Anatomy - SUGER COPY Flashcards
What is the inguinal canal?
What does it lie superiorly to?
-Oblique passageway through the muscles of the anterior abdominal wall
-Lies superior to the medial half of the inguinal ligament
Through where does the inguinal canal pass?
-Through each layer of the abdominal wall as it travels medially and inferiorly
-Starting at the transversalis fascia deep and laterally
-Finishing with the external oblique aponeurosis superficially and medially
How long is the inguinal canal in adults and from where does it extend to and from?
-5cm long in adults
-Extends from deep inguinal ring (aperature in transversalis fascia) to superficial inguinal ring (aperature in the external oblique aponeurosis)
What do these mark?
Entry and exit of inguinal canal
What do these show?
Inguinal canal
What forms the anterior border of the inguinal canal?
-External oblique aponeurosis
-Laterally only: internal oblique aponeurosis
What forms the posterior border of the inguinal canal?
-Transversalis fascia
-Medially only: medial fibres of the aponeuroses of the internal oblique and transversus abdominis (together called conjoint tendon)
What forms the roof and floor of the inguinal canal?
Roof:
-Transversalis fascia
-Arching fibres of the internal oblique and transversus abdominis
Floor:
-Inguinal ligament - rolled up lower border of the external oblique aponeurosis
What are the contents of the inguinal canal in females?
-Round ligament of uterus
-Ilioinguinal nerve
-Genital branch of the genitofemoral nerve
What is this and what does it form?
-Inguinal ligament
-Floor of the inguinal canal
What do these form?
(arching fibres of internal oblique)
-Form roof of inguinal canal
What are these?
Contents of inguinal canal in females
In males what are all the contents of the inguinal canal contained within?
-Spermatic cord
-EXCEPT for ilioinguinal nerve which runs in the canal but lies outside the spermatic cord
What can the contents of the spermatic cord be divided into?
-Two nerves
-Three arteries
-Three fascial layers
-Four other structures
What are the nerves spermatic cord?
-Gential branch of genitofemoral nerve
-Sympathetic nerve fibres
What are the 3 arteries of the spermatic cord?
-Testicular artery
-Cremastatic artery
-Artery to vas deferens
What are the 3 fascial layers of the spermatic cord and their derivations?
-External spermatic fascia - EO aponeurosis derived
-Cremaster muscle and fascia - IO muscle derived
-Internal spermatic fascia - transversalis fascia derived
What are these?
Three fascial layers of spermatic cord
What are the four other structures in the spermatic cord?
-Pampiniform venous plexus
-Lymphatics
-Vas deferens
-Processus vaginalis
Describe scrotal skin and what is beneath it:
-Thin, wrinkled and more darkly pigmented that elsewhere
-Beneath is a thin layer of superficial fascia and a thin, involuntary muscle called the dartos
What does the superficial fascia of the testes extend to form?
Extends between the testicles to form a septum dividing the scrotum into right and left halves
What does each half of the scrotum contain?
-Testis
-Epididymis
-Lower part of spermatic cord
What is the function of testes?
-Male reproductive organs
-Produce sperm and secrete the sex hormone testosterone
Describe the testes and their coverings:
-Ovoid structures
-Covered by the same three layers of spermatic fascia that cover the spermatic cord
What are the testes partially covered by and what is it derived from?
Partially surrounded by a sac derived from peritoneum called tunica vaginalis
Describe the epididymis:
-Coiled tube lying along posterior border of each testis
-Expanded head superiorly
-Body
-Pointed tail lying at the lower pole of the testis
Describe the formation and movement of spermatozoa in the testes:
-Formed in the testes
-Stored in the epididymis
-Vas deferens carries sperm from the epididymis and travels with the testicular vessels in the spermatic cord
Where do testicular arteries arise?
Direct branches from the abdominal aorta
What is the venous drainage of the testes?
-Venous blood from the testis and epididymis enters the pampiform venous plexus
-Pampiform venous plexus forms testicular vein
-Right testicular vein enters the inferior vena cava
-Left testicular vein joins the left renal vein
What is the penis function?
Male organ of sexual intercourse
What is the penis primarily made up of?
-Three cylinders of erectile tissue
-Two corpus cavernosa dorsally (top of penis)
-One corpus spongiosum ventrally (bottom of penis)
What are the cylinders of the penis and what are they enclosed in?
-Corpus cavernosa and corpus spongiosum
-Enclosed within deep fascia of the penis - Buck’s fascia
Describe the end of the penis:
-Called the glans
-Expansion of the corpus spongiosum
What carries urine and semen and where does it lie in the penis?
-Penile urethra
-Lies within corpus spongiosum
-Approaches end of penis and opens via external urethral meatus
What is the arterial supply of the penis?
-Penile arteries
-Branch from the internal pudendal arteries which branch from the internal iliac arteries
What is the nerve supply to the penis?
-S2-S4 segments
-General sensation + sympathetic innervation = dorsal nerve of penis - branch of pudendal nerve
-Parasympathetic arise from peri-prostatic nerve plexus
What are parasympathetic nerves of the penis responsible for?
Dilating arteries of the corpora
What are primarily responsible for the increase in size and rigidity of the penis during erection?
Corpora cavernosa
What happens to the penis during sexual intercourse?
-Arterial blood flow into the corpora of the penis increases
-Corpora become engorged with bloods
-Spongiosum does not engorge to the same extent as the cavernosa
What is the main role of the corpus spongiosum during erection?
