Anatomy Flashcards
Vertebral levels: T2, T5, T9, L1, L3, L4, S2
Suprasternal notch - T2
Angle of Louis - T5
Xiphoid - T9
Transpyloric plane of Addison - L1 - one hand width beneath xiphoid, crosses pancreatic neck, duodenojejunal flexure, fundus of gallbladder, tip of 9th costal cartilage, renal hilum
- where the spinal cord terminates
(umbilicus around L3-5, dermatome is T10)
Subcostal plane - L3 (bottom of 10th rib)
Iliac crest plane - L4 - bifurcation of aorta
Posterior superior iliac spines - S2 - termination of dural sheath, posterior superior iliac spines, see dimple above buttocks
McBurney’s point
Palmer’s point
McBurney - 2/3 of the way from umbilicus to ASIS on right
Palmer - 2/3 of the way from umbilicus to point of intersection between midclavicular line and costal margins of 9th rib - used as laparotomy entry point if v obese or v thin, or midline adhesions
Arcuate line of Douglas
Where inferior epigastric vessels enter rectus sheath, where posterior rectus sheath terminates
Halfway between umbilicus and pubis
Linea alba
Fusion of abdominal muscle aponeuroses
Stretches from xiphoid to pubic symphysis
Fascia of abdomen
Fatty layer of Camper
Deep fibrous layer of Scarpa - blends with deep fascia of upper thigh, in perineum becomes Colles’ fascia
Muscles of anterior abdominal wall
Rectus abdominus
- originate at 5-7th costal cartilage
- insert at pubic crest
- tendinous insertions on anterior rectus, superior epigastric vessels pierce at these sites
External oblique
- originate at outer surface of lower 8 ribs
- insert at xiphoid, linea alba, pubic crest, pubic tubercle, ant half of iliac crest
- innervate by ant primary rami of T7-12
Internal oblique
- originate at lumbar fasciae, ant 2/3 iliac crest, lateral 2/3 inguinal ligament
- insert at lower 6 costal cartilages, linea alba, pubic crest
- innervate by ant primary rami of T7-12
Transversus abdominus
- originate at lower 6 costal cartilages, lumbar fascia, ant 2/3 iliac crest, lateral 2/3 inguinal ligament
- insert at linea alba and pubic crest
- innervate by ant primary rami of T7-12
Muscles of posterior abdominal wall
Psoas major
- originate at transverse process of lumbar vertebrae
- insert at lesser trochanter of femur
- innervate by ant primary rami of L1/2, acts as hip flexor
Psoas minor
- originate at bodies of T12/L1
- insert at ileopectineal eminence
- lies on psoas major, absent in 40%
Iliacus
- originates at upper 2/3 inner iliac crest
- inserts at lateral side of psoas major tendon
- innervation by femoral nerve, acts as hip flexor
Inguinal canal
Contains round ligament of uterus (or spermatic cord) and ilioinguinal nerve
Parallel and above inguinal ligament
- which runs from ASIS to pubic tubercle, aponeurosis by external oblique
Internal ring
- on transversalis fascia, midpoint of IngLig, medially demarcated by inferior epigastric vessels
External ring
- V shaped defect in external oblique aponeurosis
- above and medial to puic tubercle
BORDERS
- superior - internal oblique, transversus abdominus
- inferior - inguinal lig
- anterior - skin, fascia, oblique aponeurosis, internal oblique
- posterior - conjoint tendon (fusion of IO and TA), transversalis fascia
Spermatic cord
3 fascial layers
- external spermatic (external oblique aponeurosis)
- cremasteric (internal oblique)
- internal spermatic (transversalis fascia)
3 arteries
- testicular (from aorta)
- vas (from inf vesicle)
- cremasteric (from inf epigastric)
3 nerves
- ilioinguinal
- cremasteric (from genitofemoral)
- sympathetic
3 others
- vas deferens
- pampiniform plexus
- lymphatics
Femoral triangle contents
Femoral nerve, artery, vein
Deep inguinal nodes
Femoral triangle boundaries
Lateral - sartorius
Medial - adductor longus
Superior - inguinal ligament
Femoral sheath
From extraperitoneal intra-abdominal fascia
Anterior - transversalis fascia
Posterior - iliacus fascia
Contains femoral canal, femoral artery, femoral vein
NOT femoral nerve
Femoral ring
Entrance to femoral canal
Oval, larger in females
Contains fat and lymph node (Cloquet’s)
Anterior - inguinal ligament
Medial - lacunar ligament
Posterior - pectineus, pectineal fascia, Astley Cooper ligament
Lateral - femoral vein
Lacunar ligament
= Gimbernat’s ligament
Part of the aponeurosis of external oblique, reflected back and lateral, attached to pectineal line of pubis
Medial wall of inguinal canal
Larger in males
Posterior margin - pectineal ligament
Anterior margin - inguinal ligament
Adductor canal
= Subsartorial / Hunter’s
Aponeurotic tunnel in middle 3rd of thigh
Apex of femoral triangle to adductor hiatus
Contains femoral vessels and saphenous nerve
Anterior/lateral boundary - vastus medialis
Posterior - adductor longus and magnus
Sartorius muscle lies on aponeurosis
Hesselbach’s triangle
Aka inguinal triangle, site of direct inguinal hernia
Lateral - inferior epigastric artery
Medial - rectus abdominus
Inferior - inguinal ligament
Peritoneal cavity
Primitive coelomic cavity of embryo
Serous lined
Closed in male
Lesser sac - cavity formed by lesser and greater omentum
Epiploic foramen
= foramen of Winslow
