This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lower limb, Subject name: Anatomy
Length of inguinal canal 
Select and explain. 
A. 2.5 cm, B. 4 cm, C. 10 cm, D. 15 cm
B: 4 cm
Answer: B: 4 cm 
Explanation: INGUINAL CANAL:- Oblique intermuscular passage in the lower pa of the anterior abdominal wall.Extends from deep inguinal ring to superficial.Deep ring- oval opening in fascia transversalis.1.25 cm above mid-inguinal point.Superficial ring: triangular gap in external oblique aponeurosis. Length: 4cm Directed downwards forwards and medially. BOUNDARIES:-1. Anterior wall A. To the whole extend: skinsuperficial fascia and external oblique aponeurosis.B. Lateral one third: internal oblique muscle 2. Posterior wall A. Whole extend fascia transversalis, extraperitoneal tissue, the parietal peritoneum.B. Medial two third: conjoint tendon, reflected pa of inguinal ligament. 3. Roof:arched fibres of internal oblique and transversus abdominis.4. Floor: grooved upper surface of inguinal ligament. Structures passing through:-1. Spermatic cord(males) Round ligament of uterus (f)2. Ilioinguinal nerve. {Reference: BDC 6E pg213}