# Proximal Humerus Fracture

> Proximal humerus fracture for NEET-PG Orthopaedics: Neer four-part classification, axillary nerve injury, sling versus surgery and AVN, with exam points.

- Canonical URL: https://prepelephant.com/topics/neet-pg/orthopaedics/proximal-humerus-fracture
- Exam / course: NEET-PG · Subject: Orthopaedics
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Proximal Humerus Fracture", PrepElephant, https://prepelephant.com/topics/neet-pg/orthopaedics/proximal-humerus-fracture

## Direct answer

A proximal humerus fracture is a break at the upper end of the arm bone, typically after a fall on an outstretched hand in an elderly osteoporotic woman or after high-energy trauma in the young. Most are minimally or non-displaced and heal with a sling and early physiotherapy. Displacement is defined by the Neer classification, which counts as a "part" any of the four segments — articular segment, surgical neck, greater tuberosity, lesser tuberosity — shifted more than 1 cm or angulated beyond 45 degrees; displaced patterns may need fixation or arthroplasty.

## What you must remember

- **Neer segments:** anatomic neck, surgical neck, greater tuberosity and lesser tuberosity; displacement means more than 1 cm of shift or more than 45 degrees of angulation, and the count of displaced parts — not fracture lines — names the injury (one-part to four-part).
- **The majority are one-part fractures** — impacted or undisplaced — and do well with a sling, pendulum exercises and staged physiotherapy to prevent stiffness.
- **Nerve to test first:** the axillary nerve, injured by surgical neck fractures and anterior shoulder dislocations; test sensation over the regimental badge area and deltoid contraction.
- **Vessel at risk:** the axillary artery, particularly in displaced four-part fractures and fracture-dislocations of the elderly.
- **Treatment by pattern:** displaced two-part fractures may need closed pinning or plate fixation; unstable three- and four-part fractures in older patients are treated with hemiarthroplasty or reverse shoulder replacement.
- **Avascular necrosis** of the head is the feared complication of four-part and anatomic-neck fractures because the retinacular blood supply is destroyed; the humeral head is the classic site after the femoral head and scaphoid.
- **Tuberosity clues:** an anterior dislocation may avulse the greater tuberosity, while a posterior dislocation or seizure-related injury implicates the lesser tuberosity.

## Common confusion

Students confuse the anatomic with the surgical neck: the anatomic neck lies at the articular rim and its fractures jeopardise the head's blood supply, while the surgical neck, just below the tuberosities, is the common fracture of the elderly and heals well. Second, fracture lines are not parts — a comminuted radiograph with no fragment shifted over 1 cm or angulated over 45 degrees is still a one-part fracture needing only a sling. And a silent deltoid after injury is more often axillary neuropraxia than a torn tendon: test sensation and power before blaming pain.

## Exam-focused takeaway

NEET-PG anchors this topic on the Neer system: vignettes describe fragment displacement to make you count parts, testing the 1 cm or 45 degree rule. Nerve questions pair surgical neck fractures with regimental-badge numbness and deltoid weakness. Management forks run from a sling for one-part injuries, to fixation of displaced two-part fractures, to hemiarthroplasty or reverse replacement for four-part fractures in the elderly. Complication one-liners feature avascular necrosis and shoulder stiffness, and image stems show a displaced surgical neck or four-part pattern.

## Frequently asked questions

### What is the Neer classification of proximal humerus fractures?

A four-segment system — articular segment, surgical neck and the two tuberosities — where a segment counts as displaced only if shifted over 1 cm or angulated over 45 degrees.

### Which nerve is injured in proximal humerus fractures?

The axillary nerve, tested by sensation over the regimental badge patch and active deltoid contraction.

### How are most proximal humerus fractures treated?

Conservatively with a sling and early graded physiotherapy, since the majority are one-part, minimally displaced injuries.

### When is surgery needed for a proximal humerus fracture?

For markedly displaced two-part fractures, unstable three- and four-part patterns, fracture-dislocations and head-splitting injuries — with arthroplasty preferred in elderly osteoporotic bone.

### What is the dreaded late complication of four-part fractures?

Avascular necrosis of the humeral head, because the retinacular vessels to the head are destroyed by the injury.