entrance to lesser sac
Superior - caudate lobe of liver
Anterior - free border of lesser omentum
Inferior - 1st part duodenum, hepatic artery
Posterior - inferior vena cava
Lesser omentum
= gastrohepatic omentum
Double layer peritoneum from liver to lesser curvature of stomach
4 ligaments - hepatogastric, hepatoduodenal, hepatophrenic, hepato-oesphageal
Free border of lesser omentum contains portal vein, common bile duct, hepatic artery (enclosed in Glisson’s capsule)
Greater omentum
= gastrocolic omentum
Peritoneum fold from stomach to posterior abdominal wall, encasing transverse colon
Duodenum on right
Gastrolineal ligament on left
Right and left gastroepiploic vessels supply
4 ligaments - gastrocolic, gastrosplenic, gastrosphenic, splenorenal
Ligaments in peritoneal cavity
Umbilical ligaments
- mediaN (urachus, embryological remnant of allantois)
- mediaL (embryological remnant of umbilical artery)
- lateral (overlies inferior epigastric artery)
Falciform ligament - umbilicus to liver
Ligamentum teres - remnant of umbilical vein, passes between quadrate and left liver lobes, attaches to free border of falciform ligament
Intraperitoneal fossae
4
Lesser sac
Intersigmoid
Paraduodenal (between duodenojejunal junction and inferior mesenteric vessels)
Retrocaecal
Subphrenic spaces
5
Subphrenic - R and L, divided by falciform ligament
R subhepatic (Morison’s)
L subhepatic (lesser sac)
R extraperitoneal (between bare area of liver and diaphragm)
Ileopectineal eminence
Point of fusion between pubis and ilium
Lateral to this, 2 muscles pass in a groove (iliacus and psoas major)
Acetabulum
Fusion point of the 3 innominate bones of pelvis: ilium, ischium, pubis
Sacrum
5 fused vertebrae, triangular
Sacral promontory is anterior border of sacrum
Ala (wings) laterally, form the anterior and posterior foramina
Sacral hiatus transmits the 5th sacral nerve
Dural sheath terminates at S2, beyond this sacral canal contains - fatty tissue of extradural space, cauda equina, filum terminale
(+ coccyx is 3-5 fused vertebrae)
Pelvic joints
Symphysis pubis - secondary cartilagenous
Sacroiliac - synovial
Pelvic brim boundaries
Pectineal line
Arcuate line
Sacral promontory
Upper margins of symphysis pubis
Pelvic outlet boundaries
Pubic arch (ischiopubic rami)
2x sciatic notch
Coccyx
(diamond shape)
Greater sciatic foramen
Superior - sacroiliac ligament
Posteromedial - sacrotuberous ligament (sacrum to ischial tuberosity)
Inferior - sacrospinous ligament (ischial spine to sacrum)
Anterolateral - greater sciatic notch
Divided from lesser sciatic by sacrospinous ligament
Contains:
- Sciatic and pudendal nerves
- Superior gluteal artery, vein and nerve
- Inferior gluteal artery, vein and nerve
- Posterior femoral cutaneous nerve, nerve to obturator internus, nerve to quadratus femoris
Lesser sciatic foramen
Anterior - ischial tuberosity
Lateral - lesser sciatic notch
Posterior - sacrotuberous ligament
Superior - sacrospinous ligament
Contains:
- Internal pudendal artery and vein
- Pudendal nerve (first leaves the pelvis via the greater sciatic foramen, and then re-enters via the lesser sciatic foramen)
- Obturator internus tendon
- Nerve to obturator internus
Male vs female pelvis
Male - large acetabulum, round obturator foramen, inturned ischial tuberosity, heart shaped pelvic inlet, long pelvic canal, small pelvic outlet, acute pubic rami angle, long and narrow sacrum
Female - small acetabulum, oval obturator foramen, everted ischial tuberosity, oval pelvic inlet, short pelvic outlet, wide pubic rami angle, 4 knuckle ischial tuberosity angle, short and wide sacrum
Pelvis measurements
Plane of inlet 60deg to horizontal
Transverse outlet = distance between ischial tuberosities
- 12.7cm at inlet, 11.5cm at mid, 10cm at outlet
Oblique outlet = midpoint of sacrotuberous ligament to junction of opposite ischial and pubic rami
- 11.5cm at inlet, mid and outlet
Anteroposterior outlet = from midpoint of pubic symphysis to apex of coccyx
- 10cm at outlet, 11.5cm at mid, 12.7cm at inlet
(INVERT TRANSVERSE AND AP)
Piriformis
Origins - ant sacrum, greater sciatic foramen, ant surface of sacrotuberous ligament
Insertion - greater trochanter of femur
- exits pelvis via greater sciatic foramen
- pierced by common peroneal nerve
Obturator internus
Origins - med surface of obturator membrane, ischium, pubis
Insertion - greater trochanter of femur
- exits pelvis via lesser sciatic foramen
Obturator externus
Origins - obturator membrane, obturator foramen
Insertion - greater trochanter of femur
Pelvic fasciae and ligaments
Pelvic fascia -connective tissue covering of pelvis, inc fascia of levator ani and obturator internus
Endopelvic fascia - extraperitoneal tissue of uterus (parametrium), vagina, bladder, rectum
- gives rise to 3 sets of ligaments which support cervix and vaginal vault, are lengthened in pelvic floor prolapse
– cardinal - laterally from cervix and upper vagina to pelvic side wall along line of insertion of levator ani, pierced by ureters, ACROSS/DIAGONAL
– uterosacral - from posterolateral aspect of cervix at level of isthmus, to periosteum of sacroiliac joints and lat part of S3, encircling the POD, BACK
