Abdomen overview & Anterolateral abdominal wall Flashcards
(219 cards)
1
Q
What structure ensures the containment of the abdominal organs and their contents?
A
- The musculo-aponeurotic walls anterolaterally,
- the diaphragm superiorly, and
- the muscles of the pelvis inferiorly.
2
Q
The anterolateral musculo-aponeurotic walls are suspended between and supported by what structures?
A
By two bony rings, the inferior margin of the thoracic skeleton superiorly and the pelvic girdle inferiorly lined by a semi-rigid lumbar vertebral column in the posterior abdominal wall.
3
Q
Interposed between the more rigid thorax and pelvis, the musculo-aponeurotic provides what functions?
A
It encloses the abdomen to protect its contents while providing the flexibility required by respiration, posture and locomotion.
4
Q
TEST YOURSELF FIG2.1 P.183
A
TEST YOURSELF FIG2.1 P.183
5
Q
The multi-layered musculo-aponeurotic abdominal walls not only contract to increase intra-abdominal pressure, but can also distend. What is the purpose of this distension?
A
To accommodate expansions caused by pregnancy, fat deposition or pathology.
6
Q
The anterolateral abdominal wall and several organs lying against the posterior wall are covered on their internal aspects with what?
A
A serous membrane or peritoneum (serosa) that reflects onto the abdominal viscera to cover organs such as the stomach, intestine, liver, and spleen.
7
Q
What is the peritoneal cavity?
A
It is a potential space formed between the walls of the viscera that normally contain only enough extracellular (parietal) fluid to lubricate the membrane covering most of the surfaces of the structures forming or occupying the abdominal cavity.
8
Q
TEST YOURSELF FIG2.3 P.184
A
TEST YOURSELF FIG2.3 P.184
9
Q
TEST YOURSELF FIG 2.4 P. 186
A
TEST YOURSELF FIG 2.4 P. 186
10
Q
List the nine (9) regions of the abdominal cavity are separated by two sagittal (vertical) and two transverse planes. They are used to describe the location of abdominal organs, pains or pathologies. What are they?
A
- RH – right hypochondrium
- RL – right flank (lateral region)
- RI – right inguinal (groin)
- E – epigastric
- U – umbilical
- P – pubic
- LH – left hypochondrium
- LL – left flank (lateral region)
- LI – left inguinal (groin)
11
Q
What ten (10) structures are located in the right upper quadrant (RUQ)?
A
- Liver: right lobe
- Gallbladder
- Stomach: pylorus
- Duodenum: parts 1-3
- Pancreas: head
- Right suprarenal gland
- Right kidney
- Right colic (hepatic flexure)
- Ascending colon: superior part
- Transverse colon: right half
12
Q
What ten (10) structures are located in the left upper quadrant (LUQ)?
A
- Liver: left lobe
- Spleen
- Stomach
- Jejunum and proximal ileum
- Pancreas: body and tail
- Left kidney
- Left suprarenal gland
- Left colic (splenic) flexure
- Transverse colon: left half
- Descending colon: superior part
13
Q
What ten (10) structures are located in the right lower quadrant (RLQ)?
A
- Cecum
- Appendix
- Most of the ileum
- Ascending colon: inferior part
- Right ovary 6. Right uterine tube
- Right spermatic cord: abdominal part
- Uterus (if enlarged)
- Right ureter: abdominal part
- Urinary bladder (if very full)
14
Q
What eight (8) structures are located in the left lower quadrant (LLQ)?
A
- Sigmoid colon
- Descending colon: inferior part
- Left ovary
- Left uterine tube
- Left spermatic cord: abdominal part
- Uterus (if enlarged)
- Left ureter: abdominal part
- Urinary bladder (if very full)
15
Q
What structures define the abdominal wall?
A
It is a continuous structure consisting of musculo-aponeurotic structure that extends to the posterior wall which then incorporates the lumbar region on of the vertebral column.
16
Q
What defines the boundary between the anterior and lateral walls of the abdominal cavity?
A
Nothing, it is a continuous structure that contains muscles and cutaneous nerves and extends from the thoracic cage to the pelvis.
17
Q
What are the boundaries of the anterolateral abdominal wall?
A
- Superiorly by the cartilages of the 7-10th ribs and the xiphoid process of the sternum
- Inferiorly by the inguinal ligament and the superior margins of the anterolateral aspects of the pelvic girdle (iliac crests, pubic crests, and pubic symphysis)
18
Q
What structures are contained in the anterolateral abdominal wall?
A
- Skin
- Subcutaneous tissue (superficial fascia) composed mainly of fat, muscles and their aponeuroses
- Deep fascia
- Extraperitoneal fat
- Parietal peritoneum
19
Q
What is the key feature of the musculotendinous layer of the anterolateral abdominal wall?
A
It’s three layers of muscles run in different directions and is similar to that of the intercostal spaces in the thorax
20
Q
Superior to the umbilicus, the subcutaneous tissue is consistent with that found in most regions. What is the difference with the subcutaneous tissue inferior to the umbilicus.
A
The deepest part of the subcutaneous tissue is reinforced by many elastic and collagen fivers and has two layers
- the superficial fatty layer (Camper fascia) of subcutaneous tissue; and
- the deep membranous layer (Scarpa fascia) of subcutaneous tissue.
