AP08 - Musculoskeletal of trunk and pelvic floor Flashcards
What are the margins of the abdominopelvic cavity?
Superior = thoracic diaphragm Inferior = Pelvic diaphragm Posterior = Posterior abdominal wall Anterior = Anterolateral abdominal walls
What are the different layers of the abdominal wall?
- Skin
- Subcutaneous tissue
- Superficial fascia
- Camper’s fascia (fatty layer)
- Scarpa’s fascia (membranous deep layer) - External oblique muscle
- Internal oblique muscle
- Transversus abdominis muscle
- Transversalis fascia
- Preperitoneal adipose and areolar tissue (extraperitoneal fascia)
- Parietal peritoenum
What happens to the Camper’s fascia in men?
- This superficial layer continues over the penis
- After losing its fat and fusing with the deeper layer of superficial fascia (Scarpa’s fascia), it continues into the scrotum where it forms a specialised fascia layer containing smooth muscle fibres (the DARTOS FASCIA)
What happens to the Camper’s fascia in women?
This superficial layer retains some fat and is a component of the labia majora
What happens to the Scarpa’s fascia in men?
- The deeper membranous later blends with the superficial layer as they both pass over the penis, forming the superficial fascia of the penis
- They then continue into the scrotum where they form the dartos fascia
- Extensions of the deeper membranous later attached to the pubic symphysis pass inferiorly into the dorsym and siedes of penis to form the FUNDIFORM LIGAMENT OF PENIS
What happens to the Scarpa’s fascia in women?
Membranous layer continues into labia majora and anterior part of perineum
What are the muscles of the abdomen?
- External oblique (flat muscle group)
- Internal oblique (flat muscle group)
- Rectus abdominis (vertical muscle group)
- Transversus abdominis (flat muscle group)
- Pyramidalis (vertical muscle group) - may be absent
What is the collective function of anterolateral muscles?
- By their positioning, the form a firm but flexible wall
- Keeps the abdominal viscera within the abdominal cavity
- Protects the viscera from injury
- Helps maintain the position of the viscera in the erect posture against the action of gravity
- Involved in any action that inc intraabdominal pressure; childbrith (parturition), urination (micturtion) and defecation
- Contraction assist sin both quiet and forced expiration by pushing the viscera upwards
- Coughing and vomiting
Where does the linea alba extend to?
Linea alba extends from xiphoid process to the pubic symphysis
What forms the inguinal ligament?
- Lower border of the external oblique aponeurosis forms the inguinal ligament on each side
- Continuous with the fascia lata of the thigh
What is the lacunar ligament?
A crescent shaped extension of fibres at the medial end of the inguinal ligament that pass backwards to attach to the pecten pubis on the superior ramus of the pubic bone
What is the pectineal (Cooper’s ligament)?
Additional fibres extending from the lacunar ligament along the pecten pubis of the pelvic brim
What gives the rectus abdominis its distinct shape?
- Extending length of anterior abdominal wall
- Widens and thins as it ascends from pubic symphysis to costal margins
- Intersected by three or four transverse fibrous bands (TENDINOUS INTERSECTIONS)
What forms the rectus sheath?
The aponeuroses of the:
- External oblique
- Internal oblique
- Transversus abdominis
What does the rectus sheath enclose?
Rectus sheath encloses the rectus abdominis and pyramidalis muscles
Where does the rectus sheath not cover?
No sheath covers the posterior surface of the lower quarter of the rectus abdominis muscle
- The muscle at this point is in direct contact with the transversalis fascia
Where is the groin (inguinal region)?
The area of junction between the anterior abdominal wall and the thigh
How and why does an inguinal hernia occur?
- In the inguinal region (the groin), the anterior abdominal wall is weakened from changes that occur during development of gonads
- A peritoneal sac or diverticulum, with or without contents, can therefore protrude through the various layers of the anterior abdominal wall and taking coverings from each layer
- Before the descent of the testes and ovaries from their initial position high in the posterior abdominal wall, a peritoneal outpouching (processus vaginalis) forms
- Can occur in both sexes but most common in males
What are the different coverings of the processus vaginalis?
- Transversalis fascia forms its deepest covering
- Second covering formed by the musculature of the internal oblique
- Its most superficial covering is the aponeurosis of the external oblique
Why is the transversus abdominis muscle not acquired in the coverings of the processus vaginalis?
The processus vaginalis passes under the arching fibres of this abdominal wall muscle
Describe the descent of testes
The testes and the accompanying vessels, ducts and nerves pass through the inguinal canal and are therefore surrounded by the same fascial laers of the abdominal wall
- Testicular descent completes the formation of the spermatic cord in men
Describe the descent of ovaries in women
The ovaries descend into the pelvic cavity and become assoc with the developing uterus
- The only remaining structure passing through the inguinal canal is the round ligament of the uterus which is a remnant of the gubernaculum
What are the contents of the inguinal canal?
- Genital branch of the the genitofemoral nerve
- Spermatic cord in men
- Round ligament of the uterus in women
- Ilio-inguinal nerve (L1) - a branch of the lumbar plexus
Where does the inguinal canal begin/ end?
Begin - deep inguinal ring
End - superficial inguinal ring
Aprrox 4cm
What makes up the anterior wall of the inguinal canal?
- Aponeurosis of the external oblique muscle
- Reinforced laterally by the lower fibres of the internal oblique that originate from the lateral 2/3 of the inguinal ligament
What makes up the posterior wall of the inguinal canal?
- Transversalis fascia
- Reinforced along its medial 1/3 by the conjoint tendon (inguinal falx) - the combined insertion of the transversus abdominis and internal oblique muscles into the pubic crest and pectineal line
What makes up the floor of the inguinal canal?
- The medial 1/2 of the inguinal ligament
What makes up the roof of the inguinal canal?
- The arching fibres of the transversus abdominis and internal oblique muscles