– pubocervical (from cardinal ligaments to pubis) UP
Pelvic floor
PELVIC DIAPHRAGM
Levator ani
- origins - post aspect of pubic bone, fascia of pelvic side wall, ischial spine
- insertion - perineal body, anal sphincter, coccyx, median fibrous raphe
- forms levator prostate, sphincter vaginae, puborectalis, pubococcygeus, iliococcygeus
Coccygeus
- origins - sacrospinous ligament, ischial spine
- insertion - coccyx
+ superficial muscles of perineum, forming the anterior (urogenital) triangle and posterior (anal) triangle, separated by line across ischial tuberosities
Perineal membrane
Covers urogenital triangle, pierced by urethra and vagina
Deep perineal pouch
- between perineal membrane and levator ani fascia
- contains external urethral sphincter, deep transverse perineal muscle, and bulbourethral (Cowper’s) glands
Superficial perineal pouch
- between perineal membrane and perineal fascia (Colles’)
- contains superficial perineal muscles, bulbospongiosus, ischiocavernosus, Bartholin’s glands (greater vestibular), crura of clitoris
Perineal body
Fibromuscular node at midline of junction anterior posterior perineum
Point of attachment for external anal sphincter, bulbospongiosus, transverse perineal muscles, levator ani
Posterior / anal triangle
Between ischial tuberosities and coccyx
Contains:
Levator ani
Anus
Ischiorectal fossa
- lobulated fat, anus, ext anal sphincter (attach to perineal body, coccyx and puborectalis, Alcock’s canal
- fossae on either side communicate behind the anus
Stomach
J shape
Body secretes pepsin and HCl (oxyntic cells)
Pyloric antrum secretes alkaline juices and gastrin
- incisura angularis marks junction between body and antrum
- vein of Mayo marks the junction between pylorus and duodenum
Sphincters at cardia and pylorus
Borders
- anterior - left costal margin, diaphragm, left lobe liver
- posterior - lesser sac, pancreas, transverse mesocolon, spleen, splenic artery, left kidney + suprarenal gland
- superior - left dome diaphragm
Blood supply of stomach
COELIAC AXIS
Left gastric
Splenic
- short gastric
- left gastroepiploic
Hepatic
- right gastric
- cystic
- gastroduodenal
- - right gastro-epiploic
- - superior pancreatoduodenal
Lymphatic and nerve supply of stomach
LYMPH
Area 1 - superior 2/3 stomach - direct to aortic nodes
Area 2 - right side of inferior 1/3 - via subpyloric node to aortic nodes
Area 3 - left 1/3 of inferior 1/3 - via suprapancreatic node to aortic nodes
NERVE
- vagus and posterior nerve of Latarjet
Duodenum
C shaped, 25.5cm
Initial 2.5cm covered by peritoneum, then is retroperitoneal
4 parts:
1st - 5cm long; liver and gallbladder anterior; IVC, portal veins, CBD, GD artery posterior
2nd - 7.5cm long; curves around head of pancreas
- contains major duodenal papilla aka ampulla of Vater (opening of major panreatic duct and CBD); minor duodenal papilla (opening of accessory panceatic duct); and sphincter of oddi
3rd - 10cm long; transversely to left; SMA and mesenteric root anterior, IVC, aorta and L3 posterior
4th - 2.5cm long
Superior pancreatoduodenal artery (branch of coeliac), and inferior pancreatoduodenal artery (branch of SMA)
Duodenojejunal junction
L2
Ligament of Treitz identifies
= peritoneal fold from right crus of diaphragm, containing smooth and skeletal muscle fibres
Inferior mesenteric vessels descend from behind pancreas immediately to left of junction
Mesentery starts here
Small intestine
3-10cm long, with valvulae conniventes
Mesentery - 15cm long, starts at duodenojejunal junction (L2) and ends at right sacroiliac joint
Jejunum vs ileum
- J thicker, larger diameter, in umbilical region
- I has thicker mesentery with more fat, more arcades formed from vessels
Large intestine segments and length
Caecum (+ appendix)
Ascending colon - 20cm
Transverse colon - 45cm
Descending colon - 25cm
Sigmoid - 12cm
Rectum - 12cm
Anal canal - 4cm
Features of large intestine
- Appendices epiploicae (fat filled peritoneal tags) - except appendix, caecum, rectum
- Taenia coli - 3 flattened bands from appendix to rectosigmoid junction
- sacculations
- goblet cells and no villi in mucosa
- Meissner’s submucosal nerve plexus, Auerbach’s muscular layer nerve plexus
Peritoneal coverings of large intestine
Peritonised - transverse colon and sigmoid
Non-peritonised - ascending and descending colon
Inconsistent - caecum and appendix
Rectum
From S3, to lower 1/4 vagina or apex of prostate
Peritoneal covering at upper 1/3 posterior, middle 1/3 posterior/lateral, entire lower 1/3
3 lateral inflexions (left right left), valves of Houston at each inflexion
Denonvillier’s fascia separates rectum from anterior structures
Levator ani on either side laterally
Anal canal
Upper half - columnar epithelium with columns of Morgagni
- superior rectal vessel (if these dilate get haemorrhoids)
- lumbar nodes
Valves of Ball separates this junction (pectinate line)
Lower half - squamous epithelium
- inferior rectal vessel
- inguinal nodes
Anteriorly perineal body, posteriorly coccyx, laterally ischiorectal fossa
Appendix
= vermiform appendix