21
Q
What does the superficial fatty layer (camper fascia) and deep membranous layer (Scarpa fascia) of subcutaneous tissue form as it continues inferiorly?
A
This membranous layer continues inferiorly into the perineal region as the superficial perineal fascia (colles fascia), but not into the thighs.
22
Q
What is an aponeuroses?
A
A flat expanded tendon.
23
Q
What is an epimysium?
A
The outer fibrous connective tissue layer surrounding all muscles.
24
Q
What constitutes the endoabdominal fascia?
A
The membranous and areolar sheets of epimysium from the internal aspects of the abdominal walls. Although continuous, it is named according to the muscle or aponeurosis it is lining.
25
What is the name of the endoabdominal fascia lining the deep surface of the transversus abdominis muscle and its aponeurosis?
It is the transversalis fascia.
26
Describe the parietal peritoneum and its location.
It is the glistening lining of the abdominal cavity formed by a single layer of epithelial cells and supporting connective tissue. It is internal to the transversalis fascia and is separated from by a variable amount of extraperitoneal fat.
27
What is the origin of the external oblique muscles?
The external surfaces of the 5th – 12th ribs
28
What is the insertion point of the external oblique muscles?
The linea alba, pubic tubercle and the anterior half of the iliac crest
29
What innervates the external oblique muscles?
The thoraco-abdominal nerves (T7-T11 spinal nerves) and subcostal nerve.
30
What are the main actions of the external oblique muscles?
To compress and support abdominal viscera, flex and rotate the trunk.
31
What is the origin of the internal oblique muscles?
The thoracolumbar fascia, anterior two thirds of the iliac crest and connective tissue deep to the lateral third of the inguinal ligament.
32
What is the insertion point of the internal oblique muscles?
The inferior border of the 10th – 12th ribs, the linea alba and the pectin pubis via conjoint tendon (inguinal falx).
33
What innervates the external internal muscles?
The thoraco-abdominal nerves (anterior rami of T6-T12 spinal nerves) and the first lumbar nerves.
34
What are the main actions of the internal oblique muscles?
To compress and support abdominal viscera, flex and rotate the trunk.
35
What is the origin of the transversus abdominis muscles?
The internal surfaces of the 7th – 12th costal cartilages, thoracolumbar fascia, iliac crest and connective tissue deep to the lateral third of the inguinal ligament
36
What is the insertion point of the transversus abdominis muscles?
The liniea alba with aponeurosis of the internal oblique, pubic cres and pectin pubis via conjoint tendon (inguinal falx).
37
What innervates the transversus abdominis muscles?
The thoraco-abdominal nerves (anterior rami of T6-T12 spinal nerves) and the first lumbar nerves.
38
What are the main actions of the transversus abdominis muscles?
To compress and support abdominal viscera
39
What is the origin of the rectus abdominis muscles?
The pubic symphysis and pubic crest
40
What is the insertion point of the rectus abdominis muscles?
The xiphoid process and 5th – 7th costal cartilages
41
What innervates the rectus abdominis muscles?
The thoraco-abdominal nerves (anterior rami of T6 – T12 spinal nerves)
42
What are the main actions of the rectus abdominis muscles?
They flex the trunk (lumbar vertebrae) and compress the abdominal viscera. They also stabilise and control tile of the pelvis (antilordosis)
43
What muscles act as antagonists of the diaphragm to produce expiration?
All the muscles of the anterolateral abdominal wall (external and internal obliques, the transversus and rectus abdominis.
44
Discuss the pyramidalis.
* It is an insignificant muscle found in about 80% of the population.
* It is located in the rectus shealth anterior to the most inferior part of the rectus abdominus and extends from the pubic crest of the hip bone to the linea alba.
* It’s function is to draw down on the linea alba.
45
What are the muscles of the anterolateral abdominal wall and what are their orientations?
The outer two layers, the external and internal obliques run diagnollay and perpendicular to each other and the fibres of the deep layer of the transversus abdominis run transversely.
46
Where is the rectus sheath and what does it consist of?
It consists of all three anterolateral abdominal wall muscles between the midclavicular line and the midline, where they form a tough apponeurotic tendinus rectus sheath enclosing the rectus abdominis muscle.
47
What structures form the linea alba and where is it positioned?
* It is formed from the aponeurotic, rectus sheath as the aponeuroses interweave with left and right, superficial and intermediate, intermediate and deep layers, forming a midline raphe (seam or suture)
* It extends from the xiphoid process to the pubic symphysis.
48
TEST YOURSELF FIG2.6 P187.
TEST YOURSELF FIG2.6 P187.
49
Which two vertical muscles of the anterolateral abdominal wall are contained within the rectus sheath?
The rectus abdominis and the small pyramidalis.
50
What are the key features of the external oblique muscle?
* It is the larges and most superficial of the three flat anterolateral abdominal muscles.
* In contrast to the two deeper layers, the external oblique does not originate posteriorly from the thoracolumbar fascia, its posterior most fibres (the thickest part of the muscle) have a free edge where they span between is costal origin and the iliac crest.
* The fleshy part of the muscle contribute primarily to the lateral part of the abdominal wall.
