Inguinal area Flashcards
Describe the Inguinal region
The inguinal region extends between the ASIS and pubic tubercle. It is the area in which structures enter and leave the abdominal cavity.
Iguinal hernias account for 75% of all abdominal hernias
Describe the inguinal ligament
Runs from the ASIS and most medial fibers insert into the pubic tubercle.
Some of the deeper fibers pass posteriorly to attach to the superior pubic ramus lateral to the tubercle forming the arching lacuna ligament. The most lateral of these fibers continue to run along the pectin pubis as the pectineal ligament (of cooper)
Some of the superior fibers fan upward bypassing the pubic tubercle and crossing the linea alba to blend with the lower fibers of the contralateral external oblique aponeurosis. These fibers from the reflected inguinal ligament
Describe the iliopubic tract.
The thickened inferior marign of the transversalis fascia, which appears as a fibrous band running parrel and posterior to the inguinal ligament
Describe the inguinal canal
Formed in relation to the descent of the tesits during foetal development.
Oblique passage approximately 4 cm long directed inferomedially
Lies parallel and superior to the medial half of the inguinal ligament.
The main occupant of the inguinal canal in men is the spermatic cord and in females the round ligament
The inguinal canal has an opening at each end
- the deep inguinal ring (entrance to the inginal canal) is located superior to the middle of the inguinal ligament and lateral to the inferior epigastric artery. It is the beginning of the evagination in the transversalis fascia forming an opening like the entrance to a cave. Through this the extraperitoneal ductus deferens and testicular vessels in males pass to enter the inguinal canal. The transversalis fascia enters into the ring its self froming the inner most covering
- the superifical ring (exit) is a split that occurs in the diagonal otherwise parallel fibers of the external oblique aponeurosis just superolateral to the pubic tubercle. The parts of the aponeurosis that lie lateral and medial to and form the margins of the superficial ring are crura. The lateral crus attaches to the pubic tubercle and the medial crus to the pubic crest . Fibres of the superficial layer of deep investiging fascia overlying the external oblique pass from one crus to other helping to prevent them from spreading aprat.
Describe the musculoaponeurotic arches of the canal
- The inferior parts of the internal oblique and transverse abdominal muscular fibers arising from the inguinal ligament arch over the inguinal canal forming its roof. These fibres become aponeurotic as they descend to attch to the superior margin of the pubic bone forming the posterior wall of the medial half of the canal
- Frequently the most inferior medial tendinous fibers of the internal oblique merge with aponeurotic fibers of the transverse abdominal muscle here to form the inguinal falx (conjoint tendon)
Describe the boundaries of the inguinal canal
1)Deep ring/lateral third
Posterior: transversalis fascia conjoint tendon
Anterior: internal oblique plus lateral crus of aponeurosis of external oblique
Roof: transversalis fasica conjoint tendon
Floor: iliopubic tract
2)Middle third
Posterior: transversalis fascia
Anterior: aponerurosis of external oblique
Roof: muscolaponeurotic arches of internal and transvers abdominal
Floor: inguinal ligament
3) Medial third/superficial ring
Posterior: inguingal falx plus reflected inguinal ligament
Anterior wall: aponeruosis of external oblique with fasica of external oblique continuing onto cord as external spermatic fascia
Roof: medial crus of aponeurosis of external oblique
Floor: lacuna ligament
Discuss the development of the inguinal canal
The male gubernaculum is fibrous cord connecting the primordial testis to the anterolateral abdominal wall at the site of the future deep ring of the inguingal canal
The processus vaginalis a peritoneal diverticulum traverses the developing inguinal canal carrying muscular and fascial layer of the anterolateral abdominal wall before it enters the primordial scrotum
By the 12 th week of development the testes are in the pelvis by 28 weeks it lites close to the development of the deep inguingal ring
They pass through the inguinal canal at 28 weeks and take approximately 3 days
Approximately 4 weeks later the testis enter the scrotum
As the testis its duct and tis vessels and nerves descend they are ensheathed by musculofascial extensions of the anteralateral abdominal wall
The female gubernaculum a fibrous cord connected the ovary and primordial uterus to the developing labium majus is represented post-natally by the ovarian ligament between the ovary and uterus and the round ligament between
Describe the spermatic cord
The spermatic cord contains structures running to and from the testis and suspends the testis in the scrotum. The spermatic cord beings at the deep inguinal ring lateral to the inferior epigastric vessels and passes through the inguinal canal, exits at the superficial ring. Fasica coverings include
- internal spermatic fascia: derived from the transversalis fasia
- cremasteric fascia: derived from the fascia of both the superficial and deep surfaces of the internal oblique. Contains loops of the cremaster muscles which is formed by the lowermost fascicles of the internal oblique msucles arising from the inguinal canal. Cremaster receives innervation from the genital branch of the genitofemoral nerve
- external spermatic fascia: derived from the external oblique
Describe the Dartos muscles
The dartus muscle is smooth muscle of the fat free subcutaneous tissue of the scrotum which inserts into skin assisting testicular elevation as it produces contraction of the skin of the scrotum. Acts coincidentally with the cremaster as it response to the same stimulus, contracting to cold and relaxing to heat.
