[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Upper limb](https://durgical.com/en/anatomy/region/upper-limb/) › 5th metacarpal [Skeletal system](https://durgical.com/en/anatomy/system/skeletal-system/) · [Upper limb](https://durgical.com/en/anatomy/region/upper-limb/) # 5th metacarpal The fifth metacarpal is the palm bone of the little finger; its neck breaks in a punch, the classic boxer's fracture. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=upper_limb&select=metacarpal_5&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The long bone in the palm leading to the little finger. ## What it does Forms the palm and the knuckle at its head. ## Key points - Boxer's fracture: the head tips toward the palm (apex dorsal); the mobile carpometacarpal joint lets the little finger tolerate the most angulation of all the metacarpals - Reverse Bennett fracture: an intra-articular fracture-dislocation of the base at the hamate, with the ECU pulling the shaft proximally - A wound over the knuckle after a punch is treated as a human bite (fight bite) that may have entered the MCP joint ## Key facts **Joints with** Base: hamate; head: proximal phalanx; adjacent metacarpals **Landmarks** Base, shaft, neck, head (knuckle); neck = boxer's fracture ## Relations **Above** [Hamate](https://durgical.com/en/anatomy/hamate/) at the base **Behind** ECU insertion on the back of the base; [extensor digiti minimi](https://durgical.com/en/anatomy/extensor-digiti-minimi/) tendon; the dorsal branch of the [ulnar nerve](https://durgical.com/en/anatomy/ulnar-nerve/) crosses near the base **In front** [Opponens digiti minimi](https://durgical.com/en/anatomy/opponens-digiti-minimi/) along the shaft; the [flexor carpi ulnaris](https://durgical.com/en/anatomy/flexor-carpi-ulnaris/) reaches the base through the pisometacarpal ligament **Lateral** Fourth dorsal interosseous and third palmar interosseous **Medial** Subcutaneous ulnar border; abductor digiti minimi passes alongside to the little finger **Below** [Proximal phalanx of the little finger](https://durgical.com/en/anatomy/proximal-phalanx-of-the-little-finger/) ## How to find it The ulnar border is subcutaneous from the base, just distal to the hamate with the ECU tendon, to the knuckle; the neck lies just behind the knuckle. ## On imaging PA, lateral and oblique views; the lateral shows how far the head is tilted. A reverse Bennett fracture is best seen on a pronated oblique view or CT. ## Common problems - Boxer's fracture of the neck, from punching a hard object. - Rotation of the broken bone can make the little finger cross over the ring finger when making a fist. ## How it is diagnosed Exam of the knuckle and of finger rotation in a fist. X-rays show the angle. ## Treatment - Splint or cast with early motion for most fractures. - Pins or a plate when the finger is rotated or the angle is large. ## Clinical notes - Rotation is judged with the fingers flexed: the nails normally point toward the [scaphoid](https://durgical.com/en/anatomy/scaphoid/) tubercle, and a rotated fracture makes the little finger cross under the ring finger - Base fractures can be accompanied by injury of the dorsal branch of the ulnar nerve ## Development Ossifies in cartilage: a primary centre appears in the shaft before birth and one secondary centre later forms at the head, not at the base as in the [1st metacarpal](https://durgical.com/en/anatomy/1st-metacarpal/). On a child's X-ray the open plate near the head shows as a dark line that should not be confused with a boxer's fracture. ## Related conditions - [Boxer fracture (fifth metacarpal neck)](https://durgical.com/en/conditions/boxer-fracture/) ## Test yourself Think of the answer, then tap the question to see it. ## What is a boxer's fracture of the 5th metacarpal? A neck fracture in which the head tips toward the palm (apex dorsal), from punching a hard object. ## Why does the 5th metacarpal tolerate the most angulation of all metacarpals? Its carpometacarpal joint with the hamate is the most mobile. ## How is a wound over the 5th knuckle after a punch treated? As a human bite (fight bite) that may have entered the MCP joint. ## How is rotation of a 5th metacarpal fracture judged? With the fingers flexed: the nails normally point to the scaphoid tubercle; a rotated fracture makes the little finger cross under the ring finger. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/5th-metacarpal/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** ossa metacarpi TA2 1264 **Official Spanish (DeCS)** Hueso metacarpiano V **English (TA2)** 5th metacarpal ## Related - [A1 pulleys](https://durgical.com/en/anatomy/a1-pulleys-of-the-flexor-tendon-sheaths/) - [Abductor digiti minimi](https://durgical.com/en/anatomy/abductor-digiti-minimi/) - [CMC ligaments](https://durgical.com/en/anatomy/carpometacarpal-and-metacarpal-ligaments/) - [Dorsal interossei](https://durgical.com/en/anatomy/dorsal-interossei/) - [ECU](https://durgical.com/en/anatomy/extensor-carpi-ulnaris/) - [Extensor tendons](https://durgical.com/en/anatomy/extensor-digitorum-tendons/) - [FCU tendon](https://durgical.com/en/anatomy/flexor-carpi-ulnaris-tendon/) - [Finger joint capsules](https://durgical.com/en/anatomy/finger-joint-capsules/) Sources: Terminologia Anatomica (TA2); [Anatomy, Shoulder and Upper Limb, Hand Bones](https://www.ncbi.nlm.nih.gov/books/NBK547684/); [8.5 Development of the Appendicular Skeleton](https://openstax.org/books/anatomy-and-physiology-2e/pages/8-5-development-of-the-appendicular-skeleton) (OpenStax (Rice University), 2022) · adapted, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/5th-metacarpal/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/5th-metacarpal/