Metacarpal Bones

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 9 min read
Patient Tools

Read, save, and share this guide

Use these quick tools to make this medical article easier to read, print, save, or share with a family member.

Patient Mode

Understand this article easily

Switch between simple English and easy Bangla patient notes. This is for education and does not replace a doctor consultation.

A metacarpal bone is a group of five bones of the hand metacarpal bones or metacarpus forms the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm....

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

এই তথ্য শিক্ষা ও সচেতনতার জন্য। এটি ডাক্তারি পরীক্ষা, রোগ নির্ণয় বা প্রেসক্রিপশনের বিকল্প নয়।

Article Summary

A metacarpal bone is a group of five bones of the hand metacarpal bones or metacarpus forms the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. Above all the metacarpal bones are small, they are classified as long bones since they have structural characteristics of long...

Key Takeaways

  • This article explains Structure in simple medical language.
Educational health guideWritten for patient understanding and clinical awareness.
Reviewed content workflowUse writer and reviewer profiles for stronger trust.
Emergency safety firstUrgent warning signs are highlighted below.

Seek urgent medical care if you notice

These warning signs are general safety guidance. Local emergency numbers and clinical judgment should always come first.

  • Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
  • New weakness, severe pain, high fever, or symptoms after a serious injury.
  • Any symptom that feels urgent, unusual, or unsafe for the patient.
1

Emergency now

Use emergency care for severe, sudden, rapidly worsening, or life-threatening symptoms.

2

See a doctor

Book a professional medical evaluation if symptoms persist, worsen, recur often, affect daily activities, or occur in a high-risk patient.

3

Learn safely

Use this article to understand possible causes, tests, treatment options, prevention, and questions to ask your clinician.

Before reading

RX Patient Tools

Use these quick guides before reading the article, or return to them when you need help preparing questions for a doctor.

Start here Choose the right pathway for symptoms, reports, medicines, or urgent warning signs. Disease article roadmap Read this topic step by step: meaning, symptoms, warning signs, diagnosis, treatment, prevention, and follow-up. Treatment planner Prepare questions about treatment choices, benefits, risks, side effects, and follow-up. Family & caregiver guide Organize symptoms, reports, medicines, questions, and follow-up safely. Nutrition & diet guide Prepare food, hydration, supplement, and medicine-timing questions safely. Prevention guide Organize risk factors, protective habits, screening, and warning signs. Recovery guide Prepare a safe plan for activity, rehabilitation, warning signs, and follow-up.
Definition

A metacarpal bone is a group of five bones of the hand metacarpal bones or metacarpus forms the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. Above all the metacarpal bones are small, they are classified as long bones since they have structural characteristics of long bones; each metacarpal bone consists of a shaft, distal head, and a wide proximal base.

Structure

The metacarpals form a transverse arch to which the rigid row of distal carpal bones is fixed. The peripheral metacarpals (those of the thumb and tiny finger) form the edges of the cup of the palmar gutter and as they’re brought together they deepen this concavity. The index metacarpal is the most firmly fixed, while the thumb metacarpal articulates with the Trapezium and acts independently from the others. the center metacarpals are tightly united to the carpus by intrinsic interlocking bone elements at their bases. The ring metacarpal is somewhat more mobile while the fifth metacarpal is semi-independent.

Each metacarpal consists of a body or shaft, and two extremities: the top at the distal or digital end (near the fingers), and therefore the base at the proximal or carpal end (close to the wrist)

Metacarpal Bones

Body

The body (shaft) is prismoid in form, and curved, so on be convex within the longitudinal direction behind, concave ahead. It presents three surfaces: medial, lateral, and dorsal.

The medial and lateral surfaces are concave, for the attachment of the interosseus muscles, and separated from each other by a prominent anterior ridge. The dorsal surface presents in its distal two-thirds a smooth, triangular, flattened area that is roofed by the tendons of the extensor muscles. This surface is bounded by two lines, which commence in small tubercles situated on either side of the digital extremity, and, passing upward, converge and meet a long way above the middle of the bone and form a ridge that runs along with the remainder of the dorsal surface to the carpal extremity. This ridge separates two sloping surfaces for the attachment of the interossei dorsales.
To the tubercles on the digital extremities are attached the collateral ligaments of the metacarpophalangeal joints.

Base

The base (basis) or carpal extremity is of a cuboidal form, and broader behind than in front: it articulates with the carpal bones and with the adjoining metacarpal bones; its dorsal and volar surfaces are rough, for the attachment of ligaments.

Head

The head (caput) or digital extremity presents an oblong surface markedly convex from before backward, less so transversely, and flattened from side to side; it articulates with the proximal phalanx. it’s broader, extends farther upward, on the volar than on the dorsal aspect, and is longer within the anteroposterior than within the transverse diameter. On either side of the top may be a tubercle for the attachment of the collateral ligament of the knuckle. The dorsal surface, broad and flat, supports the tendons of the extensor muscles. The volar surface is grooved within the middle line for the passage of the flexor tendons and marked on either side by an articular eminence continuous with the terminal articular surface.

