Upper limb · Hand
Phalanges of the hand
There are fourteen phalanges in each hand: three in each finger (proximal, middle and distal) and two in the thumb. They form the skeleton of the digits.
- Latin (TA)
- Ossa digitorum manus (phalanges)
- Type
- Miniature long bones: each phalanx has a base, a shaft
- Side
- Paired — right and left
- Model size
- 11.8 cm longest
Showing a right set. Rotate it to inspect every surface; switch sides to practise siding.
3D model: Z-Anatomy (CC BY-SA 4.0), derived from BodyParts3D © DBCLS (CC BY-SA 2.1 JP). Adapted by PharmaWallah. Credits & licence
Landmarks
5 of 6 marked on the modelTap a landmark to find it on the bones and read what it is.
The proximal, expanded end of a phalanx.
Where: Proximal end of each phalanx.
Why it matters: On a proximal phalanx it has a single concave facet for the metacarpal head; on middle and distal phalanges it has two facets separated by a ridge.
Related: Metacarpophalangeal and interphalangeal joints
Marked on the model at the point Z-Anatomy places this label.
The shaft between base and head.
Where: Middle part of each phalanx.
Why it matters: Flat on its palmar surface, where the margins give attachment to the fibrous flexor sheath; convex dorsally under the extensor expansion.
Marked on the model at the point Z-Anatomy places this label.
The distal end of a proximal or middle phalanx.
Where: Distal end of proximal and middle phalanges.
Why it matters: Articulates with the base of the next phalanx at an interphalangeal joint.
Related: Interphalangeal joints
Marked on the model at the point Z-Anatomy places this label.
The pulley-shaped articular surface on the head, with two small condyles separated by a groove.
Where: Distal end of proximal and middle phalanges.
Why it matters: Makes the interphalangeal joints hinge joints, allowing only flexion and extension.
Related: Interphalangeal joints
Viva: Why do interphalangeal joints only flex and extend?
Marked on the model at the point Z-Anatomy places this label.
A rough, horseshoe-shaped expansion at the tip of a distal phalanx.
Where: Distal end of each distal phalanx, on its palmar side.
Why it matters: Supports the pulp of the fingertip and lies under the nail bed; identifies a distal phalanx.
Viva: How do you recognise a distal phalanx?
Marked on the model at the point Z-Anatomy places this label.
Classification & region
Miniature long bones: each phalanx has a base, a shaft (body) and a head.
- Proximal phalanges (five)
- The longest; the base has a single concave oval facet for the metacarpal head, and the head is pulley-shaped (trochlea).
- Middle phalanges (four)
- Present in the fingers only; the base has two shallow facets separated by a ridge, fitting the trochlea of the proximal phalanx.
- Distal phalanges (five)
- The smallest; the tip carries a rough, horseshoe-shaped tuberosity on its palmar side that supports the pulp of the fingertip.
- Thumb
- Has only two phalanges, proximal and distal; there is no middle phalanx.
Hold it in the anatomical position
- Hold a phalanx with the base proximal and the head (or, for a distal phalanx, the tuberosity) distal.
- The palmar surface is flat from side to side, with rough margins for the fibrous flexor sheath; the dorsal surface is smooth and convex.
Right or left? Side determination
- First decide the row: a single concave facet on the base and a trochlear head = proximal; two facets on the base and a trochlear head = middle; a small bone ending in a tuberosity = distal.
- Then place it: base proximal, flat palmar surface forwards, convex dorsal surface behind.
- Isolated phalanges cannot be reliably assigned to a right or left hand, nor usually to a particular finger, from their shape alone. The thumb's phalanges are recognisable by being shorter and broader. Say this honestly in a viva.
- In an articulated hand the side follows from the rest of the hand: the thumb is on the lateral side.
Side is usually determined from the articulated hand, not from a single phalanx.
Check yourself: switch the 3D model to “Left bone” and apply the same steps.
Articulations
- With the heads of the metacarpals at the Metacarpophalangeal joints — Concave facet on the base of each proximal phalanx..
- With the adjacent phalanges at the Proximal and distal interphalangeal joints — Trochlea of the head and the ridged base of the next phalanx..
