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    Related Topics

    From Musculoskeletal System

    Cervical Vertebrae (C1 - C7)
    Vertebrae in the neck region (C1-C7).
    Adductors
    Muscles that bring the thighs toward the midline.
    Soleus
    Calf muscle responsible for plantarflexion of the foot.
    Sartorius
    Longest muscle in the body responsible for hip flexion.
    Wormian Bones
    Sutural bones in the skull.
    Ribs (12 Pairs)
    12 pairs of bones that form the sides of the thoracic cage.
    Maxillae
    Upper jaw bones that house the teeth and form part of the orbit.
    Lacrimal Bones
    Bones forming part of the eye socket and housing the tear ducts.
    Thoracic Vertebrae (T1 - T12)
    Vertebrae in the upper and mid-back (T1-T12).
    Coracoacromial Ligament
    Ligament that connects the acromion to the coracoid process.
    Sacrum
    Triangular bone at the base of the spine.
    Cranial Bones
    Bones of the skull that protect the brain.
    Syndesmoses
    Fibrous joints where bones are connected by ligaments.
    Anterior Cruciate Ligament (ACL)
    Knee ligament that stabilizes the joint.
    Temporalis
    Muscle involved in closing the jaw.
    Sesamoid Bones
    e.g., patella, some found in hands/feet.
    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.
    Skull
    Bony structure of the head that encases the brain.
    Biceps Tendon
    Tendon that attaches the biceps muscle to the bone.
    Latissimus Dorsi
    Back muscle responsible for arm adduction and extension.
    Thoracic Cage
    Ribs and sternum forming the protective cage for the heart and lungs.
    Quadriceps Tendon
    Tendon that connects the quadriceps to the patella.
    Ellipsoidal (Condyloid) Joints
    e.g., wrist
    Quadriceps
    Rectus Femoris, Vastus Medialis, Vastus Lateralis, Vastus Intermedius.
    Radius
    Forearm bone on the thumb side.

    Metacarpals (5 bones)

    Reviewed by our medical team

    5 bones forming the palm of the hand.

    1. Overview

    The metacarpals are five long bones located in the hand, forming the skeleton of the palm. They connect the carpal (wrist) bones to the phalanges (finger bones) and are essential in hand structure, grip, and fine motor function. Each metacarpal bone is associated with one of the five digits and plays a key role in hand movement and force transmission.

    2. Location

    The metacarpals are found in the middle region of the hand:

    • Proximally: Articulate with the carpal bones via the carpometacarpal (CMC) joints.

    • Distally: Articulate with the proximal phalanges through the metacarpophalangeal (MCP) joints.

    • Situated between: The wrist and fingers, deep to the palmar skin and muscles.

    3. Structure

    Each of the five metacarpals is a miniature long bone with three main parts:

    • Base: Proximal end that articulates with carpal bones.

    • Shaft (body): Long, narrow mid-portion with a slight curve for hand contour.

    • Head: Distal, rounded end that forms the knuckle and articulates with the proximal phalanx.

    The five metacarpals are numbered I to V (lateral to medial, thumb to little finger):

    • 1st Metacarpal: Shortest and most mobile; connects to the thumb.

    • 2nd Metacarpal: Index finger; the longest metacarpal.

    • 3rd Metacarpal: Middle finger; has a prominent styloid process on its base.

    • 4th Metacarpal: Ring finger; shorter and more mobile than the 2nd and 3rd.

    • 5th Metacarpal: Little finger; allows greater flexion and opposition.

    4. Function

    The metacarpals serve as vital components in hand mechanics and structure:

    • Support: Form the framework of the palm and maintain hand shape.

    • Movement: Enable flexion, extension, abduction, and adduction of the fingers via MCP joints.

    • Transmission of force: Transmit mechanical loads from the fingers to the wrist during gripping, pushing, and lifting.

    • Dexterity: Allow precise and independent finger movements essential for fine motor tasks.

    5. Physiological role(s)

    Beyond structural support, the metacarpals contribute to:

    • Prehension (grasping): Serve as anchor points for muscles and ligaments involved in gripping and holding objects.

    • Balance and weight distribution: Disperse forces evenly across the hand during load-bearing activities.

    • Muscle attachment: Serve as origin points for intrinsic and extrinsic muscles of the hand, contributing to coordinated hand motion.

    6. Clinical Significance

    Metacarpal bones are frequently involved in trauma and orthopedic conditions:

    • Metacarpal fractures:

      • Common in sports injuries and falls; "boxer's fracture" refers to a fracture of the 5th metacarpal neck.

      • Symptoms include swelling, pain, deformity, and limited hand function.

    • Osteoarthritis:

      • Degenerative changes in the CMC or MCP joints, especially the base of the 1st metacarpal (thumb), leading to pain and reduced grip strength.

    • Congenital anomalies:

      • May involve absent, duplicated, or fused metacarpals affecting hand function and development.

    • Metacarpal shortening or malunion:

      • Improper healing after fracture can lead to loss of strength and range of motion, sometimes requiring surgical correction.

    • Carpometacarpal instability:

      • Ligament laxity at the CMC joints can impair grip and lead to chronic pain, particularly at the base of the thumb.

    Did you know? The tibia is the second largest bone in the body after the femur.