- connected to caecum posteriomedially
- base is 2.5cm below ileocaecal valve
- ileocolic artery supplies
- 2 folds of peritoneal attachment - ileocaecal fold and appendix mesentery (containing ileocolic artery)
Portal vein system
Drains from alimentary tract (not anus) to liver
- IMV joins splenic at L3
- SMV joins splenic at L1 behind neck of pancreas, giving rise to portal vein
- portal vein then divides into L and R
Collaterals between portal and systemic venous systems
Meckel’s diverticulum
Remnant of vitello-intestinal duct (communication between midgut and yolk sac)
2% prevalence
2:1 more in males
2inches (5cm) long
2ft (61cm) from ileocaecal junction
Liver
Largest organ, 4 lobes (right, left, ant quadrate and post caudate)
Contains falciform ligament, ligamentum teres (left umbilical vein remnant), ligamentum venosum (ductus venosum remnant)
Lesser omentum from porta hepatis (containing bile duct, portal vein, hepatic artery) and ligamentum venosum
3 veins - left, right, central
3 arteries - left, right, cystic
Biliary system
GALLBLADDER (holds 50ml bile, columnar epithelium, separates R and quadrate lobes of liver)
into CYSTIC DUCT (3.8cm long)
Merges with COMMON HEPATIC DUCT (fusion of right and left ducts, 3.8cm long)
to form COMMON BILE DUCT (10cm long)
Pancreas
Retroperitoneal
Endocrine and exocrine
Supplied by splenic and pancreatoduodenal arteries
Anterior - stomach, lesser sac
Posterior - left kidney + gland, diaphram
Development of pancreas
Ventral bud - smaller, forms part of head and uctinate process
- drained by duct of Wirsung (major pancreatic duct)
Dorsal bud - larger, forms body, tail, and part of head and uctinate process
- contains accessory duct of Santorini (accessory pancreatic duct, non functional)
Islets of Langerhans secrete…
- glucagon from alpha cells
- insulin from beta cells
- somatostatin from delta cells
- pancreatic polypeptide from F cells
Splenic ligaments
Intraperitoneal
Gastrosplenic ligament to greater curve of stomach, containing short gastric and left gastroepiploic artery
Lienorenal ligament to posterior abdominal wall, containing splenic artery and tail of pancreas
Kidney
Retroperitoneal
R slightly lower than L
Supplied by sympathetic nerve fibres
3 capsules - renal fascia, perinephric fat, true capsule
- renal fascia blends with diaphragm above, IVC and aorta medially, transversalis fascia laterally, ureteric tracts inferiorly
- suprarenal glands NOT in the renal fascia
Ureters
25cm long, valveless
Pass anterior to medial edge of psoas major, cross into pelvis at bifurcation of common iliac A in front of SI joint. On lateral wall of pelvis in front of internal iliac A and under uterine A.
Cross into bladder at level of ischial spine.
Pierce the cardinal and broad ligaments.
Bladder
Extraperitoneal
(intra-abdominal in children <3yo)
Ureteric orifices 2.5cm apart
Trigone is triangular area bounded by ureteric orifices and internal meatus
Urethra
3.8cm long in females
25cm long in males - 3 portions including prostatic, membranous, spongy
Spiral grooves inside
Mucus containing urethral glands.
Epithelium - transitional near bladder, stratified columnar in middle, then stratified squamous near external urethral orifice
Urethral sphincter
Internal - at junction of urethra and bladder
- smooth muscle (continuation of detrusor)
- autonomous sympathetic control from inferior hypogastric plexus
- not anatomically distinct in females, in males it prevents retrograde ejaculation
External - at junction of urethra and bladder in females, and after prostate in males
- skeletal muscle
- voluntary control via perineal branch of pudendal nerve
Scrotum
Contains median longitudinal raphe, sebaceous glands, dartos muscle
Divided into 2 sacs
2.5 degrees cooler than body temperature
Epididymes
Efferent ductules in from testes
Head, body, tail
6m long
Lined by ciliated epithelium
Passage of sperm through takes 8-14days
Vas deferens
From epididymis to seminal vesicles in spermatic cord
45cm long - similar length to femur/spinal cord
Ejaculatory ducts connect to urethra
Seminal vesicles
Irregular shaped sacs between bladder and rectum
5cm long
Reservoir for and secrete nourishing fluid for sperm
Testes structure
L lower than R
3 layers - tunica vaginalis, albuginea, vasculosa
Sertoli cells - spermatozoa
Leydig cells - testosterone
Divided into 300 lobules, each containing 1-3 seminiferous tubules, each tubule 60cm long
Seminiferous tubules
Make up lobules of testes, 90%
Anastamose at rete testes (way into epididymis)
Lined with germinal epithelium
Basement membrane acts as blood barrier
Vascular/lymph/nerve supply of testes
Testicular artery (branch off aorta) anastamoses with vas artery (branch of inferior vesical, off external iliac)
Lymph drainage via para-aortic nodes, and cervical nodes
Nerve supply via T10
Cells of testes
Sertoli
- WITHIN seminiferous tubules
- nourish spermatozoa
- produce inhibin and oestrogen
- contain FSH receptors
Leydig
- BETWEEN seminiferous tubules
- produce testosterone
- contains LH receptors
Development of testes
3 month - reach iliac fossa
7 months - traverse inguinal canal
