Anatomy Flashcards
What is iliopubic tract?
▪ Thickening of fascia transversalis
▪ Iliopectineal arch to the pubic ramus
Borders of inguinal canal.
Inguinal canal – 4cm long
▪ Inferior:
• Inguinal ligament
• Lacunar ligament (medial 1/3)
• Iliopubic tract (lateral 1/3)
▪ Anterior
• Aponeurosis of external oblique
• Superficial inguinal ring (medial 1/3)
• Internal oblique (lateral 1/3)
▪ Posterior
• Transversalis fascia
• Conjoint tendon (medial 1/3)
• Deep inguinal ring (lateral 1/3)
▪ Roof
• External oblique aponeurosis
• Internal oblique and transversus abdominis arching fibres
• Transversalis fascia
Femoral canal boundaries
o Lacunar ligament (medial), pectineal ligament (inferior), inguinal ligament (superior), femoral vein (lateral)
o Below and lateral to pubic tubercle
Contents of spermatic cord
3 arteries
- artery to vas
- artery to cremastaric
- testicular artery
3 veins
3 fascial coverings
- external spermatic fascia (ext oblique)
- cremasteric fascia (internal oblique and transversals abdominis)
- internal spermatic fascia (transversalis fascia)
3 nerves
- genital branch of the genitofemoral nerve
- ilioinguinal nerve
- sympathetics
3 others
- VAS deferens
- lymphatics
- patent processus vaginalis
Abodminal wall anatomy
External oblique
o Arises ribs 5-12 → xiphoid, iliac crest, pubic tubercle, ASIS linea alba
o T7-12, subcostal nerve
Internal oblique
o Arises inguinal ligament, iliac crest, lumbodorsal fascia → linea alba, ribs 10-12
o T7-12, ilioinguinal, iliohypogastric nerves
Transversus abdominis
o Arises inguinal ligament, iliac crest, thoracolumbar fascia costal cartilages 7-12 → xiphoid, linea alba, pubic crest
o T6-12, ilioinguinal, lliohypogastric nerves
Management of omphalocele and gastroschisis
Congenital umbilical hernia (omphalocele)
o Specialised centre
o If unexpected finding:
▪ Keep baby warm and hydrated
▪ IV Abx
▪ NGT
▪ Handle sac with care to avoid rupture ▪ Cover sac in moist sterile gauze then cover with impervious plastic sheeting or aluminium foil
▪ Transfer to tertiary centre
• Primary closure
• Prosthetic patch
• Skin flap closure
• Silo and staged closure
• Escharotic agents to encourage thickening of sac (giant omphalocele)
Gastroschisis
▪ Place infant in warm, saline-filled plastic organ bag up to nipple line
▪ IVF 1.5x maintenance
▪ IV Abx
▪ OG tube
▪ Repair
• Primary closure
• Patch
• Silo with serial reduction of viscera over 5-7 days
▪ TPN
▪ May need orchidopexy (if testes found extracoelomic)
Anatomy of breast
Overview
In superficial fascia of anterior thoracic wall, from midline to mid-axillary line, 2nd to 6th ribs +/- axillary tail.
Modified apocrine sweat gland. 15-20 lactiferous ducts converge on nipple (surrounded by areola), sebaceous glands open into areola.
superficial fascia (continuation of fascia of Scarpa) condenses to form posterior capsule
suspensory ligaments of Cooper connect dermis to above capsule
retromammary space between capsule & pectoralis major fascia (relatively avascular)
Blood Supply
Lateral thoracic artery
o from axillary A at lateral margin of pec minor (2nd part of axillary artery)
Internal thoracic artery (through intercostal spaces, especially 2nd & 3rd)
Intercostal arteries (perforating branches)
Thoracoacromial artery (2nd part of axillary artery)
Venous drainage
deep veins with arteries to internal thoracic & axillary V’s
posterior intercostal veins -> vertebral veins
Lymph drainage
lateral
axillary & infraclavicular nodes
medial
internal thoracic nodes
75% -> axilla, rest to internal thoracic
other possible paths: opposite breast, cervical nodes, peritoneal cavity & liver (through diaphragm / rectus sheath), inguinal nodes (anterior abdominal wall)
involvement of LN by cancer tends to follow an orderly progression proximal -> distal (i.e. pectoral -> central)
Nerve supply
skin by intercostal N’s
sympathetic N’s to blood vessels & glands
Development
modified apocrine sweat gland
begins to develop from 4th week from mammary ridge of ectoderm along line from axilla to inguinal region
Anatomy of pectoralis major.
Origin:
o clavicular head: medial 1/2 of clavicle
o sternocostal head: lateral manubrium, body of sternum & aponeurosis of ext oblique (also fibres from 1st - 6th costal cartilages)
Insertion
o trilaminar insertion into lateral lip of intertubercular groove
o anterior lamina: fibres of clavicular head
o intermediate lamina: manubrial fibres
o posterior lamina: sternocostal fibres (insertion runs higher than anterior lamina)
Nerve supply:
o medial (pierces pectoralis minor) & lateral (pierces clavipectoral fascia) pectoral nerves (from medial & lateral cords of brachial plexus)
o only muscle to be supplied by all 5 segments of brachial plexus (C5-8 & T1)
Action
o medial rotation, adduction
o abduct & flex to test
Anantomy of pec minor.