Neck

The neck, or subcapital segment, is the transition zone between the body and therefore the head.

Articulations

Besides the metacarpophalangeal joints, the metacarpal bones articulate by carpometacarpal joints as follows:

  • the first with the trapezium;
  • the second with Trapezium, trapezoid, capitate, and third metacarpal;
  • the third with the capitate and second and fourth metacarpals;
  • the fourth with the capitate, hamate, and third and fifth metacarpals;
  • and the fifth with the hamate and fourth metacarpal;

Metacarpal Bones

First metacarpal

The metacarpal 1 is the most lateral, thickest, and shortest metacarpal. it’s directed laterally, with its long axis being medially rotated for 90° as compared to the opposite metacarpals. thanks to this axial motion, the edges of the bone are rotated in order that its anterior surface faces medially towards the palm, the ulnar border faces posteriorly, while the radial faces anteriorly. Aside from the common features that it shares with other metacarpals, the primary metacarpal is recognizable by a longitudinal ridge on its medial (palmar) surface, which divides this surface into an outsized lateral and alittle medial part. Also, the top of this bone is flatter than within the other metacarpals. the primary metacarpal features a saddle-shaped articular surface on its base, via which it articulates with Trapezium.

The first metacarpal provides the attaching points to the several hand muscles;

The opponent pollicis muscle attaches to the radial border and therefore the adjacent part of the shaft. The radial head of the primary dorsal interosseous muscle attaches to the ulnar border and therefore the adjacent part of the shaft.
The abductor pollicis longus inserts to the palmar surface of the shaft.

Metacarpal Bones

Second metacarpal

Synonyms: Os metacarpals 2

The metacarpal 2 is the one with the most important base and therefore the longest shaft. Its base shows several areas for the articulations with the carpal bones;
A groove within the coronal plane via which it articulates with the trapezoid. Medially to the present groove may be a ridge for the articulation with the capitate, while laterally may be a quadrangular surface for the joint with Trapezium bone. An elongated facet on its medial surface for the articulation with the third metacarpal. Dorsally to the facet for Trapezium may be a shallow impression of the insertion of the extensor carpi radialis longus muscle. The palmar surface of the bottom provides the attaching site for the flexor carpi radialis muscle. The shaft of the second metacarpal is convex towards the dorsum of the hand. The interossei muscles attach to the proximal part of the shaft; the ulnar head of the primary dorsal interosseous attaches from the lateral side, while the second palmar and second dorsal interossei attach from the medial side.

Third metacarpal

Synonyms: Os metacarpals 3

The metacarpal 3 is found at the bottom of the center finger. It differs from the others by a process that projects proximally from the laterodorsal fringe of its base. This process participates within the joint with the capitate. The lateral surface of the bottom articulates with the second metacarpal, while the medial surface articulates with the fourth metacarpal via two oval articular surfaces. The palmar surface of the bottom is where the flexor carpi radialis insert, while the extensor carpi radialis brevis inserts to its dorsal surface.

The shaft is analogous thereto of the second metacarpal, being dorsally convex. Its lateral side is an insertion point for the ulnar head of the second dorsal interosseous, while the medial side is where the radial head of the third dorsal interosseous attaches. The distal two-thirds of the medial surface of the shaft provide an insertion point for the transverse head of adductor pollicis muscle.

Fourth metacarpal

The metacarpal 4 shows a couple of specificities of its base.

It has two oval facets on the lateral surface via which it articulates with the bottom of the third metacarpal. It features one elongated facet on the medial surface for the articulation with the bottom of the fifth metacarpal. The proximal surface is quadrangular and serves for the articulation with the hamate. The shaft provides the insertion point for the third palmar interosseous and therefore the ulnar head of the third dorsal interosseous on its lateral side, while the medial side is where the fourth dorsal interosseous attaches.

Fifth metacarpal

The metacarpal 5 is the smallest of all five metacarpals. Its base slightly differs from the opposite metacarpals, as its lateral part is non-articular and instead features a tubercle for the attachment of the extensor carpi ulnaris muscle. The lateral side of the bottom, however, articulates with the hamate.

The proximal part of the lateral surface of the shaft articulates with the fourth metacarpal, while the medial surface serves to connect the opponent’s digit minimi muscle. The distal part of the lateral surface receives the fibers from the fourth palmar and fourth dorsal interossei muscles.

Metacarpal Bones

References

Doctor visit helper

Prepare before seeing a doctor

A simple rural-patient checklist to help you explain symptoms clearly, ask better questions, and avoid unsafe self-treatment.

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

  • Write when the problem started and how it changed.
  • Bring old prescriptions, investigation reports, and current medicines.
  • Write allergies, pregnancy status, diabetes, kidney/liver disease, and major past illnesses.
  • Bring one family member if the patient is weak, elderly, confused, or a child.

Questions to ask

  • What is the most likely cause of my symptoms?
  • Which danger signs mean I should go to hospital quickly?
  • Which tests are necessary now, and which can wait?
  • How should I take medicines safely and what side effects should I watch for?
  • When should I come for follow-up?

