Logo

    Related Topics

    From Musculoskeletal System

    Trapezius
    Muscle responsible for moving, rotating, and stabilizing the scapula.
    Triceps Brachii
    Muscle responsible for elbow extension.
    Coccyx
    Tailbone, the remnant of the tail in humans.
    Soleus
    Calf muscle responsible for plantarflexion of the foot.
    Patella
    Knee cap, protecting the knee joint.
    Radius
    Forearm bone on the thumb side.
    Rectus Abdominis
    Abs muscle that flexes the trunk.
    Inferior Nasal Conchae
    Bones inside the nasal cavity that filter and humidify air.
    Gliding (Plane) Joints
    e.g., between carpals
    Patellar Tendon
    Tendon connecting the patella to the tibia.
    Sphenoid Bone
    Bone forming part of the base of the skull and sides of the orbits.
    Tibia
    Shin bone, the larger bone in the lower leg.
    Cervical Vertebrae (C1 - C7)
    Vertebrae in the neck region (C1-C7).
    Quadriceps Tendon
    Tendon that connects the quadriceps to the patella.
    Maxillae
    Upper jaw bones that house the teeth and form part of the orbit.
    Vomer Bone
    Bone forming the nasal septum.
    Temporal Bones
    Bones forming the lower sides of the skull and housing the ears.
    Sacroiliac Ligaments
    Ligaments connecting the sacrum to the iliac bones.
    Ischium
    Part of the pelvis that supports weight while sitting.
    Sacrum
    Triangular bone at the base of the spine.
    Sternum
    Breastbone located in the center of the chest.
    Anterior Longitudinal Ligament
    Spinal ligament running along the front of the vertebral column.
    Metatarsals (5 bones)
    5 bones forming the mid-foot.
    Gluteus Maximus
    Largest muscle in the buttocks responsible for hip extension.
    Zygomatic Bones
    Cheekbones that form part of the orbit.

    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 smallest joint in the body is the stapes in the ear.