Origin: 3rd to 5th ribs near costal cartilages
Insertion: medial border and superior surface of coracoid process of the scapula
Action: stabilisation of the scapula (draws inferiorly and anteriorly against the thoracic wall)
Innervation: medial pectoral nerves
Anatomy of Latissimus dorsi
Forms posterior wall of axilla
Origin: T7 – S5, posterior part of iliac crest via lumbar fascia, posterior 1 /3 outer lip of iliac crest (reinforced by slips from ribs 8-12
interdigitate with external oblique)
Insertion: floor of intertubercular groove (spirals)
Nerve supply: thoracodorsal nerve (C6, 7, 8 from posterior cord of brachial plexus) (vulnerable in op’s on axilla)
Action: extends shoulder, medially rotates humerus, adducts shoulder (with pectoralis major), an accessory muscle of both inspiration (costal fibres) & expiration
Anatomy of Serratus anterior
Covers medial wall of axilla
Origin: ribs 1-8
Insertion: vertebral border of scapula
Nerve supply: long thoracic nerve (roots of C5, 6, 7)
Action: protracts the scapula (pushing), lower 4 digitations assist trapezius in rotating scapula laterally; paralysis =‘winging’
Anatomy of axilla.
Borders
Anterior: Pectoralis major & minor, subclavius, clavipectoral fascia
Posterior: subscapularis, teres major, lat dorsi
Medial: upper part of serratus anterior (lower limit = 4th rib)
Lateral: intertubercular groove
Floor: axillary fascia
Apex: clavicle, upper boarder of scapula, outer boarder of 1st rib
Levels of dissection
I – below lateral edge of pec minor
II – behind pec minor
III – above & medial to pec minor
Clavipectoral fascia
Clavicle -> encloses subclavius -> encloses pec minor -> floor of axilla
Lies ant to neurovascular structures of axilla
Pierced by
o Lateral pectoral nerve
o Thoraco-acromial artery
o Cephalic vein
o Lymph nodes from pectoral region to apical group of axillary node
Anatomy of subscapularis
Origin: medial 4/5 costal surface of scapula
Insertion: lesser tuberosity of humerus & medial lip of intertubercular groove
Nerve supply: upper & lower subscapular N’s (C5, 6 posterior cord of brachial plexus)
Action: shoulder stability, medial rotation of humerus
Other: subscapular bursa communicates with shoulder joint
Anatomy of teres major
Origin: dorsal surface of scapula, lateral part of inferior angle
Insertion: medial lip of intertubercular groove
Nerve supply: lower subscapular N
Action: adductor & medial rotator of humerus
Anatomy of Axillary artery
Lateral border of 1st rib to inferior border of teres major -> brachial artery
enters apex of axilla over 1st digitation of serratus anterior, becomes brachial at lower border of teres major
invested in axillary sheath (continuation of prevertebral fascia)
Parts
o 1st part medial pec minor (1 branch)
Superior thoracic – pectoral muscles
o 2nd part behind pec minor (2 branches)
Thoracoacromial – clavicular, humeral, acromial and pectoral branches
Lateral thoracic – pectoral muscles, breast
o 3rd part lateral pec minor (3 branches)
Subscapular -> thoracodorsal (lat dorsi), circumflex scapular
Anterior circumflex humeral artery (coracobrachialis, biceps, shoulder joint)
Posterior circumflex humeral artery -> Travels through quadrangular space -> long and lateral heads of triceps, shoulder joint, anastomoses with profunda brachii artery
Anatomy of axillary vein.
direct continuation of Basilic V – changes name at lower border of teres major
runs medial then inferior to A
leaves apex anterior to 3rd part of subclavian A
corresponding tributaries to branches of A
- plus Cephalic V drains into 1st part
Separated distally from artery by ulnar nerve and the medial cutaneous nerve of the forearm.
medial cutaneous nerve of the arm emerges between the axillary A and V
medial to the vein.
More proximally the medial head of the median nerve emerges from between A & V.
At an even higher level the medial pectoral nerve also emerges from between A & V.
Anatomy of intercostobrachial nerve.
Cutaneous branch from 2nd intercostal N
Exits b/w 1st & 2nd ribs -> across axilla -> skin on medial upper arm
Often 2nd intercostobrachial from 3rd intercostal N
Lymph nodes of Axilla
Anterior / Pectoral group o with lateral thoracic A
Posterior / Subscapular group
o along subscapular A
Lateral group
o along medial side of axillary V
Central group
Apical group
o drain via subclavian lymph trunk to supraclavicular nodes
Anatomy of brachial plexus.