* Its aponeurosis contributes to the anterior part of the wall
51
TEST YOURSELF 2.7 P.188
TEST YOURSELF 2.7 P.188
52
TEST YOURSELF 2.8 P.188
TEST YOURSELF 2.8 P.188
53
TEST YOURSELF 2.9 P.190
TEST YOURSELF 2.9 P.190
54
What is the alignment of the transversus abdominis muscles and what specifically does this make them ideal for?
They are oriented in a transverse, circumferential orientation and ideal for increasing intra-abdominal pressure.
55
Where is the neurovascular plane of the anterolateral abdominal wall located and what does it contain?
It is located between the middle and deepest layers of muscle, the internal oblique and transversus abdominis muscles and contains the nerves and arteries that supply the anterolateral abdominal wall.
56
Describe the rectus sheath and identify what structures it contains.
* It is a strong, incomplete fibrous compartment of the rectus abdominis and pyramidalis muscles.
* It contains the superior and inferior epigastric arteries and veins, lymphatic vessels and distal portions of the throaco-abdominal nerves.
57
TEST YOURSELF FIG2.10 P.293
TEST YOURSELF FIG2.10 P.293
58
What is the sensory distribution of T7 – T9?
The skin superior to the umbilicus
59
What is the sensory distribution of T10?
The skin around the umbilicus
60
What is the sensory distribution of T11 & T12?
The skin inferior to the umbilicus
61
What is the sensory distribution of L1?
The skin within the inguinal fold
62
What nerve supplies the distribution of T7 – T11?
The thoraco-abdominal nerves, which are the distal, abdominal parts of the anterior rami of the inferior six thoracic spinal nerves (T6-T11) and are the former inferior intercostal nerves distal to the costal margin.
63
What nerve supplies the distribution of T7 – T9 or T10?
The lateral (thoracic) cutaneous branches of the thoracic spinal nerves.
64
What nerve supplies the distribution of T12?
The subcostal nerve, the large anterior ramus of spinal nerve T12
65
What nerves supply the distribution of L1?
The iliohypogastric and ilio-inguinal nerves, the terminal branches of the anterior ramus of spinal nerve L1.
66
What are the primary blood vessels (arteries and veins) of the anterolateral abdominal wall?
1. Superior epigastric vessels and branches of the musculophrenic vessels from the internal thoracic vessels
2. Inferior epigastric and deep circumflex iliac vessels from the external iliac vessels
3. Superficial circumflex iliac and superficial epigastric vessels from the femoral artery and greater saphenous vein, respectively
4. Posterior intercostal vessels of the 11th intercostal space and the anterior branches of the subcostal vessels.
67
What vessel drains the skin and subcutaneous tissue of the superior abdominal wall?
The internal thoracic vein medially
68
What vessel drains the skin and subcutaneous tissue of the lateral abdominal wall?
To the lateral thoracic vein, a tributary of the femoral vein.
69
What vessel drains the skin and subcutaneous tissue of the inferior abdominal wall?
The inferior epigastric vein, a tributary of the external iliac vein.
70
The cutaneous veins surrounding the umbilicus anastomose with what?
The para-umbilical veins, small tributaries of the hepatic portal vein that parallel the obliterated umbilical vein (the round ligament of the liver).
71
What could cause the development of the thoraco-epigastric vein and what structures are involved?
It may exist or develop as a result of altered venous flow between the superficial epigastric vein (a femoral vein tributary) and the lateral thoracic vein (an axillary vein tributary).
72
Other than the anastomotic channel of the thoraco-epigastric vein between the superficial epigastric vein and the lateral thoracic vein, what deeper venous anastomosis may also exist or develop to afford collateral circulation during blockage of either vena cava?
A venous anastomosis between the inferior epigastric vein (an external iliac vein tributary) and the superior epigastric/internal thoracic veins (subclavian tributaries).
73
TEST YOURSELF FIG 2.11 P. 198
TEST YOURSELF FIG 2.11 P. 198
74
TEST YOURSELF FIG 2.12 P. 199
TEST YOURSELF FIG 2.12 P. 199
75
Superficial lymphatic vessels superior to the transumblical plane drain where?
The majority drain to the axillary lymph nodes, however a few drain tohte parasternal lymph nodes.
76
Superficial lymphatic vessels inferior to the transumbilical plane drain to where?
The superficial inguinal lymph nodes.
77
Deep lymphatic vessels accompany the deep veins of the abdominal wall and drain where?
The deep lymphatic vessles drain tohte external iliac, common iliac, right and left lumbar (caval and aortic) lymph nodes.
78
The internal (posterior) surface of the anterolateral abdominal wall is covered with what THREE (3) structures?
1. Transversalis fascia
2. A variable amount of extraperitoneal fat
3. Parietal peritoneum.
79
1. The infraumbilical surface of the anterolateral abdominal wall exhibits FIVE (5) umbilical peritoneal folds passing towards the umbilicals. What are they?
1. A median umbilical fold attached to the apex of the bladder
2. Two median umbilical folds that cover the medial umbilical ligaments
3. Two lateral umbilical folds that cover the inferior epigastric vessels (and bleed if cut).
80
The depressions lateral to the umbilical folds form peritoneal fossae. What is the significance of the supravesical fossae?
It reflects form the anterior abdominal wall on to the bladder and rises and falls with filling and emptying of the bladder.
