Alikhan Flashcards
What are Langer’s lines?
Lines along skin that will “gape when punctured with a spike”
Run parallel to underlying muscles (in contrast to relaxed skin tension lines, which run perpendicular to underlying muscles”
What are relaxed skin tension lines?
Lines that run perpendicular to underlying muscles
Also known as Kraissl and Borges lines
What are the important branches of the external carotid artery?
- Superficial temporal artery (temple, scalp, lateral forehead)
- Maxillary artery (supplies infraorbital and mental arteries)
- Facial artery (supplies superior and inferior labial arteries)
What regions of the face does the superficial temporal artery supply?
Temple, scalp and lateral forehead
What arteries are supplied by the maxillary artery? (2)
What regions of the face does each of these arteries supply? (2 each)
- Infraorbital artery (mid face, nasal dorsum)
- Mental artery (lower lip, chin)
What arteries does the facial artery supply? (2)
What regions of the face do these arteries supply? (5)
- Superior labial artery
- Inferior labial artery
These supply the upper and lower lips, chin, nasal ala and columella.
What is important about the facial artery and filler injection?
The facial artery courses medially deep to melolabial fold, giving rise to the angular artery at the base of the ala.
This area is susceptible to intra-arterial injection during filler injection!
What branch of the internal carotid artery does the facial artery anastamose with?
Dorsal nasal artery (a branch of the internal carotid artery)
Occurs near medial canthus
What artery is responsible for most of the facial arteries supplied by the internal carotid artery?
Ophthalmic artery
What are the important branches of the ophthalmic artery? (9)
What regions of the face do these branches all supply? (4)
- Retinal
- Supraorbital
- Supratrochlear
- Infratrochlear
- Dorsal nasal
- External nasal
- Anterior ethmoidal
- Posterior ethmoidal
- Lacrimal
These branches supply the retina, forehead, upper dorsal nose and eyelids.
What is the risk of injection of steroids or filler into the glabella?
Intraarterial injection of the underlying supratrochlear artery and its anastamoses may occur.
This can lead to skin necrosis or blindness due to communication with the retinal artery.
Where do the supratrochlear and supraorbital veins drain?
What is the related “danger triangle”?
Drain through orbit into the cavernous sinus
The danger triangle extends from corners of mouth to nasal bridge.
Infections of danger triangle can cause cavernous sinus thrombosis, meningitis and brain abscesses for this reason.
Into what lymph nodes do each of the following facial areas drain?
- Forehead, lateral temporal, frontal and periocular areas
- Medial midface
- Lower face
- Forehead, lateral temporal, frontal and periocular areas
- Upper jugular nodes
- Medial midface
- Submandibular nodes
- Lower face
- Submental nodes
What does SMAS stand for?
Superficial musculoaponeurotic system
Relative to the superficial musculoaponeurotic system (SMAS), where are motor and sensory nerves located?
- Motor nerves are deep to SMAS
- Sensory nerves are superficial to SMAS
Sensory innervation of the face is almost entirely supplied by what cranial nerve?
CN V (trigeminal nerve)
What syndromes can damage to CN V (trigeminal nerve) lead to? (2)
- Trigeminal trophic syndrome (classically involving the nasal ala, upper lip or paranasal area)
- Frey’s syndrome (also known as auriculotemporal syndrome; gustatory sweating of facial and periauricular areas with eating)
What are the three branches of CN V (trigeminal nerve)?
- Ophthalmic (V1)
- Maxillary (V2)
- Mandibular (V3)
What are the three major branches of CN V1 (ophthalmic nerve)?
- Frontal (two divisions: supraorbital and supratrochlear nerves)
- Nasociliary (three divisions: infratrochlear and anterior ethmoidal nerves)
- Ciliary (supplies lacrimal nerve)
What is Hutchinson’s sign?
- Involvement of nasociliary branch by VZV
- Presents with distal nasal vesicles and ulcers
- Almost always associated with herpes zoster ophthalmicus!
What are the three main divisions of CN V2 (maxillary nerve)?
- Infraorbital (includes nasal sidewall, nasal ala and upper lip)
- Zygomaticofacial (malar eminence)
- Zygomaticotemporal (temple and supratemporal scalp)
What are the main divisions of CN V3 (mandibular nerve)?