8 months - at external ring
9 months - descend into scrotum
Appendix testes is remnant of paramesonephric duct
Appendix epididymis is remnant of mesonephros
Prostate
3x4cm, pyramidal
Between bladder neck and external urethral sphincter
Two capsules - true capsule, false capsule (extraperitoneal fascia - which continues with bladder and Denonvillers’ fascia)
Blood supply by inferior vesical artery
Prostatic plexus lies between 2 capsules, from dorsal vein of penis and then drains into internal iliac vein and valveless vertebral veins of Batson
Labia majora
Analogous to scrotum
Hair bearing skin, sebaceous glands, smooth muscle (tunica Dartos), and nerve endings
Insertion point of round ligament
Nerve supply - iliohypogastric (L1), ilioinguinal (L1), genitofemoral (L1-2), posterior femoral cutaneous (S1-3), pudendal nerve (S2-4)
Labia minora
Hairless skin folds
Give rise to prepuce, frenulum, fourchette
Contain sweat and sebaceous glands
Encloses the vestibule, which contains urethral and vaginal orifice
- blood supply by azygous A of vagina and pudendal A
Clitoris
Erectile tissues
Glans, shaft attached to pubis, and paired crura attached to inferior pubic rami
Ischiocavernosus muscles overlie crura, orginate from ischial tuberosity
Bulbospongiosus muscles originate from perineal body, insert into clitoral shalft and overlies vestibular bulb and Bartholin’s glands
Bartholin’s glands
Paired pea-sized, lying between perineal membrane and bulbospongiosus muscle at tail end of vestibular bulb, deep to posterior labia majora
At 5 and 7 o clock positions between hymen and labium minus
Remnants of hymen are carunculae myrtiformes
Vagina
Anterior wall 7.5cm, posterior wall 10cm - proportional to height
NO glands. Kept moist by cervical glands and seepage of fluid from blood capillaries
- vaginal fluid pH 4, high K low Na, but alkaline for 6hrs post coitus
- Doderlein’s bacilli converts glycogen to lactic acid
Only posterior upper 1/4 is covered by peritoneum
Ureters above and lateral to fornix, 1.5cm from cervix
4 layers in the wall - inner squamous epithelium in arbour vitae folds, connective tissue, muscular layer (inner circular and outer longitudinal), connective tissue
Blood and lymphatic supply of vagina
Blood supply from (sup to inf) uterine, vaginal, internal pudendal arteries - all branches of internal iliac
Upper 1/3 - lymph to external and internal iliac nodes
Middle 1/3 - internal iliac nodes
Lower 1/3 - inguinal nodes
Sacral plexus nerve supply
Uterus
50g in P0, 70g in multip, 1kg at term
Flexion at level of internal os, to ante or retroflex, usually 170degrees
Ante or retroversion at axis of cervix on vagina, usually 90degrees
Endometrium - functional and basal layer
Myometrium - inner circular, middle oblique, outer longitudinal
Primetrium = peritoneum
Supply to uterus
Nerve - sacral plexus
Blood
- basal layer - straight arterioles
- functional layer - spiral arterioles
Lymph
- fundus via round ligament to inguinal node, and via ovarian vessel to para-aortic node
- body via broad ligament to external iliac node
Cervix
Supravaginal epithelium - columnar
Vaginal epithelium - stratified squamous
Mucosa has arbour vitae ridges, spinnbarkeit (stretchy) mucus
Lymph drainage
- lateral via broad ligament to external iliac node
- posterolateral via uterine vessels to internal iliac node
- posterior via sacral node
Uterine changes in pregnancy
Lower segment formed 70% isthmus, 30% cervix
Retraction to shorten upper segment
Decidua is endometrium under influence of progesterone, high glycogen content, produces prolactin and insulin-like growth factor
25mmHg pressure can cause cervical dilatation. Braxton Hicks can be as early as 8w.
Fallopian tubes
10cm long, isthmus, ampulla, infundibulum, fimbriae
4 layers
- ciliated columnar epithelium
- inner circular muscle
- outer longitudinal muscle
- peritoneum
Nerve supply via ovarian plexus
Uterine ligaments
Broad ligaments - double fold of peritoneum
Round ligaments - from cornua to labia majora
Cardinal ligaments - from cervix to lateral wall of pelvic cavity
Uterosacral ligaments - from cervix to periosteum of sacrum
Pubocervical ligaments - from cervix to pubic bone
Infundibulopelvic ligaments
= IFPs
Folds of broad ligament, from infundibulum (end of fallopian tubes) to lateral wall of pelvis
Contain ovarian vessels
Ovaries
3x2x1cm, around 5-8g, almond shape
4 layers - germinal epithelium (CUBOIDAL), tunica albuginea, cortex (containing ovarian follicles), medulla (containing vessels)
Supported by IFP ligament, broad ligament (attached by mesovarium), ovarian ligament
Nerve supply T10
Ovarian fossa
AKA Waldeyer’s
Shallow depression on lateral wall of pelvis
Contains obturator nerve
External iliac vessel above, obliterated umbilical artery anterior, internal iliac vessels and ureter posterior
Breasts
Modified sudoriferous glands that produce milk. Ectoderm origin.
Over 2-6th ribs, serratus anterior, pec major, rectus sheath
20 lobules, draining to nipple via lactiferous ducts. Separated by ligaments of Cooper which run subcut tissue to fascia of chest wall.
