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    Related Topics

    From Musculoskeletal System

    Adductors
    Muscles that bring the thighs toward the midline.
    Coccyx
    Tailbone, the remnant of the tail in humans.
    Gomphoses
    Fibrous joints where a peg fits into a socket (e.g., teeth in jaw).
    Ellipsoidal (Condyloid) Joints
    e.g., wrist
    Lacrimal Bones
    Bones forming part of the eye socket and housing the tear ducts.
    Hamstrings
    Biceps Femoris, Semitendinosus, Semimembranosus.
    Buccinator
    Muscle that helps with chewing and blowing air out.
    Acetabulum
    The acetabulum is the pelvic socket that connects with the femoral head to form the hip joint, vital for stability, movement, and weight-bearing.
    Gastrocnemius
    Calf muscle responsible for plantarflexion of the foot.
    Parietal Bones
    Bones forming the sides and roof of the skull.
    Frontal Bone
    Bone forming the forehead and upper part of the orbits.
    Annular Ligament
    The annular ligament is a strong fibrous band encircling the head of the radius, stabilizing the proximal radioulnar joint and allowing smooth rotation of the forearm.
    Facial Bones
    Bones forming the structure of the face.
    Occipital Bone
    Bone forming the back and base of the skull.
    Anterior Scalene Muscle
    The anterior scalene muscle is a deep neck muscle that elevates the first rib during inspiration and aids in neck flexion and stability, located between key neurovascular structures.
    Extensor Tendons
    Tendons that help extend the fingers and toes.
    Zygomaticus
    Muscle that raises the corners of the mouth.
    Hyoid Bone
    U-shaped bone in the neck that supports the tongue.
    Masseter
    Muscle that elevates the mandible.
    Coccygeus
    Pelvic floor muscle supporting the coccyx.
    Deltoid
    Shoulder muscle responsible for arm abduction.
    Cervical Vertebrae (C1 - C7)
    Vertebrae in the neck region (C1-C7).
    Sutures (in the skull)
    Fibrous joints between skull bones.
    Hinge Joints
    e.g., elbow, knee
    Inferior Nasal Conchae
    Bones inside the nasal cavity that filter and humidify air.

    Latissimus Dorsi

    Reviewed by our medical team

    Back muscle responsible for arm adduction and extension.

    1. Overview

    The latissimus dorsi is a large, flat, triangular muscle located in the lower back. Commonly referred to as the "lats," it is one of the broadest muscles in the human body. This powerful muscle plays a central role in upper limb movement, particularly in actions involving pulling, extension, and internal rotation of the shoulder. It also contributes to posture and trunk stabilization.

    2. Location

    The latissimus dorsi is located in the posterior thoracic and lumbar regions of the body:

    • Origin:

      • Spinous processes of T7–T12 vertebrae

      • Thoracolumbar fascia

      • Iliac crest (posterior part)

      • Inferior 3 to 4 ribs

      • (Sometimes) the inferior angle of the scapula

    • Insertion:

      • Floor of the intertubercular sulcus (bicipital groove) of the humerus

    • Superficial to: Deeper muscles of the back such as the erector spinae

    3. Structure

    The latissimus dorsi is a broad, fan-shaped muscle with a wide origin and a narrow tendon of insertion:

    • Shape: Triangular and sheet-like

    • Fibers: Run superolaterally from the spine and lower back to converge into a tendon that passes anterior to the shoulder joint

    • Innervation: Thoracodorsal nerve (C6, C7, C8), a branch of the posterior cord of the brachial plexus

    • Blood supply: Thoracodorsal artery (a branch of the subscapular artery)

    4. Function

    The latissimus dorsi is involved in several key movements of the upper limb:

    • Extension of the shoulder: Moves the arm backward

    • Adduction of the arm: Brings the arm toward the body's midline

    • Internal (medial) rotation of the humerus: Rotates the arm inward

    • Assists in respiration: Acts as an accessory muscle in forceful expiration (e.g., coughing or heavy breathing)

    5. Physiological role(s)

    In addition to movement, the latissimus dorsi supports various physiological functions:

    • Postural support: Helps stabilize the spine and pelvis during dynamic upper limb movements

    • Trunk motion: Assists in lateral flexion and rotation of the trunk when the arm is fixed

    • Force generation: Critical for pulling motions such as climbing, swimming, and rowing

    • Muscle synergy: Works with the teres major, pectoralis major, and rotator cuff muscles to coordinate shoulder movements

    6. Clinical Significance

    The latissimus dorsi is clinically relevant in musculoskeletal health, injury, and reconstructive surgery:

    • Muscle strain or tear:

      • Can occur during sports involving sudden pulling motions (e.g., gymnastics, rock climbing); leads to pain and weakness in shoulder extension

    • Thoracodorsal nerve injury:

      • May occur during axillary surgery or trauma, resulting in weakness of shoulder adduction and extension

    • Myofascial pain syndrome:

      • Trigger points in the latissimus can refer pain to the mid-back or posterior shoulder area

    • Reconstructive surgery:

      • The muscle is commonly used in flap procedures, such as latissimus dorsi flap for breast reconstruction after mastectomy

    • Posture and imbalance:

      • Overactivation or tightness can contribute to shoulder internal rotation and poor posture, often seen in athletes with repetitive pulling tasks

    Did you know? Bone marrow is the site where red blood cells are made.