81
The depressions lateral to the umbilical folds form peritoneal fossae. What is the significance of the medial inguinal fossae?
It lies between the medial and the lateral umbilical folds in areas called the inguinal triangles (Hesselbach triangles), which are potential sites for the less common direct inguinal hernias.
82
What is the falciform ligament?
It is a sagittally oriented peritoneal reflection on the supra-umbilical part of the internal surface of the anterior abdominal wall that extends between the anterior abdominal wall and the liver.
83
What structures are enclosed in the falciform ligament?
The round ligament of the liver (ligamentum teres hepatis) and para-umbilical veins on the inferior free edge.
84
What is the significance of the round ligament?
It is a fibrous remnant of the umbilical vein, which passed from the umbilicus to the liver prenatally.
85
TEST YOURSELF FIG 2.13 P202
TEST YOURSELF FIG 2.13 P202
86
What are the major landmarks of the inguinal region?
The inguinal ligament and the iliopubic tract that extends from the ASIS to the pubic tubercle and constitute a bilaminar anterior (flexor) retinaculum of the hip joint.
87
What structures make up the retinaculum of the inguinal ligament?
The fibrous bands are the thickened inferolateral-most portions of the external oblique and aponeurosis and the inferior margin of the transversalis fascia.
88
The retinaculum of the inguinal ligament and iliopubic tract span what structure?
The subinguinal space, through which pass the flexors of the hip and neurovascular structures serving much of the lower limb.
89
TEST YOURSELF FIG2.14 P.202
TEST YOURSELF FIG2.14 P.202
90
What forms the inguinal ligament?
A dense band of the inferior most part of the external oblique aponeurosis.
91
Where are the insertion points for the fibres of the inguinal ligament?
* The majority of the fibres from the medial end insert into the pubic tubercle
* Some of the deeper fibres pass posteriorly to attach to the superior pubic ramus lateral to the tubercle forming the lacunar ligament (of Gimbernat)
* Most of the lateral fibres run along the pecten pubis as the pectineal ligament (of Cooper)
* Some of the more superior fibres fan upwards bypassing the pubic tubercle and crossing the linea alba to blend with the lower fibers of the contralateral external oblique aponeurosis to form the reflected inguinal ligament
92
What forms the lacunar ligament and what is its significance?
• The lacunar ligament is formed by the deeper fibres of the inguinal ligament that pass posteriorly to attach to the superior pubic ramus lateral to the tubercle. • It forms the medial boundary of the subinguinal space.
93
TEST YOURSELF FIG 2.15 P203
TEST YOURSELF FIG 2.15 P203
94
What forms the iliopubic tract?
It is the thickened inferior margin of the transversalis fascia, which appears as a fibrous band running parallel and posterior (deep) to the inguinal ligament.
95
How is the iliopubic tract best seen?
It is best viewed from its internal (posterior) aspect (eg. During laparoscopy) and is seen in place of the inguinal ligament from this view.
96
What is the function of the iliopubic tract?
It reinforces the posterior wall and floor of the inguinal canal as it bridges the structures traversing the subinguinal space.
97
What area does the inguinal ligament and iliopubic tract span and what is its significance?
The span an area of innate weakness in the body wall in the inguinal region called the myopectineal orifice and is the site of direct and indirect inguinal and femoral hernias.
98
When is the inguinal canal formed?
It is formed in relation to the relocation of the testis during foetal development.
99
Describe the position of the inguinal canal in an adult.
It is an oblique passage, approximately 4cm long and directed inferomedially through the inferior part of the anterolateral abdominal wall and lies parallel and superior to the medial half of the inguinal ligament.
100
What structures form the walls of the inguinal canal? (2MALT)
**2MALT**: 2**M**, 2**A**, 2**L**, 2**T** (moving superior to posterior in order)
* Superior - **M**uscles – internal oblique & transverse abdominus
* Anterior – **A**poneurosis – of external oblique & internal oblique
* Lower – **L**igaments – inguinal & lacunar ligaments
* Posterior – **T**ransversalis fascia & conjoint Tendon (inguinal falx).
101
What are the main occupants of the inguinal canal?
* The spermatic cord in males and the round ligament of the uterus in females which are functionally and developmentally distinct structures that occur in the same location.
* It also contains blood and lymphatic vessels and the ilio-inguinal nerve in both sexes.
102
The inguinal canal has an opening at each end, what are they called?
The deep (internal) inguinal ring forms the entrance to the inguinal canal and the superficial (external) inguinal ring is the exit point for the spermatic cord or round ligament.
103
Where is the deep (internal) inguinal ring located?
It is superior to the middle of the inguinal ligament, lateral to the inferior epigastric artery and the beginning of an evagination in the transversalis fascia that forms an opening like the entrance to a cave and continues to form the innermost covering (internal fascia) of the structures traversing the canal.
104
Describe the structure of the superficial (external) inguinal ring.
It is a split that occurs in the diagonal, otherwise parallel fibers of the external oblique aponeurosis just superolateral to the pubic tubercle.
105
Where is the superficial (external) inguinal ring located?
The parts of the aponeurosis that lie lateral and medial to, and form the margins of the superficial ring are the lateral crus that attaches to the pubic tubercle and the medial crus which attaches to the pubic crest.
106
What is the function of the intercrural fibers and where are they located within the superficial (external) inguinal ring?