Glands of Montgomery are modified sebaceous glands to lubricate the areola
Supply to breast
BLOOD
- axillary artery via lateral thoracic and acromiothoracic
- internal thoracic
- intercostal
NERVE
- breast from T4-6
- nipple from T4
LYMPH
- axillary
- parasternal
- abdominal
Branches of abdominal aorta
Enters abdomen at T12
Inferior phrenic
Coeliac trunk
Suprarenal
Superior mesenteric
Renal
Gonadal
Lumbar (4 paired lateral arteries)
Inferior mesenteric
Median (/middle) sacral
At L4, bifurcates to common iliac
Common iliac arteries
Commence at L4 bifurcation
End at L5/S1 sacroiliac joints, where they bifurcate again to external and internal
External - will branch further to inferior epigastric and deep circumflex iliac
Internal - aka hypogastric. Supply pelvic organs, buttocks, medial compartments of thigh. Divide at the margin of greater sciatic foramen.
Branches of internal iliac artery
Anterior - uterine, vaginal, vesical, umbilical, obturator, gluteal, rectal, internal pudendal
Posterior - ilio lumbar, lateral sacral, superior gluteal
Relations of internal iliac artery
Anterior - ureter, fallopian tubes, ovary
Posterior - internal iliac vein, lumbosacral trunk, piriformis
Medial - small bowel
Lateral - external iliac vessels, obturator nerve, psoas major
Femoral arteries
Branches of external iliac
Pass under inguinal ligament, lie in femoral triangle on tendon of psoas major
Branches into:
- profunda femoris
- superficial artery (epigastric and circumflex iliac)
- descending genicular
- external pudendal (superficial and deep)
Run medial to femur, cross via adductor hiatus (hole in tendon of adductor magnus), enter into popliteal fossa and become popliteal arteries
Obturator arteries
Arise from anterior division of internal iliac (usually)
Pass anteroinferiorly on lateral wall of pelvis to obturator foramen
Leave pelvic cavity via obturator canal
Inside pelvis branch to iliac, pubic and vesical branch
Outside pelvis branch to anterior and posterior
Internal pudendal arteries
Branch of internal iliac (terminal branch of anterior division) to supply external genitalia
Smaller in females
Exit pelvis via greater sciatic foramen, curve around sacrospinous ligament, enter ischio-anal fossa via lesser sciatic foramen and travel in pudendal canal
Branch into inferior rectal, perineal, posterior labial, dorsal A of clitoris, deep A of clitoris, anterior bulb of vestibule
Homologous male and female arteries
Vaginal = inferior vesical in males
Uterine = middle rectal in males
IVC, gonadal and saphenous veins
IVC commences at L5, terminates T8
Gonadal veins - right drains directly in, left drains to left RENAL vein
Greater saphenous - large superficial veins originating at dorsal vein of big toe, pass anterior to medial malleolus, enters fascia lata via saphenous opening on anterior aspect of thigh, joins femoral vein in femoral triangle
- receives the tibial veins and femoral vein branches
Thoracoepigastric veins connect femoral and axillary, running lateral to superficial epigastric veins
Lymphatic system
Thoracic duct originates T12, from cisterna chyli
Drains into left subclavian vein
45cm long
Right lymphatic duct arises anterior to scalenus anterior, drains into right subclavian vein
10mm long
Pelvic nodes drain to para-aortic nodes drain to cisterna chyli drains to thoracic duct
4 principal parts of brain
Brain stem - midbrain, pons, medulla oblongata
Cerebellum
Diencephalon - thalamus, hypothalamus, pineal gland
Cerebrum
Cerebrum
Cerebral cortex = grey matter, superficial layer. Contains gyri and sulci.
Corpus collusum = white matter, connecting cerebral hemispheres.
- frontal, parietal, temporal, occipital lobes
Precentral gyrus - anterior to central sulcus, primary motor area
Postcentral gyrus - posterior to central sulcus, primary somatosensory area
Basal ganglia
Several groups of nuclei in each cerebral hemisphere
Corpus striatum (inc caudate and lenticular nuclei), substantia nigra, red nuclei, subthalamic nuclei
Cerebrospinal fluid
In subarachnoid space, and 4 cavities in the brain - 2x lateral ventricles, third ventricle, fourth ventricle
Total 80-150ml in body, produced and absorbed at around 20ml/hr
- produced by choroid plexus, via filtration of blood plasma
- reabsorbed via arachnoid villi in superior sagittal sinus, and choroid plexus
CSF journey:
- lateral ventricles, to foramina of Monro, to third ventricle, to Aqueduct of Sylvius, to Fourth ventricle, to subarachnoid space
Cranial nerves and routes
Olfactory - exits via olfactory foramina
Optic - exits via optic canal
Occulomotor - from midbrain, via cavernous sinus, exits via superior orbital fissure
Trochlear - from midbrain, via cavernous sinus, exits via superior orbital fissure
Trigeminal - from pons, via cavernous sinus, exits in three divisions (ophthlamic - sup orbital, maxillary - foramen rotundum, mandibular - foramen ovale)
Abducens - from pons, via cavernous sinus, exits via sup orbital fissure
Facial - from cerebellopontine angle, via internal acoustic canal, exits via stylomastoid foramen
Vestibulocochlear - from cerebellopontine angle, exits via internal acoustic canal
Glossopharyngeal - from medulla, exits via jugular foramen
Vagus - from medulla, via carotid sheath, exits via jugular foramen
Accessory - runs via foramen magnum to jugular foramen
Hypoglossal - from medulla, via carotid sheath, exits via hypoglossal canal
Somatic pathways
Motor - pyramidal tract and extrapyramidal pathway (rubrospinal, tectospinal, vestibulospinal tracts)
