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    Related Topics

    From Musculoskeletal System

    Flexor and Extensor Groups
    Muscles responsible for flexing and extending the hand and wrist.
    Sternocleidomastoid
    Muscle that rotates and flexes the neck.
    Rotator Cuff Tendons
    Tendons of the rotator cuff muscles.
    Pectoralis Major
    Chest muscle responsible for shoulder movement.
    Soleus
    Calf muscle responsible for plantarflexion of the foot.
    Sutures (in the skull)
    Fibrous joints between skull bones.
    Radius
    Forearm bone on the thumb side.
    Cervical Vertebrae (C1 - C7)
    Vertebrae in the neck region (C1-C7).
    Facial Bones
    Bones forming the structure of the face.
    Lacrimal Bones
    Bones forming part of the eye socket and housing the tear ducts.
    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.
    Quadriceps
    Rectus Femoris, Vastus Medialis, Vastus Lateralis, Vastus Intermedius.
    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.
    Glenohumeral Ligaments
    Shoulder ligaments that stabilize the shoulder joint.
    Ilium
    Uppermost and largest part of the hip bone.
    Patellar Tendon
    Tendon connecting the patella to the tibia.
    Anterior Cruciate Ligament (ACL)
    Knee ligament that stabilizes the joint.
    Acromioclavicular Joint
    The acromioclavicular joint connects the clavicle and scapula at the top of the shoulder, enabling smooth scapular motion and stability during arm movements.
    Adductors
    Muscles that bring the thighs toward the midline.
    Ribs (12 Pairs)
    12 pairs of bones that form the sides of the thoracic cage.
    Levator Ani
    Pelvic floor muscle responsible for lifting the anus.
    Biceps Tendon
    Tendon that attaches the biceps muscle to the bone.
    Achilles Tendon
    Tendon connecting the calf muscle to the heel bone.

    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? The pelvic girdle consists of the ilium, ischium, and pubis.