The intercrural fibers run perpendicular from the fascia overlying external obliques and aponeurosis to pass from one crus to the other across the superolateral part of the ring. They prevent the crusa from spreading apart (splitting apart).
107
What structure forms the anterior wall of the inguinal canal?
The external oblique aponeurosis throughout the length of the canal with its lateral part being reinforced by muscle fibres of the internal oblique.
108
What structures form the posterior wall of the inguinal canal?
It is formed by the transversalis fascia. Its medial part is reinforced by pubic attachments of the internal oblique and transversus abdominis aponeurosis that frequently merge to variable extents into a common tendon – the inguinal falx (conjoint tendon) and the reflected inguinal ligament.
109
What structures form the roof of the inguinal canal?
It is formed laterally by the transversalis fascia, centrally but the musclo-aponeurotic arches of the internal oblique and transversus abdominis, and medially but the medial crus of the external oblique aponeurosis.
110
What structures form the floor of the inguinal canal?
The floor is formed laterally but the iliopubic tract, centrally by gutter formed by the infolded inguinal ligament, and medially by the lacunar ligament.
111
What structures span the myopectineal orifice and what does it demarcate?
The inguinal ligament and the iliopubic tract and they demarcate the inferior boundaries of the inguinal canal and its openings
112
The inguinal triangle separates what?
The inguinal triangle separates the inguinal ligament and iliopubic tract from the structures of the femoral sheath (femoral vessels and femoral canal) that traverse the medial part of the subinguinal space.
113
Where do most groin hernias occur in males?
They pass superior to the iliopubic tract (inguinal hernias)
114
Where do most groin hernias occur in females?
They pass inferior to the iliopubic tract (femoral hernias).
115
Where do the testes develop?
In the extraperitoneal connective tissue in the superior lumbar region of the posterior abdominal wall.
116
What is the gubernaculum?
The gubernaculum is a fibrous tract that connects the primordial testis to the anterolateral abdominal was at the site of the future deep ring of the inguinal canal.
117
What is the processus vaginalis?
It is a peritoneal diverticulum that traverses the developing inguinal canal, carrying muscular and fascial layers of the anterolateral abdominal wall before it enters the primordial scrotum.
118
As the testis and associated structures move from the pelvis at 12 weeks to traversing the inguinal canal at the 28th week, what structures are included in the musclofascial extensions of the anterolateral abdominal wall?
The testes and its duct (ductus deferens), its vessels and nerves that are ensheathed by the musculofascial extension of the anterolateral abdominal wall to include the internal and external spermatic fasciae and cremaster muscle.
119
What is the mnemonic for the layers of the scrotum?
**S**ome **D**amn **E**nglishman **C**alled **I**t **T**he **T**estis (superficial to deep)
* **S**kin
* **D**artos
* **E**xternal spermatic fascia
* **C**remaster
* **I**nternal spermatic fascia
* **T**unica vaginalis
* **T**estis
120
What is the tunica vaginalis?
It is the distal saccular part of the processus vaginalis that makes the serous sheath of the testis and epididymis.
121
What is the female gubernaculum?
It is a fibrous cord that connects the ovary and primordial uterus to the developing labium majus and is represented postnatally by the ovarian ligament, between the ovary and uterus, and the round ligament of the uterus between the uterus and labium majus.
122
What stops the ovaries from relocating to the inguinal region?
The attachment of the ovarian ligament to the uterus, however the round ligament still passes through the inguinal canal.
123
REVIEW FIG 2.17 P.205
REVIEW FIG 2.17 P.205
124
When does the process vaginalis obliterate?
By the 6th month of fetal development, with the exception of the most inferior part which becomes the serous sac that engulfs the testis.
125
What is the difference in the inguinal canal between males and females?
The inguinal canals in females are narrower than those in males.
126
What is the difference in the inguinal canal in infants (of both sexes) compared to adults?
The canals in infants of both sexes are shorter and much less oblique than in adults. Secondly, the superficial inguinal rings in infants lie almost directly anterior to the deep inguinal rings.
127
What factors reduce the likelihood of herniation from increases in intra-abdominal pressure?
1. The deep and superficial inguinal rings in the adult do not overlap because of he oblique path of the inguinal canal, thus forcing the posterior wall against the anterior wall and strengthening this wall.
2. Simultaneously, contraction of the external oblique approximates the anterior wall of the canal to the posterior wall and increases tension on the musculature that makes the roof of the canal descend, thus constricting the canal.
128
In general terms, what does the spermatic cord contain and what does it do?
The structures that run to and from the testis and suspends the testis in the scrotum.
129
What is the path of the spermatic cord?
* The spermatic cord begins at the deep inguinal ring lateral to the inferior epigastric vessels
* It passes through the inguinal canal and exits at the superficial inguinal ring
* It ends at the scrotum at the posterior border of the testis
130
What are the facial coverings of the spermatic cord?
* Internal spermatic fascia: derived from the transversalis fascia
* Cremasteric fascia: derived from the investing fascia of both the superficial and deep surfaces of the internal oblique muscle arising from the inguinal ligament
* External spermatic fascia: derived from the external oblique aponeurosis and its investing fascia.
131
What does the cremaster muscle reflex do?