Prevent the urethra from being compressed, which would prevent ejaculation
What two terms are used interchangeably for the adrenal glands?
-Adrenal
-Suprarenal
Where do the adrenal glands lie?
-Close to upper pole of each kidney
-Right - lies behind the liver and inferior vena cava
-Left - lies behind the stomach and pancreas
What arteries supply each adrenal gland?
-3 arteries
-Superior adrenal artery - phrenic artery branch
-Middle adrenal artery - abdo aorta branch
-Inferior adrenal artery - renal artery branch
Label:
What are they?
Blood supply to adrenal glands
What is the venous drainage of the adrenal glands?
-Single vein on either side
-Right adrenal vein - IVC
-Left adrenal vein - drains first into left renal vein which then joins IVC
What is the adrenal gland composed of?
-Cortex (outer part)
-Medulla (inner part)
What do the cortex and medulla of the adrenal glands produce?
-Cortex - steroid hormones including cortisol, aldosterone and testosterone
-Medulla produces adrenaline
Are the kidneys intraperitoneal or retroperitoneal?
-Extra-peritoneal
-Retro-peritoneal as they are behind the peritoneum
Where do the kidneys lie?
-There is one on either side of the upper lumbar vertebrae
What are the layers that the kidney is embedded in?
-Each kidney embedded in perinephric fact
-This fatty layer is covered by renal fascia
-A further layer of paranephric fat is found outside the renal fascia
What is found on the medial border of each kidney?
-Renal hilum
-Renal vessels, nerves, lymphatics and ureter enter or leave the kidney
Where do the renal arteries and veins branch or drain into?
-Both renal arteries are branches of abdominal aorta
-Both renal veins drain into IVC
What makes up the internal aspect of the kidney?
-Cortex - outer part
-Medulla - inner part arranged into pyramids
-Calyces
Which parts of the nephron are in which parts of the kidney?
-Glomeruli, bowman’s capsule, proximal + distal convoluted tubules + part of collecting ducts are in the cortex
-Nephron loop (of henle) and rest of collecting ducts are in the renal pyramids
What is the pathway of urine through the kidney?
-From collecting ducts, travels down pyramid to renal papilla (apex of pyramid) to enter minor calyx
-Minor calyces merge with others to form major calyx
-Major calyces merge to form renal pelvis which is continuous with ureter
What does the ureter do and describe it:
-Carry urine to urinary bladder
-Narrow tubes with muscular walls that transport urine via peristalsis
Where do the ureters run?
-Anterior to psoas major on posterior abdominal wall
-Cross pelvic brim to enter the pelvis
-Enter bladder on its inferomedial aspect
What is the typical pain felt from obstructing kidney stone?
-Loin to groin
-Fibres supplying ureters are from T12 to L2 so pain is referred and felt in these dermatomes
Where is the posterior abdominal wall?
-Region behind the abdominal cavity
-Extends from attachments of the diaphragm above to pelvic brim below
What does the posterior abdominal wall consist of?
Lumbar spine together with the psoas and quadratus lumborum muscles
What structures pass along the posterior abdominal wall?
-IVC
-Aorta with associated autonomic plexuses and lymph nodes
-Sympathetic trunks on either side of the lumbar spine
What pass laterally through the posterior abdominal wall?
-Ureters pass down from the kidneys towards the pelvis on surface of psoas muscles
-Gonadal vessels run down over ureters to supply the gonads
What plexus forms on the posterior abdominal wall and what forms it?
-Lumbar plexus
-Lumbar spinal nerves L1-L4 with contribution with T12
What does the lumbar plexus give rise to and what are some notable ones?
-Several branches that innervate the skin and muscles of the abdominal wall and thigh
Notable branches:
-Iliohypogastric and ilioinguinal
-Genitofemoral
-Lateral femoral cutaneous
-Femoral
-Obturator
What do the iliohypogastric, ileoinguinal and genitofemoral nerves innervate?
-Iliohypogastric + ilioinguinal = anterior abdominal wall muscles and skin of external genitalia
-Genitofemoral - skin of external genitalia
What does the lateral femoral cutaneous nerve and femoral nerve innervate?
LFC - skin over lateral thigh
Femoral - large nerve supplies muscles and skin of anterior thigh
What does the obturator nerve innervate?
Supplies muscles and skin of the medial thigh
What is the pathway of the descending aorta?
-Pierces diaphragm at T12 and descends through abdomen as abdominal aorta
-Descends on posterior wall just left of midline
-Terminates by bifurcating into the left and right common iliac arteries at level L4
What does the abdominal aorta give rise to?
-Several paired and unpaired branches
Unpaired:
-Coelic trunk
-SMA
-IMA
Paired:
-renal
-adrenal
-gonadal
-lumbar
What forms the IVC and where?
-Union of left and right common iliac veins
-Approx level of L5
Where does the inferior vena cava ascend in the abdomen and what drains into it?
-Ascends on the posterior abdominal wall just right of the midline
-Veins corresponding to the paired arterial branches of aorta drain into IVC
-EXCEPT left gonadal vein drains into left renal vein
-Also receives hepatic vessels
What are the main functions of the bony pelvis?
-Numerous functions
-Supporting the spine, torso and upper body
-Locomotion
-Housing and protecting the pelvic viscera
What bones make up the bony pelvis?
Three bones:
-Sacrum
-Left and right hip (innominate) bones