Cervical Rib

Original Editor - Chelsea Mclene

Top Contributors - Chelsea Mclene, Aminat Abolade and Kim Jackson  

Introduction

Cervical rib also known as "neck rib" or "supernumerary rib in cervical region" is an extra rib that forms above first rib which grows from the base of the neck just above the collarbone. It is a congenital overdevelopment of transverse process of cervical spine vertebra. It can be on right, left or both sides and may be floating with no connection, fully formed bony rib or a thin strand of tissue fibre. They vary in size and shape.

In few cases, people having cervical rib may develop thoracic outlet syndrome because of pressure on the nerves that may be caused by the presence of the rib. Partially formed extra rib may end in a swelling that shows as a lump in neck or it may tail off into a fibrous band of tissue that connects to the first proper rib. Most cases are not clinically relevant and do not have symptoms. They are generally discovered incidentally during x-rays and CT scans.

A cervical rib represents a persistent ossification of the C7 lateral costal element. During early development, this ossified costal element typically becomes re-absorbed. Failure of this process results in a variably elongated transverse process or complete rib that can be anteriorly fused with the T1 first rib below.

Structure And Function

The cervical rib consists of a head, neck, and tubercle. It is attached posteriorly to the first rib by a fibrous band near in the insertion of the anterior scalene muscle. Cervical rib has no physiological function.

There are four types of cervical ribs:

• Type 1: Complete rib that articulates with the first rib or manubrium
• Type 2: Incomplete rib with a free distal tip
• Type 3: Incomplete rib with a distal fibrous band attachment
• Type 4: Short piece of bone extending beyond the C7 transverse process

Associated Conditions

• Thoracic outlet syndrome due to compression of the lower trunk of the brachial plexus or subclavian artery.
• Compression of the brachial plexus may be identified by weakness of the muscles around the muscles in the hand.
• Compression of the subclavian artery is often diagnosed.
• Compression of the sympathetic chain may cause Horner's syndrome.

Symptoms

Local Symptoms

• Tender supraclavicular lump which is bony hard and is fixed when palpated.

Sensory Symptoms

• Tingling in hands or fingers; confined either to radial side or ulnar side or sometimes involve even whole hand.
• Pain which may radiate down the arm.

Vascular symptoms

• Cold and clumsy extremities, particularly the fingers.
• Skin colour changes to blue associated with trophic changes.
• There is rare risk of gangrene.
• Radial pulse becomes feeble or may even be absent.

Motor Symptoms

• Loss of hand grip.
• Tendency of dropping things from the hand.
• Wasting of palmar muscles

Diagnosis

Imaging

Cervical ribs are a rare occurrence in the population with an incidence of under 1% and are often an incidental finding on radiographic imaging. they can be distinguished because their transverse processes are directed inferolaterally, whereas those of the adjacent thoracic spine are directed anterolaterally.

Special Tests

• Adson's test
• Spurling's test
• Shoulder Abduction test: It is an orthopaedic test used to diagnose a cervical nerve root injury or cervical disc herniation. It is performed by having the patient abduct their shoulder and place their hand on top of their head. A positive test will involve a decrease in radiculopathy or pain.

Differential Diagnosis

• Herniated cervical disk
• Cervical spondylosis
• Peripheral neuropathies
• Raynaud's disease
• Syringomyelia
• Polio
• Muscular dystrophy
• Motor neuron disease

Management

1. Medical Management

• Anti-inflammatory drugs
• Analgesics

2. Surgical Management

• Removal of extra segment.
• Complete resection of the rib.
• Dividing the scalene group of muscles.
• Resection of cervical ribs for thoracic outlet syndrome.

3. Physiotherapy Management

On the basis of symptoms, the regime is planned.

• Pain relief: Short wave diathermy is used but it is contraindicated in case of sensory impairments.
• To improve distal circulation: Gripping exercise.
• Strengthening exercises of whole arm to improve tone, power and endurance.
• Posture Correction.
• Specific exercises like Self resisted scapular elevation and adduction.
• Endurance training.
• Progressive resistance exercises for shoulder girdle muscles.