dehiscent, 30% septum inserts to canal

Answer 99

**Finding the sphenoid ostium:** medial to superior turbinate in 83% 1. Junction of upper 2/3 and lower 1/3 of superior turbinate 2. 12mm above bony choana 3. 7cm at 30 degree angle from anterior nasal spine 4. Trans-septal and raised mucosa off front face of sphenoid 5. Level of roof of the antrum

Answer 100

**Uncinate process insertions**: 1. Lamina papyracea 54% 2. Middle turbinate 34% 3. Skull base 7%

Answer 101

**Components**: - Cartilage - Perpendicular plate of ethmoid - Vomer - Rostrum of sphenoid contributes small amount - Maxillary crest and crest of palatine bone

Answer 102

**Blood supply:** 1. Posterior nasal artery - branch of SPA 2. Incisive branch - Greater Palatine artery 3. Superior labial artery - Facial artery 4. Anterior ethmoidal artery - Ophthalmic artery 5. Posterior ethmoidal artery - Ophthalmic artery

Answer 103

**Nerve supply:** 1. Nasopalatine nerve - branch of PPG 2. Anterior ethmoidal nerve - from Nasociliary N (V1) 3. Posterior ethmoidal nerve - from Nasociliary N (from V1)

Answer 104

**Cottle's areas of the septum**: I = external nasal valve II = internal nasal valve III = attic of nasal cavity IV = anterior middle turbinate V = posterior middle turbinate

Answer 105

**3rd branch of Ophthalmic artery** Exits orbit through anterior ethmoid foramen (at or above fronto-ethmoidal suture- marks floor of ACF) Traverses roof of sinus (anteromedial) in the orbitocranial canal to enter the ACF - 30% on a mesentery Enters ACF at lateral lamella of lamina cribrosa (lateral wall of olfactory fossa) Curves anteriorly in ethmoidal sulcus (gives off branch to anterior meningeal artery) Then exits ACF back into nose via cribroethmoidal foramen **Terminal branches are:** - Anterior nasal artery (sup/med/lat branches) - Posterior branch - Small meningeal branches **Area of supply:** - Previously thought it supplied all of MT (watershed between AEA and SPA territories) - Now thought to supply less of MT

Answer 106

**Locating artery in orbit, distances from anterior lacrimal crest** (24,36,42) - AEA - 24mm - PEA- 12mm - Orbital apex - 6mm Use a Ferris-Smith retractor for the Lynch Howarth incision **Area of supply:** - Previously thought it supplied all of MT (watershed between AEA and SPA territories) - Now thought to supply less of MT

Answer 107

**Nerve**: 1. V1 branches - Frontal —\> supraorbital and supratrochlear - Nasociliary —\> infratrochlear and external nasal (terminal branch of AEN) 2. V2 branches - ION terminal branches —\> palpebral, nasal, labial - ASAN Also motor supply from CN VII

Answer 108

**Blood**: 1. AEA derived - Dorsal Nasal artery 2. Facial artery derived - Angular artery (terminal branch of facial artery) - Lateral nasal artery - Columellar artery (branch from superior labial artery)

Answer 109

**Anatomy of the ventricular system:** 2 lateral ventricles --\> Foramen of Monro --\> 3rd ventricle --\> cerebral aqueduct of Sylvius --\> 4th ventricle --- 2x Foramen of Luschka and 1 x Foramen of Magendie —\> subarachnoid space - Luschka --- subarachnoid space via the pontine cisterns - Magendie — subarachnoid space via the cerebello-medullary cistern **Arachnoid villi** - situated along the cerebral convexities - Project into the dural sinuses and act as one-way valve - Valve will close when pressure \<1.5 cm H2O

Answer 110

**CSF Physiology**: Production = 450mL/day, Total volume = 150mL --- turned over 3x/day Produced in choroid plexus 50% and walls of lat/3rd/4th ventricles 50% Filtrate of venous blood, modified by ependymal cells - Slightly higher NaCL, Lower K+, Glu, Ptn Normal ICF pressure = 5-15 cmH2O Absorbed by arachnoid villi (90%) and direct to cerebral venules (10%)

Answer 111

**B-2 transferrin:** Produced by desialisation of B1 transferrin (by cerebral neuraminidase) Found in CSF, perilymph, vitreous humour High sensitivity and specificity for CSF from nasal secretions - Stable at room temperature for 7 days (Bleier et al)