- Auriculotemporal (superior portion of anterior external ear, external auditory canal, temple, temporoparietal scalp, TMJ, parasympathetic innervation of parotid gland)
- Buccal
- Inferior alveolar
- Mental (chin and lower lip)
- Lingual (somatic sensation of anterior two-thirds of tongue)
What nerve may be injuried with TMJ surgery or parotidectomy?
Auriculotemporal nerve
- Can lead to paresthesia of anterior external ear and temple, as well as Frey syndrome
What cervical nerves provide the sensory innervation to the following areas?
- Neck, postauricular scalp
- Occipital scalp (majority)
- Lateral neck, angle of jaw, majority of external ear (anterior and posterior portions, and earlobe), postauricular scalp
- Anterior neck
- Anterior chest and shoulder
- Neck, postauricular scalp
- Lesser occipital (C2)
- Occipital scalp (majority)
- Greater occipital (C2)
- Lateral neck, angle of jaw, majority of external ear (anterior and posterior portions, and earlobe), postauricular scalp
- Great auricular (C2, C3)
- Anterior neck
- Transverse cervical (C2, C3)
- Anterior chest and shoulder
- Supraclavicular (C3, C4)
In decreasing order, name the sensory nerves innervating the ear. (4)
- Great auricular (majority of posterior ear, three-fourths of anterior ear)
- Auriculotemporal (anterior-superior quadrant of ear, external auditory meatus, superior portion of posterior helix)
- CNs VII, IX, X (conchal bowl and external auditory meatus)
- Lesser occipital (posterior notch)
A ring block around ear anesthetizes everything except what structures?
Conchal bowl and external auditory meatus
These are innervated by CNs VII, IX and X.
What is the maximum volume of anesthetic that can be used in a digital block?
Use 1-2 mL on each side
Do NOT exceed 8 mL per digit to avoid tourniquet effect.
Safe to use lido+epi unless patient has underlying vasooclusive disease
What nerves provides taste and somatic sensory input to the tongue? (3)
- Taste: CN VII (anterior 2/3) and CN IX (posterior 1/3)
- Somatic sensory: CN V3 (via lingual nerve, anterior 2/3) and CN IX (posterior 1/3)
Name the regions of the hand given sensory innervation by the following nerves.
- Ulnar
- Radial
- Median
Name the regions of the foot given sensory innervation by the following nerves.
- Deep peroneal
- Posterior tibial
- Saphenous
- Superficial peroneal
- Sural
Where does CN VII (facial nerve) emerge from?
What are its 5 branches?
CN VII emerges from stylomastoid foramen, then travels within parotid gland and splits into 5 branches
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
Mnemonic: “To Zanzibar By Motor Car”
What muscles are innervated by the temporal branch of CN VII? (3)
- Frontalis (eyebrow elevation; horizontal forehead wrinkles)
- Corrugator supercilii (pulls brows inferomedially; scowling appearance, vertical glabellar lines)
- Upper portion of orbicularis oculi (tight closure of eyelids, blinking; “crow’s feet”)
What muscles are innervated by the zygomatic branch of CN VII? (4)
- Lower portion of orbicularis oculi (for tightly shutting eyelids)
- Alar portion of nasalis (flares nostrils)
- Procerus (horizontal glabellar lines)
- Zygomaticus major (main muscle responsible for smiling)
What muscles are innervated by the buccal branch of CN VII? (9)
- Buccinator (important masticator; keeps food from accumulating between cheek and teeth)
- Depressor septi nasi (pulls columella toward lip)
- Transverse portion of nasalis (“bunny lines”)
- Orbicularis oris (important for clear, unmuffled speech)
- Zygomaticus major and minor (responsible for smiling)
- Risorius (lesser role in smiling)
- Levator anguli oris
- Levator labii superioris (“gummy smile”)
- Levator labii superioris alaque nasi (flares nostril and elevates upper lip)
What muscles are innervated by the (marginal) mandibular branch of CN VII? (5)
- Orbicularis oris
- Depressor anguli oris (responsible for “RBF”)
- Depressor labii inferioris
- Mentalis (lower lip protrusion, chin elevation)
- Upper portion of platysma
Why is the marginal mandibular nerve at highest risk of permanent motor deficits?
What does such a deficit look like?
- It has only 1-2 rami and is covered by thin skin and platysma only.