Roots (5)
anterior rami of C5, 6, 7, 8, T1 (after segmental supply to prevertebral & scalene muscles)
lie behind scalenus anterior & emerge on scalenus medius
Branches:
C5: Dorsal scapular N
C5, 6: N to subclavius (in front of roots)
C5, 6, 7: Long thoracic N
Trunks (3)
cross posterior triangle of neck
Superior (C5,6):
o Suprascapular N (C5, 6)
Middle (C7)
Inferior (C8, T1)
Divisions (2)
anterior & posterior: behind clavicle
Posterior divisions -> posterior cord
Anterior divisions -> lateral & medial cords
Cords (infraclavicular part) (3)
Named for their relationship to the 2nd part of the axillary artery
Lateral (3)
Lateral Pectoral N (C5, 6, 7)
Musculocutaneous N (C5, 6)
Lateral root of Median N
Posterior (5)
Upper subscapular (C5, 6)
Thoracodorsal (C6, 7, 8)
Lower subscapular (C5, 6)
Axillary (C5, 6)
Radial (C5, 6, 7, 8, T1)
Medial (5)
Medial Pectoral N (C8, T1)
Medial root of Median N (C8, T1)
Medial Cutaneous N of arm (C8, T1)
Medial Cutaneous N of forearm (C8, T1)
Ulnar N (C7, 8, T1)
Anatomy of long thoracic nerve.
C5, 6, 7
path: behind roots, emerges from lateral border of scalenus medius & passes into axilla on serratus anterior (posterior to midaxillary line)
Passes vertically downward to enter axilla
In proximal axilla it is superficial to serratus anterior fascia, embedded in fatty tissue
Travels medially & at level of 4th & 5th intercostal spaces, pierces fascia to lie on muscle
Courses behind mid-axillary line & posterior to lateral thoracic perforating vessels
Supplies: serratus anterior
Anatomy of lateral pectoral nerve.
C5, 6, 7
o path: crosses in front of axillary A & V at level of medial border of pec minor to communicate with medial pectoral N, pierces clavipectoral fascia
o supplies: pectoralis major & minor
Anatomy of musculocutaneous nerve
C5, 6
o path: through coracobrachialis, becomes Lateral cutaneous N of forearm
o supplies: coracobrachialis, biceps, brachialis
Anatomy of thoracodorsal nerve.
C6, 7, 8
o path: runs down post axillary wall behind axillary A & V to lie on subscapularis -> enter deep surface of lat dorsi, lies ant to subscapular A then thoracodorsal A (vulnerable in axillary surgery)
o supplies: latissimus dorsi
Anatomy of axillary nerve
C5, 6
o path: backwards through quadrangular space
o anterior branch: winds behind humerus to deep surface of deltoid then skin
o posterior branch: winds around post border of deltoid to become Upper Lateral cutaneous N of arm
o supplies: shoulder joint, deltoid, teres minor, skin
Anatomy of radial nerve
C5, 6, 7, 8, T1
o path: lies on latissimus dorsi tendon, through triangular space
o supplies: long, medial & lateral heads of triceps (in that order & before winding ‘round spiral groove), skin via Post Cutaneous N of arm
Anatomy of medial pectoral nerve.
C8, T1
o path: arises behind axillary A, emerges b/w A & V -> pierces pectoralis minor to supply pectoralis major (joined by lateral pectoral N)
o supplies: pectoralis minor & major
Anatomy of axillary artery
o Lateral margin 1st rib → lower margin of teres major
o Parts
▪ A1 – superior to pec minor
▪ A2 – posterior to pec minor
▪ A3 – inferior to pec minor
o Branches
▪ Screw the lawyers save a patient
▪ A1:
• Superior thoracic
▪ A2:
• Thoracoacromial
• Lateral thoracic
▪ A3:
• Subscapular → thoracodorsal
• Anterior circumflex humeral
• Posterior circumflex humeral
Anatomy of Subclavian artery
o Aortic arch or brachiocephalic trunk to lateral margin of 1st rib
o Parts:
▪ S1 – medial to scalenus anterior
▪ S2 – posterior to scalenus anterior
▪ S3 – lateral to scalenus anterior
o Branches
▪ Vit C+D
▪ S1:
• Vertebral
• Internal mammary
• Thyrocervical
o Inferior thyroid
o Suprascapular
o Ascending cervical
o Transverse cervical
▪ S2:
• Costocervical
o Superior intercostal
o Deep cervical
▪ S3:
• Dorsal scapular
Anatomy of thoracic duct
Course
Originates atcisterna chyli in midline at level of L2
Passes cephalad through the diaphramatic hiatus
Ascends on right side of thoracic spine
Crossed toleft side at level of T4
Continues along theleft side of oesophagus
Arches forward and laterally at the root of the neck
Emerges betweenleft subclavian and common carotid arteries
Passes between internal jugular vein and scalenus anterior muscle
Joinsleft subclavian vein at eh angle it makes with IJV
