Rectal

Rectum
Details
System	Digestive system
Artery	Superior rectal artery, Middle rectal artery, Inferior rectal artery
Vein	Superior rectal vein, Middle rectal vein, Inferior rectal vein
Nerve	Inferior hypogastric plexus
Identifiers
Latin	Rectum
TA98
TH	{{#property:P1694}}
TE	{{#property:P1693}}
FMA	{{#property:P1402}}
Anatomical terminology

The rectum is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. The adult human rectum is about 12 centimeters long, and connects the sigmoid colon to the anal canal. Its primary role is as a temporary storage site for feces before they are expelled from the body.

Anatomy

The rectum begins at the end of the sigmoid colon, at the level of the third sacral vertebra. It ends at the anal canal, which is typically 2-4 cm long. The rectum is surrounded by muscles that are part of the pelvic floor, which support the rectal structure and control defecation.

Blood Supply and Nervous Innervation

The blood supply to the rectum comes from the superior, middle, and inferior rectal arteries. Venous return is through the corresponding veins. The rectum is innervated by the inferior hypogastric plexus, which provides both sympathetic and parasympathetic control.

Function

The primary function of the rectum is to store feces until defecation. The rectum expands in response to the arrival of fecal matter from the colon, triggering the urge to defecate. During defecation, the rectal muscles contract to expel feces through the anal canal.

Clinical Significance

1. 1. 1. Common Disorders ###

- **Hemorrhoids**: Swollen blood vessels in and around the rectum that can cause pain, itching, and bleeding. - **Rectal cancer**: Cancer that begins in the rectum. It is often preceded by polyps that grow in the lining of the rectum. - **Proctitis**: Inflammation of the rectum lining, often caused by infections or inflammatory bowel diseases like ulcerative colitis.

1. 1. 1. Diagnostic Tests ###

- **Colonoscopy**: A test that allows examination of the interior lining of the rectum and colon. - **Sigmoidoscopy**: A similar test to colonoscopy but limited to the sigmoid colon and rectum.

See Also

• Digestive system
• Large intestine
• Fecal incontinence
• Rectal examination