Gross II exam 3

abdomen

divided topographically into 9 regions by 2 vertical planes (midclavicular) and 2 horizontal planes (subcostal and intertubercular)

midclavicular planes

vertical planes that extend inferiorly from midpoints of clavicles to midpoints of limed joining anterior superior iliac spine to pubic symphysis

subcostal plane

horizontal plane joining lowest point of the costal margin on each side, lies at inferior margin of rib 10 (L3 level)

intertubercular/transtubercular plane

horizontal plane which joins the tubercles of the iliac crest (L5 level)

9 regions of abdomen

right hypochondrium, epigastric, left hypochodrium, right flank (lateral), umbilical, left flank (lateral), right groin (inguinal), pubic, left groin (inguinal)

what regions of the abdomen does the liver lie in?

mostly in right hypochondrium and epigastric region

what organs are found in the left hypochodrium region of the abdomen?

spleen and fundus of stomach

quadrants of abdomen

the simpler abdomen dividing system, divides abdomen into 4 quadrants (right/left upper, right/left lower) using a median plane and transumbilical plane, umbilicus is central landmark that lies between L2 and L5

layers of anterior abdominal wall

skin, superficial layer of superficial fascia (camper’s fascia), deep layer of superficial fascia (scarpa’s fascia), deep/investing fascia, external oblique muscle, internal oblique muscle, transversus abdominis, transversalis fascia, extraperitoneal fascia, parietal peritoneum, peritoneal cavity, visceral peritoneum, abdominal organs

superficial layer of superficial fascia (camper’s fascia)

a thin fatty layer of fascia which is continuous with the superficial fascia of the perineum and thigh

deep layer of superficial facia (scarpa’s fascia)

a membranous layer of fascia which is firmly fastened to the fascia lata of the thigh just below inguinal ligament, covers each of anterior abdominal wall muscles on its anterior and posterior surface

extravasation of urine

occurs in potential space between scarpa’s fascia and deep fascia of the abdomen where fluid can accumulate, rupture of spongy urethra allows accumulation of urine within space, urine can spread superiorly in anterior abdominal wall within space, can’t spread inferiorly due to firm attachment of scarpa’s fascia to fascia lata, almost exclusive to males becuase their urethra is longer/more superficial/more horizontal, caused by trauma

muscles of anterior abdominal wall

external oblique, internal oblique, transversus abdominis, rectus abdominis, pyramidalis

linea alba

a median tendinous raphe which extends from xiphoid process to pubic symphysis, anterior abdominal wall muscles insert into this raphe via aponeuroses; lies between let and right rectus abdominis muscles

external oblique muscle

compresses abdomen and supports abdominal viscera, lateral flexor of trunk; segmentally innervated by anterior primary rami of lower 6 thoracic nerves

internal oblique muscle

compresses the abdomen and supports abdominal viscera, lateral flexor of trunk; innervated by anterior primary rami of lower 6 thoracic and 1st lumbar nerves; fibers run downward and backward

transversus abdominis muscle

acts as an internal back brace, compresses abdomen and supports abdominal viscera; innervated by anterior primary rami of lower 6 thoracic and 1st lumbar nerves; fibers run horizontally across abdomen; homologous to innermost intercostal muscle

rectus abdominis muscle

compresses abdomen and supports abdominal viscera, anterior flexor of trunk, left and right muscles separated by linea alba

T/F lower back pain is often associated with or due to weak abdominal muscles

T

linea semilunaris

a curves line along the lateral border of the rectus abdominis muscle

tendinous intersections

3 bundles of connective tissue which run transversely across the rectus abdominis muscle and fuse with rectus sheath

pyramidalis muscle

a small and often absent slip of muscle that lies anterior to rectus abdominis within its sheath; inserts into linea alba

actions of anterior abdominal wall muscles

coughing (vagus), sneezing (trigeminal), defecation, micturition, vomiting, parturition

rectus sheath

an envelope, formed by aponeuroses of external oblique, internal oblique, and transversus abdominis muscles; consists of anterior and posterior layers- composition of which changes when one passes above or below the arcuate line

what is enclosed by the rectus sheath

rectus abdominis, pyramidalis, superior/inferior epigastric arteries/veins, anterior primary rami of lower 6 thoracic nerves

arcuate line

crescent shaped line in posterior layer of rectus sheath, located midway between umbilicus and pubic crest

above arcuate line

aponeurosis of internal oblique muscle splits to enclose rectus abdominis; anterior layer of rectus sheath- composed of external and internal oblique muscles; posterior layer of rectus sheath- composed of aponeuroses of internal oblique and transversus abdominis muscles

below arcuate line

anterior layer of rectus sheath- composed of aponeuroses of external oblique, internal oblique, and transversus abdominis muscles (all 3 fuse); posterior payer of rectus sheath- formed by transversalis fascia

