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    Related Topics

    From Musculoskeletal System

    Masseter
    Muscle that elevates the mandible.
    Metatarsals (5 bones)
    5 bones forming the mid-foot.
    Obliques (External and Internal)
    Muscles responsible for torso rotation.
    Pectoralis Major
    Chest muscle responsible for shoulder movement.
    Vomer Bone
    Bone forming the nasal septum.
    Phalanges (14 bones)
    14 bones forming the toes.
    Posterior Longitudinal Ligament
    Spinal ligament running along the back of the vertebral column.
    Latissimus Dorsi
    Back muscle responsible for arm adduction and extension.
    Femur
    Thigh bone, the longest and strongest bone in the body.
    Flexor Tendons
    Tendons that help flex the fingers and toes.
    Carpals (8 bones)
    8 wrist bones.
    Coracoacromial Ligament
    Ligament that connects the acromion to the coracoid process.
    Rotator Cuff Tendons
    Tendons of the rotator cuff muscles.
    Wormian Bones
    Sutural bones in the skull.
    Vertebral Column
    Spinal column consisting of vertebrae.
    Deltoid
    Shoulder muscle responsible for arm abduction.
    Extensor Tendons
    Tendons that help extend the fingers and toes.
    Ulna
    Forearm bone on the pinky side.
    Synchondroses
    Cartilaginous joints where bones are connected by hyaline cartilage.
    Pivot Joints
    e.g., atlanto-axial joint
    Lacrimal Bones
    Bones forming part of the eye socket and housing the tear ducts.
    Ilium
    Uppermost and largest part of the hip bone.
    Quadriceps
    Rectus Femoris, Vastus Medialis, Vastus Lateralis, Vastus Intermedius.
    Frontal Bone
    Bone forming the forehead and upper part of the orbits.
    Tibialis Anterior
    Muscle that dorsiflexes and inverts the foot.

    Rectus Abdominis

    Reviewed by our medical team

    Abs muscle that flexes the trunk.

    1. Overview

    The rectus abdominis is a long, flat, paired muscle that runs vertically along the anterior abdominal wall. Commonly referred to as the “six-pack” muscle due to its segmented appearance, it plays a major role in flexing the trunk, stabilizing the pelvis, and increasing intra-abdominal pressure. It is a key muscle in core strength and postural stability.

    2. Location

    The rectus abdominis is located in the midline of the anterior abdominal wall:

    • Extends from: The pubic symphysis and pubic crest (inferiorly) to the xiphoid process and costal cartilages of ribs 5–7 (superiorly).

    • Medially: Meets its contralateral counterpart at the linea alba.

    • Enclosed within: The rectus sheath, formed by the aponeuroses of the external oblique, internal oblique, and transversus abdominis muscles.

    3. Structure

    The rectus abdominis is a strap-like, segmented muscle divided horizontally by fibrous bands called tendinous intersections:

    • Shape: Long, vertical, and narrow, running parallel to the midline.

    • Tendinous intersections: Transverse fibrous bands that give rise to the “six-pack” appearance; typically three per side.

    • Linea alba: A fibrous midline seam that separates the left and right rectus muscles.

    • Innervation: Supplied by lower thoracoabdominal nerves (T7–T12).

    • Blood supply: Primarily from the superior and inferior epigastric arteries.

    4. Function

    The rectus abdominis performs several key musculoskeletal functions:

    • Trunk flexion: Flexes the vertebral column, particularly during activities like sit-ups or bending forward.

    • Posterior pelvic tilt: Stabilizes the pelvis by preventing anterior tilt, especially during leg raises.

    • Assists in forced expiration: Helps in expelling air by depressing the ribs and compressing the abdomen.

    • Contributes to abdominal compression: Works with other abdominal muscles to compress the abdominal cavity during defecation, childbirth, and lifting.

    5. Physiological role(s)

    Beyond mechanical movement, the rectus abdominis supports important physiological processes:

    • Core stability: Provides stability to the trunk, supporting the spine and preventing injury during dynamic movement.

    • Intra-abdominal pressure regulation: Works with the diaphragm and pelvic floor to maintain pressure needed for urination, defecation, and parturition.

    • Breathing support: Acts as an accessory muscle of respiration during forceful exhalation (e.g., coughing, blowing).

    • Spinal health: Protects the lumbar spine by resisting excessive extension and rotation.

    6. Clinical Significance

    The rectus abdominis is clinically significant in several conditions:

    • Muscle strain:

      • Common in athletes, especially during activities involving sudden trunk flexion or rotation.

    • Diastasis recti:

      • Separation of the rectus abdominis along the linea alba, often seen postpartum or in individuals with significant abdominal distension.

    • Hernias:

      • Weakness in the anterior abdominal wall near the rectus sheath may lead to epigastric or umbilical hernias.

    • Surgical relevance:

      • The rectus sheath is often incised in abdominal surgeries; care must be taken to avoid damaging underlying structures.

    • Cosmetic and functional rehabilitation:

      • Targeted in physical therapy and fitness programs for strengthening, posture correction, and aesthetic training (e.g., six-pack formation).

    Did you know? Your skeleton is 5 times stronger than steel.