Describe the contents of the spermatic cord
1: ductus deferens: a muscular tube approximtaly 45 long that conveys sperms from the epididymis to the ejaculatory duct
2: testicular artery a branch of the aortoa and supplying the testis and epididymis
3: Artery of the ductus deferens: which arises from the inferior vesical artery
4: cremasteric artery
5: pampiniform plexus: a network formed by up to 12 veins that converge superiorly as right or left testicular veins
6: sympathetic nerve fibres
7: genital branch of the genitofemeroal nerve supplying the cremastic muscle
8: lymphatic vessles: draining the testis and closely associated structures
9: vestige of the processus vaginalis
Describe the scrotum
Cutaneous sac consisting of two layers
- heavily pigmented skin and closely related dartos fascia,
- a fat free fascial layer including smooth muscle fibers
Contraction of the dartos which attaches to the skin causes wrinkling of the scrotal skin thickening the integumentary layer while reducing scrotal surface area
Divided into left and right compartment by the septum of the scrotum, this demarcation is seen external as the scrotal raphe
Discuss the neurovascular supply of the scrotum
Arterial supply from
-posterior scrotal branches of the perineal artery: a branch of the internal pudendal
- anterior scrotal branches of the deep external peudendal artery- a branch of the femoral
- cremasteric artery a branch of the inferior epigastric artery
Nerve supply
-genital branches of the genitofemoral nerve (L1,L2) supplying the anterolateral surface
- anterior scrotal nerves : branch of the ilioinguinal nerve supplying the anterior surface
- Posterior scrotal nerves branches if the pudendal nerve (s2-4) supplying the posterior surface
- perineal branches of the posterior femoral cutaneous nerve (s2,3)
Discuss the testis:
Testes produce the male germ cells and male hormones, primarily testosterone.
They are suspended by the spermatic cord with the left testis usually hanging more inferiorly than the right testis
The testes have a tough fibrous outer surface the tunica albuginea, thickens at its internal posterior aspect as the miadistinum of the teists. From this ridge fibrous septa extend inwards between lobules of minute but long and highly coiled seminiferous tubules
The semniferous tubules are joined by straight tubules to the rete testis a network of canals in the mediastinum of the testis
The surface of each tesits is covered by the visceral layer of the tunica vaginalis, except where the testis attached to the epididymis and spermatic cord. Tunica vaginalis is a remnant of the processus vaginalis.
There is a slit like recess in the tunica vaginalis the sinus of the epididymis between the body of the epididymis and the posterolateral surface of the testis
Pareital layer of the tunica vaginalis extends further then the visceral layer
The longer and slender teticular arteries arise from the anterolaterals aspect of the abdominal aorta just inferior to the renal arteries. They pass retroperitoneally over the ureters and inferior parts of the external iliac arteries. They anastomose with the artery of the ductus deferns and cremasteric
Lymphatics drainage follows the testicular artery /vein to the right and left lumbar and pre-aortic nodes.
Discuss the Pampiniform plexus
A network of veins fomed by 8-12 veins lying anterior to the ductus deferens and surrounding the testicular artery in the spermatic cord
Part of the thermoregulatory system of the testis helping keep the gland at a constant temperature.
Veins converge to form a right testicular artery draining into the IVC and a left which enters the left renal vein
Discuss the epididymis
The epididymis is an elongated structure on the posterior surface of the testis.
Efferent ductules of the testis transport newly developed sperms to the epididymis from the rete testis. Formed by minute convolutions of the duct of the epididymis.
Duct becomes progressively small passing from the head on the superior part of the testis to its tail. At the tail of the epididymis the ductus deferens beings as a continuation of the epididymal duct. The epididymis consist of
- head of the epididymis: the superior expanded part aht is composed of lobules formed by the colied ends of 12-14 efferent ducutules
- body: consists of the convuluted duct of the epididymis
- Tail of the epididiymis: conitnous with the ducuts deferens