5 folds of posterior surface of anterior abdominal wall

1 median umbilical fold, 2 medial umbilical folds, 2 lateral umbilical folds; form boundaries between 3 paired fossae- supravesical fossa, medial inguinal fossa, lateral inguinal fossa

median umbilical fold

extends from apex of bladder to umbilicus, contains urachus

medial umbilical folds

extend from side of bladder to umbilicus, contains obliterated umbilical artery

lateral umbilical folds

extend from deep inguinal ring to arcuate line, contains inferior epigastric vessels

supravesical fossa

between median and medial umbilical folds

medial inguinal fossa

between medial and lateral umbilical folds

lateral inguinal fossa

lateral to lateral umbilical folds; fluid can accumulate here

ligamentum teres

lies above umbilicus, contains obliterated umbilical vein, the free edge of falciform ligament which is attached to liver

blood supply to anterior abdominal wall

superior/inferior epigastric artery, lumbar arteries, deep circumflex iliac artery

innervation of anterior abdominal wall

lower 6 thoracic nerves- run between 2 layers of muscles (internal oblique and transversus abdominis)

inguinal ligament

formed by lower edge of external oblique aponeurosis, extends from ASIS to pubic tubercle

lacunar ligament

most medial fibers of inguinal ligament that insert into the superior pubic ramus

pectineal ligament

a lateral extension of the lacunar ligament along the pecten pubis (pectineal line)

inguinal canal

an oblique passage 3-5 cm in length through anterior abdominal wall, begins at deep inguinal ring and ends at superficial inguinal ring, much larger in males than females; transmits spermatic cord(males), round ligament of uterus(females), ilioinguinal nerve (both sexes)

conjoint tendon (inguninal falx)

formed by fusion of aponeuroses of internal oblique and transversus abdominis muscles as they insert into the pubic crest and pecten pubis (deep to inguinal ligament), strengthens posterior wall of medial half of the inguinal canal

boundaries of inguinal canal

anterior wall- aponeurosis of external oblique; posterior wall- conjoint tendon and transversalis fascia; roof- arching fibers of internal oblique and transversus abdominis; floor- inguinal and lacunar ligaments

superficial inguinal ring

a triangular opening in external oblique aponeurosis, immediately lateral to pubic tubercle, transmits spermatic cord in males, round ligament of uterus in females, and ilioinguinal nerve in both sexes, structures it transmits become subcutaneous, formed by splitting of external oblique aponeurosis into 2 crura

crura of superficial inguinal ring

lateral crus- inserts into pubic tubercle (some fibers reflect to superior pubic ramus as lacunar ligament); medial crus- inserts into pubic crest

intercrural fibers

strengthen apex of superficial inguinal ring

deep inguinal ring

an opening within transversalis fascia, located above inguinal ligament midway between ASIS and pubic symphysis, lies just lateral to inferior epigastric vessels

inguinal triangle boundaries

medially- lateral edge of rectus abdominis muscle; laterally- inferior epigastric vessels; inferiorly- inguinal ligament

where is an area of potential weakness in the anterior abdominal wall where direct inguinal hernias occur?

inguinal triangle

development of inguinal canal

present before birth, is shorter and much less oblique in kids than adults, at birth superficial inguinal ring lies almost directly anterior to deep inguinal ring, during childhood development the inguinal canal lengthens and assumes its characteristically oblique position

mechanics of inguinal canal

an area of weakness (can become a potential space) within anterior abdominal wall making it susceptible to hernias; contraction of muscles of anterior abdominal wall during coughing and straining elevates intra-abdominal pressure- potentially forcing abdominal contents into canal; 2 anatomical adaptations function to strengthen inguinal canal- oblique and conjoint tendon

obliqueness of inguinal canal

allows to canal to be compressed by the muscles of the anterior abdominal wall when they contract

conjoint tendon/inguinal falx

reinforces the posterior wall of the inguinal canal

T/F paradoxically, the same muscles that increase intra-abdominal pressure (promoting hernia) also narrow the inguinal canal (preventing hernia)

T

inguinal hernias

an abnormal protrusion of tissue through the inguinal region, more common in males than females due to: large diameter of inguinal canal in males for passage of the spermatic cord, fact that the scrotum is an outpouching of anterior abdominal wall and creates a large potential space for abdominal viscera to fill; can be direct or indirect

labia majora

a female structure that is homologous to the scrotum of males, mostly filled with fat

indirect inguinal hernia

passes through deep inguinal ring, inguinal canal, and superficial inguinal ring before descending into the scrotum (or labia majora); passes lateral to inferior epigastric vessels; may be congenital or acquired; accounts for 75% of inguinal hernias

processus vaginalis

an embryological outpouching of peritoneum which forms the inguinal canal and tunica vaginalis of the scrotum, normally obliterates- when it doesn’t it leaves a sizeable passageway for intestines to pass into the scrotum