Muscle and ligament attachments
| Structure | Type | Where on the bone |
|---|---|---|
| Flexor digitorum superficialis | insertion | Sides of the middle phalanges of the fingers. |
| Flexor digitorum profundus | insertion | Palmar surface of the bases of the distal phalanges of the fingers. |
| Extensor digitorum (via the extensor expansion) | insertion | Central slip to the dorsal base of the middle phalanx; lateral bands to the dorsal base of the distal phalanx. |
| Flexor pollicis longus | insertion | Palmar surface of the base of the distal phalanx of the thumb. |
| Extensor pollicis longus | insertion | Dorsal surface of the base of the distal phalanx of the thumb. |
| Extensor pollicis brevis | insertion | Dorsal surface of the base of the proximal phalanx of the thumb. |
| Abductor pollicis brevis and flexor pollicis brevis | insertion | Lateral side of the base of the proximal phalanx of the thumb. |
| Adductor pollicis | insertion | Medial side of the base of the proximal phalanx of the thumb. |
| Abductor digiti minimi and flexor digiti minimi brevis | insertion | Medial side of the base of the proximal phalanx of the little finger. |
| Dorsal and palmar interossei; lumbricals | insertion | Bases of the proximal phalanges and/or the extensor expansions. |
| Fibrous flexor sheaths | ligament | Margins of the palmar surfaces of the proximal and middle phalanges. |
| Collateral ligaments and palmar plates of the MCP and IP joints | ligament | Sides of the heads and bases. |
Functions
- Form the skeleton of the fingers and thumb.
- Act as a chain of levers that lets the digits flex, extend and grip.
- Give insertion to the long flexors and extensors and to the small muscles of the hand.
Clinical & practical relevance
- Mallet finger: the extensor tendon is torn from, or pulls a fragment off, the dorsal base of the distal phalanx, so the fingertip droops and cannot be actively straightened.
- Avulsion of flexor digitorum profundus from the base of the distal phalanx ("jersey finger") leaves the patient unable to flex the fingertip.
- Crush injuries of the fingertip commonly fracture the tuberosity of the distal phalanx.
- Phalangeal fractures may rotate or angulate, so finger alignment is checked with the fingers flexed.
Identification tips
- Superficialis splits to insert on the middle phalanx; profundus passes through the split to reach the distal phalanx.
- Proximal base: one cup. Middle base: two shallow cups. Distal: ends in a rough tip.
- The thumb has no middle phalanx.
Common student mistakes
- Saying the thumb has three phalanges.
- Swapping the insertions of flexor digitorum superficialis and profundus.
- Claiming that an isolated phalanx can be sided reliably.
- Calling the tuberosity of the distal phalanx its "head".
Common exam questions
How many phalanges are there in one hand?Show answer
Fourteen: three in each finger and two in the thumb.
How do you tell a proximal phalanx from a middle phalanx?Show answer
The proximal phalanx base has a single concave facet; the middle phalanx base has two facets separated by a ridge.
Where does flexor digitorum profundus insert?Show answer
Into the palmar surface of the base of the distal phalanx.
Where does flexor digitorum superficialis insert?Show answer
Into the sides of the middle phalanx.
What type of joint is an interphalangeal joint?Show answer
A synovial hinge joint.
Can you tell the side of an isolated phalanx?Show answer
Not reliably; side is determined from the articulated hand.
What is a mallet finger?Show answer
Loss of active extension of the distal interphalangeal joint after the extensor tendon is torn from the base of the distal phalanx.
Revision summary
- 14 phalanges per hand: 3 per finger, 2 in the thumb.
- Each: base, shaft, head (distal phalanx ends in a tuberosity).
- Proximal base: single facet (MCP joint). Middle base: two facets.
- Trochlear heads → hinge interphalangeal joints.
- FDS → middle phalanx; FDP → distal phalanx.
- Mallet finger: extensor off the base of the distal phalanx.
Test yourself on the phalanges of the hand
Spotting questions on bones, sides and landmarks — untimed, with explanations.
Joints of the phalanges of the hand
References
- Drake RL, Vogl AW, Mitchell AWM. Gray's Anatomy for Students. 5th ed. Philadelphia: Elsevier; 2023.
- Moore KL, Dalley AF, Agur AMR. Moore's Clinically Oriented Anatomy. 9th ed. Philadelphia: Wolters Kluwer; 2023.
- Federative International Programme for Anatomical Terminology (FIPAT). Terminologia Anatomica. 2nd ed. FIPAT.library.dal.ca; 2019. fipat.library.dal.ca/TA2
- Kervyn G, Zielinski M, Vinent L, et al. Z-Anatomy: the libre 3D atlas of anatomy. Models derived from BodyParts3D, The Database Center for Life Science (CC BY-SA 2.1 JP). CC BY-SA 4.0. www.z-anatomy.com/
Prepared by the PharmaWallah student team. Verify results with your textbook or instructor. Report an error · Editorial policy