Sensory - posterior and spinothalamic columns
Spinothalamic tract
3 neurone sets:
- pseudounipolar neurones in dorsal root ganglion - to cord
- tract cells (secondary neurones) - along cord
- thalamic nuclei (third order neurones) - to brain
Pathway decussates at level of spinal cord in anterior white commissure
Anterior tract - crude touch and pressure
Lateral tract - pain and temperature
Posterior column
aka dorsal column-medial lemniscus pathway
3 neurone sets:
- Meissner’s corpuscles 1st
- Gracile and cuneate nucleus (medial lemniscus) 2nd
- Ventral posteromedial nucleus of thalamus 3rd
For proprioception, discriminative touch, pressure, vibration
Test with Romberg’s
Corticospinal tract
Lateral - 90% - decussate in medulla to contralateral side
Anterior - 10% - stay on ipsilateral side
Motor neurones originating in precentral gyrus
Spinal meninges
Cover brain and spinal cord
3 layers:
space between wall of vertebral canal and dura is epidural space
Dura matter - brain to 2nd sacral vertebrae
** space between is subdural**
Arachnoid
** space between is subarachnoid**
Pia matter
Spinal cord
From medulla oblongata to vertebral level (L1 adults, L3/4 in infants)
At end there is conus medullaris bulge, giving rise to filum terminale (extension of pia matter, ending at coccyx)
- inferior to conus medullaris, nerve roots are cauda equina
Spinal nerves
31 pairs
- 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
Posterior / dorsal root - SENSORY
Anterior / ventral root - MOTOR
Nerve plexuses
Cervical C1-5
Branchial C5-T1
Lumbar T12-L5
Sacral L4-S5
Lumbar plexus gives rise to…
Iliohypogastric L1
Ilioninguinal L1
Genitofemoral L1-2
Lateral femoral cutaneous L2-3
Obturator L2-4
Femoral L2-4
I (twice) Get Laid On Fridays
Originates from anterior primary rami of L1-4
Traverses the psoas major and emerges from its lateral border (except obturator from medial border and genitofemoral from anterior aspects)
Iliohypogastric nerve
From L1 (and some T12 fibres), emerges lateral border of psoas major
Perforates transversus abdominus muscle
Branches into lateral cutaneous and anterior cutaneous
Communicates with ilioinguinal nerve
Genitofemoral nerve
From L1 - L2, emerges anterior surface of psoas major
Branches:
- femoral (lumboinguinal) - travels lateral to external iliac artery beneath inguinal ligament
- genital - via deep inguinal ring to innervate cremaster, scrotum, mons pubis, labia majora
Obturator nerve
From L2-L4, emerges from medial border of psoas major
Passes behind common iliac vessels, lateral to internal iliac vessels and ureter, along lateral wall of lesser pelvis, above and in front of obturator vessels, then into thigh via obturator canal and divides into anterior and posterior (both are then divided by obturator externus and adductor brevis muscles)
Innervate medial thigh, knee joint, adductor muscles of lower limb (external obturator, pectineus, adductor longus/brevis/magnus, gracialis)
Femoral nerve
L2-L4, largest branch of lumbar plexus
From lateral border of psoas major, then passes between PM and iliacus muscles, behind iliac fascia, divides anterior/posterior beneath inguinal ligament (straddling lateral circumflex femoral artery)
Anterior - intermediate anterior cutaneous nerve, medial anterior cutaneous nerve
Posterior - saphenous nerve, vastus lateralis, vastus medialis, vastus intermedius
Innervates hip and knee joints, and anterior compartment of thigh (quadriceps, sartorius, pectineus)
Saphenous nerve
Branch of femoral
Descends in femoral triangle into adductor canal, continues with long saphenous vein, crosses anterior to medial malleolus
Sacral plexus
S1-S4
Between piriformis muscle and pelvic fascia
Behind internal iliac vessels, ureter, sigmoid colon
Gives rise to:
- superior gluteal nerve L4-S1
- sciatic nerve L4-S3
- inferior gluteal nerve L5-S2
- posterior cutaneous nerve S1-S3
- pudendal nerve S2-S4
Posterior cutaneous nerve
S1-S3
Innervates perineum and skin of posterior thigh and leg
- exits pelvis via greater sciatic foramen, descends beneath gluteus maximus with inferior gluteal artery, runs down back of thigh beneath fascia lata then pierces the deep fascia at the knee and accompanies small saphenous vein
Superior gluteal nerve
L4-S1
Innervates gluteus medius, gluteus minimus, tensor fascia lata
- leaves pelvis via greater sciatic foramen above piriformis, accompanies superior gluteal vessels
Pudendal nerve
S2-S4
Passes between piriformis and coccygeus, leaves via greater sciatic foramen, crosses ischial spines, re-enters pelvis via lesser sciatic foramen, runs along pudendal vessels in ischiorectal fossa, within obturator internus fascia aka Alcock’s canal
Branches into inferior anal nerve, perineal (superficial), and dorsal nerve of penis/clitoris
Inferior gluteal nerve
L5-S2
Innervates gluteus maximus
- leaves pelvis via greater sciatic foramen below piriformis
Sciatic nerve
L4-S3, longest nerve in body
Innervates most of skin of leg, obturator internus, biceps femoris, semitendinosus, semimembranosus, adductor magnus, hip joint
Exits pelvis via greater sciatic foramen below piriformis, descends between greater trochanter of femur and tuberosity of ischium, divides around lower 1/3 or posterior thigh. Travels with posterior femoral cutaneous nerve and inferior gluteal artery, covered by gluteus maximus.
Tibial - via popliteal fossa, innervates most muscles of foot via plantar branch (except extensor digitorum brevis), knee joint, ankle joint, skin over lateral foot (sural branch).