direct inguinal hernia

punches directly through the posterior wall of the inguinal canal bypassing the deep inguinal ring, is always acquired due to weakness in the conjoint tendon or transversalis fascia, passes medial to inferior epigastric vessels through inguinal triangle, causes a general bulging of anterior abdominal wall but doesn’t descend into the scrotum, accounts for 25% of inguinal hernias mostly in men over 40

lower thoracic and upper lumbar subluxations may increase the risk of

inguinal hernias because of their connection to the anterior abdominal wall muscles

femoral hernia

more common in females, passes through femoral canal, occurs inferior to inguinal ligament while inguinal hernias occur superior to inguinal ligament

umbilical hernia

can occur due to defects in linea alba, usually results from incomplete closure of anterior abdominal wall after ligation of umbilicus at birth

spermatic cord

begins at deep inguinal ring and ends at testis, covered by 3 concentric layers of fascia derived from anterior abdominal wall, contains ductus deferens, testicular artery, pampiniform plexus of veins, artery to ductus deferens, cremasteric artery, genital branch of genitofemoral artery, remnant of processus vaginalis, autonomic nerves, lymphatics

3 concentric layers of spermatic cord fascia and their origins

external spermatic fascia- derived from external oblique aponeurosis; cremasteric fascia- derived from internal oblique aponeurosis, can be recognized by bundles of muscle fibers (cremaster muscle); internal spermatic fascia- derived from transversalis fascia

cremaster muscle

derived from internal oblique muscle, innervated by genital branch of genitofemoral nerve (L1, L2), runs longitudinal, functions to retract testis for temperature regulation

ductus deferens

muscular duct which transports sperm from epididymis to ejaculatory duct

testicular artery

a branch of the abdominal aorta

pampiniform plexus of veins

an extensive network of veins which makes up the bulk of the spermatic cord, veins join together at deep inguinal ring to form testicular vein, cool testicular artery as it ascends, made of left/right testicular veins

left testicular vein drains

into left renal vein

right testicular vein drains

directly into inferior vena cave

varicocele

varicose veins within the pampiniform plexus (dilated with thin walls)

artery to ductus deferens

a branch of the superior vesical artery

cremasteric artery

a brnach of the inferior epigastric artery

genital branch of genitofemoral nerve

supplies cremaster muscle

lymphatics of spermatic cord drain

into lumbar lymph nodes

ilioinguinal nerve runs

through inguinal canal and superficial inguinal ring, accompanies spermatic cord but is not part of it, has 2 branches- femoral and anterior scrotal/labial nerve

femoral nerve

supplies upper medial part of thigh

anterior scrotal and anterior labial nerve

scrotal- supplies root of penis and anterior part of scrotum; labial- supplies mons pubis and anterior part of labia majora

scrotum

an outpouching of anterior abdominal wall, skin is thin with little or no fat, important for maintaining a temperature below body temperature, contains- testes, epididymis, lower part of spermatic cord; consists of a series of concentric layers which are derived from corresponding layers of anterior abdominal wall

layers of abdominal wall

skin, subcutaneous tissue and superficial/deep fascia, external oblique muscle, internal oblique muscle, transverse abdominis muscle, transversalis fascia, extraperitoneal fascia, peritoneum

layers of scrotum

skin, dartos muscle, external spermatic fascia, cremasteric fascia and cremaster muscle, internal spermatic fascia, tunica vaginalis

which layers of the anterior abdominal wall have no continuation into the scrotum?

transversus abdominis muscle and extraperitoneal fascia

dartos muscle

smooth muscle fibers which are firmly adherent to the skin of the scrotum, functions in temperature regulation

hydrocele

accumulation of fluid in cavity of tunica vaginalis

layers of tunica vaginalis

parietal- superficial, lies internal to internal spermatic fascia; visceral- deep, firmly adherent to testis and epididymis

testis

paired and mobile organs in scrotum, 2 functions- production of spermatozoa, secretion of androgens

tunica albuginea

fibrous outer covering of testis, lies deep to visceral layer of tunica vaginalis (deepest layer of scrotum)

internal structure of testis

divided by septa into wedge-shaped lobules- mediastinum testis, seminiferous tubules, rete testis, efferent ductules

mediastinum testis

a fibrous compartment in posterior part of testis where septa converge

seminiferous tubules

functional, sperm producing portion of testis, each lobule contains 2-3, unite to form straight tubules, drain into rete testis

rete testis

an elaborate network of canals located within mediastinum testis into which straight tubules empty

efferent ductules

ducts which connect the rete testis to the head of the epididymis

epididymis

a c-shaped structure attached to the superior and posterior aspect of the testis, functions to store sperm until they mature, consists of 3 parts- head, body, and tail

head of epididymis

connected to superior surface of testis by efferent ductules

body of epididymis

located along posterior surface of testis

tail of epididymis

ends in ductus deferens

lymphatic drainage of testis

drains into lumbar nodes

lymphatic drainage of scrotum

drains into superficial inguinal nodes

where do the testes develop?

in the lumbar region inside the abdominal cavity