- Face appears normal at rest but asymmetric with smiling
- Inability to evert lower lip
- Drooling
What muscle is innervated by the cervical branch of CN VII? (1)
Platysma (depresses lower jaw, tenses neck skin)
Damage could lead to inability to grimace.
What are possible treatments for vascular occlusion from filler/steroid injection at the angular artery (base of ala) or supratrochlear artery (glabella)? (3)
- Nitroglycerin paste
- LMWH
- Hyaluronidase (if HA filler used)
How does the temporal nerve (of CN VII) course?
- Runs diagonally from 0.5 cm below tragus to 1.5 cm above lateral eyebrow
- Superficially located within fascia as it crosses zygomatic arch, where it is most susceptible to injury, leading to unilateral frontalis paralysis and eyelid ptosis
Where is the marginal mandibular nerve (of CN VII) most susceptible to injury?
2-3 cm inferolateral to oral commissure as it passes over mandible
Leads to facial asymmetry upon smiling, inability to protrude lower lip and drooling
Where is Erb’s point?
6 cm inferior to midpoint of imaginary line drawn between mastoid process and angle of jaw (along posterior border of SCM)
- Spinal accessory (CN XI), great auricular and lesser occipital nerves arise here.
Damage to the ulnar nerve at the medial epicondyle of humerus leads to what “deformity”?
“Claw-hand deformity”
- Weakness with wrist flexion
- Loss of flexion of fourth and fifth digits
- Los of sensation in ulnar distribution
What is the name of the most common scalpel handle?
Bard-Parker (standard) handle
What is the name of the scalpel used for confined spaces or delicate tissue?
Beaver handle
Name the scissor type.
Iris scissors
- Sharp-tipped, short-handled
- Blades may be straight or curved
- Best for sharp dissection
Name the scissor type.
Gradle scissors
- Similar to iris scissors, but blades are curved and tapered to fine point at tip
- Best for dissection of delicate tissue such as periorbital skin
Name the scissors type.
Castroviejo scissors
- Similar in appearance to Westcott scissors
- Good for delicate eyelid dissection
Name the scissors type.
Westcott scissors
- Spring-loaded instrument
- Similar in appearance to Castroviejo scissors
- Good for delicate eyelid dissection
Name the scissors type.
Mayo scissors
- 1:1 handle-to-blade ratio
- Used for coarse dissection
Name the scissors type.
Metzenbaum scissors
- Long handles with blunt tips
- Used for blunt dissection in areas requiring long reach
Name the scissor type.
(Pay attention to the handles.)
Supercut scissors
- Denoted with black handles
- One blade has a razor edge
- Supercut blades are available across most scissor types
Name the forceps type.
Adson forceps
- Relatively large forceps
- Useful for trunk and extremities
Name the forceps type.
Bishop-Harmon forceps
- Used for delicate tissues like eyelids
- Always have 3 holes in handles
Name the forceps type.
Jeweler’s forceps
- Have very pointy ends
- Used for suture removal
Name the instrument.
Periosteal elevator
- Used to remove periosteum or separate nail plate from nail bed
What are the three parts of a surgical needle?
- Shank (swage): connects needle to suture; weakest part of needle
- Body: strongest part of needle; most common curvature is 3/8 circle
- Tip: can be round (tapered) or cutting
When should a round (tapered) needle tip be used?
Deep soft tissues (muscle and fat)
- Less likely than cutting needles to tear tissues
- Difficult to pass through skin
What is the difference between a conventional cutting and reverse cutting needle point?
- Conventional cutting: cutting surface is on inner portion of needle arc (i.e., facing the wound edge); increased risk of sutures tearing through wound edge
- Reverse cutting: cutting surface is on outer portion of needle arc; decreased risk of sutures tearing through wound edge
What type of special knot can be used to tie the end of a running subcuticular suture?
Aberdeen hitch knot
What is the benefit and risk of running locked sutures?
Provides hemostasis but risks strangulation
What is the benefit of vertical mattress sutures?
Strongly everts wound edges
(Vertical = eVert)
What is the benefit and risk of horizontal mattress sutures?
Provides hemostasis but risks strangulation
Do not use in poorly vascularized areas
What is the benefit of running horizontal mattress sutures?
Increased eversion, less strangulation risk
Improved outcomes relative to simple running sutures, but takes longer
What is a tip stitch?
Half-buried horizontal mattress suture
Best stitch for flap and M-plasty tips