Tests to discuss

  • Vital signs: temperature, pulse, blood pressure, oxygen saturation
  • Basic physical examination by a clinician
  • CBC, urine test, blood sugar, or imaging only when clinically needed

Avoid these mistakes

  • Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
  • Do not hide pregnancy, kidney disease, ulcer, allergy, or blood thinner use.
  • Do not delay emergency care when danger signs are present.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

  • Rest, drink safe water, and observe symptoms carefully.
  • Keep a written note of symptoms, duration, temperature, medicines already taken, and allergy history.
  • Seek medical care quickly if symptoms are severe, worsening, or unusual for the patient.

OTC medicine safety

  • For mild pain or fever, ask a registered pharmacist or doctor before using common over-the-counter pain/fever medicines.
  • Do not combine multiple pain medicines without advice, especially if you have kidney disease, liver disease, stomach ulcer, asthma, pregnancy, or take blood thinners.
  • Do not give adult medicines to children unless a qualified clinician advises it.

Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
  • Do not use steroid tablets or injections casually for quick relief.
  • Do not delay emergency care because of home remedies.

Get urgent help if

  • Severe symptoms, confusion, fainting, breathing difficulty, chest pain, severe dehydration, or sudden weakness need urgent medical care.
Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Doctor / qualified healthcare provider
Tests to discuss with doctor
  • Basic vital signs: temperature, pulse, blood pressure, oxygen level if needed
  • Relevant blood, urine, imaging, or specialist tests only after clinical assessment
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: Metacarpal Bones

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

RX Patient Help

Ask a health question safely

Write your symptom story. A health professional or site editor can review it before any answer is prepared. This box is not for emergency care.

Emergency first: Severe chest pain, breathing trouble, unconsciousness, stroke signs, severe injury, heavy bleeding, or rapidly worsening symptoms need urgent local medical care now.

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

More from this topic
  1. Roifman-Chitayat Syndrome

    DefinitionRoifman-Chitayat syndrome (often shortened to ROCHIS) is a combined primary immunodeficiency. “Combined” means both the antibody-producing (B-cell) and T-cell parts of the immune system do not...

    February 17, 2026 • Rx Autoimmune, Genetic and Rare Diseases (A - Z)
  2. Combined Immunodeficiency with Faciooculoskeletal Anomalies

    DefinitionCombined immunodeficiency with faciooculoskeletal anomalies is a very rare genetic disease. It affects the immune system, the face, the eyes, the bones, and body development at...

    February 17, 2026 • Rx Autoimmune, Genetic and Rare Diseases (A - Z)
  3. Chondrodysplasia With Joint Dislocations, gPAPP Type

    DefinitionChondrodysplasia with joint dislocations, gPAPP type, is a very rare genetic bone disease. Babies are usually born with short arms and legs, loose joints, and joints...

    January 13, 2026 • Degenerative Bones, Joints, and Spine Care (A - Z)
  4. Chondrodysplasia Punctata, Tibial-Metacarpal Type

    DefinitionChondrodysplasia punctata, tibial-metacarpal type, is a very rare birth bone condition. It mainly affects the small bones of the hands and the shin bone (tibia). The...

    January 13, 2026 • Degenerative Bones, Joints, and Spine Care (A - Z)
  5. Chondrodysplasia Punctata with Stippled Epiphyses

    DefinitionChondrodysplasia punctata with stippled epiphyses is a name for a group of rare bone growth disorders, not just one single disease. In all of them, small...

    January 13, 2026 • Degenerative Bones, Joints, and Spine Care (A - Z)
  6. Goldblatt-Viljoen Syndrome

    DefinitionGoldblatt-Viljoen syndrome is a very rare birth condition where a baby is born with three main problems together: the bones on the thumb side of the...

    January 9, 2026 • Rx Autoimmune, Genetic and Rare Diseases (A - Z)
  7. Choanal Atresia with Radial Ray Hypoplasia

    DefinitionChoanal atresia with radial ray hypoplasia is a very rare birth syndrome. In this condition, the back part of the nose (the choanae) is blocked or...

    January 9, 2026 • Rx Pregnancy, Baby & Mom Care
  8. Generalized Enchondromatosis with Platyspondyly

    DefinitionGeneralised enchondromatosis with platyspondyly is an extremely rare bone growth problem. It means that many small benign? (non-cancer) cartilage? tumours, called enchondromas, grow inside many bones,...

    January 6, 2026 • Rx Autoimmune, Genetic and Rare Diseases (A - Z)
  9. Cheirospondyloenchondromatosis

    DefinitionCheirospondyloenchondromatosis is a very rare bone disease that starts very early in life, often in babies or young children. It belongs to a group of diseases...

    January 6, 2026 • Rx Autoimmune, Genetic and Rare Diseases (A - Z)
  10. Distal Neurogenic Amyotrophy

    DefinitionDistal neurogenic amyotrophy is a general medical phrase that means nerve-related muscle wasting that mainly affects the far (distal) parts of the arms and/or legs, such...

    January 5, 2026 • Rx Autoimmune, Genetic and Rare Diseases (A - Z)