It draws the testis superiorly in the scrotum, particularly in response to cold and in a warm environment (such as hot bath), the cremaster relaxes and the testis descend deeply into the scrotum.
132
What is the purpose of the cremaster reflex?
It aims to regulate temperature of the testis for spermatogenesis, which requires a constant temperature approximately one degree cooler than core temperature, or during sexual activity as a protective response.
133
What muscle coincidentally acts with the cremaster muscle to assist with testicular elevation and how does it achieve this?
It is the dartos muscle, a smooth muscle of the fat-free subcutaneous tissue of the scrotum (dartos fascia), which inserts into the skin to assist with skin retraction in response to the same stimuli as that of the cremaster muscle.
134
What nerve innervates the cremaster muscle and what is it a derivative of?
The genital branch of the genitofemoral nerve (L1, L2) and it is a derivative of the lumbar plexus.
135
What is the difference in the innervation of the cremaster muscle in comparison to the dartos muscle
The cremaster is striated muscle receiving somatic innervation whereas the dartos is smooth muscle receiving autonomic innervation.
136
What are the constituents of the spermatic cord?
**3 arteries, 3 nerves & 3 other things**
* 3 arteries: testicular, ductus deferens & cremasteric
* 3 nerves: genital branch of the genitofemoral, cremasteric, autonomic
* 3 other things: ductus deferens, pampiniform plexus & lymphatics
137
What is the ductus deferens (vas deferens)?
A muscular tube approximately 45cm long that conveys sperm from the epididymis to the ejaculatory duct
138
Where does the testicular artery arise from and what does it supply?
The aorta and it supplies the testis and epididymis.
139
What vessel does the artery of ducts deferens originate and what other structures does it supply?
The inferior vesical artery, a branch of the anterior division of the internal iliac artery. It frequently arises in common with the middle rectal artery, and is distributed to the fundus of the bladder. In males, it also supplies the prostate and the seminal vesicles.
140
The cremasteric artery arises from what vessel?
The inferior epigastric artery.
141
What is the pampiniform venous plexus?
A network formed by up to 12 veins that converge superiorly as right or left testicular veins.
142
The lymphatic vessels that drain the testis are closely associated structures and pass to which lymph nodes?
The lumbar lymph nodes.
143
What is the vestige of the process vaginalis?
It is a fibrous thread in the anterior part of the spermatic cord that extends between the abdominal peritoneum and the tunica vaginalis. It may not be detectable.
144
The round ligament is not a homolog of the spermatic cord, and does not contain comparable structures. What does it include?
The vestiges of the lower part of the ovarian gubernaculum and the processus vaginalis.
145
TEST YOURSELF FIG 2.19 P 208
TEST YOURSELF FIG 2.19 P 208
146
TEST YOURSELF FIG 2.20 P 208
TEST YOURSELF FIG 2.20 P 208
147
How does the dartos muscle assist with heat retention when it is cold?
As it is attached to the skin, its contraction causes the scrotum to wrinkle when cold, thus thickening the integumentary layer and reducing scrotal surface area. It also assists in holding the testis closer to the body to reduce heat loss.
148
What structure divides the scrotum into left and right compartments?
The dartos fascia which is externally demarcated by the scrotal raphe, a cutaneous ridge marking the line of fusion of the embryonic labioscrotal swellings.
149
The superficial dartos fascia is devoid of fat and is continuous anteriorly with what two membranes?
The membranous layer of subcutaneous tissue of the abdomen (Scarpa fascia) and posteriorly with the membranous layer of subcutaneous tissue of the perineum (Colles fascia).
150
The arterial supply of the scrotum is from what THREE (3) vessels?
1. Posterior scrotal branches of the perineal artery, a branch of the internal pudendal artery
2. Anterior scrotal branches of the deep external pudendal artery, a branch of the femoral artery
3. Cremasteric artery, a branch of the inferior epigastric artery.
151
The lymphatic vessels of the scrotum drain to which nodes?
The superficial inguinal lymph nodes
152
What nerves supply the anterior/ anteriolateral scrotum?
Branches of the lumbar plexus to the anterolateral surface: genitofemoral nerve (L1L2) and ilio-inguinal nerve (L1) to the anterior surface
153
What nerve supplies the posterior scrotal surface?
The perineal branch of the pudendal nerve (S2-S4)
154
What nerves supply the postero-inferior surface of the scrotum?
Branches of the sacral plexus to include the perineal branches of the posterior cutaneous nerve of the thigh (S2,S3).
155
Provide a functional description of the testis.
* They are the male gonads – a pair of ovoid reproductive glands that produce spermatozoa and male hormones, primarily testosterone
* They are suspended in the scrotum by the spermatic cords, with the left testis usually suspended (hanging) lower than the right.
156
What is the surface of each testis covered by?
A visceral layer of the tunica vaginalis, except where the testis attaches to the epididymis and spermatic cord.
157
What is the tunica vaginalis?
It is a closed peritoneal sac closely applied to and partially surrounding the testis, which represents the closed-off distal part of the embryonic processus vaginalis.
158
The parietal layer of the tunica vaginalis is adjacent to what structure and does what?
It is adjacent to the internal spermatic fascia and has a small amount of fluid in the cavity of the tunica vaginalis to separate the visceral and parietal layers, thus allowing the testis to move freely in the scrotum.
