Internal Obliques

Definition

The internal oblique muscles are a pair of flat, broad muscles that make up part of the lateral abdominal wall. They are responsible for various functions related to the abdominal wall and thorax, including trunk rotation, flexion, and stabilization.

5 Must Know Facts For Your Next Test

1. The internal oblique muscles originate from the inguinal ligament, iliac crest, and thoracolumbar fascia, and insert onto the lower ribs and linea alba.
2. They act to flex the vertebral column, rotate the trunk, and compress the abdominal cavity, which is important for functions like coughing, sneezing, and defecation.
3. The internal obliques work synergistically with the transverse abdominis to provide core stability and maintain intra-abdominal pressure.
4. Weakness or imbalance of the internal obliques can contribute to low back pain, hernias, and poor posture.
5. The internal obliques are innervated by the lower thoracic and upper lumbar nerves, which originate from the spinal cord.

Review Questions

• Describe the anatomical location and attachments of the internal oblique muscles.
  • The internal oblique muscles are located on the lateral aspect of the abdominal wall, deep to the external oblique muscles. They originate from the inguinal ligament, iliac crest, and thoracolumbar fascia, and insert onto the lower ribs and linea alba. This strategic positioning allows the internal obliques to play a crucial role in trunk rotation, flexion, and abdominal wall stabilization.
• Explain the functional relationship between the internal obliques and the transverse abdominis muscles.
  • The internal obliques and transverse abdominis work synergistically to provide core stability and maintain intra-abdominal pressure. The internal obliques assist the transverse abdominis in compressing the abdominal cavity, which is important for functions like coughing, sneezing, and defecation. Together, these deep abdominal muscles help to stabilize the spine and transfer forces between the upper and lower body during movements and activities.
• Analyze the potential consequences of weakness or imbalance in the internal oblique muscles.
  • Weakness or imbalance of the internal oblique muscles can have significant consequences for an individual's overall health and function. Such muscular imbalances can contribute to the development of low back pain, as the internal obliques play a crucial role in stabilizing the spine. Additionally, weakened internal obliques may lead to the formation of hernias, as they are responsible for maintaining intra-abdominal pressure. Poor posture and decreased core stability are also common outcomes of internal oblique dysfunction, which can impair an individual's ability to perform daily activities and sports-related movements.

Related terms

Transverse Abdominis: The deepest of the abdominal wall muscles, the transverse abdominis assists the internal obliques in compressing the abdomen and stabilizing the trunk.

External Obliques:

The most superficial of the lateral abdominal wall muscles, the external obliques work in opposition to the internal obliques to rotate and flex the trunk.

Abdominal Aponeurosis: The broad, flat tendons that cover the abdominal muscles and provide attachment points for the internal and external obliques.