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    Related Topics

    From Musculoskeletal System

    Thoracic Vertebrae (T1 - T12)
    Vertebrae in the upper and mid-back (T1-T12).
    Ischium
    Part of the pelvis that supports weight while sitting.
    Sphenoid Bone
    Bone forming part of the base of the skull and sides of the orbits.
    Vertebral Column
    Spinal column consisting of vertebrae.
    Hamstrings
    Biceps Femoris, Semitendinosus, Semimembranosus.
    Parietal Bones
    Bones forming the sides and roof of the skull.
    Gliding (Plane) Joints
    e.g., between carpals
    Scapula
    Shoulder blade providing attachment for muscles of the upper limb.
    Fibula
    Smaller bone in the lower leg, located alongside the tibia.
    Hinge Joints
    e.g., elbow, knee
    Thoracic Cage
    Ribs and sternum forming the protective cage for the heart and lungs.
    Deltoid
    Shoulder muscle responsible for arm abduction.
    Lumbar Vertebrae (L1 - L5)
    Vertebrae in the lower back (L1-L5).
    Hyoid Bone
    U-shaped bone in the neck that supports the tongue.
    Ribs (12 Pairs)
    12 pairs of bones that form the sides of the thoracic cage.
    Cervical Vertebrae (C1 - C7)
    Vertebrae in the neck region (C1-C7).
    Clavicle
    Collarbone connecting the arm to the body.
    Diaphragm
    Primary muscle for breathing.
    Frontal Bone
    Bone forming the forehead and upper part of the orbits.
    Pectoralis Major
    Chest muscle responsible for shoulder movement.
    Saddle Joints
    e.g., thumb joint
    Humerus
    Upper arm bone connecting the shoulder to the elbow.
    Brachioradialis
    Muscle responsible for forearm flexion.
    Zygomaticus
    Muscle that raises the corners of the mouth.
    Anterior Longitudinal Ligament
    Spinal ligament running along the front of the vertebral column.

    Pelvic Floor Muscles

    Reviewed by our medical team

    Muscles that support pelvic organs.

    1. Overview

    The pelvic floor muscles are a group of muscles that span the bottom of the pelvis, forming a supportive hammock-like structure. These muscles support the pelvic organs (bladder, intestines, uterus in females), maintain continence, aid in sexual function, and stabilize the core. The pelvic floor consists of both deep and superficial layers and includes voluntary skeletal muscles under somatic control.

    2. Location

    The pelvic floor muscles are located at the base of the pelvic cavity, extending from the pubic bone anteriorly to the coccyx posteriorly, and from one ischial tuberosity to the other laterally:

    • Inferior boundary: Of the abdominopelvic cavity.

    • Superficial layer: Lies just beneath the perineal skin.

    • Deep layer: Forms the true pelvic diaphragm, situated above the perineal membrane.

    3. Structure

    The pelvic floor is composed of three main layers:

    1. Pelvic Diaphragm (deepest layer)

    • Levator ani group:

      • Pubococcygeus

      • Puborectalis

      • Iliococcygeus

    • Coccygeus (ischiococcygeus): Supports the coccyx and helps close off the pelvic outlet.

    2. Deep Perineal Layer

    • Includes the deep transverse perineal muscle and external urethral sphincter.

    3. Superficial Perineal Layer

    • Includes the bulbospongiosus, ischiocavernosus, and superficial transverse perineal muscles.

    All pelvic floor muscles are innervated primarily by the pudendal nerve (S2–S4), with some contributions from the nerve to levator ani and coccygeal plexus.

    4. Function

    Pelvic floor muscles perform several critical functions:

    • Support of pelvic organs: Maintain the position and structural integrity of the bladder, rectum, and reproductive organs.

    • Continence: Control voluntary contraction and relaxation of the urethral and anal sphincters, essential for urinary and fecal continence.

    • Sexual function: Contract during orgasm and help maintain erection in males and vaginal tone in females.

    • Childbirth: Stretch and support the baby’s passage through the birth canal; puborectalis and pubococcygeus play crucial roles.

    • Postural support: Contribute to core stability in coordination with abdominal and back muscles.

    5. Physiological role(s)

    Beyond mechanical function, the pelvic floor integrates with broader physiological systems:

    • Respiratory rhythm: Works with the diaphragm during breathing to maintain intra-abdominal pressure.

    • Pressure regulation: Coordinates with the abdominal wall to manage internal pressures during lifting, coughing, and defecation.

    • Neurovascular control: Supports autonomic function for micturition, defecation, and arousal via reflex arcs and sensory feedback.

    6. Clinical Significance

    Pelvic floor dysfunction can lead to a range of conditions affecting quality of life:

    • Pelvic organ prolapse:

      • Weakness or damage to the pelvic floor may allow descent of the uterus, bladder (cystocele), or rectum (rectocele) into the vaginal canal.

    • Urinary incontinence:

      • Stress incontinence (e.g., during coughing or sneezing) is often due to weak pelvic floor muscles, especially post-childbirth or in aging.

    • Fecal incontinence:

      • Damage to the external anal sphincter or puborectalis muscle may impair bowel control.

    • Chronic pelvic pain:

      • May result from spasm, trigger points, or tension in pelvic floor musculature.

    • Pelvic floor myalgia:

      • Characterized by painful muscle contractions; often linked to trauma, overuse, or psychological stress.

    • Rehabilitation and therapy:

      • Pelvic floor physical therapy, including Kegel exercises and biofeedback, is effective in managing dysfunctions.

    Did you know? The largest muscle in the body is the gluteus maximus, responsible for hip extension.