Variation
Traditionally described as a two-headed muscle, biceps brachii is one of the most variable muscles of the human body and has a third head arising from the humerus in 10% of cases (normal variation)—most commonly originating near the insertion of the coracobrachialis and joining the short head—but four, five, and even seven supernumerary heads have been reported in rare cases.One study found a higher than expected number of female cadavers with a third head of biceps brachii, equal incidence between sides of the body, and uniform innervation by musculocutaneous nerve.The distal biceps tendons are completely separated in 40% and bifurcated in 25% of cases. Nerve supply
The biceps shares its nerve supply with the other two muscles of the anterior compartment. The muscles are supplied by the  musculocutaneous nerve. Fibers of the fifth, sixth and seventh cervical nerves make up the components of the musculocutaneous nerve which supply the biceps. Blood supply
The blood supply of the biceps is the brachial artery. The distal tendon of the biceps can be useful for palpating the brachial pulse, as the artery runs medial to the tendon in the cubital fossa. Function
The biceps works across three joints. The most important of these functions is to supinate the forearm and flex the elbow. Besides, the long head of biceps prevents the upward displacement of the head of the humerus. In more detail, the actions are, by joint:
Proximal radioulnar joint of the elbow – The biceps brachii functions as a powerful supinator of the forearm, i.e. it turns the palm upwards.
Hemoperitoneum  (also haemoperitoneum, sometimes also hematoperitoneum) is the presence of blood in the peritoneal cavity. The blood accumulates in the space between the inner lining of the abdominal wall and the internal abdominal organs. Hemoperitoneum is generally classified as a surgical emergency; in most cases, urgent laparotomy is needed to identify and control the source of the bleeding. In selected cases, careful observation may be permissible. The abdominal cavity is highly distensible and may easily hold greater than five liters of blood, or more than the entire circulating blood volume for an average-sized individual. Therefore, large-scale or rapid blood loss into the abdomen will reliably induce hemorrhagic shock and, if untreated, may rapidly lead to death. Causes
Causes of hemoperitoneum include:
Penetrating trauma
Blunt trauma, most commonly injuries to solid organs such as the liver and spleen. Vascular accidents, such as rupture of an abdominal aortic aneurysm, iliac aneurysm, or splenic aneurysm. Bleeding due to a ruptured ectopic pregnancy or uterine rupture. Rupture of corpus luteum in some cases. Less commonly, bleeding due to a perforated gastric ulcer. Bleeding due to rupture of an intra-abdominal neoplasm, (e.g., Hepatoblastoma)
Disseminated intravascular coagulation
People on high dose of anticoagulants (blood thinners)
Perforation of the colon

Diagnosis
Hemoperitoneum can be reliably diagnosed with the following examinations:
Focused assessment with sonography for trauma (FAST)
Paracentesis or diagnostic peritoneal lavage
Computed tomography
Diagnostic laparoscopy or exploratory laparotomy

Treatment
Initial management consists of immediate blood transfusion if the patient is in hemorrhagic shock.