159
What is the tough fibrous outer surface of the testes called?
The tunica albuginea.
160
Where are sperms produced?
In the long and highly coiled seminiferous tubules of the testis.
161
TEST YOURSELF FIG. 2.21 p210
TEST YOURSELF FIG. 2.21 p210
162
Where does the testicular artery arise?
It arises form the anterolateral aspect of the abdominal aorta just inferior to the renal arteries.
163
What is the course of the testicular artery from the aorta to the testes?
* It passes retroperitoneally in an oblique direction, crossing over the ureters and the inferior parts of the external iliac arteries to reach the deep inguinal rings.
* Passing through the deep rings, the canal and exiting through the superficial inguinal rings they enter the spermatic cords to supply the testes.
164
In the testis, what does the testicular artery (or one of its branches) anastomose with?
The artery of the ductus deferens.
165
What is the function of the pampiniform venous plexus (other than venous return)?
To assist with the thermoregulatory function of the testis (along with the cremasteric and dartos muscles).
166
What is the course of the pampiniform plexus?
The veins of each pampiniform plexus converge superiorly, forming a right testicular vein which enters the inferior vena cava anda left testicular vein which enters the left renal vein.
167
The lymphatic drainage of the testis follows what?
The testicular artery and vein to the right and left lumbar (caval/aortic) and pre-aortic lymph nodes.
168
The autonomic nerves of the testis arise from where?
The testicular plexus of nerves on the testicular artery.
169
The testicular plexus of nerves contains what?
Vagal parasympathetic and visceral afferent fibers and sympathetic fibres from T10-T11 segment of the spinal cord.
170
Provide a functional description of the epididymis.
It is an elongated structure on the posterior surface of the testis that contains efferent ductules to transport the newly developed sperms to the epididymis from the rete testis.
171
What happens to the sperm as they traverse the lengthy course of the epididymal duct?
Beyond being a storage area for sperm, the sperm also mature as they move along the epididymal duct.
172
What is the key characteristic of the head of the epididymis?
It is the superior expanded part that is composed of lobules formed by the coiled ends of 12-14 efferent ductules.
173
What is the key characteristic of the body of the epididymis?
It is the major part of the epididymis and consists of the tightly convoluted duct of the epididymis.
174
What is the key characteristic of the tail of the epididymis?
It is the tapering continuation with the ductus deferens, the duct that transports the sperms from the epididymis to the ejaculatory duct for expulsion via the urethra during ejaculation.
175
Provide a functional description of the umbilicus.
It is a puckered indentation of the skin in the center of the anterior abdomen at the 4th disc between L3 & L4 and indicates the level of the T10 dermatome.
176
What structures form the medial borders of the costal margins?
The medial borders of the united costal cartilages of the 7th-10th ribs.
177
TEST YOURSELF FIG2.22 P210
TEST YOURSELF FIG2.22 P210
178
Describe the position of the linea alba
* In lean individuals it may be observed because of the vertical skin groove superficial to this raphe.
* It is approximately 1cm wide between the two pars of the rectus abdominis superior to the umbilicus but not indicated by a groove below the umbilicus.
* It may be seen as a heavily pigmented line in some pregnant women, the linea nigra.
179
What level is the iliac crest?
L4 vertebra when palpated posteriorly.
180
What structures demarcate the inferior limit of the anterior abdominal wall, distinguishing it from the perineum centrally and the lower limbs laterally?
1. Pubic crest
2. Inguinal folds
3. Iliac crests
181
What are the semilunar lines and why are they important?
* They are slightly curved, linear impressions in the skin that extend from the inferior costal margin near the 9th costal cartilages to the pubic tubercles approximately 5-8cm from the midline.
* They are important because they parallel with the lateral edges of the rectus sheath.
182
Where is the inguinal groove and what does it divide?
Parallel and just inferior to the inguinal ligament and marks the division between the anterolateral abdominal wall and the thigh.
183
What is the term for an undescended testis or one that is not capable of being drawn down?
Cryptorchidism.
184
Undescended (cryptorchid) testis occur how frequently?
3% of full term babies and 30% of premature infants and 95% of the time is unilateral.
185
Where does the undescended testis like and what is the concern with cryptorchidism?
* The undescended testis usually lies somewhere along the normal path of its prenatal descent, commonly in the inguinal canal, and because of the greatly increased risk for developing malignancy in the undescended testis.
* It is particularly problematic because it is not palpable and not usually detected until cancer has progressed.
186
Where do external supravesical hernias occur?
Through the peritoneal cavity through the supravesical fossa, with the site being medial to that of a direct inguinal hernia.
187
What is the risk with supravesical hernias?
Of the iliohypogastric nerve being damaged during the repair.
188
What does the occluded umbilical vein form post natally?
The round ligament of the liver.
189
Lymphogenous metastasis of cancer commonly follow what pathways?
The lymphatic pathways that parallel the venous drainage of the organ that is the site of the primary tumor.
190
In a patient with cancer to the labium majus, where might you suspect the primary tumour to be?
A metastatic uterine cancer, with a tumour adjacent to the proximal attachment of the round ligament which assist with the spread of the cancer to superficial inguinal nodes which receive lymph from the skin of the perineum, including the labia.
191
What are some of the statistics associated with inguinal hernias?
