Forearm Fractures

22 Forearm Fractures



Anatomy of the Forearm



image

Forearm Bones



Ulna



• Parts and landmarks: olecranon, trochlear notch, coronoid process, shaft, anterior border, styloid process

• Cylindrical long bone; olecranon palpable subcutaneously at elbow joint; (medial) styloid process distal

• Bears major forces transmitted across elbow joint


Radius



• Parts and landmarks: head, neck, radial tuberosity, shaft, styloid process, carpal articular fossa, scaphoid fossa, lunate fossa, ulnar notch

• Cylindrical long bone with head in elbow joint; (lateral) styloid process distal

• Radiocarpal joint has articular disc that articulates with carpals and ulnar styloid process.

• Bears major forces transmitted across wrist joint


Elbow Joint



• Compound joint involving humeral-radial, humeral-ulnar, and proximal radioulnar joints
image Medial: trochlea of humerus with trochlear notch of the ulna

image Median: proximal radioulnar joint

image Lateral: capitulum of humerus with head of radius

• Ulnar (medial) collateral ligament: from medial epicondyle of humerus to (1) coronoid process and (2) medial olecranon

• Annular ligament passes around radial neck, stabilizing it via insertions into the ulna

• Lateral (radial) collateral ligament passes from lateral epicondyle (humerus) to annular ligament.

• Large fibrous joint capsule underlies collateral ligaments.

image

Forearm: Serial Cross Sections



Compartments of the Forearm



• External investing antebrachial fascia is relatively tough and nonexpansile, with fascial septa between compartments.

• Proximal forearm
image Anterior (flexors, pronators)
image Median nerve, to all flexors except flexor carpi ulnaris and 2 medial heads of flexor digitorum superficialis (ulnar nerve supplied)

image Anterior interosseus nerve (deep branch median) innervates distal pronator quadratus and flexor pollicis longus.

image Interosseus membrane separates deep anterior and posterior compartments.

image Posterior (extensor): radial nerve > deep radial and posterior interosseus nerves

• Lower forearm: flexor digitorum superficialis and profundus tendons, flexor pollicis longus, pronator quadratus

• Spaces around flexors digitorum tendons and sheaths communicate with hand spaces: pathway for forearm-hand compartment syndrome.

• Dorsal antebrachial spaces communicate with dorsal hand and digit spaces.


Vessels and Nerves



image

Forearm: Arteries and Nerves (Anterior View)



Arterial Supply of the Forearm



• Brachial artery
image Typically divides into main radial and ulnar artery branches in cubital fossa

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Aug 12, 2016 | Posted by in ANATOMY | Comments Off on Forearm Fractures

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