Fibular / common peroneal - divides into deep and superficial
Autonomic plexuses
Coeliac - by coeliac ganglia, supplied by greater splanchnic nerve and vagus nerve
Superior mesenteric
Aortic
Inferior mesenteric
Superior hypogastric - at bifurcation of aorta
Inferior hypogastric - one on either side of pelvic side wall, together form the pelvic hypogastric plexus
Splanchnic nerve
Preganglionic sympathetic fibres:
Greater splanchnic T5-T9
Lesser splanchnic T10-T11
Least splanchnic T12
Lumbar splanchnic L1-L4 - joins sup hypogastric plexus
Sacral splanchnic S1-S4 - joins inf hypogastric plexus
Preganglionic parasympathetic fibres:
Pelvic splanchnic nerve S2-S4 joins inf hypogastric plexus
Pelvic splanchnic nerve
= nervi erigentes
On side of rectum
Motor innervation to beyond left 1/3 of transverse colon, uterus and bladder
Sensory innervation to bladder, urethra, rectum, anal canal, cervix, upper vagina, prostate
Inferior hypogastric plexus postganglionic sympathetic innervations
Motor - seminal vesicles, prostate, anal sphincter, urethral sphincter
Sensory - upper rectum, body of uterus
Hypothalamus
Below thalamus, above brainstem, forms the floor of the 3rd ventricle
2 portions:
- posteromedial - symptathetic innervation
- anterolateral - parasympathetic innervation
Pituitary gland
= hypophysis
Pea sized, sits on sella turcica (pituitary fossa) in sphenoid bone, covered by dural fold (sella diaphragm), below optic chiasm
Develops from ectoderm
3 parts:
Anterior lobe (adenohypophysis) - develops from Rathke’s pouch
Posterior lobe (neurohypophysis)
Pars intermedia
Pituitary gland blood supply
ANTERIOR blood supply from internal carotid and posterior communicating arteries, into superior hypophyseal artery, forms primary plexus at base of hypothalamus, into hypophyseal portal veins, secondary plexus, into anterior hypophyseal vein
POSTERIOR blood supply direct from ICA, inferior hypophyseal artery, plexus of infundibular process, posterior hypophyseal vein
Anterior pituitary
3 cell types - chromophobe, eosinophilic, basophilic
6 hormones secreted
Acidophil cells:
- prolactin
- growth hormone
Basophil cells:
- gonadotrophins LH/FSH
- thyroid stimulating TSH
Chromophobe cells:
- adrenocorticotrophic ACTH
- melanocyte-stimulating hormone
Posterior pituitary
Secretes and stores two hormones, both produced by the hypothalamus
- oxytocin
- antidiuretic ADH
Pineal gland
Secretes melatonin
Often calcified
Attached to roof of third ventricle
Covered by capsule of pia matter
Thyroid gland structure and supply
1st endocrine organ to appear, at day 24 embryonic development
Enclosed in pretracheal fascia
Isthmus - over 2-3rd tracheal ring
Lateral lobes - to 6th tracheal ring
Pyramidal lobe
Arterial supply - superior thyroid (branch of external carotid), inferior thyroid (branch of subclavian), thyroid ima (branch of aortic arch/brachiocephalic)
Venous drainage - superior thyroid and middle thyroid (to internal jugular), inferior thyroid to left brachiocephalic
Thyroid function
Follicles contain 2 cell types, follicular and parafollicular (C cells)
Secrete 3 principal hormones
- T4 thyroxine
- T3 triiodothyronine
- calcitonin (from C cells)
Parathyroid glands
Usually 4, pea sized yellow/brown
To control calcium and phosphate levels - PTH increases calcium and reduces phosphate
Two cell types - chief and oxyphilic
Carotid sheath
From base of skull to 1st rib + sternum
Contents:
- internal carotid artery (medial)
- internal jugular vein (lateral)
- vagus nerve
- deep cervical lymph node
Pierced by glossopharyngeal, accessory and hypoglossal nerves
Adrenal glands function
Cortex - from mesoderm, in 3 zones
- zona glomerulosa - secretes mineralcorticoids
- zona fasciculata - secretes glucocorticoids
- zona reticularis - secretes androgens
Medulla - from ectoderm, contains chromaffin cells (sympathetic postganglionic, secrete catecholamines adrenaline and noradrenaline)
Adrenal glands supply
Arterial - from renal artery, phrenic artery and aorta
Venous drainage - right suprarenal to IVC, left suprarenal to left renal vein
Nervous - preganglionic sympathetic fibres only, NO parasympathetic supply
Fetal skull
9 bones
- 2 frontal
- 2 parietal
- 2 temporal
- 2 sphenoidal
- 1 occipital
8 sutures
- 1 frontal
- 1 sagittal
- 2 coronal
- 2 lambdoidal
- 2 squamous (between parietal and temporal bones)
6 fontanelles
- 1 anterior
- 1 posterior
- 2 sphenoidal
- 2 mastoid
Vertex top of head, occiput behind posterior fontanelle, sinciput in front of anterior fontanelle (brow and face)
Fetal skull fontanelles
Anterior - between frontal and parietal bones
- diamond shaped
- closes at 18months
Posterior - between parietal and occipital bones
- closes at 2 months
Sphenoidal (anterolateral) - between frontal, parietal, temporal and sphenoidal bones, one each side
Mastoid (posterolateral) - between parietal, temporal and occipital bones, one each side
Pelvic Organ Prolapse Quantification (POPQ) system
0 No prolapse
1 >1 cm above hymen
2 Within 1 cm (proximal or distal) to the plane of the hymen
3 > 1 cm below the plane of the hymen but protrudes < 2 cm less than the total length of the vagina
4 Complete eversion of the vagina