1. Inguinal hernias account for 75% of abdominal hernias.
2. About 86% of inguinal hernias occur in males because of the passage of the spermatic cord through the inguinal canal.
3. 25%-30% are direct (acquired) and 70%-75% are indirect (congenital)
192
Provide a functional description of an inguinal hernia.
It is a protrusion of parietal peritoneum and viscera, such as the small intestine, through a normal or abnormally opening from the cavity in which they belong.
193
What are the predisposing factors for a direct (acquired) inguinal hernia?
Weakness of the anterior abdominal wall in the inguinal triangle to include:
1. Distension of the superficial ring
2. Narrow inguinal falx
3. Attenuation of aponeurosis in males \>40 years of age
194
What are the predisposing factors for an indirect (congenital) inguinal hernia?
Patency of the processus vaginalis (complete or at least superior part) in younger persons, the majority of whom are males.
195
Where do direct (acquired) inguinal hernias exit from the anterior abdominal wall and what is their relationship with the scrotum?
Via the superficial ring, lateral to the cord. They rarely enter the scrotum.
196
Where do indirect (congenial) inguinal hernias exit from the anterior abdominal wall and what is the relationship with the scrotum?
Via the superficial ring inside the cord, commonly passing into the scrotum/labium majus.
197
Which part of the processus vaginalis does not obliterate before birth?
The distal part that forms the tunica vaginalis of the testis.
198
What is the peritoneal part of the hernial sac of an indirect inguinal hernia formed by?
The persistence of the entire stalk of the processus vaginalis, with the hernia extending into the scrotum superior to the testis to form an indirect inguinal hernia.
199
How do you palpate the superficial inguinal ring?
By palpating superolateral to the pubic tubercle and invaginating the skin of the upper scrotum with the index finger to follow the spermatic cord superolaterally to the superficial inguinal ring.
200
Does a palpation impulse at the superficial inguinal ring help differentiate the type of inguinal hernia?
No, as both types exit the superficial ring.
201
What factors suggest an indirect hernia clinically?
* Having the palmar surface of the finger against the anterior abdominal wall and feeling for the deep inguinal ring as a skin depression superior to the inguinal ligament, 2-4cm superolateral to the pubic tubercle.
* Detection of an impulse at the superficial ring and a mass at the site of the deep ring suggest an indirect hernia.
202
How do you elicit the cremasteric reflex and what nerve is involved?
* By lightly stroking the skin on the medial aspect of the superior part of the thigh with a tongue depressor.
* The ilio-inguinal nerve.
203
If the processus vaginalis persists in females, it may form a small peritonea pouch called what?
The canal of Nuck in the inguinal canal that extends to the labium majus.
204
A bulge in the anterior part of the labium majus in female infants may be what?
A small peritoneal pouch, the canal of Nuck that has enlarged to form a cyst in the inguinal canal and has the potential to develop into an indirect inguinal hernia.
205
What is a hydrocele and what can cause it?
It is the presence of excess fluid in a persistent processus vaginalis and may be associated with an indirect inguinal hernia. Injury and or inflammation of the epididymis in adults can also result in a hydrocele.
206
A hydrocele of the testis is confined to where and distends what?
The scrotum and distends the tunica vaginalis.
207
A hydrocele of the spermatic cord is confined to where and distends what?
The spermatic cord and distends the persistent part of the stalk of the process vaginalis.
208
A congenital hydrocele of the cord and testis may communicate with what?
The peritoneal cavity.
209
How can a hydrocele be differentiated from a haematocele?
A hydrocele will transilluminate where as a haematocele will not.
210
What can cause a haematocele of the testis?
A collection of blood in the tunica vaginalis from a traumatic injury to the testicular artery.
211
How could you anesthetise the scrotum?
By a spinal anaesthetic injected above the anterolateral surface of the scrotum to anaesthetise the lumbar plexus (primary L1 fibers via the ilio-inguinal nerve) and the postero-inferior surface supplied the sacral plexus (primarily S3 fibres via the pudendal nerve).
212
What is a spermatocele?
A retention cyst in the epididymis, usually near its head.
213
What is an epididymal cyst?
A collection of fluid anywhere in the epididymis.
214
What is a varicocele?
Dilated (varicose) and tortuous veins of the pampiniform plexus and may be visible when standing or straining with enlargement disappearing when supine.
215
What factors can potentiate a varicocele?
Defective valves in the testicular vein, but renal vein problems can also result in distension of the pampiniform veins.
216
Where do varicoceles predominately occur?
On the left side. The acute angle at which the right vein enters the IVC makes it more favourable to flow than the nearly 90 degree angle at which the left testicular vein enters the left renal vein, thus making it more susceptible to obstruction or reversal of flow.
217
Which lymph nodes does cancer of the testis metastasise too?
Initially to the retroperitoneal lumbar lymph nodes, which lie just inferior to the renal veins. Subsequent spread may be to mediastinal and supraclavicular nodes.
218
Where is haematogenous spread of testicular cancer cells likely to eventuate?
In the lungs, liver, brain and bone.
219
Which lymph nodes does cancer of the scrotum metastasise too?
The superficial inguinal lymph nodes, which lie in the subcutaneous tissue inferior to the inguinal ligament and along the terminal part of the great saphenous vein.
